Extract csv

11 files changed, 0 insertions, 6387 deletions

diff --git a/lib/csv.rb b/lib/csv.rb
deleted file mode 100644
index e8aa20ddd2..0000000000
--- a/lib/csv.rb
+++ /dev/null
@@ -1,2882 +0,0 @@
-# encoding: US-ASCII
-# frozen_string_literal: true
-# = csv.rb -- CSV Reading and Writing
-#
-# Created by James Edward Gray II on 2005-10-31.
-#
-# See CSV for documentation.
-#
-# == Description
-#
-# Welcome to the new and improved CSV.
-#
-# This version of the CSV library began its life as FasterCSV. FasterCSV was
-# intended as a replacement to Ruby's then standard CSV library. It was
-# designed to address concerns users of that library had and it had three
-# primary goals:
-#
-# 1.  Be significantly faster than CSV while remaining a pure Ruby library.
-# 2.  Use a smaller and easier to maintain code base. (FasterCSV eventually
-#     grew larger, was also but considerably richer in features. The parsing
-#     core remains quite small.)
-# 3.  Improve on the CSV interface.
-#
-# Obviously, the last one is subjective. I did try to defer to the original
-# interface whenever I didn't have a compelling reason to change it though, so
-# hopefully this won't be too radically different.
-#
-# We must have met our goals because FasterCSV was renamed to CSV and replaced
-# the original library as of Ruby 1.9. If you are migrating code from 1.8 or
-# earlier, you may have to change your code to comply with the new interface.
-#
-# == What's the Different From the Old CSV?
-#
-# I'm sure I'll miss something, but I'll try to mention most of the major
-# differences I am aware of, to help others quickly get up to speed:
-#
-# === \CSV Parsing
-#
-# * This parser is m17n aware. See CSV for full details.
-# * This library has a stricter parser and will throw MalformedCSVErrors on
-#   problematic data.
-# * This library has a less liberal idea of a line ending than CSV. What you
-#   set as the <tt>:row_sep</tt> is law. It can auto-detect your line endings
-#   though.
-# * The old library returned empty lines as <tt>[nil]</tt>. This library calls
-#   them <tt>[]</tt>.
-# * This library has a much faster parser.
-#
-# === Interface
-#
-# * CSV now uses keyword parameters to set options.
-# * CSV no longer has generate_row() or parse_row().
-# * The old CSV's Reader and Writer classes have been dropped.
-# * CSV::open() is now more like Ruby's open().
-# * CSV objects now support most standard IO methods.
-# * CSV now has a new() method used to wrap objects like String and IO for
-#   reading and writing.
-# * CSV::generate() is different from the old method.
-# * CSV no longer supports partial reads. It works line-by-line.
-# * CSV no longer allows the instance methods to override the separators for
-#   performance reasons. They must be set in the constructor.
-#
-# If you use this library and find yourself missing any functionality I have
-# trimmed, please {let me know}[mailto:[email protected]].
-#
-# == Documentation
-#
-# See CSV for documentation.
-#
-# == What is CSV, really?
-#
-# CSV maintains a pretty strict definition of CSV taken directly from
-# {the RFC}[https://www.ietf.org/rfc/rfc4180.txt]. I relax the rules in only one
-# place and that is to make using this library easier. CSV will parse all valid
-# CSV.
-#
-# What you don't want to do is to feed CSV invalid data. Because of the way the
-# CSV format works, it's common for a parser to need to read until the end of
-# the file to be sure a field is invalid. This consumes a lot of time and memory.
-#
-# Luckily, when working with invalid CSV, Ruby's built-in methods will almost
-# always be superior in every way. For example, parsing non-quoted fields is as
-# easy as:
-#
-#   data.split(",")
-#
-# == Questions and/or Comments
-#
-# Feel free to email {James Edward Gray II}[mailto:[email protected]]
-# with any questions.
-
-require "forwardable"
-require "date"
-require "stringio"
-
-require_relative "csv/fields_converter"
-require_relative "csv/input_record_separator"
-require_relative "csv/parser"
-require_relative "csv/row"
-require_relative "csv/table"
-require_relative "csv/writer"
-
-# == \CSV
-#
-# === \CSV Data
-#
-# \CSV (comma-separated values) data is a text representation of a table:
-# - A _row_ _separator_ delimits table rows.
-#   A common row separator is the newline character <tt>"\n"</tt>.
-# - A _column_ _separator_ delimits fields in a row.
-#   A common column separator is the comma character <tt>","</tt>.
-#
-# This \CSV \String, with row separator <tt>"\n"</tt>
-# and column separator <tt>","</tt>,
-# has three rows and two columns:
-#   "foo,0\nbar,1\nbaz,2\n"
-#
-# Despite the name \CSV, a \CSV representation can use different separators.
-#
-# For more about tables, see the Wikipedia article
-# "{Table (information)}[https://en.wikipedia.org/wiki/Table_(information)]",
-# especially its section
-# "{Simple table}[https://en.wikipedia.org/wiki/Table_(information)#Simple_table]"
-#
-# == \Class \CSV
-#
-# Class \CSV provides methods for:
-# - Parsing \CSV data from a \String object, a \File (via its file path), or an \IO object.
-# - Generating \CSV data to a \String object.
-#
-# To make \CSV available:
-#   require 'csv'
-#
-# All examples here assume that this has been done.
-#
-# == Keeping It Simple
-#
-# A \CSV object has dozens of instance methods that offer fine-grained control
-# of parsing and generating \CSV data.
-# For many needs, though, simpler approaches will do.
-#
-# This section summarizes the singleton methods in \CSV
-# that allow you to parse and generate without explicitly
-# creating \CSV objects.
-# For details, follow the links.
-#
-# === Simple Parsing
-#
-# Parsing methods commonly return either of:
-# - An \Array of Arrays of Strings:
-#   - The outer \Array is the entire "table".
-#   - Each inner \Array is a row.
-#   - Each \String is a field.
-# - A CSV::Table object.  For details, see
-#   {\CSV with Headers}[#class-CSV-label-CSV+with+Headers].
-#
-# ==== Parsing a \String
-#
-# The input to be parsed can be a string:
-#   string = "foo,0\nbar,1\nbaz,2\n"
-#
-# \Method CSV.parse returns the entire \CSV data:
-#   CSV.parse(string) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# \Method CSV.parse_line returns only the first row:
-#   CSV.parse_line(string) # => ["foo", "0"]
-#
-# \CSV extends class \String with instance method String#parse_csv,
-# which also returns only the first row:
-#   string.parse_csv # => ["foo", "0"]
-#
-# ==== Parsing Via a \File Path
-#
-# The input to be parsed can be in a file:
-#   string = "foo,0\nbar,1\nbaz,2\n"
-#   path = 't.csv'
-#   File.write(path, string)
-#
-# \Method CSV.read returns the entire \CSV data:
-#  CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# \Method CSV.foreach iterates, passing each row to the given block:
-#  CSV.foreach(path) do |row|
-#    p row
-#  end
-# Output:
-#   ["foo", "0"]
-#   ["bar", "1"]
-#   ["baz", "2"]
-#
-# \Method CSV.table returns the entire \CSV data as a CSV::Table object:
-#   CSV.table(path) # => #<CSV::Table mode:col_or_row row_count:3>
-#
-# ==== Parsing from an Open \IO Stream
-#
-# The input to be parsed can be in an open \IO stream:
-#
-# \Method CSV.read returns the entire \CSV data:
-#   File.open(path) do |file|
-#     CSV.read(file)
-#   end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# As does method CSV.parse:
-#   File.open(path) do |file|
-#     CSV.parse(file)
-#   end # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# \Method CSV.parse_line returns only the first row:
-#   File.open(path) do |file|
-#    CSV.parse_line(file)
-#   end # => ["foo", "0"]
-#
-# \Method CSV.foreach iterates, passing each row to the given block:
-#   File.open(path) do |file|
-#     CSV.foreach(file) do |row|
-#       p row
-#     end
-#   end
-# Output:
-#   ["foo", "0"]
-#   ["bar", "1"]
-#   ["baz", "2"]
-#
-# \Method CSV.table returns the entire \CSV data as a CSV::Table object:
-#   File.open(path) do |file|
-#     CSV.table(file)
-#   end # => #<CSV::Table mode:col_or_row row_count:3>
-#
-# === Simple Generating
-#
-# \Method CSV.generate returns a \String;
-# this example uses method CSV#<< to append the rows
-# that are to be generated:
-#   output_string = CSV.generate do |csv|
-#     csv << ['foo', 0]
-#     csv << ['bar', 1]
-#     csv << ['baz', 2]
-#   end
-#   output_string # => "foo,0\nbar,1\nbaz,2\n"
-#
-# \Method CSV.generate_line returns a \String containing the single row
-# constructed from an \Array:
-#   CSV.generate_line(['foo', '0']) # => "foo,0\n"
-#
-# \CSV extends class \Array with instance method <tt>Array#to_csv</tt>,
-# which forms an \Array into a \String:
-#   ['foo', '0'].to_csv # => "foo,0\n"
-#
-# === "Filtering" \CSV
-#
-# \Method CSV.filter provides a Unix-style filter for \CSV data.
-# The input data is processed to form the output data:
-#   in_string = "foo,0\nbar,1\nbaz,2\n"
-#   out_string = ''
-#   CSV.filter(in_string, out_string) do |row|
-#     row[0] = row[0].upcase
-#     row[1] *= 4
-#   end
-#   out_string # => "FOO,0000\nBAR,1111\nBAZ,2222\n"
-#
-# == \CSV Objects
-#
-# There are three ways to create a \CSV object:
-# - \Method CSV.new returns a new \CSV object.
-# - \Method CSV.instance returns a new or cached \CSV object.
-# - \Method \CSV() also returns a new or cached \CSV object.
-#
-# === Instance Methods
-#
-# \CSV has three groups of instance methods:
-# - Its own internally defined instance methods.
-# - Methods included by module Enumerable.
-# - Methods delegated to class IO. See below.
-#
-# ==== Delegated Methods
-#
-# For convenience, a CSV object will delegate to many methods in class IO.
-# (A few have wrapper "guard code" in \CSV.) You may call:
-# * IO#binmode
-# * #binmode?
-# * IO#close
-# * IO#close_read
-# * IO#close_write
-# * IO#closed?
-# * #eof
-# * #eof?
-# * IO#external_encoding
-# * IO#fcntl
-# * IO#fileno
-# * #flock
-# * IO#flush
-# * IO#fsync
-# * IO#internal_encoding
-# * #ioctl
-# * IO#isatty
-# * #path
-# * IO#pid
-# * IO#pos
-# * IO#pos=
-# * IO#reopen
-# * #rewind
-# * IO#seek
-# * #stat
-# * IO#string
-# * IO#sync
-# * IO#sync=
-# * IO#tell
-# * #to_i
-# * #to_io
-# * IO#truncate
-# * IO#tty?
-#
-# === Options
-#
-# The default values for options are:
-#   DEFAULT_OPTIONS = {
-#     # For both parsing and generating.
-#     col_sep:            ",",
-#     row_sep:            :auto,
-#     quote_char:         '"',
-#     # For parsing.
-#     field_size_limit:   nil,
-#     converters:         nil,
-#     unconverted_fields: nil,
-#     headers:            false,
-#     return_headers:     false,
-#     header_converters:  nil,
-#     skip_blanks:        false,
-#     skip_lines:         nil,
-#     liberal_parsing:    false,
-#     nil_value:          nil,
-#     empty_value:        "",
-#     strip:              false,
-#     # For generating.
-#     write_headers:      nil,
-#     quote_empty:        true,
-#     force_quotes:       false,
-#     write_converters:   nil,
-#     write_nil_value:    nil,
-#     write_empty_value:  "",
-#   }
-#
-# ==== Options for Parsing
-#
-# Options for parsing, described in detail below, include:
-# - +row_sep+: Specifies the row separator; used to delimit rows.
-# - +col_sep+: Specifies the column separator; used to delimit fields.
-# - +quote_char+: Specifies the quote character; used to quote fields.
-# - +field_size_limit+: Specifies the maximum field size + 1 allowed.
-#   Deprecated since 3.2.3. Use +max_field_size+ instead.
-# - +max_field_size+: Specifies the maximum field size allowed.
-# - +converters+: Specifies the field converters to be used.
-# - +unconverted_fields+: Specifies whether unconverted fields are to be available.
-# - +headers+: Specifies whether data contains headers,
-#   or specifies the headers themselves.
-# - +return_headers+: Specifies whether headers are to be returned.
-# - +header_converters+: Specifies the header converters to be used.
-# - +skip_blanks+: Specifies whether blanks lines are to be ignored.
-# - +skip_lines+: Specifies how comments lines are to be recognized.
-# - +strip+: Specifies whether leading and trailing whitespace are to be
-#   stripped from fields. This must be compatible with +col_sep+; if it is not,
-#   then an +ArgumentError+ exception will be raised.
-# - +liberal_parsing+: Specifies whether \CSV should attempt to parse
-#   non-compliant data.
-# - +nil_value+: Specifies the object that is to be substituted for each null (no-text) field.
-# - +empty_value+: Specifies the object that is to be substituted for each empty field.
-#
-# :include: ../doc/csv/options/common/row_sep.rdoc
-#
-# :include: ../doc/csv/options/common/col_sep.rdoc
-#
-# :include: ../doc/csv/options/common/quote_char.rdoc
-#
-# :include: ../doc/csv/options/parsing/field_size_limit.rdoc
-#
-# :include: ../doc/csv/options/parsing/converters.rdoc
-#
-# :include: ../doc/csv/options/parsing/unconverted_fields.rdoc
-#
-# :include: ../doc/csv/options/parsing/headers.rdoc
-#
-# :include: ../doc/csv/options/parsing/return_headers.rdoc
-#
-# :include: ../doc/csv/options/parsing/header_converters.rdoc
-#
-# :include: ../doc/csv/options/parsing/skip_blanks.rdoc
-#
-# :include: ../doc/csv/options/parsing/skip_lines.rdoc
-#
-# :include: ../doc/csv/options/parsing/strip.rdoc
-#
-# :include: ../doc/csv/options/parsing/liberal_parsing.rdoc
-#
-# :include: ../doc/csv/options/parsing/nil_value.rdoc
-#
-# :include: ../doc/csv/options/parsing/empty_value.rdoc
-#
-# ==== Options for Generating
-#
-# Options for generating, described in detail below, include:
-# - +row_sep+: Specifies the row separator; used to delimit rows.
-# - +col_sep+: Specifies the column separator; used to delimit fields.
-# - +quote_char+: Specifies the quote character; used to quote fields.
-# - +write_headers+: Specifies whether headers are to be written.
-# - +force_quotes+: Specifies whether each output field is to be quoted.
-# - +quote_empty+: Specifies whether each empty output field is to be quoted.
-# - +write_converters+: Specifies the field converters to be used in writing.
-# - +write_nil_value+: Specifies the object that is to be substituted for each +nil+-valued field.
-# - +write_empty_value+: Specifies the object that is to be substituted for each empty field.
-#
-# :include: ../doc/csv/options/common/row_sep.rdoc
-#
-# :include: ../doc/csv/options/common/col_sep.rdoc
-#
-# :include: ../doc/csv/options/common/quote_char.rdoc
-#
-# :include: ../doc/csv/options/generating/write_headers.rdoc
-#
-# :include: ../doc/csv/options/generating/force_quotes.rdoc
-#
-# :include: ../doc/csv/options/generating/quote_empty.rdoc
-#
-# :include: ../doc/csv/options/generating/write_converters.rdoc
-#
-# :include: ../doc/csv/options/generating/write_nil_value.rdoc
-#
-# :include: ../doc/csv/options/generating/write_empty_value.rdoc
-#
-# === \CSV with Headers
-#
-# CSV allows to specify column names of CSV file, whether they are in data, or
-# provided separately. If headers are specified, reading methods return an instance
-# of CSV::Table, consisting of CSV::Row.
-#
-#   # Headers are part of data
-#   data = CSV.parse(<<~ROWS, headers: true)
-#     Name,Department,Salary
-#     Bob,Engineering,1000
-#     Jane,Sales,2000
-#     John,Management,5000
-#   ROWS
-#
-#   data.class      #=> CSV::Table
-#   data.first      #=> #<CSV::Row "Name":"Bob" "Department":"Engineering" "Salary":"1000">
-#   data.first.to_h #=> {"Name"=>"Bob", "Department"=>"Engineering", "Salary"=>"1000"}
-#
-#   # Headers provided by developer
-#   data = CSV.parse('Bob,Engineering,1000', headers: %i[name department salary])
-#   data.first      #=> #<CSV::Row name:"Bob" department:"Engineering" salary:"1000">
-#
-# === \Converters
-#
-# By default, each value (field or header) parsed by \CSV is formed into a \String.
-# You can use a _field_ _converter_ or  _header_ _converter_
-# to intercept and modify the parsed values:
-# - See {Field Converters}[#class-CSV-label-Field+Converters].
-# - See {Header Converters}[#class-CSV-label-Header+Converters].
-#
-# Also by default, each value to be written during generation is written 'as-is'.
-# You can use a _write_ _converter_ to modify values before writing.
-# - See {Write Converters}[#class-CSV-label-Write+Converters].
-#
-# ==== Specifying \Converters
-#
-# You can specify converters for parsing or generating in the +options+
-# argument to various \CSV methods:
-# - Option +converters+ for converting parsed field values.
-# - Option +header_converters+ for converting parsed header values.
-# - Option +write_converters+ for converting values to be written (generated).
-#
-# There are three forms for specifying converters:
-# - A converter proc: executable code to be used for conversion.
-# - A converter name: the name of a stored converter.
-# - A converter list: an array of converter procs, converter names, and converter lists.
-#
-# ===== Converter Procs
-#
-# This converter proc, +strip_converter+, accepts a value +field+
-# and returns <tt>field.strip</tt>:
-#   strip_converter = proc {|field| field.strip }
-# In this call to <tt>CSV.parse</tt>,
-# the keyword argument <tt>converters: string_converter</tt>
-# specifies that:
-# - \Proc +string_converter+ is to be called for each parsed field.
-# - The converter's return value is to replace the +field+ value.
-# Example:
-#   string = " foo , 0 \n bar , 1 \n baz , 2 \n"
-#   array = CSV.parse(string, converters: strip_converter)
-#   array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# A converter proc can receive a second argument, +field_info+,
-# that contains details about the field.
-# This modified +strip_converter+ displays its arguments:
-#   strip_converter = proc do |field, field_info|
-#     p [field, field_info]
-#     field.strip
-#   end
-#   string = " foo , 0 \n bar , 1 \n baz , 2 \n"
-#   array = CSV.parse(string, converters: strip_converter)
-#   array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-# Output:
-#  [" foo ", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
-#  [" 0 ", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
-#  [" bar ", #<struct CSV::FieldInfo index=0, line=2, header=nil>]
-#  [" 1 ", #<struct CSV::FieldInfo index=1, line=2, header=nil>]
-#  [" baz ", #<struct CSV::FieldInfo index=0, line=3, header=nil>]
-#  [" 2 ", #<struct CSV::FieldInfo index=1, line=3, header=nil>]
-# Each CSV::FieldInfo object shows:
-# - The 0-based field index.
-# - The 1-based line index.
-# - The field header, if any.
-#
-# ===== Stored \Converters
-#
-# A converter may be given a name and stored in a structure where
-# the parsing methods can find it by name.
-#
-# The storage structure for field converters is the \Hash CSV::Converters.
-# It has several built-in converter procs:
-# - <tt>:integer</tt>: converts each \String-embedded integer into a true \Integer.
-# - <tt>:float</tt>: converts each \String-embedded float into a true \Float.
-# - <tt>:date</tt>: converts each \String-embedded date into a true \Date.
-# - <tt>:date_time</tt>: converts each \String-embedded date-time into a true \DateTime
-# .
-# This example creates a converter proc, then stores it:
-#   strip_converter = proc {|field| field.strip }
-#   CSV::Converters[:strip] = strip_converter
-# Then the parsing method call can refer to the converter
-# by its name, <tt>:strip</tt>:
-#   string = " foo , 0 \n bar , 1 \n baz , 2 \n"
-#   array = CSV.parse(string, converters: :strip)
-#   array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# The storage structure for header converters is the \Hash CSV::HeaderConverters,
-# which works in the same way.
-# It also has built-in converter procs:
-# - <tt>:downcase</tt>: Downcases each header.
-# - <tt>:symbol</tt>: Converts each header to a \Symbol.
-#
-# There is no such storage structure for write headers.
-#
-# In order for the parsing methods to access stored converters in non-main-Ractors, the
-# storage structure must be made shareable first.
-# Therefore, <tt>Ractor.make_shareable(CSV::Converters)</tt> and
-# <tt>Ractor.make_shareable(CSV::HeaderConverters)</tt> must be called before the creation
-# of Ractors that use the converters stored in these structures. (Since making the storage
-# structures shareable involves freezing them, any custom converters that are to be used
-# must be added first.)
-#
-# ===== Converter Lists
-#
-# A _converter_ _list_ is an \Array that may include any assortment of:
-# - Converter procs.
-# - Names of stored converters.
-# - Nested converter lists.
-#
-# Examples:
-#   numeric_converters = [:integer, :float]
-#   date_converters = [:date, :date_time]
-#   [numeric_converters, strip_converter]
-#   [strip_converter, date_converters, :float]
-#
-# Like a converter proc, a converter list may be named and stored in either
-# \CSV::Converters or CSV::HeaderConverters:
-#   CSV::Converters[:custom] = [strip_converter, date_converters, :float]
-#   CSV::HeaderConverters[:custom] = [:downcase, :symbol]
-#
-# There are two built-in converter lists:
-#   CSV::Converters[:numeric] # => [:integer, :float]
-#   CSV::Converters[:all] # => [:date_time, :numeric]
-#
-# ==== Field \Converters
-#
-# With no conversion, all parsed fields in all rows become Strings:
-#   string = "foo,0\nbar,1\nbaz,2\n"
-#   ary = CSV.parse(string)
-#   ary # => # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# When you specify a field converter, each parsed field is passed to the converter;
-# its return value becomes the stored value for the field.
-# A converter might, for example, convert an integer embedded in a \String
-# into a true \Integer.
-# (In fact, that's what built-in field converter +:integer+ does.)
-#
-# There are three ways to use field \converters.
-#
-# - Using option {converters}[#class-CSV-label-Option+converters] with a parsing method:
-#     ary = CSV.parse(string, converters: :integer)
-#     ary # => [0, 1, 2] # => [["foo", 0], ["bar", 1], ["baz", 2]]
-# - Using option {converters}[#class-CSV-label-Option+converters] with a new \CSV instance:
-#     csv = CSV.new(string, converters: :integer)
-#     # Field converters in effect:
-#     csv.converters # => [:integer]
-#     csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
-# - Using method #convert to add a field converter to a \CSV instance:
-#     csv = CSV.new(string)
-#     # Add a converter.
-#     csv.convert(:integer)
-#     csv.converters # => [:integer]
-#     csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
-#
-# Installing a field converter does not affect already-read rows:
-#   csv = CSV.new(string)
-#   csv.shift # => ["foo", "0"]
-#   # Add a converter.
-#   csv.convert(:integer)
-#   csv.converters # => [:integer]
-#   csv.read # => [["bar", 1], ["baz", 2]]
-#
-# There are additional built-in \converters, and custom \converters are also supported.
-#
-# ===== Built-In Field \Converters
-#
-# The built-in field converters are in \Hash CSV::Converters:
-# - Each key is a field converter name.
-# - Each value is one of:
-#   - A \Proc field converter.
-#   - An \Array of field converter names.
-#
-# Display:
-#   CSV::Converters.each_pair do |name, value|
-#     if value.kind_of?(Proc)
-#       p [name, value.class]
-#     else
-#       p [name, value]
-#     end
-#   end
-# Output:
-#   [:integer, Proc]
-#   [:float, Proc]
-#   [:numeric, [:integer, :float]]
-#   [:date, Proc]
-#   [:date_time, Proc]
-#   [:all, [:date_time, :numeric]]
-#
-# Each of these converters transcodes values to UTF-8 before attempting conversion.
-# If a value cannot be transcoded to UTF-8 the conversion will
-# fail and the value will remain unconverted.
-#
-# Converter +:integer+ converts each field that Integer() accepts:
-#   data = '0,1,2,x'
-#   # Without the converter
-#   csv = CSV.parse_line(data)
-#   csv # => ["0", "1", "2", "x"]
-#   # With the converter
-#   csv = CSV.parse_line(data, converters: :integer)
-#   csv # => [0, 1, 2, "x"]
-#
-# Converter +:float+ converts each field that Float() accepts:
-#   data = '1.0,3.14159,x'
-#   # Without the converter
-#   csv = CSV.parse_line(data)
-#   csv # => ["1.0", "3.14159", "x"]
-#   # With the converter
-#   csv = CSV.parse_line(data, converters: :float)
-#   csv # => [1.0, 3.14159, "x"]
-#
-# Converter +:numeric+ converts with both +:integer+ and +:float+..
-#
-# Converter +:date+ converts each field that Date::parse accepts:
-#   data = '2001-02-03,x'
-#   # Without the converter
-#   csv = CSV.parse_line(data)
-#   csv # => ["2001-02-03", "x"]
-#   # With the converter
-#   csv = CSV.parse_line(data, converters: :date)
-#   csv # => [#<Date: 2001-02-03 ((2451944j,0s,0n),+0s,2299161j)>, "x"]
-#
-# Converter +:date_time+ converts each field that DateTime::parse accepts:
-#   data = '2020-05-07T14:59:00-05:00,x'
-#   # Without the converter
-#   csv = CSV.parse_line(data)
-#   csv # => ["2020-05-07T14:59:00-05:00", "x"]
-#   # With the converter
-#   csv = CSV.parse_line(data, converters: :date_time)
-#   csv # => [#<DateTime: 2020-05-07T14:59:00-05:00 ((2458977j,71940s,0n),-18000s,2299161j)>, "x"]
-#
-# Converter +:numeric+ converts with both +:date_time+ and +:numeric+..
-#
-# As seen above, method #convert adds \converters to a \CSV instance,
-# and method #converters returns an \Array of the \converters in effect:
-#   csv = CSV.new('0,1,2')
-#   csv.converters # => []
-#   csv.convert(:integer)
-#   csv.converters # => [:integer]
-#   csv.convert(:date)
-#   csv.converters # => [:integer, :date]
-#
-# ===== Custom Field \Converters
-#
-# You can define a custom field converter:
-#   strip_converter = proc {|field| field.strip }
-#   string = " foo , 0 \n bar , 1 \n baz , 2 \n"
-#   array = CSV.parse(string, converters: strip_converter)
-#   array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-# You can register the converter in \Converters \Hash,
-# which allows you to refer to it by name:
-#   CSV::Converters[:strip] = strip_converter
-#   string = " foo , 0 \n bar , 1 \n baz , 2 \n"
-#   array = CSV.parse(string, converters: :strip)
-#   array # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-#
-# ==== Header \Converters
-#
-# Header converters operate only on headers (and not on other rows).
-#
-# There are three ways to use header \converters;
-# these examples use built-in header converter +:downcase+,
-# which downcases each parsed header.
-#
-# - Option +header_converters+ with a singleton parsing method:
-#     string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
-#     tbl = CSV.parse(string, headers: true, header_converters: :downcase)
-#     tbl.class # => CSV::Table
-#     tbl.headers # => ["name", "count"]
-#
-# - Option +header_converters+ with a new \CSV instance:
-#     csv = CSV.new(string, header_converters: :downcase)
-#     # Header converters in effect:
-#     csv.header_converters # => [:downcase]
-#     tbl = CSV.parse(string, headers: true)
-#     tbl.headers # => ["Name", "Count"]
-#
-# - Method #header_convert adds a header converter to a \CSV instance:
-#     csv = CSV.new(string)
-#     # Add a header converter.
-#     csv.header_convert(:downcase)
-#     csv.header_converters # => [:downcase]
-#     tbl = CSV.parse(string, headers: true)
-#     tbl.headers # => ["Name", "Count"]
-#
-# ===== Built-In Header \Converters
-#
-# The built-in header \converters are in \Hash CSV::HeaderConverters.
-# The keys there are the names of the \converters:
-#   CSV::HeaderConverters.keys # => [:downcase, :symbol]
-#
-# Converter +:downcase+ converts each header by downcasing it:
-#   string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
-#   tbl = CSV.parse(string, headers: true, header_converters: :downcase)
-#   tbl.class # => CSV::Table
-#   tbl.headers # => ["name", "count"]
-#
-# Converter +:symbol+ converts each header by making it into a \Symbol:
-#   string = "Name,Count\nFoo,0\n,Bar,1\nBaz,2"
-#   tbl = CSV.parse(string, headers: true, header_converters: :symbol)
-#   tbl.headers # => [:name, :count]
-# Details:
-# - Strips leading and trailing whitespace.
-# - Downcases the header.
-# - Replaces embedded spaces with underscores.
-# - Removes non-word characters.
-# - Makes the string into a \Symbol.
-#
-# ===== Custom Header \Converters
-#
-# You can define a custom header converter:
-#   upcase_converter = proc {|header| header.upcase }
-#   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-#   table = CSV.parse(string, headers: true, header_converters: upcase_converter)
-#   table # => #<CSV::Table mode:col_or_row row_count:4>
-#   table.headers # => ["NAME", "VALUE"]
-# You can register the converter in \HeaderConverters \Hash,
-# which allows you to refer to it by name:
-#   CSV::HeaderConverters[:upcase] = upcase_converter
-#   table = CSV.parse(string, headers: true, header_converters: :upcase)
-#   table # => #<CSV::Table mode:col_or_row row_count:4>
-#   table.headers # => ["NAME", "VALUE"]
-#
-# ===== Write \Converters
-#
-# When you specify a write converter for generating \CSV,
-# each field to be written is passed to the converter;
-# its return value becomes the new value for the field.
-# A converter might, for example, strip whitespace from a field.
-#
-# Using no write converter (all fields unmodified):
-#   output_string = CSV.generate do |csv|
-#     csv << [' foo ', 0]
-#     csv << [' bar ', 1]
-#     csv << [' baz ', 2]
-#   end
-#   output_string # => " foo ,0\n bar ,1\n baz ,2\n"
-# Using option +write_converters+ with two custom write converters:
-#   strip_converter = proc {|field| field.respond_to?(:strip) ? field.strip : field }
-#   upcase_converter = proc {|field| field.respond_to?(:upcase) ? field.upcase : field }
-#   write_converters = [strip_converter, upcase_converter]
-#   output_string = CSV.generate(write_converters: write_converters) do |csv|
-#     csv << [' foo ', 0]
-#     csv << [' bar ', 1]
-#     csv << [' baz ', 2]
-#   end
-#   output_string # => "FOO,0\nBAR,1\nBAZ,2\n"
-#
-# === Character Encodings (M17n or Multilingualization)
-#
-# This new CSV parser is m17n savvy.  The parser works in the Encoding of the IO
-# or String object being read from or written to. Your data is never transcoded
-# (unless you ask Ruby to transcode it for you) and will literally be parsed in
-# the Encoding it is in. Thus CSV will return Arrays or Rows of Strings in the
-# Encoding of your data. This is accomplished by transcoding the parser itself
-# into your Encoding.
-#
-# Some transcoding must take place, of course, to accomplish this multiencoding
-# support. For example, <tt>:col_sep</tt>, <tt>:row_sep</tt>, and
-# <tt>:quote_char</tt> must be transcoded to match your data.  Hopefully this
-# makes the entire process feel transparent, since CSV's defaults should just
-# magically work for your data. However, you can set these values manually in
-# the target Encoding to avoid the translation.
-#
-# It's also important to note that while all of CSV's core parser is now
-# Encoding agnostic, some features are not. For example, the built-in
-# converters will try to transcode data to UTF-8 before making conversions.
-# Again, you can provide custom converters that are aware of your Encodings to
-# avoid this translation. It's just too hard for me to support native
-# conversions in all of Ruby's Encodings.
-#
-# Anyway, the practical side of this is simple: make sure IO and String objects
-# passed into CSV have the proper Encoding set and everything should just work.
-# CSV methods that allow you to open IO objects (CSV::foreach(), CSV::open(),
-# CSV::read(), and CSV::readlines()) do allow you to specify the Encoding.
-#
-# One minor exception comes when generating CSV into a String with an Encoding
-# that is not ASCII compatible. There's no existing data for CSV to use to
-# prepare itself and thus you will probably need to manually specify the desired
-# Encoding for most of those cases. It will try to guess using the fields in a
-# row of output though, when using CSV::generate_line() or Array#to_csv().
-#
-# I try to point out any other Encoding issues in the documentation of methods
-# as they come up.
-#
-# This has been tested to the best of my ability with all non-"dummy" Encodings
-# Ruby ships with. However, it is brave new code and may have some bugs.
-# Please feel free to {report}[mailto:[email protected]] any issues you
-# find with it.
-#
-class CSV
-
-  # The error thrown when the parser encounters illegal CSV formatting.
-  class MalformedCSVError < RuntimeError
-    attr_reader :line_number
-    alias_method :lineno, :line_number
-    def initialize(message, line_number)
-      @line_number = line_number
-      super("#{message} in line #{line_number}.")
-    end
-  end
-
-  # The error thrown when the parser encounters invalid encoding in CSV.
-  class InvalidEncodingError < MalformedCSVError
-    attr_reader :encoding
-    def initialize(encoding, line_number)
-      @encoding = encoding
-      super("Invalid byte sequence in #{encoding}", line_number)
-    end
-  end
-
-  #
-  # A FieldInfo Struct contains details about a field's position in the data
-  # source it was read from.  CSV will pass this Struct to some blocks that make
-  # decisions based on field structure.  See CSV.convert_fields() for an
-  # example.
-  #
-  # <b><tt>index</tt></b>::  The zero-based index of the field in its row.
-  # <b><tt>line</tt></b>::   The line of the data source this row is from.
-  # <b><tt>header</tt></b>:: The header for the column, when available.
-  # <b><tt>quoted?</tt></b>:: True or false, whether the original value is quoted or not.
-  #
-  FieldInfo = Struct.new(:index, :line, :header, :quoted?)
-
-  # A Regexp used to find and convert some common Date formats.
-  DateMatcher     = / \A(?: (\w+,?\s+)?\w+\s+\d{1,2},?\s+\d{2,4} |
-                            \d{4}-\d{2}-\d{2} )\z /x
-  # A Regexp used to find and convert some common DateTime formats.
-  DateTimeMatcher =
-    / \A(?: (\w+,?\s+)?\w+\s+\d{1,2}\s+\d{1,2}:\d{1,2}:\d{1,2},?\s+\d{2,4} |
-            # ISO-8601 and RFC-3339 (space instead of T) recognized by DateTime.parse
-            \d{4}-\d{2}-\d{2}
-              (?:[T\s]\d{2}:\d{2}(?::\d{2}(?:\.\d+)?(?:[+-]\d{2}(?::\d{2})|Z)?)?)?
-        )\z /x
-
-  # The encoding used by all converters.
-  ConverterEncoding = Encoding.find("UTF-8")
-
-  # A \Hash containing the names and \Procs for the built-in field converters.
-  # See {Built-In Field Converters}[#class-CSV-label-Built-In+Field+Converters].
-  #
-  # This \Hash is intentionally left unfrozen, and may be extended with
-  # custom field converters.
-  # See {Custom Field Converters}[#class-CSV-label-Custom+Field+Converters].
-  Converters  = {
-    integer:   lambda { |f|
-      Integer(f.encode(ConverterEncoding)) rescue f
-    },
-    float:     lambda { |f|
-      Float(f.encode(ConverterEncoding)) rescue f
-    },
-    numeric:   [:integer, :float],
-    date:      lambda { |f|
-      begin
-        e = f.encode(ConverterEncoding)
-        e.match?(DateMatcher) ? Date.parse(e) : f
-      rescue  # encoding conversion or date parse errors
-        f
-      end
-    },
-    date_time: lambda { |f|
-      begin
-        e = f.encode(ConverterEncoding)
-        e.match?(DateTimeMatcher) ? DateTime.parse(e) : f
-      rescue  # encoding conversion or date parse errors
-        f
-      end
-    },
-    all:       [:date_time, :numeric],
-  }
-
-  # A \Hash containing the names and \Procs for the built-in header converters.
-  # See {Built-In Header Converters}[#class-CSV-label-Built-In+Header+Converters].
-  #
-  # This \Hash is intentionally left unfrozen, and may be extended with
-  # custom field converters.
-  # See {Custom Header Converters}[#class-CSV-label-Custom+Header+Converters].
-  HeaderConverters = {
-    downcase: lambda { |h| h.encode(ConverterEncoding).downcase },
-    symbol:   lambda { |h|
-      h.encode(ConverterEncoding).downcase.gsub(/[^\s\w]+/, "").strip.
-                                           gsub(/\s+/, "_").to_sym
-    },
-    symbol_raw: lambda { |h| h.encode(ConverterEncoding).to_sym }
-  }
-
-  # Default values for method options.
-  DEFAULT_OPTIONS = {
-    # For both parsing and generating.
-    col_sep:            ",",
-    row_sep:            :auto,
-    quote_char:         '"',
-    # For parsing.
-    field_size_limit:   nil,
-    max_field_size:     nil,
-    converters:         nil,
-    unconverted_fields: nil,
-    headers:            false,
-    return_headers:     false,
-    header_converters:  nil,
-    skip_blanks:        false,
-    skip_lines:         nil,
-    liberal_parsing:    false,
-    nil_value:          nil,
-    empty_value:        "",
-    strip:              false,
-    # For generating.
-    write_headers:      nil,
-    quote_empty:        true,
-    force_quotes:       false,
-    write_converters:   nil,
-    write_nil_value:    nil,
-    write_empty_value:  "",
-  }.freeze
-
-  class << self
-    # :call-seq:
-    #   instance(string, **options)
-    #   instance(io = $stdout, **options)
-    #   instance(string, **options) {|csv| ... }
-    #   instance(io = $stdout, **options) {|csv| ... }
-    #
-    # Creates or retrieves cached \CSV objects.
-    # For arguments and options, see CSV.new.
-    #
-    # This API is not Ractor-safe.
-    #
-    # ---
-    #
-    # With no block given, returns a \CSV object.
-    #
-    # The first call to +instance+ creates and caches a \CSV object:
-    #   s0 = 's0'
-    #   csv0 = CSV.instance(s0)
-    #   csv0.class # => CSV
-    #
-    # Subsequent calls to +instance+ with that _same_ +string+ or +io+
-    # retrieve that same cached object:
-    #   csv1 = CSV.instance(s0)
-    #   csv1.class # => CSV
-    #   csv1.equal?(csv0) # => true # Same CSV object
-    #
-    # A subsequent call to +instance+ with a _different_ +string+ or +io+
-    # creates and caches a _different_ \CSV object.
-    #   s1 = 's1'
-    #   csv2 = CSV.instance(s1)
-    #   csv2.equal?(csv0) # => false # Different CSV object
-    #
-    # All the cached objects remains available:
-    #   csv3 = CSV.instance(s0)
-    #   csv3.equal?(csv0) # true # Same CSV object
-    #   csv4 = CSV.instance(s1)
-    #   csv4.equal?(csv2) # true # Same CSV object
-    #
-    # ---
-    #
-    # When a block is given, calls the block with the created or retrieved
-    # \CSV object; returns the block's return value:
-    #   CSV.instance(s0) {|csv| :foo } # => :foo
-    def instance(data = $stdout, **options)
-      # create a _signature_ for this method call, data object and options
-      sig = [data.object_id] +
-            options.values_at(*DEFAULT_OPTIONS.keys)
-
-      # fetch or create the instance for this signature
-      @@instances ||= Hash.new
-      instance = (@@instances[sig] ||= new(data, **options))
-
-      if block_given?
-        yield instance  # run block, if given, returning result
-      else
-        instance        # or return the instance
-      end
-    end
-
-    # :call-seq:
-    #   filter(in_string_or_io, **options) {|row| ... } -> array_of_arrays or csv_table
-    #   filter(in_string_or_io, out_string_or_io, **options) {|row| ... } -> array_of_arrays or csv_table
-    #   filter(**options) {|row| ... } -> array_of_arrays or csv_table
-    #
-    # - Parses \CSV from a source (\String, \IO stream, or ARGF).
-    # - Calls the given block with each parsed row:
-    #   - Without headers, each row is an \Array.
-    #   - With headers, each row is a CSV::Row.
-    # - Generates \CSV to an output (\String, \IO stream, or STDOUT).
-    # - Returns the parsed source:
-    #   - Without headers, an \Array of \Arrays.
-    #   - With headers, a CSV::Table.
-    #
-    # When +in_string_or_io+ is given, but not +out_string_or_io+,
-    # parses from the given +in_string_or_io+
-    # and generates to STDOUT.
-    #
-    # \String input without headers:
-    #
-    #   in_string = "foo,0\nbar,1\nbaz,2"
-    #   CSV.filter(in_string) do |row|
-    #     row[0].upcase!
-    #     row[1] = - row[1].to_i
-    #   end # => [["FOO", 0], ["BAR", -1], ["BAZ", -2]]
-    #
-    # Output (to STDOUT):
-    #
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # \String input with headers:
-    #
-    #   in_string = "Name,Value\nfoo,0\nbar,1\nbaz,2"
-    #   CSV.filter(in_string, headers: true) do |row|
-    #     row[0].upcase!
-    #     row[1] = - row[1].to_i
-    #   end # => #<CSV::Table mode:col_or_row row_count:4>
-    #
-    # Output (to STDOUT):
-    #
-    #   Name,Value
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # \IO stream input without headers:
-    #
-    #   File.write('t.csv', "foo,0\nbar,1\nbaz,2")
-    #   File.open('t.csv') do |in_io|
-    #     CSV.filter(in_io) do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   end # => [["FOO", 0], ["BAR", -1], ["BAZ", -2]]
-    #
-    # Output (to STDOUT):
-    #
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # \IO stream input with headers:
-    #
-    #   File.write('t.csv', "Name,Value\nfoo,0\nbar,1\nbaz,2")
-    #   File.open('t.csv') do |in_io|
-    #     CSV.filter(in_io, headers: true) do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   end # => #<CSV::Table mode:col_or_row row_count:4>
-    #
-    # Output (to STDOUT):
-    #
-    #   Name,Value
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # When both +in_string_or_io+ and +out_string_or_io+ are given,
-    # parses from +in_string_or_io+ and generates to +out_string_or_io+.
-    #
-    # \String output without headers:
-    #
-    #   in_string = "foo,0\nbar,1\nbaz,2"
-    #   out_string = ''
-    #   CSV.filter(in_string, out_string) do |row|
-    #     row[0].upcase!
-    #     row[1] = - row[1].to_i
-    #   end # => [["FOO", 0], ["BAR", -1], ["BAZ", -2]]
-    #   out_string # => "FOO,0\nBAR,-1\nBAZ,-2\n"
-    #
-    # \String output with headers:
-    #
-    #   in_string = "Name,Value\nfoo,0\nbar,1\nbaz,2"
-    #   out_string = ''
-    #   CSV.filter(in_string, out_string, headers: true) do |row|
-    #     row[0].upcase!
-    #     row[1] = - row[1].to_i
-    #   end # => #<CSV::Table mode:col_or_row row_count:4>
-    #   out_string # => "Name,Value\nFOO,0\nBAR,-1\nBAZ,-2\n"
-    #
-    # \IO stream output without headers:
-    #
-    #   in_string = "foo,0\nbar,1\nbaz,2"
-    #   File.open('t.csv', 'w') do |out_io|
-    #     CSV.filter(in_string, out_io) do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   end # => [["FOO", 0], ["BAR", -1], ["BAZ", -2]]
-    #   File.read('t.csv') # => "FOO,0\nBAR,-1\nBAZ,-2\n"
-    #
-    # \IO stream output with headers:
-    #
-    #   in_string = "Name,Value\nfoo,0\nbar,1\nbaz,2"
-    #   File.open('t.csv', 'w') do |out_io|
-    #     CSV.filter(in_string, out_io, headers: true) do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   end # => #<CSV::Table mode:col_or_row row_count:4>
-    #   File.read('t.csv') # => "Name,Value\nFOO,0\nBAR,-1\nBAZ,-2\n"
-    #
-    # When neither +in_string_or_io+ nor +out_string_or_io+ given,
-    # parses from {ARGF}[rdoc-ref:ARGF]
-    # and generates to STDOUT.
-    #
-    # Without headers:
-    #
-    #   # Put Ruby code into a file.
-    #   ruby = <<-EOT
-    #     require 'csv'
-    #     CSV.filter do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   EOT
-    #   File.write('t.rb', ruby)
-    #   # Put some CSV into a file.
-    #   File.write('t.csv', "foo,0\nbar,1\nbaz,2")
-    #   # Run the Ruby code with CSV filename as argument.
-    #   system(Gem.ruby, "t.rb", "t.csv")
-    #
-    # Output (to STDOUT):
-    #
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # With headers:
-    #
-    #   # Put Ruby code into a file.
-    #   ruby = <<-EOT
-    #     require 'csv'
-    #     CSV.filter(headers: true) do |row|
-    #       row[0].upcase!
-    #       row[1] = - row[1].to_i
-    #     end
-    #   EOT
-    #   File.write('t.rb', ruby)
-    #   # Put some CSV into a file.
-    #   File.write('t.csv', "Name,Value\nfoo,0\nbar,1\nbaz,2")
-    #   # Run the Ruby code with CSV filename as argument.
-    #   system(Gem.ruby, "t.rb", "t.csv")
-    #
-    # Output (to STDOUT):
-    #
-    #   Name,Value
-    #   FOO,0
-    #   BAR,-1
-    #   BAZ,-2
-    #
-    # Arguments:
-    #
-    # * Argument +in_string_or_io+ must be a \String or an \IO stream.
-    # * Argument +out_string_or_io+ must be a \String or an \IO stream.
-    # * Arguments <tt>**options</tt> must be keyword options.
-    #   See {Options for Parsing}[#class-CSV-label-Options+for+Parsing].
-    def filter(input=nil, output=nil, **options)
-      # parse options for input, output, or both
-      in_options, out_options = Hash.new, {row_sep: InputRecordSeparator.value}
-      options.each do |key, value|
-        case key
-        when /\Ain(?:put)?_(.+)\Z/
-          in_options[$1.to_sym] = value
-        when /\Aout(?:put)?_(.+)\Z/
-          out_options[$1.to_sym] = value
-        else
-          in_options[key]  = value
-          out_options[key] = value
-        end
-      end
-
-      # build input and output wrappers
-      input  = new(input  || ARGF, **in_options)
-      output = new(output || $stdout, **out_options)
-
-      # process headers
-      need_manual_header_output =
-        (in_options[:headers] and
-         out_options[:headers] == true and
-         out_options[:write_headers])
-      if need_manual_header_output
-        first_row = input.shift
-        if first_row
-          if first_row.is_a?(Row)
-            headers = first_row.headers
-            yield headers
-            output << headers
-          end
-          yield first_row
-          output << first_row
-        end
-      end
-
-      # read, yield, write
-      input.each do |row|
-        yield row
-        output << row
-      end
-    end
-
-    #
-    # :call-seq:
-    #   foreach(path_or_io, mode='r', **options) {|row| ... )
-    #   foreach(path_or_io, mode='r', **options) -> new_enumerator
-    #
-    # Calls the block with each row read from source +path_or_io+.
-    #
-    # \Path input without headers:
-    #
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   in_path = 't.csv'
-    #   File.write(in_path, string)
-    #   CSV.foreach(in_path) {|row| p row }
-    #
-    # Output:
-    #
-    #   ["foo", "0"]
-    #   ["bar", "1"]
-    #   ["baz", "2"]
-    #
-    # \Path input with headers:
-    #
-    #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   in_path = 't.csv'
-    #   File.write(in_path, string)
-    #   CSV.foreach(in_path, headers: true) {|row| p row }
-    #
-    # Output:
-    #
-    #   <CSV::Row "Name":"foo" "Value":"0">
-    #   <CSV::Row "Name":"bar" "Value":"1">
-    #   <CSV::Row "Name":"baz" "Value":"2">
-    #
-    # \IO stream input without headers:
-    #
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   File.open('t.csv') do |in_io|
-    #     CSV.foreach(in_io) {|row| p row }
-    #   end
-    #
-    # Output:
-    #
-    #   ["foo", "0"]
-    #   ["bar", "1"]
-    #   ["baz", "2"]
-    #
-    # \IO stream input with headers:
-    #
-    #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   File.open('t.csv') do |in_io|
-    #     CSV.foreach(in_io, headers: true) {|row| p row }
-    #   end
-    #
-    # Output:
-    #
-    #   <CSV::Row "Name":"foo" "Value":"0">
-    #   <CSV::Row "Name":"bar" "Value":"1">
-    #   <CSV::Row "Name":"baz" "Value":"2">
-    #
-    # With no block given, returns an \Enumerator:
-    #
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   CSV.foreach(path) # => #<Enumerator: CSV:foreach("t.csv", "r")>
-    #
-    # Arguments:
-    # * Argument +path_or_io+ must be a file path or an \IO stream.
-    # * Argument +mode+, if given, must be a \File mode.
-    #   See {Access Modes}[rdoc-ref:File@Access+Modes].
-    # * Arguments <tt>**options</tt> must be keyword options.
-    #   See {Options for Parsing}[#class-CSV-label-Options+for+Parsing].
-    # * This method optionally accepts an additional <tt>:encoding</tt> option
-    #   that you can use to specify the Encoding of the data read from +path+ or +io+.
-    #   You must provide this unless your data is in the encoding
-    #   given by <tt>Encoding::default_external</tt>.
-    #   Parsing will use this to determine how to parse the data.
-    #   You may provide a second Encoding to
-    #   have the data transcoded as it is read. For example,
-    #     encoding: 'UTF-32BE:UTF-8'
-    #   would read +UTF-32BE+ data from the file
-    #   but transcode it to +UTF-8+ before parsing.
-    def foreach(path, mode="r", **options, &block)
-      return to_enum(__method__, path, mode, **options) unless block_given?
-      open(path, mode, **options) do |csv|
-        csv.each(&block)
-      end
-    end
-
-    #
-    # :call-seq:
-    #   generate(csv_string, **options) {|csv| ... }
-    #   generate(**options) {|csv| ... }
-    #
-    # * Argument +csv_string+, if given, must be a \String object;
-    #   defaults to a new empty \String.
-    # * Arguments +options+, if given, should be generating options.
-    #   See {Options for Generating}[#class-CSV-label-Options+for+Generating].
-    #
-    # ---
-    #
-    # Creates a new \CSV object via <tt>CSV.new(csv_string, **options)</tt>;
-    # calls the block with the \CSV object, which the block may modify;
-    # returns the \String generated from the \CSV object.
-    #
-    # Note that a passed \String *is* modified by this method.
-    # Pass <tt>csv_string</tt>.dup if the \String must be preserved.
-    #
-    # This method has one additional option: <tt>:encoding</tt>,
-    # which sets the base Encoding for the output if no no +str+ is specified.
-    # CSV needs this hint if you plan to output non-ASCII compatible data.
-    #
-    # ---
-    #
-    # Add lines:
-    #   input_string = "foo,0\nbar,1\nbaz,2\n"
-    #   output_string = CSV.generate(input_string) do |csv|
-    #     csv << ['bat', 3]
-    #     csv << ['bam', 4]
-    #   end
-    #   output_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
-    #   input_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
-    #   output_string.equal?(input_string) # => true # Same string, modified
-    #
-    # Add lines into new string, preserving old string:
-    #   input_string = "foo,0\nbar,1\nbaz,2\n"
-    #   output_string = CSV.generate(input_string.dup) do |csv|
-    #     csv << ['bat', 3]
-    #     csv << ['bam', 4]
-    #   end
-    #   output_string # => "foo,0\nbar,1\nbaz,2\nbat,3\nbam,4\n"
-    #   input_string # => "foo,0\nbar,1\nbaz,2\n"
-    #   output_string.equal?(input_string) # => false # Different strings
-    #
-    # Create lines from nothing:
-    #   output_string = CSV.generate do |csv|
-    #     csv << ['foo', 0]
-    #     csv << ['bar', 1]
-    #     csv << ['baz', 2]
-    #   end
-    #   output_string # => "foo,0\nbar,1\nbaz,2\n"
-    #
-    # ---
-    #
-    # Raises an exception if +csv_string+ is not a \String object:
-    #   # Raises TypeError (no implicit conversion of Integer into String)
-    #   CSV.generate(0)
-    #
-    def generate(str=nil, **options)
-      encoding = options[:encoding]
-      # add a default empty String, if none was given
-      if str
-        str = StringIO.new(str)
-        str.seek(0, IO::SEEK_END)
-        str.set_encoding(encoding) if encoding
-      else
-        str = +""
-        str.force_encoding(encoding) if encoding
-      end
-      csv = new(str, **options) # wrap
-      yield csv         # yield for appending
-      csv.string        # return final String
-    end
-
-    # :call-seq:
-    #   CSV.generate_line(ary)
-    #   CSV.generate_line(ary, **options)
-    #
-    # Returns the \String created by generating \CSV from +ary+
-    # using the specified +options+.
-    #
-    # Argument +ary+ must be an \Array.
-    #
-    # Special options:
-    # * Option <tt>:row_sep</tt> defaults to <tt>"\n"> on Ruby 3.0 or later
-    #   and <tt>$INPUT_RECORD_SEPARATOR</tt> (<tt>$/</tt>) otherwise.:
-    #     $INPUT_RECORD_SEPARATOR # => "\n"
-    # * This method accepts an additional option, <tt>:encoding</tt>, which sets the base
-    #   Encoding for the output. This method will try to guess your Encoding from
-    #   the first non-+nil+ field in +row+, if possible, but you may need to use
-    #   this parameter as a backup plan.
-    #
-    # For other +options+,
-    # see {Options for Generating}[#class-CSV-label-Options+for+Generating].
-    #
-    # ---
-    #
-    # Returns the \String generated from an \Array:
-    #   CSV.generate_line(['foo', '0']) # => "foo,0\n"
-    #
-    # ---
-    #
-    # Raises an exception if +ary+ is not an \Array:
-    #   # Raises NoMethodError (undefined method `find' for :foo:Symbol)
-    #   CSV.generate_line(:foo)
-    #
-    def generate_line(row, **options)
-      options = {row_sep: InputRecordSeparator.value}.merge(options)
-      str = +""
-      if options[:encoding]
-        str.force_encoding(options[:encoding])
-      else
-        fallback_encoding = nil
-        output_encoding = nil
-        row.each do |field|
-          next unless field.is_a?(String)
-          fallback_encoding ||= field.encoding
-          next if field.ascii_only?
-          output_encoding = field.encoding
-          break
-        end
-        output_encoding ||= fallback_encoding
-        if output_encoding
-          str.force_encoding(output_encoding)
-        end
-      end
-      (new(str, **options) << row).string
-    end
-
-    # :call-seq:
-    #   CSV.generate_lines(rows)
-    #   CSV.generate_lines(rows, **options)
-    #
-    # Returns the \String created by generating \CSV from
-    # using the specified +options+.
-    #
-    # Argument +rows+ must be an \Array of row. Row is \Array of \String or \CSV::Row.
-    #
-    # Special options:
-    # * Option <tt>:row_sep</tt> defaults to <tt>"\n"</tt> on Ruby 3.0 or later
-    #   and <tt>$INPUT_RECORD_SEPARATOR</tt> (<tt>$/</tt>) otherwise.:
-    #     $INPUT_RECORD_SEPARATOR # => "\n"
-    # * This method accepts an additional option, <tt>:encoding</tt>, which sets the base
-    #   Encoding for the output. This method will try to guess your Encoding from
-    #   the first non-+nil+ field in +row+, if possible, but you may need to use
-    #   this parameter as a backup plan.
-    #
-    # For other +options+,
-    # see {Options for Generating}[#class-CSV-label-Options+for+Generating].
-    #
-    # ---
-    #
-    # Returns the \String generated from an
-    #   CSV.generate_lines([['foo', '0'], ['bar', '1'], ['baz', '2']]) # => "foo,0\nbar,1\nbaz,2\n"
-    #
-    # ---
-    #
-    # Raises an exception
-    #   # Raises NoMethodError (undefined method `each' for :foo:Symbol)
-    #   CSV.generate_lines(:foo)
-    #
-    def generate_lines(rows, **options)
-      self.generate(**options) do |csv|
-        rows.each do |row|
-          csv << row
-        end
-      end
-    end
-
-    #
-    # :call-seq:
-    #   open(file_path, mode = "rb", **options ) -> new_csv
-    #   open(io, mode = "rb", **options ) -> new_csv
-    #   open(file_path, mode = "rb", **options ) { |csv| ... } -> object
-    #   open(io, mode = "rb", **options ) { |csv| ... } -> object
-    #
-    # possible options elements:
-    #   keyword form:
-    #     :invalid => nil      # raise error on invalid byte sequence (default)
-    #     :invalid => :replace # replace invalid byte sequence
-    #     :undef => :replace   # replace undefined conversion
-    #     :replace => string   # replacement string ("?" or "\uFFFD" if not specified)
-    #
-    # * Argument +path+, if given, must be the path to a file.
-    # :include: ../doc/csv/arguments/io.rdoc
-    # * Argument +mode+, if given, must be a \File mode.
-    #   See {Access Modes}[rdoc-ref:File@Access+Modes].
-    # * Arguments <tt>**options</tt> must be keyword options.
-    #   See {Options for Generating}[#class-CSV-label-Options+for+Generating].
-    # * This method optionally accepts an additional <tt>:encoding</tt> option
-    #   that you can use to specify the Encoding of the data read from +path+ or +io+.
-    #   You must provide this unless your data is in the encoding
-    #   given by <tt>Encoding::default_external</tt>.
-    #   Parsing will use this to determine how to parse the data.
-    #   You may provide a second Encoding to
-    #   have the data transcoded as it is read. For example,
-    #     encoding: 'UTF-32BE:UTF-8'
-    #   would read +UTF-32BE+ data from the file
-    #   but transcode it to +UTF-8+ before parsing.
-    #
-    # ---
-    #
-    # These examples assume prior execution of:
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #
-    # ---
-    #
-    # With no block given, returns a new \CSV object.
-    #
-    # Create a \CSV object using a file path:
-    #   csv = CSV.open(path)
-    #   csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    #
-    # Create a \CSV object using an open \File:
-    #   csv = CSV.open(File.open(path))
-    #   csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    #
-    # ---
-    #
-    # With a block given, calls the block with the created \CSV object;
-    # returns the block's return value:
-    #
-    # Using a file path:
-    #   csv = CSV.open(path) {|csv| p csv}
-    #   csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    # Output:
-    #   #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    #
-    # Using an open \File:
-    #   csv = CSV.open(File.open(path)) {|csv| p csv}
-    #   csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    # Output:
-    #   #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-    #
-    # ---
-    #
-    # Raises an exception if the argument is not a \String object or \IO object:
-    #   # Raises TypeError (no implicit conversion of Symbol into String)
-    #   CSV.open(:foo)
-    def open(filename, mode="r", **options)
-      # wrap a File opened with the remaining +args+ with no newline
-      # decorator
-      file_opts = options.dup
-      unless file_opts.key?(:newline)
-        file_opts[:universal_newline] ||= false
-      end
-      options.delete(:invalid)
-      options.delete(:undef)
-      options.delete(:replace)
-      options.delete_if {|k, _| /newline\z/.match?(k)}
-
-      begin
-        f = File.open(filename, mode, **file_opts)
-      rescue ArgumentError => e
-        raise unless /needs binmode/.match?(e.message) and mode == "r"
-        mode = "rb"
-        file_opts = {encoding: Encoding.default_external}.merge(file_opts)
-        retry
-      end
-      begin
-        csv = new(f, **options)
-      rescue Exception
-        f.close
-        raise
-      end
-
-      # handle blocks like Ruby's open(), not like the CSV library
-      if block_given?
-        begin
-          yield csv
-        ensure
-          csv.close
-        end
-      else
-        csv
-      end
-    end
-
-    #
-    # :call-seq:
-    #   parse(string) -> array_of_arrays
-    #   parse(io) -> array_of_arrays
-    #   parse(string, headers: ..., **options) -> csv_table
-    #   parse(io, headers: ..., **options) -> csv_table
-    #   parse(string, **options) {|row| ... }
-    #   parse(io, **options) {|row| ... }
-    #
-    # Parses +string+ or +io+ using the specified +options+.
-    #
-    # - Argument +string+ should be a \String object;
-    #   it will be put into a new StringIO object positioned at the beginning.
-    # :include: ../doc/csv/arguments/io.rdoc
-    # - Argument +options+: see {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
-    #
-    # ====== Without Option +headers+
-    #
-    # Without {option +headers+}[#class-CSV-label-Option+headers] case.
-    #
-    # These examples assume prior execution of:
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #
-    # ---
-    #
-    # With no block given, returns an \Array of Arrays formed from the source.
-    #
-    # Parse a \String:
-    #   a_of_a = CSV.parse(string)
-    #   a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # Parse an open \File:
-    #   a_of_a = File.open(path) do |file|
-    #     CSV.parse(file)
-    #   end
-    #   a_of_a # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # ---
-    #
-    # With a block given, calls the block with each parsed row:
-    #
-    # Parse a \String:
-    #   CSV.parse(string) {|row| p row }
-    #
-    # Output:
-    #   ["foo", "0"]
-    #   ["bar", "1"]
-    #   ["baz", "2"]
-    #
-    # Parse an open \File:
-    #   File.open(path) do |file|
-    #     CSV.parse(file) {|row| p row }
-    #   end
-    #
-    # Output:
-    #   ["foo", "0"]
-    #   ["bar", "1"]
-    #   ["baz", "2"]
-    #
-    # ====== With Option +headers+
-    #
-    # With {option +headers+}[#class-CSV-label-Option+headers] case.
-    #
-    # These examples assume prior execution of:
-    #   string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #
-    # ---
-    #
-    # With no block given, returns a CSV::Table object formed from the source.
-    #
-    # Parse a \String:
-    #   csv_table = CSV.parse(string, headers: ['Name', 'Count'])
-    #   csv_table # => #<CSV::Table mode:col_or_row row_count:5>
-    #
-    # Parse an open \File:
-    #   csv_table = File.open(path) do |file|
-    #     CSV.parse(file, headers: ['Name', 'Count'])
-    #   end
-    #   csv_table # => #<CSV::Table mode:col_or_row row_count:4>
-    #
-    # ---
-    #
-    # With a block given, calls the block with each parsed row,
-    # which has been formed into a CSV::Row object:
-    #
-    # Parse a \String:
-    #   CSV.parse(string, headers: ['Name', 'Count']) {|row| p row }
-    #
-    # Output:
-    #   # <CSV::Row "Name":"foo" "Count":"0">
-    #   # <CSV::Row "Name":"bar" "Count":"1">
-    #   # <CSV::Row "Name":"baz" "Count":"2">
-    #
-    # Parse an open \File:
-    #   File.open(path) do |file|
-    #     CSV.parse(file, headers: ['Name', 'Count']) {|row| p row }
-    #   end
-    #
-    # Output:
-    #   # <CSV::Row "Name":"foo" "Count":"0">
-    #   # <CSV::Row "Name":"bar" "Count":"1">
-    #   # <CSV::Row "Name":"baz" "Count":"2">
-    #
-    # ---
-    #
-    # Raises an exception if the argument is not a \String object or \IO object:
-    #   # Raises NoMethodError (undefined method `close' for :foo:Symbol)
-    #   CSV.parse(:foo)
-    def parse(str, **options, &block)
-      csv = new(str, **options)
-
-      return csv.each(&block) if block_given?
-
-      # slurp contents, if no block is given
-      begin
-        csv.read
-      ensure
-        csv.close
-      end
-    end
-
-    # :call-seq:
-    #   CSV.parse_line(string) -> new_array or nil
-    #   CSV.parse_line(io) -> new_array or nil
-    #   CSV.parse_line(string, **options) -> new_array or nil
-    #   CSV.parse_line(io, **options) -> new_array or nil
-    #   CSV.parse_line(string, headers: true, **options) -> csv_row or nil
-    #   CSV.parse_line(io, headers: true, **options) -> csv_row or nil
-    #
-    # Returns the data created by parsing the first line of +string+ or +io+
-    # using the specified +options+.
-    #
-    # - Argument +string+ should be a \String object;
-    #   it will be put into a new StringIO object positioned at the beginning.
-    # :include: ../doc/csv/arguments/io.rdoc
-    # - Argument +options+: see {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
-    #
-    # ====== Without Option +headers+
-    #
-    # Without option +headers+, returns the first row as a new \Array.
-    #
-    # These examples assume prior execution of:
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #
-    # Parse the first line from a \String object:
-    #   CSV.parse_line(string) # => ["foo", "0"]
-    #
-    # Parse the first line from a File object:
-    #   File.open(path) do |file|
-    #     CSV.parse_line(file) # => ["foo", "0"]
-    #   end # => ["foo", "0"]
-    #
-    # Returns +nil+ if the argument is an empty \String:
-    #   CSV.parse_line('') # => nil
-    #
-    # ====== With Option +headers+
-    #
-    # With {option +headers+}[#class-CSV-label-Option+headers],
-    # returns the first row as a CSV::Row object.
-    #
-    # These examples assume prior execution of:
-    #   string = "Name,Count\nfoo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #
-    # Parse the first line from a \String object:
-    #   CSV.parse_line(string, headers: true) # => #<CSV::Row "Name":"foo" "Count":"0">
-    #
-    # Parse the first line from a File object:
-    #   File.open(path) do |file|
-    #     CSV.parse_line(file, headers: true)
-    #   end # => #<CSV::Row "Name":"foo" "Count":"0">
-    #
-    # ---
-    #
-    # Raises an exception if the argument is +nil+:
-    #   # Raises ArgumentError (Cannot parse nil as CSV):
-    #   CSV.parse_line(nil)
-    #
-    def parse_line(line, **options)
-      new(line, **options).each.first
-    end
-
-    #
-    # :call-seq:
-    #   read(source, **options) -> array_of_arrays
-    #   read(source, headers: true, **options) -> csv_table
-    #
-    # Opens the given +source+ with the given +options+ (see CSV.open),
-    # reads the source (see CSV#read), and returns the result,
-    # which will be either an \Array of Arrays or a CSV::Table.
-    #
-    # Without headers:
-    #   string = "foo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   CSV.read(path) # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # With headers:
-    #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   CSV.read(path, headers: true) # => #<CSV::Table mode:col_or_row row_count:4>
-    def read(path, **options)
-      open(path, **options) { |csv| csv.read }
-    end
-
-    # :call-seq:
-    #   CSV.readlines(source, **options)
-    #
-    # Alias for CSV.read.
-    def readlines(path, **options)
-      read(path, **options)
-    end
-
-    # :call-seq:
-    #   CSV.table(source, **options)
-    #
-    # Calls CSV.read with +source+, +options+, and certain default options:
-    # - +headers+: +true+
-    # - +converters+: +:numeric+
-    # - +header_converters+: +:symbol+
-    #
-    # Returns a CSV::Table object.
-    #
-    # Example:
-    #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   path = 't.csv'
-    #   File.write(path, string)
-    #   CSV.table(path) # => #<CSV::Table mode:col_or_row row_count:4>
-    def table(path, **options)
-      default_options = {
-        headers:           true,
-        converters:        :numeric,
-        header_converters: :symbol,
-      }
-      options = default_options.merge(options)
-      read(path, **options)
-    end
-  end
-
-  # :call-seq:
-  #   CSV.new(string)
-  #   CSV.new(io)
-  #   CSV.new(string, **options)
-  #   CSV.new(io, **options)
-  #
-  # Returns the new \CSV object created using +string+ or +io+
-  # and the specified +options+.
-  #
-  # - Argument +string+ should be a \String object;
-  #   it will be put into a new StringIO object positioned at the beginning.
-  # :include: ../doc/csv/arguments/io.rdoc
-  # - Argument +options+: See:
-  #   * {Options for Parsing}[#class-CSV-label-Options+for+Parsing]
-  #   * {Options for Generating}[#class-CSV-label-Options+for+Generating]
-  #   For performance reasons, the options cannot be overridden
-  #   in a \CSV object, so those specified here will endure.
-  #
-  # In addition to the \CSV instance methods, several \IO methods are delegated.
-  # See {Delegated Methods}[#class-CSV-label-Delegated+Methods].
-  #
-  # ---
-  #
-  # Create a \CSV object from a \String object:
-  #   csv = CSV.new('foo,0')
-  #   csv # => #<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-  #
-  # Create a \CSV object from a \File object:
-  #   File.write('t.csv', 'foo,0')
-  #   csv = CSV.new(File.open('t.csv'))
-  #   csv # => #<CSV io_type:File io_path:"t.csv" encoding:UTF-8 lineno:0 col_sep:"," row_sep:"\n" quote_char:"\"">
-  #
-  # ---
-  #
-  # Raises an exception if the argument is +nil+:
-  #   # Raises ArgumentError (Cannot parse nil as CSV):
-  #   CSV.new(nil)
-  #
-  def initialize(data,
-                 col_sep: ",",
-                 row_sep: :auto,
-                 quote_char: '"',
-                 field_size_limit: nil,
-                 max_field_size: nil,
-                 converters: nil,
-                 unconverted_fields: nil,
-                 headers: false,
-                 return_headers: false,
-                 write_headers: nil,
-                 header_converters: nil,
-                 skip_blanks: false,
-                 force_quotes: false,
-                 skip_lines: nil,
-                 liberal_parsing: false,
-                 internal_encoding: nil,
-                 external_encoding: nil,
-                 encoding: nil,
-                 nil_value: nil,
-                 empty_value: "",
-                 strip: false,
-                 quote_empty: true,
-                 write_converters: nil,
-                 write_nil_value: nil,
-                 write_empty_value: "")
-    raise ArgumentError.new("Cannot parse nil as CSV") if data.nil?
-
-    if data.is_a?(String)
-      if encoding
-        if encoding.is_a?(String)
-          data_external_encoding, data_internal_encoding = encoding.split(":", 2)
-          if data_internal_encoding
-            data = data.encode(data_internal_encoding, data_external_encoding)
-          else
-            data = data.dup.force_encoding(data_external_encoding)
-          end
-        else
-          data = data.dup.force_encoding(encoding)
-        end
-      end
-      @io = StringIO.new(data)
-    else
-      @io = data
-    end
-    @encoding = determine_encoding(encoding, internal_encoding)
-
-    @base_fields_converter_options = {
-      nil_value: nil_value,
-      empty_value: empty_value,
-    }
-    @write_fields_converter_options = {
-      nil_value: write_nil_value,
-      empty_value: write_empty_value,
-    }
-    @initial_converters = converters
-    @initial_header_converters = header_converters
-    @initial_write_converters = write_converters
-
-    if max_field_size.nil? and field_size_limit
-      max_field_size = field_size_limit - 1
-    end
-    @parser_options = {
-      column_separator: col_sep,
-      row_separator: row_sep,
-      quote_character: quote_char,
-      max_field_size: max_field_size,
-      unconverted_fields: unconverted_fields,
-      headers: headers,
-      return_headers: return_headers,
-      skip_blanks: skip_blanks,
-      skip_lines: skip_lines,
-      liberal_parsing: liberal_parsing,
-      encoding: @encoding,
-      nil_value: nil_value,
-      empty_value: empty_value,
-      strip: strip,
-    }
-    @parser = nil
-    @parser_enumerator = nil
-    @eof_error = nil
-
-    @writer_options = {
-      encoding: @encoding,
-      force_encoding: (not encoding.nil?),
-      force_quotes: force_quotes,
-      headers: headers,
-      write_headers: write_headers,
-      column_separator: col_sep,
-      row_separator: row_sep,
-      quote_character: quote_char,
-      quote_empty: quote_empty,
-    }
-
-    @writer = nil
-    writer if @writer_options[:write_headers]
-  end
-
-  # :call-seq:
-  #   csv.col_sep -> string
-  #
-  # Returns the encoded column separator; used for parsing and writing;
-  # see {Option +col_sep+}[#class-CSV-label-Option+col_sep]:
-  #   CSV.new('').col_sep # => ","
-  def col_sep
-    parser.column_separator
-  end
-
-  # :call-seq:
-  #   csv.row_sep -> string
-  #
-  # Returns the encoded row separator; used for parsing and writing;
-  # see {Option +row_sep+}[#class-CSV-label-Option+row_sep]:
-  #   CSV.new('').row_sep # => "\n"
-  def row_sep
-    parser.row_separator
-  end
-
-  # :call-seq:
-  #   csv.quote_char -> character
-  #
-  # Returns the encoded quote character; used for parsing and writing;
-  # see {Option +quote_char+}[#class-CSV-label-Option+quote_char]:
-  #   CSV.new('').quote_char # => "\""
-  def quote_char
-    parser.quote_character
-  end
-
-  # :call-seq:
-  #   csv.field_size_limit -> integer or nil
-  #
-  # Returns the limit for field size; used for parsing;
-  # see {Option +field_size_limit+}[#class-CSV-label-Option+field_size_limit]:
-  #   CSV.new('').field_size_limit # => nil
-  #
-  # Deprecated since 3.2.3. Use +max_field_size+ instead.
-  def field_size_limit
-    parser.field_size_limit
-  end
-
-  # :call-seq:
-  #   csv.max_field_size -> integer or nil
-  #
-  # Returns the limit for field size; used for parsing;
-  # see {Option +max_field_size+}[#class-CSV-label-Option+max_field_size]:
-  #   CSV.new('').max_field_size # => nil
-  #
-  # Since 3.2.3.
-  def max_field_size
-    parser.max_field_size
-  end
-
-  # :call-seq:
-  #   csv.skip_lines -> regexp or nil
-  #
-  # Returns the \Regexp used to identify comment lines; used for parsing;
-  # see {Option +skip_lines+}[#class-CSV-label-Option+skip_lines]:
-  #   CSV.new('').skip_lines # => nil
-  def skip_lines
-    parser.skip_lines
-  end
-
-  # :call-seq:
-  #   csv.converters -> array
-  #
-  # Returns an \Array containing field converters;
-  # see {Field Converters}[#class-CSV-label-Field+Converters]:
-  #   csv = CSV.new('')
-  #   csv.converters # => []
-  #   csv.convert(:integer)
-  #   csv.converters # => [:integer]
-  #   csv.convert(proc {|x| x.to_s })
-  #   csv.converters
-  #
-  # Notes that you need to call
-  # +Ractor.make_shareable(CSV::Converters)+ on the main Ractor to use
-  # this method.
-  def converters
-    parser_fields_converter.map do |converter|
-      name = Converters.rassoc(converter)
-      name ? name.first : converter
-    end
-  end
-
-  # :call-seq:
-  #   csv.unconverted_fields? -> object
-  #
-  # Returns the value that determines whether unconverted fields are to be
-  # available; used for parsing;
-  # see {Option +unconverted_fields+}[#class-CSV-label-Option+unconverted_fields]:
-  #   CSV.new('').unconverted_fields? # => nil
-  def unconverted_fields?
-    parser.unconverted_fields?
-  end
-
-  # :call-seq:
-  #   csv.headers -> object
-  #
-  # Returns the value that determines whether headers are used; used for parsing;
-  # see {Option +headers+}[#class-CSV-label-Option+headers]:
-  #   CSV.new('').headers # => nil
-  def headers
-    if @writer
-      @writer.headers
-    else
-      parsed_headers = parser.headers
-      return parsed_headers if parsed_headers
-      raw_headers = @parser_options[:headers]
-      raw_headers = nil if raw_headers == false
-      raw_headers
-    end
-  end
-
-  # :call-seq:
-  #   csv.return_headers? -> true or false
-  #
-  # Returns the value that determines whether headers are to be returned; used for parsing;
-  # see {Option +return_headers+}[#class-CSV-label-Option+return_headers]:
-  #   CSV.new('').return_headers? # => false
-  def return_headers?
-    parser.return_headers?
-  end
-
-  # :call-seq:
-  #   csv.write_headers? -> true or false
-  #
-  # Returns the value that determines whether headers are to be written; used for generating;
-  # see {Option +write_headers+}[#class-CSV-label-Option+write_headers]:
-  #   CSV.new('').write_headers? # => nil
-  def write_headers?
-    @writer_options[:write_headers]
-  end
-
-  # :call-seq:
-  #   csv.header_converters -> array
-  #
-  # Returns an \Array containing header converters; used for parsing;
-  # see {Header Converters}[#class-CSV-label-Header+Converters]:
-  #   CSV.new('').header_converters # => []
-  #
-  # Notes that you need to call
-  # +Ractor.make_shareable(CSV::HeaderConverters)+ on the main Ractor
-  # to use this method.
-  def header_converters
-    header_fields_converter.map do |converter|
-      name = HeaderConverters.rassoc(converter)
-      name ? name.first : converter
-    end
-  end
-
-  # :call-seq:
-  #   csv.skip_blanks? -> true or false
-  #
-  # Returns the value that determines whether blank lines are to be ignored; used for parsing;
-  # see {Option +skip_blanks+}[#class-CSV-label-Option+skip_blanks]:
-  #   CSV.new('').skip_blanks? # => false
-  def skip_blanks?
-    parser.skip_blanks?
-  end
-
-  # :call-seq:
-  #   csv.force_quotes? -> true or false
-  #
-  # Returns the value that determines whether all output fields are to be quoted;
-  # used for generating;
-  # see {Option +force_quotes+}[#class-CSV-label-Option+force_quotes]:
-  #   CSV.new('').force_quotes? # => false
-  def force_quotes?
-    @writer_options[:force_quotes]
-  end
-
-  # :call-seq:
-  #   csv.liberal_parsing? -> true or false
-  #
-  # Returns the value that determines whether illegal input is to be handled; used for parsing;
-  # see {Option +liberal_parsing+}[#class-CSV-label-Option+liberal_parsing]:
-  #   CSV.new('').liberal_parsing? # => false
-  def liberal_parsing?
-    parser.liberal_parsing?
-  end
-
-  # :call-seq:
-  #   csv.encoding -> encoding
-  #
-  # Returns the encoding used for parsing and generating;
-  # see {Character Encodings (M17n or Multilingualization)}[#class-CSV-label-Character+Encodings+-28M17n+or+Multilingualization-29]:
-  #   CSV.new('').encoding # => #<Encoding:UTF-8>
-  attr_reader :encoding
-
-  # :call-seq:
-  #   csv.line_no -> integer
-  #
-  # Returns the count of the rows parsed or generated.
-  #
-  # Parsing:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #   CSV.open(path) do |csv|
-  #     csv.each do |row|
-  #       p [csv.lineno, row]
-  #     end
-  #   end
-  # Output:
-  #   [1, ["foo", "0"]]
-  #   [2, ["bar", "1"]]
-  #   [3, ["baz", "2"]]
-  #
-  # Generating:
-  #   CSV.generate do |csv|
-  #     p csv.lineno; csv << ['foo', 0]
-  #     p csv.lineno; csv << ['bar', 1]
-  #     p csv.lineno; csv << ['baz', 2]
-  #   end
-  # Output:
-  #   0
-  #   1
-  #   2
-  def lineno
-    if @writer
-      @writer.lineno
-    else
-      parser.lineno
-    end
-  end
-
-  # :call-seq:
-  #   csv.line -> array
-  #
-  # Returns the line most recently read:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #   CSV.open(path) do |csv|
-  #     csv.each do |row|
-  #       p [csv.lineno, csv.line]
-  #     end
-  #   end
-  # Output:
-  #   [1, "foo,0\n"]
-  #   [2, "bar,1\n"]
-  #   [3, "baz,2\n"]
-  def line
-    parser.line
-  end
-
-  ### IO and StringIO Delegation ###
-
-  extend Forwardable
-  def_delegators :@io, :binmode, :close, :close_read, :close_write,
-                       :closed?, :external_encoding, :fcntl,
-                       :fileno, :flush, :fsync, :internal_encoding,
-                       :isatty, :pid, :pos, :pos=, :reopen,
-                       :seek, :string, :sync, :sync=, :tell,
-                       :truncate, :tty?
-
-  def binmode?
-    if @io.respond_to?(:binmode?)
-      @io.binmode?
-    else
-      false
-    end
-  end
-
-  def flock(*args)
-    raise NotImplementedError unless @io.respond_to?(:flock)
-    @io.flock(*args)
-  end
-
-  def ioctl(*args)
-    raise NotImplementedError unless @io.respond_to?(:ioctl)
-    @io.ioctl(*args)
-  end
-
-  def path
-    @io.path if @io.respond_to?(:path)
-  end
-
-  def stat(*args)
-    raise NotImplementedError unless @io.respond_to?(:stat)
-    @io.stat(*args)
-  end
-
-  def to_i
-    raise NotImplementedError unless @io.respond_to?(:to_i)
-    @io.to_i
-  end
-
-  def to_io
-    @io.respond_to?(:to_io) ? @io.to_io : @io
-  end
-
-  def eof?
-    return false if @eof_error
-    begin
-      parser_enumerator.peek
-      false
-    rescue MalformedCSVError => error
-      @eof_error = error
-      false
-    rescue StopIteration
-      true
-    end
-  end
-  alias_method :eof, :eof?
-
-  # Rewinds the underlying IO object and resets CSV's lineno() counter.
-  def rewind
-    @parser = nil
-    @parser_enumerator = nil
-    @eof_error = nil
-    @writer.rewind if @writer
-    @io.rewind
-  end
-
-  ### End Delegation ###
-
-  # :call-seq:
-  #   csv << row -> self
-  #
-  # Appends a row to +self+.
-  #
-  # - Argument +row+ must be an \Array object or a CSV::Row object.
-  # - The output stream must be open for writing.
-  #
-  # ---
-  #
-  # Append Arrays:
-  #   CSV.generate do |csv|
-  #     csv << ['foo', 0]
-  #     csv << ['bar', 1]
-  #     csv << ['baz', 2]
-  #   end # => "foo,0\nbar,1\nbaz,2\n"
-  #
-  # Append CSV::Rows:
-  #   headers = []
-  #   CSV.generate do |csv|
-  #     csv << CSV::Row.new(headers, ['foo', 0])
-  #     csv << CSV::Row.new(headers, ['bar', 1])
-  #     csv << CSV::Row.new(headers, ['baz', 2])
-  #   end # => "foo,0\nbar,1\nbaz,2\n"
-  #
-  # Headers in CSV::Row objects are not appended:
-  #   headers = ['Name', 'Count']
-  #   CSV.generate do |csv|
-  #     csv << CSV::Row.new(headers, ['foo', 0])
-  #     csv << CSV::Row.new(headers, ['bar', 1])
-  #     csv << CSV::Row.new(headers, ['baz', 2])
-  #   end # => "foo,0\nbar,1\nbaz,2\n"
-  #
-  # ---
-  #
-  # Raises an exception if +row+ is not an \Array or \CSV::Row:
-  #   CSV.generate do |csv|
-  #     # Raises NoMethodError (undefined method `collect' for :foo:Symbol)
-  #     csv << :foo
-  #   end
-  #
-  # Raises an exception if the output stream is not opened for writing:
-  #   path = 't.csv'
-  #   File.write(path, '')
-  #   File.open(path) do |file|
-  #     CSV.open(file) do |csv|
-  #       # Raises IOError (not opened for writing)
-  #       csv << ['foo', 0]
-  #     end
-  #   end
-  def <<(row)
-    writer << row
-    self
-  end
-  alias_method :add_row, :<<
-  alias_method :puts,    :<<
-
-  # :call-seq:
-  #   convert(converter_name) -> array_of_procs
-  #   convert {|field, field_info| ... } -> array_of_procs
-  #
-  # - With no block, installs a field converter (a \Proc).
-  # - With a block, defines and installs a custom field converter.
-  # - Returns the \Array of installed field converters.
-  #
-  # - Argument +converter_name+, if given, should be the name
-  #   of an existing field converter.
-  #
-  # See {Field Converters}[#class-CSV-label-Field+Converters].
-  # ---
-  #
-  # With no block, installs a field converter:
-  #   csv = CSV.new('')
-  #   csv.convert(:integer)
-  #   csv.convert(:float)
-  #   csv.convert(:date)
-  #   csv.converters # => [:integer, :float, :date]
-  #
-  # ---
-  #
-  # The block, if given, is called for each field:
-  # - Argument +field+ is the field value.
-  # - Argument +field_info+ is a CSV::FieldInfo object
-  #   containing details about the field.
-  #
-  # The examples here assume the prior execution of:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #
-  # Example giving a block:
-  #   csv = CSV.open(path)
-  #   csv.convert {|field, field_info| p [field, field_info]; field.upcase }
-  #   csv.read # => [["FOO", "0"], ["BAR", "1"], ["BAZ", "2"]]
-  #
-  # Output:
-  #   ["foo", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
-  #   ["0", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
-  #   ["bar", #<struct CSV::FieldInfo index=0, line=2, header=nil>]
-  #   ["1", #<struct CSV::FieldInfo index=1, line=2, header=nil>]
-  #   ["baz", #<struct CSV::FieldInfo index=0, line=3, header=nil>]
-  #   ["2", #<struct CSV::FieldInfo index=1, line=3, header=nil>]
-  #
-  # The block need not return a \String object:
-  #   csv = CSV.open(path)
-  #   csv.convert {|field, field_info| field.to_sym }
-  #   csv.read # => [[:foo, :"0"], [:bar, :"1"], [:baz, :"2"]]
-  #
-  # If +converter_name+ is given, the block is not called:
-  #   csv = CSV.open(path)
-  #   csv.convert(:integer) {|field, field_info| fail 'Cannot happen' }
-  #   csv.read # => [["foo", 0], ["bar", 1], ["baz", 2]]
-  #
-  # ---
-  #
-  # Raises a parse-time exception if +converter_name+ is not the name of a built-in
-  # field converter:
-  #   csv = CSV.open(path)
-  #   csv.convert(:nosuch) => [nil]
-  #   # Raises NoMethodError (undefined method `arity' for nil:NilClass)
-  #   csv.read
-  def convert(name = nil, &converter)
-    parser_fields_converter.add_converter(name, &converter)
-  end
-
-  # :call-seq:
-  #   header_convert(converter_name) -> array_of_procs
-  #   header_convert {|header, field_info| ... } -> array_of_procs
-  #
-  # - With no block, installs a header converter (a \Proc).
-  # - With a block, defines and installs a custom header converter.
-  # - Returns the \Array of installed header converters.
-  #
-  # - Argument +converter_name+, if given, should be the name
-  #   of an existing header converter.
-  #
-  # See {Header Converters}[#class-CSV-label-Header+Converters].
-  # ---
-  #
-  # With no block, installs a header converter:
-  #   csv = CSV.new('')
-  #   csv.header_convert(:symbol)
-  #   csv.header_convert(:downcase)
-  #   csv.header_converters # => [:symbol, :downcase]
-  #
-  # ---
-  #
-  # The block, if given, is called for each header:
-  # - Argument +header+ is the header value.
-  # - Argument +field_info+ is a CSV::FieldInfo object
-  #   containing details about the header.
-  #
-  # The examples here assume the prior execution of:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #
-  # Example giving a block:
-  #   csv = CSV.open(path, headers: true)
-  #   csv.header_convert {|header, field_info| p [header, field_info]; header.upcase }
-  #   table = csv.read
-  #   table # => #<CSV::Table mode:col_or_row row_count:4>
-  #   table.headers # => ["NAME", "VALUE"]
-  #
-  # Output:
-  #   ["Name", #<struct CSV::FieldInfo index=0, line=1, header=nil>]
-  #   ["Value", #<struct CSV::FieldInfo index=1, line=1, header=nil>]
-
-  # The block need not return a \String object:
-  #   csv = CSV.open(path, headers: true)
-  #   csv.header_convert {|header, field_info| header.to_sym }
-  #   table = csv.read
-  #   table.headers # => [:Name, :Value]
-  #
-  # If +converter_name+ is given, the block is not called:
-  #   csv = CSV.open(path, headers: true)
-  #   csv.header_convert(:downcase) {|header, field_info| fail 'Cannot happen' }
-  #   table = csv.read
-  #   table.headers # => ["name", "value"]
-  # ---
-  #
-  # Raises a parse-time exception if +converter_name+ is not the name of a built-in
-  # field converter:
-  #   csv = CSV.open(path, headers: true)
-  #   csv.header_convert(:nosuch)
-  #   # Raises NoMethodError (undefined method `arity' for nil:NilClass)
-  #   csv.read
-  def header_convert(name = nil, &converter)
-    header_fields_converter.add_converter(name, &converter)
-  end
-
-  include Enumerable
-
-  # :call-seq:
-  #   csv.each -> enumerator
-  #   csv.each {|row| ...}
-  #
-  # Calls the block with each successive row.
-  # The data source must be opened for reading.
-  #
-  # Without headers:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.each do |row|
-  #     p row
-  #   end
-  # Output:
-  #   ["foo", "0"]
-  #   ["bar", "1"]
-  #   ["baz", "2"]
-  #
-  # With headers:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string, headers: true)
-  #   csv.each do |row|
-  #     p row
-  #   end
-  # Output:
-  #   <CSV::Row "Name":"foo" "Value":"0">
-  #   <CSV::Row "Name":"bar" "Value":"1">
-  #   <CSV::Row "Name":"baz" "Value":"2">
-  #
-  # ---
-  #
-  # Raises an exception if the source is not opened for reading:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.close
-  #   # Raises IOError (not opened for reading)
-  #   csv.each do |row|
-  #     p row
-  #   end
-  def each(&block)
-    return to_enum(__method__) unless block_given?
-    begin
-      while true
-        yield(parser_enumerator.next)
-      end
-    rescue StopIteration
-    end
-  end
-
-  # :call-seq:
-  #   csv.read -> array or csv_table
-  #
-  # Forms the remaining rows from +self+ into:
-  # - A CSV::Table object, if headers are in use.
-  # - An \Array of Arrays, otherwise.
-  #
-  # The data source must be opened for reading.
-  #
-  # Without headers:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #   csv = CSV.open(path)
-  #   csv.read # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-  #
-  # With headers:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   path = 't.csv'
-  #   File.write(path, string)
-  #   csv = CSV.open(path, headers: true)
-  #   csv.read # => #<CSV::Table mode:col_or_row row_count:4>
-  #
-  # ---
-  #
-  # Raises an exception if the source is not opened for reading:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.close
-  #   # Raises IOError (not opened for reading)
-  #   csv.read
-  def read
-    rows = to_a
-    if parser.use_headers?
-      Table.new(rows, headers: parser.headers)
-    else
-      rows
-    end
-  end
-  alias_method :readlines, :read
-
-  # :call-seq:
-  #   csv.header_row? -> true or false
-  #
-  # Returns +true+ if the next row to be read is a header row\;
-  # +false+ otherwise.
-  #
-  # Without headers:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.header_row? # => false
-  #
-  # With headers:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string, headers: true)
-  #   csv.header_row? # => true
-  #   csv.shift # => #<CSV::Row "Name":"foo" "Value":"0">
-  #   csv.header_row? # => false
-  #
-  # ---
-  #
-  # Raises an exception if the source is not opened for reading:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.close
-  #   # Raises IOError (not opened for reading)
-  #   csv.header_row?
-  def header_row?
-    parser.header_row?
-  end
-
-  # :call-seq:
-  #   csv.shift -> array, csv_row, or nil
-  #
-  # Returns the next row of data as:
-  # - An \Array if no headers are used.
-  # - A CSV::Row object if headers are used.
-  #
-  # The data source must be opened for reading.
-  #
-  # Without headers:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.shift # => ["foo", "0"]
-  #   csv.shift # => ["bar", "1"]
-  #   csv.shift # => ["baz", "2"]
-  #   csv.shift # => nil
-  #
-  # With headers:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string, headers: true)
-  #   csv.shift # => #<CSV::Row "Name":"foo" "Value":"0">
-  #   csv.shift # => #<CSV::Row "Name":"bar" "Value":"1">
-  #   csv.shift # => #<CSV::Row "Name":"baz" "Value":"2">
-  #   csv.shift # => nil
-  #
-  # ---
-  #
-  # Raises an exception if the source is not opened for reading:
-  #   string = "foo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string)
-  #   csv.close
-  #   # Raises IOError (not opened for reading)
-  #   csv.shift
-  def shift
-    if @eof_error
-      eof_error, @eof_error = @eof_error, nil
-      raise eof_error
-    end
-    begin
-      parser_enumerator.next
-    rescue StopIteration
-      nil
-    end
-  end
-  alias_method :gets,     :shift
-  alias_method :readline, :shift
-
-  # :call-seq:
-  #   csv.inspect -> string
-  #
-  # Returns a \String showing certain properties of +self+:
-  #   string = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   csv = CSV.new(string, headers: true)
-  #   s = csv.inspect
-  #   s # => "#<CSV io_type:StringIO encoding:UTF-8 lineno:0 col_sep:\",\" row_sep:\"\\n\" quote_char:\"\\\"\" headers:true>"
-  def inspect
-    str = ["#<", self.class.to_s, " io_type:"]
-    # show type of wrapped IO
-    if    @io == $stdout then str << "$stdout"
-    elsif @io == $stdin  then str << "$stdin"
-    elsif @io == $stderr then str << "$stderr"
-    else                      str << @io.class.to_s
-    end
-    # show IO.path(), if available
-    if @io.respond_to?(:path) and (p = @io.path)
-      str << " io_path:" << p.inspect
-    end
-    # show encoding
-    str << " encoding:" << @encoding.name
-    # show other attributes
-    ["lineno", "col_sep", "row_sep", "quote_char"].each do |attr_name|
-      if a = __send__(attr_name)
-        str << " " << attr_name << ":" << a.inspect
-      end
-    end
-    ["skip_blanks", "liberal_parsing"].each do |attr_name|
-      if a = __send__("#{attr_name}?")
-        str << " " << attr_name << ":" << a.inspect
-      end
-    end
-    _headers = headers
-    str << " headers:" << _headers.inspect if _headers
-    str << ">"
-    begin
-      str.join('')
-    rescue  # any encoding error
-      str.map do |s|
-        e = Encoding::Converter.asciicompat_encoding(s.encoding)
-        e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
-      end.join('')
-    end
-  end
-
-  private
-
-  def determine_encoding(encoding, internal_encoding)
-    # honor the IO encoding if we can, otherwise default to ASCII-8BIT
-    io_encoding = raw_encoding
-    return io_encoding if io_encoding
-
-    return Encoding.find(internal_encoding) if internal_encoding
-
-    if encoding
-      encoding, = encoding.split(":", 2) if encoding.is_a?(String)
-      return Encoding.find(encoding)
-    end
-
-    Encoding.default_internal || Encoding.default_external
-  end
-
-  def normalize_converters(converters)
-    converters ||= []
-    unless converters.is_a?(Array)
-      converters = [converters]
-    end
-    converters.collect do |converter|
-      case converter
-      when Proc # custom code block
-        [nil, converter]
-      else # by name
-        [converter, nil]
-      end
-    end
-  end
-
-  #
-  # Processes +fields+ with <tt>@converters</tt>, or <tt>@header_converters</tt>
-  # if +headers+ is passed as +true+, returning the converted field set. Any
-  # converter that changes the field into something other than a String halts
-  # the pipeline of conversion for that field. This is primarily an efficiency
-  # shortcut.
-  #
-  def convert_fields(fields, headers = false)
-    if headers
-      header_fields_converter.convert(fields, nil, 0)
-    else
-      parser_fields_converter.convert(fields, @headers, lineno)
-    end
-  end
-
-  #
-  # Returns the encoding of the internal IO object.
-  #
-  def raw_encoding
-    if @io.respond_to? :internal_encoding
-      @io.internal_encoding || @io.external_encoding
-    elsif @io.respond_to? :encoding
-      @io.encoding
-    else
-      nil
-    end
-  end
-
-  def parser_fields_converter
-    @parser_fields_converter ||= build_parser_fields_converter
-  end
-
-  def build_parser_fields_converter
-    specific_options = {
-      builtin_converters_name: :Converters,
-    }
-    options = @base_fields_converter_options.merge(specific_options)
-    build_fields_converter(@initial_converters, options)
-  end
-
-  def header_fields_converter
-    @header_fields_converter ||= build_header_fields_converter
-  end
-
-  def build_header_fields_converter
-    specific_options = {
-      builtin_converters_name: :HeaderConverters,
-      accept_nil: true,
-    }
-    options = @base_fields_converter_options.merge(specific_options)
-    build_fields_converter(@initial_header_converters, options)
-  end
-
-  def writer_fields_converter
-    @writer_fields_converter ||= build_writer_fields_converter
-  end
-
-  def build_writer_fields_converter
-    build_fields_converter(@initial_write_converters,
-                           @write_fields_converter_options)
-  end
-
-  def build_fields_converter(initial_converters, options)
-    fields_converter = FieldsConverter.new(options)
-    normalize_converters(initial_converters).each do |name, converter|
-      fields_converter.add_converter(name, &converter)
-    end
-    fields_converter
-  end
-
-  def parser
-    @parser ||= Parser.new(@io, parser_options)
-  end
-
-  def parser_options
-    @parser_options.merge(header_fields_converter: header_fields_converter,
-                          fields_converter: parser_fields_converter)
-  end
-
-  def parser_enumerator
-    @parser_enumerator ||= parser.parse
-  end
-
-  def writer
-    @writer ||= Writer.new(@io, writer_options)
-  end
-
-  def writer_options
-    @writer_options.merge(header_fields_converter: header_fields_converter,
-                          fields_converter: writer_fields_converter)
-  end
-end
-
-# Passes +args+ to CSV::instance.
-#
-#   CSV("CSV,data").read
-#     #=> [["CSV", "data"]]
-#
-# If a block is given, the instance is passed the block and the return value
-# becomes the return value of the block.
-#
-#   CSV("CSV,data") { |c|
-#     c.read.any? { |a| a.include?("data") }
-#   } #=> true
-#
-#   CSV("CSV,data") { |c|
-#     c.read.any? { |a| a.include?("zombies") }
-#   } #=> false
-#
-# CSV options may also be given.
-#
-#   io = StringIO.new
-#   CSV(io, col_sep: ";") { |csv| csv << ["a", "b", "c"] }
-#
-# This API is not Ractor-safe.
-#
-def CSV(*args, **options, &block)
-  CSV.instance(*args, **options, &block)
-end
-
-require_relative "csv/version"
-require_relative "csv/core_ext/array"
-require_relative "csv/core_ext/string"
diff --git a/lib/csv/core_ext/array.rb b/lib/csv/core_ext/array.rb
deleted file mode 100644
index 8beb06b082..0000000000
--- a/lib/csv/core_ext/array.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-class Array # :nodoc:
-  # Equivalent to CSV::generate_line(self, options)
-  #
-  #   ["CSV", "data"].to_csv
-  #     #=> "CSV,data\n"
-  def to_csv(**options)
-    CSV.generate_line(self, **options)
-  end
-end
diff --git a/lib/csv/core_ext/string.rb b/lib/csv/core_ext/string.rb
deleted file mode 100644
index 9b1d31c2a4..0000000000
--- a/lib/csv/core_ext/string.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-class String # :nodoc:
-  # Equivalent to CSV::parse_line(self, options)
-  #
-  #   "CSV,data".parse_csv
-  #     #=> ["CSV", "data"]
-  def parse_csv(**options)
-    CSV.parse_line(self, **options)
-  end
-end
diff --git a/lib/csv/csv.gemspec b/lib/csv/csv.gemspec
deleted file mode 100644
index 11c5b0f2a6..0000000000
--- a/lib/csv/csv.gemspec
+++ /dev/null
@@ -1,64 +0,0 @@
-# frozen_string_literal: true
-
-begin
-  require_relative "lib/csv/version"
-rescue LoadError
-  # for Ruby core repository
-  require_relative "version"
-end
-
-Gem::Specification.new do |spec|
-  spec.name          = "csv"
-  spec.version       = CSV::VERSION
-  spec.authors       = ["James Edward Gray II", "Kouhei Sutou"]
-  spec.email         = [nil, "[email protected]"]
-
-  spec.summary       = "CSV Reading and Writing"
-  spec.description   = "The CSV library provides a complete interface to CSV files and data. It offers tools to enable you to read and write to and from Strings or IO objects, as needed."
-  spec.homepage      = "https://github.com/ruby/csv"
-  spec.licenses      = ["Ruby", "BSD-2-Clause"]
-
-  lib_path = "lib"
-  spec.require_paths = [lib_path]
-  files = []
-  lib_dir = File.join(__dir__, lib_path)
-  if File.exist?(lib_dir)
-    Dir.chdir(lib_dir) do
-      Dir.glob("**/*.rb").each do |file|
-        files << "lib/#{file}"
-      end
-    end
-  end
-  doc_dir = File.join(__dir__, "doc")
-  if File.exist?(doc_dir)
-    Dir.chdir(doc_dir) do
-      Dir.glob("**/*.rdoc").each do |rdoc_file|
-        files << "doc/#{rdoc_file}"
-      end
-    end
-  end
-  spec.files = files
-  spec.rdoc_options.concat(["--main", "README.md"])
-  rdoc_files = [
-    "LICENSE.txt",
-    "NEWS.md",
-    "README.md",
-  ]
-  recipes_dir = File.join(doc_dir, "csv", "recipes")
-  if File.exist?(recipes_dir)
-    Dir.chdir(recipes_dir) do
-      Dir.glob("**/*.rdoc").each do |recipe_file|
-        rdoc_files << "doc/csv/recipes/#{recipe_file}"
-      end
-    end
-  end
-  spec.extra_rdoc_files = rdoc_files
-
-  spec.required_ruby_version = ">= 2.5.0"
-
-  # spec.add_dependency "stringio", ">= 0.1.3"
-  spec.add_development_dependency "bundler"
-  spec.add_development_dependency "rake"
-  spec.add_development_dependency "benchmark_driver"
-  spec.add_development_dependency "test-unit", ">= 3.4.8"
-end
diff --git a/lib/csv/fields_converter.rb b/lib/csv/fields_converter.rb
deleted file mode 100644
index d15977d379..0000000000
--- a/lib/csv/fields_converter.rb
+++ /dev/null
@@ -1,89 +0,0 @@
-# frozen_string_literal: true
-
-class CSV
-  # Note: Don't use this class directly. This is an internal class.
-  class FieldsConverter
-    include Enumerable
-    #
-    # A CSV::FieldsConverter is a data structure for storing the
-    # fields converter properties to be passed as a parameter
-    # when parsing a new file (e.g. CSV::Parser.new(@io, parser_options))
-    #
-
-    def initialize(options={})
-      @converters = []
-      @nil_value = options[:nil_value]
-      @empty_value = options[:empty_value]
-      @empty_value_is_empty_string = (@empty_value == "")
-      @accept_nil = options[:accept_nil]
-      @builtin_converters_name = options[:builtin_converters_name]
-      @need_static_convert = need_static_convert?
-    end
-
-    def add_converter(name=nil, &converter)
-      if name.nil?  # custom converter
-        @converters << converter
-      else          # named converter
-        combo = builtin_converters[name]
-        case combo
-        when Array  # combo converter
-          combo.each do |sub_name|
-            add_converter(sub_name)
-          end
-        else        # individual named converter
-          @converters << combo
-        end
-      end
-    end
-
-    def each(&block)
-      @converters.each(&block)
-    end
-
-    def empty?
-      @converters.empty?
-    end
-
-    def convert(fields, headers, lineno, quoted_fields)
-      return fields unless need_convert?
-
-      fields.collect.with_index do |field, index|
-        if field.nil?
-          field = @nil_value
-        elsif field.is_a?(String) and field.empty?
-          field = @empty_value unless @empty_value_is_empty_string
-        end
-        @converters.each do |converter|
-          break if field.nil? and @accept_nil
-          if converter.arity == 1  # straight field converter
-            field = converter[field]
-          else                     # FieldInfo converter
-            if headers
-              header = headers[index]
-            else
-              header = nil
-            end
-            quoted = quoted_fields[index]
-            field = converter[field, FieldInfo.new(index, lineno, header, quoted)]
-          end
-          break unless field.is_a?(String)  # short-circuit pipeline for speed
-        end
-        field  # final state of each field, converted or original
-      end
-    end
-
-    private
-    def need_static_convert?
-      not (@nil_value.nil? and @empty_value_is_empty_string)
-    end
-
-    def need_convert?
-      @need_static_convert or
-        (not @converters.empty?)
-    end
-
-    def builtin_converters
-      @builtin_converters ||= ::CSV.const_get(@builtin_converters_name)
-    end
-  end
-end
diff --git a/lib/csv/input_record_separator.rb b/lib/csv/input_record_separator.rb
deleted file mode 100644
index 7a99343c0c..0000000000
--- a/lib/csv/input_record_separator.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require "English"
-require "stringio"
-
-class CSV
-  module InputRecordSeparator
-    class << self
-      if RUBY_VERSION >= "3.0.0"
-        def value
-          "\n"
-        end
-      else
-        def value
-          $INPUT_RECORD_SEPARATOR
-        end
-      end
-    end
-  end
-end
diff --git a/lib/csv/parser.rb b/lib/csv/parser.rb
deleted file mode 100644
index 4da87fbac8..0000000000
--- a/lib/csv/parser.rb
+++ /dev/null
@@ -1,1288 +0,0 @@
-# frozen_string_literal: true
-
-require "strscan"
-
-require_relative "input_record_separator"
-require_relative "row"
-require_relative "table"
-
-class CSV
-  # Note: Don't use this class directly. This is an internal class.
-  class Parser
-    #
-    # A CSV::Parser is m17n aware. The parser works in the Encoding of the IO
-    # or String object being read from or written to. Your data is never transcoded
-    # (unless you ask Ruby to transcode it for you) and will literally be parsed in
-    # the Encoding it is in. Thus CSV will return Arrays or Rows of Strings in the
-    # Encoding of your data. This is accomplished by transcoding the parser itself
-    # into your Encoding.
-    #
-
-    # Raised when encoding is invalid.
-    class InvalidEncoding < StandardError
-    end
-
-    # Raised when unexpected case is happen.
-    class UnexpectedError < StandardError
-    end
-
-    #
-    # CSV::Scanner receives a CSV output, scans it and return the content.
-    # It also controls the life cycle of the object with its methods +keep_start+,
-    # +keep_end+, +keep_back+, +keep_drop+.
-    #
-    # Uses StringScanner (the official strscan gem). Strscan provides lexical
-    # scanning operations on a String. We inherit its object and take advantage
-    # on the methods. For more information, please visit:
-    # https://ruby-doc.org/stdlib-2.6.1/libdoc/strscan/rdoc/StringScanner.html
-    #
-    class Scanner < StringScanner
-      alias_method :scan_all, :scan
-
-      def initialize(*args)
-        super
-        @keeps = []
-      end
-
-      def each_line(row_separator)
-        position = pos
-        rest.each_line(row_separator) do |line|
-          position += line.bytesize
-          self.pos = position
-          yield(line)
-        end
-      end
-
-      def keep_start
-        @keeps.push(pos)
-      end
-
-      def keep_end
-        start = @keeps.pop
-        string.byteslice(start, pos - start)
-      end
-
-      def keep_back
-        self.pos = @keeps.pop
-      end
-
-      def keep_drop
-        @keeps.pop
-      end
-    end
-
-    #
-    # CSV::InputsScanner receives IO inputs, encoding and the chunk_size.
-    # It also controls the life cycle of the object with its methods +keep_start+,
-    # +keep_end+, +keep_back+, +keep_drop+.
-    #
-    # CSV::InputsScanner.scan() tries to match with pattern at the current position.
-    # If there's a match, the scanner advances the "scan pointer" and returns the matched string.
-    # Otherwise, the scanner returns nil.
-    #
-    # CSV::InputsScanner.rest() returns the "rest" of the string (i.e. everything after the scan pointer).
-    # If there is no more data (eos? = true), it returns "".
-    #
-    class InputsScanner
-      def initialize(inputs, encoding, row_separator, chunk_size: 8192)
-        @inputs = inputs.dup
-        @encoding = encoding
-        @row_separator = row_separator
-        @chunk_size = chunk_size
-        @last_scanner = @inputs.empty?
-        @keeps = []
-        read_chunk
-      end
-
-      def each_line(row_separator)
-        return enum_for(__method__, row_separator) unless block_given?
-        buffer = nil
-        input = @scanner.rest
-        position = @scanner.pos
-        offset = 0
-        n_row_separator_chars = row_separator.size
-        # trace(__method__, :start, input)
-        while true
-          input.each_line(row_separator) do |line|
-            @scanner.pos += line.bytesize
-            if buffer
-              if n_row_separator_chars == 2 and
-                buffer.end_with?(row_separator[0]) and
-                line.start_with?(row_separator[1])
-                buffer << line[0]
-                line = line[1..-1]
-                position += buffer.bytesize + offset
-                @scanner.pos = position
-                offset = 0
-                yield(buffer)
-                buffer = nil
-                next if line.empty?
-              else
-                buffer << line
-                line = buffer
-                buffer = nil
-              end
-            end
-            if line.end_with?(row_separator)
-              position += line.bytesize + offset
-              @scanner.pos = position
-              offset = 0
-              yield(line)
-            else
-              buffer = line
-            end
-          end
-          break unless read_chunk
-          input = @scanner.rest
-          position = @scanner.pos
-          offset = -buffer.bytesize if buffer
-        end
-        yield(buffer) if buffer
-      end
-
-      def scan(pattern)
-        # trace(__method__, pattern, :start)
-        value = @scanner.scan(pattern)
-        # trace(__method__, pattern, :done, :last, value) if @last_scanner
-        return value if @last_scanner
-
-        read_chunk if value and @scanner.eos?
-        # trace(__method__, pattern, :done, value)
-        value
-      end
-
-      def scan_all(pattern)
-        # trace(__method__, pattern, :start)
-        value = @scanner.scan(pattern)
-        # trace(__method__, pattern, :done, :last, value) if @last_scanner
-        return value if @last_scanner
-
-        # trace(__method__, pattern, :done, :nil) if value.nil?
-        return nil if value.nil?
-        while @scanner.eos? and read_chunk and (sub_value = @scanner.scan(pattern))
-          # trace(__method__, pattern, :sub, sub_value)
-          value << sub_value
-        end
-        # trace(__method__, pattern, :done, value)
-        value
-      end
-
-      def eos?
-        @scanner.eos?
-      end
-
-      def keep_start
-        # trace(__method__, :start)
-        adjust_last_keep
-        @keeps.push([@scanner, @scanner.pos, nil])
-        # trace(__method__, :done)
-      end
-
-      def keep_end
-        # trace(__method__, :start)
-        scanner, start, buffer = @keeps.pop
-        if scanner == @scanner
-          keep = @scanner.string.byteslice(start, @scanner.pos - start)
-        else
-          keep = @scanner.string.byteslice(0, @scanner.pos)
-        end
-        if buffer
-          buffer << keep
-          keep = buffer
-        end
-        # trace(__method__, :done, keep)
-        keep
-      end
-
-      def keep_back
-        # trace(__method__, :start)
-        scanner, start, buffer = @keeps.pop
-        if buffer
-          # trace(__method__, :rescan, start, buffer)
-          string = @scanner.string
-          if scanner == @scanner
-            keep = string.byteslice(start,
-                                    string.bytesize - @scanner.pos - start)
-          else
-            keep = string
-          end
-          if keep and not keep.empty?
-            @inputs.unshift(StringIO.new(keep))
-            @last_scanner = false
-          end
-          @scanner = StringScanner.new(buffer)
-        else
-          if @scanner != scanner
-            message = "scanners are different but no buffer: "
-            message += "#{@scanner.inspect}(#{@scanner.object_id}): "
-            message += "#{scanner.inspect}(#{scanner.object_id})"
-            raise UnexpectedError, message
-          end
-          # trace(__method__, :repos, start, buffer)
-          @scanner.pos = start
-        end
-        read_chunk if @scanner.eos?
-      end
-
-      def keep_drop
-        _, _, buffer = @keeps.pop
-        # trace(__method__, :done, :empty) unless buffer
-        return unless buffer
-
-        last_keep = @keeps.last
-        # trace(__method__, :done, :no_last_keep) unless last_keep
-        return unless last_keep
-
-        if last_keep[2]
-          last_keep[2] << buffer
-        else
-          last_keep[2] = buffer
-        end
-        # trace(__method__, :done)
-      end
-
-      def rest
-        @scanner.rest
-      end
-
-      def check(pattern)
-        @scanner.check(pattern)
-      end
-
-      private
-      def trace(*args)
-        pp([*args, @scanner, @scanner&.string, @scanner&.pos, @keeps])
-      end
-
-      def adjust_last_keep
-        # trace(__method__, :start)
-
-        keep = @keeps.last
-        # trace(__method__, :done, :empty) if keep.nil?
-        return if keep.nil?
-
-        scanner, start, buffer = keep
-        string = @scanner.string
-        if @scanner != scanner
-          start = 0
-        end
-        if start == 0 and @scanner.eos?
-          keep_data = string
-        else
-          keep_data = string.byteslice(start, @scanner.pos - start)
-        end
-        if keep_data
-          if buffer
-            buffer << keep_data
-          else
-            keep[2] = keep_data.dup
-          end
-        end
-
-        # trace(__method__, :done)
-      end
-
-      def read_chunk
-        return false if @last_scanner
-
-        adjust_last_keep
-
-        input = @inputs.first
-        case input
-        when StringIO
-          string = input.read
-          raise InvalidEncoding unless string.valid_encoding?
-          # trace(__method__, :stringio, string)
-          @scanner = StringScanner.new(string)
-          @inputs.shift
-          @last_scanner = @inputs.empty?
-          true
-        else
-          chunk = input.gets(@row_separator, @chunk_size)
-          if chunk
-            raise InvalidEncoding unless chunk.valid_encoding?
-            # trace(__method__, :chunk, chunk)
-            @scanner = StringScanner.new(chunk)
-            if input.respond_to?(:eof?) and input.eof?
-              @inputs.shift
-              @last_scanner = @inputs.empty?
-            end
-            true
-          else
-            # trace(__method__, :no_chunk)
-            @scanner = StringScanner.new("".encode(@encoding))
-            @inputs.shift
-            @last_scanner = @inputs.empty?
-            if @last_scanner
-              false
-            else
-              read_chunk
-            end
-          end
-        end
-      end
-    end
-
-    def initialize(input, options)
-      @input = input
-      @options = options
-      @samples = []
-
-      prepare
-    end
-
-    def column_separator
-      @column_separator
-    end
-
-    def row_separator
-      @row_separator
-    end
-
-    def quote_character
-      @quote_character
-    end
-
-    def field_size_limit
-      @max_field_size&.succ
-    end
-
-    def max_field_size
-      @max_field_size
-    end
-
-    def skip_lines
-      @skip_lines
-    end
-
-    def unconverted_fields?
-      @unconverted_fields
-    end
-
-    def headers
-      @headers
-    end
-
-    def header_row?
-      @use_headers and @headers.nil?
-    end
-
-    def return_headers?
-      @return_headers
-    end
-
-    def skip_blanks?
-      @skip_blanks
-    end
-
-    def liberal_parsing?
-      @liberal_parsing
-    end
-
-    def lineno
-      @lineno
-    end
-
-    def line
-      last_line
-    end
-
-    def parse(&block)
-      return to_enum(__method__) unless block_given?
-
-      if @return_headers and @headers and @raw_headers
-        headers = Row.new(@headers, @raw_headers, true)
-        if @unconverted_fields
-          headers = add_unconverted_fields(headers, [])
-        end
-        yield headers
-      end
-
-      begin
-        @scanner ||= build_scanner
-        if quote_character.nil?
-          parse_no_quote(&block)
-        elsif @need_robust_parsing
-          parse_quotable_robust(&block)
-        else
-          parse_quotable_loose(&block)
-        end
-      rescue InvalidEncoding
-        if @scanner
-          ignore_broken_line
-          lineno = @lineno
-        else
-          lineno = @lineno + 1
-        end
-        raise InvalidEncodingError.new(@encoding, lineno)
-      rescue UnexpectedError => error
-        if @scanner
-          ignore_broken_line
-          lineno = @lineno
-        else
-          lineno = @lineno + 1
-        end
-        message = "This should not be happen: #{error.message}: "
-        message += "Please report this to https://github.com/ruby/csv/issues"
-        raise MalformedCSVError.new(message, lineno)
-      end
-    end
-
-    def use_headers?
-      @use_headers
-    end
-
-    private
-    # A set of tasks to prepare the file in order to parse it
-    def prepare
-      prepare_variable
-      prepare_quote_character
-      prepare_backslash
-      prepare_skip_lines
-      prepare_strip
-      prepare_separators
-      validate_strip_and_col_sep_options
-      prepare_quoted
-      prepare_unquoted
-      prepare_line
-      prepare_header
-      prepare_parser
-    end
-
-    def prepare_variable
-      @need_robust_parsing = false
-      @encoding = @options[:encoding]
-      liberal_parsing = @options[:liberal_parsing]
-      if liberal_parsing
-        @liberal_parsing = true
-        if liberal_parsing.is_a?(Hash)
-          @double_quote_outside_quote =
-            liberal_parsing[:double_quote_outside_quote]
-          @backslash_quote = liberal_parsing[:backslash_quote]
-        else
-          @double_quote_outside_quote = false
-          @backslash_quote = false
-        end
-        @need_robust_parsing = true
-      else
-        @liberal_parsing = false
-        @backslash_quote = false
-      end
-      @unconverted_fields = @options[:unconverted_fields]
-      @max_field_size = @options[:max_field_size]
-      @skip_blanks = @options[:skip_blanks]
-      @fields_converter = @options[:fields_converter]
-      @header_fields_converter = @options[:header_fields_converter]
-    end
-
-    def prepare_quote_character
-      @quote_character = @options[:quote_character]
-      if @quote_character.nil?
-        @escaped_quote_character = nil
-        @escaped_quote = nil
-      else
-        @quote_character = @quote_character.to_s.encode(@encoding)
-        if @quote_character.length != 1
-          message = ":quote_char has to be nil or a single character String"
-          raise ArgumentError, message
-        end
-        @escaped_quote_character = Regexp.escape(@quote_character)
-        @escaped_quote = Regexp.new(@escaped_quote_character)
-      end
-    end
-
-    def prepare_backslash
-      return unless @backslash_quote
-
-      @backslash_character = "\\".encode(@encoding)
-
-      @escaped_backslash_character = Regexp.escape(@backslash_character)
-      @escaped_backslash = Regexp.new(@escaped_backslash_character)
-      if @quote_character.nil?
-        @backslash_quote_character = nil
-      else
-        @backslash_quote_character =
-          @backslash_character + @escaped_quote_character
-      end
-    end
-
-    def prepare_skip_lines
-      skip_lines = @options[:skip_lines]
-      case skip_lines
-      when String
-        @skip_lines = skip_lines.encode(@encoding)
-      when Regexp, nil
-        @skip_lines = skip_lines
-      else
-        unless skip_lines.respond_to?(:match)
-          message =
-            ":skip_lines has to respond to \#match: #{skip_lines.inspect}"
-          raise ArgumentError, message
-        end
-        @skip_lines = skip_lines
-      end
-    end
-
-    def prepare_strip
-      @strip = @options[:strip]
-      @escaped_strip = nil
-      @strip_value = nil
-      @rstrip_value = nil
-      if @strip.is_a?(String)
-        case @strip.length
-        when 0
-          raise ArgumentError, ":strip must not be an empty String"
-        when 1
-          # ok
-        else
-          raise ArgumentError, ":strip doesn't support 2 or more characters yet"
-        end
-        @strip = @strip.encode(@encoding)
-        @escaped_strip = Regexp.escape(@strip)
-        if @quote_character
-          @strip_value = Regexp.new(@escaped_strip +
-                                    "+".encode(@encoding))
-          @rstrip_value = Regexp.new(@escaped_strip +
-                                     "+\\z".encode(@encoding))
-        end
-        @need_robust_parsing = true
-      elsif @strip
-        strip_values = " \t\f\v"
-        @escaped_strip = strip_values.encode(@encoding)
-        if @quote_character
-          @strip_value = Regexp.new("[#{strip_values}]+".encode(@encoding))
-          @rstrip_value = Regexp.new("[#{strip_values}]+\\z".encode(@encoding))
-        end
-        @need_robust_parsing = true
-      end
-    end
-
-    begin
-      StringScanner.new("x").scan("x")
-    rescue TypeError
-      STRING_SCANNER_SCAN_ACCEPT_STRING = false
-    else
-      STRING_SCANNER_SCAN_ACCEPT_STRING = true
-    end
-
-    def prepare_separators
-      column_separator = @options[:column_separator]
-      @column_separator = column_separator.to_s.encode(@encoding)
-      if @column_separator.size < 1
-        message = ":col_sep must be 1 or more characters: "
-        message += column_separator.inspect
-        raise ArgumentError, message
-      end
-      @row_separator =
-        resolve_row_separator(@options[:row_separator]).encode(@encoding)
-
-      @escaped_column_separator = Regexp.escape(@column_separator)
-      @escaped_first_column_separator = Regexp.escape(@column_separator[0])
-      if @column_separator.size > 1
-        @column_end = Regexp.new(@escaped_column_separator)
-        @column_ends = @column_separator.each_char.collect do |char|
-          Regexp.new(Regexp.escape(char))
-        end
-        @first_column_separators = Regexp.new(@escaped_first_column_separator +
-                                              "+".encode(@encoding))
-      else
-        if STRING_SCANNER_SCAN_ACCEPT_STRING
-          @column_end = @column_separator
-        else
-          @column_end = Regexp.new(@escaped_column_separator)
-        end
-        @column_ends = nil
-        @first_column_separators = nil
-      end
-
-      escaped_row_separator = Regexp.escape(@row_separator)
-      @row_end = Regexp.new(escaped_row_separator)
-      if @row_separator.size > 1
-        @row_ends = @row_separator.each_char.collect do |char|
-          Regexp.new(Regexp.escape(char))
-        end
-      else
-        @row_ends = nil
-      end
-
-      @cr = "\r".encode(@encoding)
-      @lf = "\n".encode(@encoding)
-      @line_end = Regexp.new("\r\n|\n|\r".encode(@encoding))
-      @not_line_end = Regexp.new("[^\r\n]+".encode(@encoding))
-    end
-
-    # This method verifies that there are no (obvious) ambiguities with the
-    # provided +col_sep+ and +strip+ parsing options. For example, if +col_sep+
-    # and +strip+ were both equal to +\t+, then there would be no clear way to
-    # parse the input.
-    def validate_strip_and_col_sep_options
-      return unless @strip
-
-      if @strip.is_a?(String)
-        if @column_separator.start_with?(@strip) || @column_separator.end_with?(@strip)
-          raise ArgumentError,
-                "The provided strip (#{@escaped_strip}) and " \
-                "col_sep (#{@escaped_column_separator}) options are incompatible."
-        end
-      else
-        if Regexp.new("\\A[#{@escaped_strip}]|[#{@escaped_strip}]\\z").match?(@column_separator)
-          raise ArgumentError,
-                "The provided strip (true) and " \
-                "col_sep (#{@escaped_column_separator}) options are incompatible."
-        end
-      end
-    end
-
-    def prepare_quoted
-      if @quote_character
-        @quotes = Regexp.new(@escaped_quote_character +
-                             "+".encode(@encoding))
-        no_quoted_values = @escaped_quote_character.dup
-        if @backslash_quote
-          no_quoted_values << @escaped_backslash_character
-        end
-        @quoted_value = Regexp.new("[^".encode(@encoding) +
-                                   no_quoted_values +
-                                   "]+".encode(@encoding))
-      end
-      if @escaped_strip
-        @split_column_separator = Regexp.new(@escaped_strip +
-                                             "*".encode(@encoding) +
-                                             @escaped_column_separator +
-                                             @escaped_strip +
-                                             "*".encode(@encoding))
-      else
-        if @column_separator == " ".encode(@encoding)
-          @split_column_separator = Regexp.new(@escaped_column_separator)
-        else
-          @split_column_separator = @column_separator
-        end
-      end
-    end
-
-    def prepare_unquoted
-      return if @quote_character.nil?
-
-      no_unquoted_values = "\r\n".encode(@encoding)
-      no_unquoted_values << @escaped_first_column_separator
-      unless @liberal_parsing
-        no_unquoted_values << @escaped_quote_character
-      end
-      @unquoted_value = Regexp.new("[^".encode(@encoding) +
-                                   no_unquoted_values +
-                                   "]+".encode(@encoding))
-    end
-
-    def resolve_row_separator(separator)
-      if separator == :auto
-        cr = "\r".encode(@encoding)
-        lf = "\n".encode(@encoding)
-        if @input.is_a?(StringIO)
-          pos = @input.pos
-          separator = detect_row_separator(@input.read, cr, lf)
-          @input.seek(pos)
-        elsif @input.respond_to?(:gets)
-          if @input.is_a?(File)
-            chunk_size = 32 * 1024
-          else
-            chunk_size = 1024
-          end
-          begin
-            while separator == :auto
-              #
-              # if we run out of data, it's probably a single line
-              # (ensure will set default value)
-              #
-              break unless sample = @input.gets(nil, chunk_size)
-
-              # extend sample if we're unsure of the line ending
-              if sample.end_with?(cr)
-                sample << (@input.gets(nil, 1) || "")
-              end
-
-              @samples << sample
-
-              separator = detect_row_separator(sample, cr, lf)
-            end
-          rescue IOError
-            # do nothing:  ensure will set default
-          end
-        end
-        separator = InputRecordSeparator.value if separator == :auto
-      end
-      separator.to_s.encode(@encoding)
-    end
-
-    def detect_row_separator(sample, cr, lf)
-      lf_index = sample.index(lf)
-      if lf_index
-        cr_index = sample[0, lf_index].index(cr)
-      else
-        cr_index = sample.index(cr)
-      end
-      if cr_index and lf_index
-        if cr_index + 1 == lf_index
-          cr + lf
-        elsif cr_index < lf_index
-          cr
-        else
-          lf
-        end
-      elsif cr_index
-        cr
-      elsif lf_index
-        lf
-      else
-        :auto
-      end
-    end
-
-    def prepare_line
-      @lineno = 0
-      @last_line = nil
-      @scanner = nil
-    end
-
-    def last_line
-      if @scanner
-        @last_line ||= @scanner.keep_end
-      else
-        @last_line
-      end
-    end
-
-    def prepare_header
-      @return_headers = @options[:return_headers]
-
-      headers = @options[:headers]
-      case headers
-      when Array
-        @raw_headers = headers
-        quoted_fields = [false] * @raw_headers.size
-        @use_headers = true
-      when String
-        @raw_headers, quoted_fields = parse_headers(headers)
-        @use_headers = true
-      when nil, false
-        @raw_headers = nil
-        @use_headers = false
-      else
-        @raw_headers = nil
-        @use_headers = true
-      end
-      if @raw_headers
-        @headers = adjust_headers(@raw_headers, quoted_fields)
-      else
-        @headers = nil
-      end
-    end
-
-    def parse_headers(row)
-      quoted_fields = []
-      converter = lambda do |field, info|
-        quoted_fields << info.quoted?
-        field
-      end
-      headers = CSV.parse_line(row,
-                               col_sep:    @column_separator,
-                               row_sep:    @row_separator,
-                               quote_char: @quote_character,
-                               converters: [converter])
-      [headers, quoted_fields]
-    end
-
-    def adjust_headers(headers, quoted_fields)
-      adjusted_headers = @header_fields_converter.convert(headers, nil, @lineno, quoted_fields)
-      adjusted_headers.each {|h| h.freeze if h.is_a? String}
-      adjusted_headers
-    end
-
-    def prepare_parser
-      @may_quoted = may_quoted?
-    end
-
-    def may_quoted?
-      return false if @quote_character.nil?
-
-      if @input.is_a?(StringIO)
-        pos = @input.pos
-        sample = @input.read
-        @input.seek(pos)
-      else
-        return false if @samples.empty?
-        sample = @samples.first
-      end
-      sample[0, 128].index(@quote_character)
-    end
-
-    class UnoptimizedStringIO # :nodoc:
-      def initialize(string)
-        @io = StringIO.new(string, "rb:#{string.encoding}")
-      end
-
-      def gets(*args)
-        @io.gets(*args)
-      end
-
-      def each_line(*args, &block)
-        @io.each_line(*args, &block)
-      end
-
-      def eof?
-        @io.eof?
-      end
-    end
-
-    SCANNER_TEST = (ENV["CSV_PARSER_SCANNER_TEST"] == "yes")
-    if SCANNER_TEST
-      SCANNER_TEST_CHUNK_SIZE_NAME = "CSV_PARSER_SCANNER_TEST_CHUNK_SIZE"
-      SCANNER_TEST_CHUNK_SIZE_VALUE = ENV[SCANNER_TEST_CHUNK_SIZE_NAME]
-      def build_scanner
-        inputs = @samples.collect do |sample|
-          UnoptimizedStringIO.new(sample)
-        end
-        if @input.is_a?(StringIO)
-          inputs << UnoptimizedStringIO.new(@input.read)
-        else
-          inputs << @input
-        end
-        begin
-          chunk_size_value = ENV[SCANNER_TEST_CHUNK_SIZE_NAME]
-        rescue # Ractor::IsolationError
-          # Ractor on Ruby 3.0 can't read ENV value.
-          chunk_size_value = SCANNER_TEST_CHUNK_SIZE_VALUE
-        end
-        chunk_size = Integer((chunk_size_value || "1"), 10)
-        InputsScanner.new(inputs,
-                          @encoding,
-                          @row_separator,
-                          chunk_size: chunk_size)
-      end
-    else
-      def build_scanner
-        string = nil
-        if @samples.empty? and @input.is_a?(StringIO)
-          string = @input.read
-        elsif @samples.size == 1 and
-              @input != ARGF and
-              @input.respond_to?(:eof?) and
-              @input.eof?
-          string = @samples[0]
-        end
-        if string
-          unless string.valid_encoding?
-            index = string.lines(@row_separator).index do |line|
-              !line.valid_encoding?
-            end
-            if index
-              raise InvalidEncodingError.new(@encoding, @lineno + index + 1)
-            end
-          end
-          Scanner.new(string)
-        else
-          inputs = @samples.collect do |sample|
-            StringIO.new(sample)
-          end
-          inputs << @input
-          InputsScanner.new(inputs, @encoding, @row_separator)
-        end
-      end
-    end
-
-    def skip_needless_lines
-      return unless @skip_lines
-
-      until @scanner.eos?
-        @scanner.keep_start
-        line = @scanner.scan_all(@not_line_end) || "".encode(@encoding)
-        line << @row_separator if parse_row_end
-        if skip_line?(line)
-          @lineno += 1
-          @scanner.keep_drop
-        else
-          @scanner.keep_back
-          return
-        end
-      end
-    end
-
-    def skip_line?(line)
-      line = line.delete_suffix(@row_separator)
-      case @skip_lines
-      when String
-        line.include?(@skip_lines)
-      when Regexp
-        @skip_lines.match?(line)
-      else
-        @skip_lines.match(line)
-      end
-    end
-
-    def validate_field_size(field)
-      return unless @max_field_size
-      return if field.size <= @max_field_size
-      ignore_broken_line
-      message = "Field size exceeded: #{field.size} > #{@max_field_size}"
-      raise MalformedCSVError.new(message, @lineno)
-    end
-
-    def parse_no_quote(&block)
-      @scanner.each_line(@row_separator) do |line|
-        next if @skip_lines and skip_line?(line)
-        original_line = line
-        line = line.delete_suffix(@row_separator)
-
-        if line.empty?
-          next if @skip_blanks
-          row = []
-          quoted_fields = []
-        else
-          line = strip_value(line)
-          row = line.split(@split_column_separator, -1)
-          quoted_fields = [false] * row.size
-          if @max_field_size
-            row.each do |column|
-              validate_field_size(column)
-            end
-          end
-          n_columns = row.size
-          i = 0
-          while i < n_columns
-            row[i] = nil if row[i].empty?
-            i += 1
-          end
-        end
-        @last_line = original_line
-        emit_row(row, quoted_fields, &block)
-      end
-    end
-
-    def parse_quotable_loose(&block)
-      @scanner.keep_start
-      @scanner.each_line(@row_separator) do |line|
-        if @skip_lines and skip_line?(line)
-          @scanner.keep_drop
-          @scanner.keep_start
-          next
-        end
-        original_line = line
-        line = line.delete_suffix(@row_separator)
-
-        if line.empty?
-          if @skip_blanks
-            @scanner.keep_drop
-            @scanner.keep_start
-            next
-          end
-          row = []
-          quoted_fields = []
-        elsif line.include?(@cr) or line.include?(@lf)
-          @scanner.keep_back
-          @need_robust_parsing = true
-          return parse_quotable_robust(&block)
-        else
-          row = line.split(@split_column_separator, -1)
-          quoted_fields = []
-          n_columns = row.size
-          i = 0
-          while i < n_columns
-            column = row[i]
-            if column.empty?
-              quoted_fields << false
-              row[i] = nil
-            else
-              n_quotes = column.count(@quote_character)
-              if n_quotes.zero?
-                quoted_fields << false
-                # no quote
-              elsif n_quotes == 2 and
-                   column.start_with?(@quote_character) and
-                   column.end_with?(@quote_character)
-                quoted_fields << true
-                row[i] = column[1..-2]
-              else
-                @scanner.keep_back
-                @need_robust_parsing = true
-                return parse_quotable_robust(&block)
-              end
-              validate_field_size(row[i])
-            end
-            i += 1
-          end
-        end
-        @scanner.keep_drop
-        @scanner.keep_start
-        @last_line = original_line
-        emit_row(row, quoted_fields, &block)
-      end
-      @scanner.keep_drop
-    end
-
-    def parse_quotable_robust(&block)
-      row = []
-      quoted_fields = []
-      skip_needless_lines
-      start_row
-      while true
-        @quoted_column_value = false
-        @unquoted_column_value = false
-        @scanner.scan_all(@strip_value) if @strip_value
-        value = parse_column_value
-        if value
-          @scanner.scan_all(@strip_value) if @strip_value
-          validate_field_size(value)
-        end
-        if parse_column_end
-          row << value
-          quoted_fields << @quoted_column_value
-        elsif parse_row_end
-          if row.empty? and value.nil?
-            emit_row([], [], &block) unless @skip_blanks
-          else
-            row << value
-            quoted_fields << @quoted_column_value
-            emit_row(row, quoted_fields, &block)
-            row = []
-            quoted_fields = []
-          end
-          skip_needless_lines
-          start_row
-        elsif @scanner.eos?
-          break if row.empty? and value.nil?
-          row << value
-          quoted_fields << @quoted_column_value
-          emit_row(row, quoted_fields, &block)
-          break
-        else
-          if @quoted_column_value
-            if liberal_parsing? and (new_line = @scanner.check(@line_end))
-              message =
-                "Illegal end-of-line sequence outside of a quoted field " +
-                "<#{new_line.inspect}>"
-            else
-              message = "Any value after quoted field isn't allowed"
-            end
-            ignore_broken_line
-            raise MalformedCSVError.new(message, @lineno)
-          elsif @unquoted_column_value and
-                (new_line = @scanner.scan(@line_end))
-            ignore_broken_line
-            message = "Unquoted fields do not allow new line " +
-                      "<#{new_line.inspect}>"
-            raise MalformedCSVError.new(message, @lineno)
-          elsif @scanner.rest.start_with?(@quote_character)
-            ignore_broken_line
-            message = "Illegal quoting"
-            raise MalformedCSVError.new(message, @lineno)
-          elsif (new_line = @scanner.scan(@line_end))
-            ignore_broken_line
-            message = "New line must be <#{@row_separator.inspect}> " +
-                      "not <#{new_line.inspect}>"
-            raise MalformedCSVError.new(message, @lineno)
-          else
-            ignore_broken_line
-            raise MalformedCSVError.new("TODO: Meaningful message",
-                                        @lineno)
-          end
-        end
-      end
-    end
-
-    def parse_column_value
-      if @liberal_parsing
-        quoted_value = parse_quoted_column_value
-        if quoted_value
-          @scanner.scan_all(@strip_value) if @strip_value
-          unquoted_value = parse_unquoted_column_value
-          if unquoted_value
-            if @double_quote_outside_quote
-              unquoted_value = unquoted_value.gsub(@quote_character * 2,
-                                                   @quote_character)
-              if quoted_value.empty? # %Q{""...} case
-                return @quote_character + unquoted_value
-              end
-            end
-            @quote_character + quoted_value + @quote_character + unquoted_value
-          else
-            quoted_value
-          end
-        else
-          parse_unquoted_column_value
-        end
-      elsif @may_quoted
-        parse_quoted_column_value ||
-          parse_unquoted_column_value
-      else
-        parse_unquoted_column_value ||
-          parse_quoted_column_value
-      end
-    end
-
-    def parse_unquoted_column_value
-      value = @scanner.scan_all(@unquoted_value)
-      return nil unless value
-
-      @unquoted_column_value = true
-      if @first_column_separators
-        while true
-          @scanner.keep_start
-          is_column_end = @column_ends.all? do |column_end|
-            @scanner.scan(column_end)
-          end
-          @scanner.keep_back
-          break if is_column_end
-          sub_separator = @scanner.scan_all(@first_column_separators)
-          break if sub_separator.nil?
-          value << sub_separator
-          sub_value = @scanner.scan_all(@unquoted_value)
-          break if sub_value.nil?
-          value << sub_value
-        end
-      end
-      value.gsub!(@backslash_quote_character, @quote_character) if @backslash_quote
-      if @rstrip_value
-        value.gsub!(@rstrip_value, "")
-      end
-      value
-    end
-
-    def parse_quoted_column_value
-      quotes = @scanner.scan_all(@quotes)
-      return nil unless quotes
-
-      @quoted_column_value = true
-      n_quotes = quotes.size
-      if (n_quotes % 2).zero?
-        quotes[0, (n_quotes - 2) / 2]
-      else
-        value = quotes[0, n_quotes / 2]
-        while true
-          quoted_value = @scanner.scan_all(@quoted_value)
-          value << quoted_value if quoted_value
-          if @backslash_quote
-            if @scanner.scan(@escaped_backslash)
-              if @scanner.scan(@escaped_quote)
-                value << @quote_character
-              else
-                value << @backslash_character
-              end
-              next
-            end
-          end
-
-          quotes = @scanner.scan_all(@quotes)
-          unless quotes
-            ignore_broken_line
-            message = "Unclosed quoted field"
-            raise MalformedCSVError.new(message, @lineno)
-          end
-          n_quotes = quotes.size
-          if n_quotes == 1
-            break
-          else
-            value << quotes[0, n_quotes / 2]
-            break if (n_quotes % 2) == 1
-          end
-        end
-        value
-      end
-    end
-
-    def parse_column_end
-      return true if @scanner.scan(@column_end)
-      return false unless @column_ends
-
-      @scanner.keep_start
-      if @column_ends.all? {|column_end| @scanner.scan(column_end)}
-        @scanner.keep_drop
-        true
-      else
-        @scanner.keep_back
-        false
-      end
-    end
-
-    def parse_row_end
-      return true if @scanner.scan(@row_end)
-      return false unless @row_ends
-      @scanner.keep_start
-      if @row_ends.all? {|row_end| @scanner.scan(row_end)}
-        @scanner.keep_drop
-        true
-      else
-        @scanner.keep_back
-        false
-      end
-    end
-
-    def strip_value(value)
-      return value unless @strip
-      return value if value.nil?
-
-      case @strip
-      when String
-        while value.delete_prefix!(@strip)
-          # do nothing
-        end
-        while value.delete_suffix!(@strip)
-          # do nothing
-        end
-      else
-        value.strip!
-      end
-      value
-    end
-
-    def ignore_broken_line
-      @scanner.scan_all(@not_line_end)
-      @scanner.scan_all(@line_end)
-      @lineno += 1
-    end
-
-    def start_row
-      if @last_line
-        @last_line = nil
-      else
-        @scanner.keep_drop
-      end
-      @scanner.keep_start
-    end
-
-    def emit_row(row, quoted_fields, &block)
-      @lineno += 1
-
-      raw_row = row
-      if @use_headers
-        if @headers.nil?
-          @headers = adjust_headers(row, quoted_fields)
-          return unless @return_headers
-          row = Row.new(@headers, row, true)
-        else
-          row = Row.new(@headers,
-                        @fields_converter.convert(raw_row, @headers, @lineno, quoted_fields))
-        end
-      else
-        # convert fields, if needed...
-        row = @fields_converter.convert(raw_row, nil, @lineno, quoted_fields)
-      end
-
-      # inject unconverted fields and accessor, if requested...
-      if @unconverted_fields and not row.respond_to?(:unconverted_fields)
-        add_unconverted_fields(row, raw_row)
-      end
-
-      yield(row)
-    end
-
-    # This method injects an instance variable <tt>unconverted_fields</tt> into
-    # +row+ and an accessor method for +row+ called unconverted_fields().  The
-    # variable is set to the contents of +fields+.
-    def add_unconverted_fields(row, fields)
-      class << row
-        attr_reader :unconverted_fields
-      end
-      row.instance_variable_set(:@unconverted_fields, fields)
-      row
-    end
-  end
-end
diff --git a/lib/csv/row.rb b/lib/csv/row.rb
deleted file mode 100644
index 86323f7d0a..0000000000
--- a/lib/csv/row.rb
+++ /dev/null
@@ -1,757 +0,0 @@
-# frozen_string_literal: true
-
-require "forwardable"
-
-class CSV
-  # = \CSV::Row
-  # A \CSV::Row instance represents a \CSV table row.
-  # (see {class CSV}[../CSV.html]).
-  #
-  # The instance may have:
-  # - Fields: each is an object, not necessarily a \String.
-  # - Headers: each serves a key, and also need not be a \String.
-  #
-  # === Instance Methods
-  #
-  # \CSV::Row has three groups of instance methods:
-  # - Its own internally defined instance methods.
-  # - Methods included by module Enumerable.
-  # - Methods delegated to class Array.:
-  #   * Array#empty?
-  #   * Array#length
-  #   * Array#size
-  #
-  # == Creating a \CSV::Row Instance
-  #
-  # Commonly, a new \CSV::Row instance is created by parsing \CSV source
-  # that has headers:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.each {|row| p row }
-  # Output:
-  #   #<CSV::Row "Name":"foo" "Value":"0">
-  #   #<CSV::Row "Name":"bar" "Value":"1">
-  #   #<CSV::Row "Name":"baz" "Value":"2">
-  #
-  # You can also create a row directly. See ::new.
-  #
-  # == Headers
-  #
-  # Like a \CSV::Table, a \CSV::Row has headers.
-  #
-  # A \CSV::Row that was created by parsing \CSV source
-  # inherits its headers from the table:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   row = table.first
-  #   row.headers # => ["Name", "Value"]
-  #
-  # You can also create a new row with headers;
-  # like the keys in a \Hash, the headers need not be Strings:
-  #   row = CSV::Row.new([:name, :value], ['foo', 0])
-  #   row.headers # => [:name, :value]
-  #
-  # The new row retains its headers even if added to a table
-  # that has headers:
-  #   table << row # => #<CSV::Table mode:col_or_row row_count:5>
-  #   row.headers # => [:name, :value]
-  #   row[:name] # => "foo"
-  #   row['Name'] # => nil
-  #
-  #
-  #
-  # == Accessing Fields
-  #
-  # You may access a field in a \CSV::Row with either its \Integer index
-  # (\Array-style) or its header (\Hash-style).
-  #
-  # Fetch a field using method #[]:
-  #   row = CSV::Row.new(['Name', 'Value'], ['foo', 0])
-  #   row[1] # => 0
-  #   row['Value'] # => 0
-  #
-  # Set a field using method #[]=:
-  #   row = CSV::Row.new(['Name', 'Value'], ['foo', 0])
-  #   row # => #<CSV::Row "Name":"foo" "Value":0>
-  #   row[0] = 'bar'
-  #   row['Value'] = 1
-  #   row # => #<CSV::Row "Name":"bar" "Value":1>
-  #
-  class Row
-    # :call-seq:
-    #   CSV::Row.new(headers, fields, header_row = false) -> csv_row
-    #
-    # Returns the new \CSV::Row instance constructed from
-    # arguments +headers+ and +fields+; both should be Arrays;
-    # note that the fields need not be Strings:
-    #   row = CSV::Row.new(['Name', 'Value'], ['foo', 0])
-    #   row # => #<CSV::Row "Name":"foo" "Value":0>
-    #
-    # If the \Array lengths are different, the shorter is +nil+-filled:
-    #   row = CSV::Row.new(['Name', 'Value', 'Date', 'Size'], ['foo', 0])
-    #   row # => #<CSV::Row "Name":"foo" "Value":0 "Date":nil "Size":nil>
-    #
-    # Each \CSV::Row object is either a <i>field row</i> or a <i>header row</i>;
-    # by default, a new row is a field row;  for the row created above:
-    #   row.field_row? # => true
-    #   row.header_row? # => false
-    #
-    # If the optional argument +header_row+ is given as +true+,
-    # the created row is a header row:
-    #   row = CSV::Row.new(['Name', 'Value'], ['foo', 0], header_row = true)
-    #   row # => #<CSV::Row "Name":"foo" "Value":0>
-    #   row.field_row? # => false
-    #   row.header_row? # => true
-    def initialize(headers, fields, header_row = false)
-      @header_row = header_row
-      headers.each { |h| h.freeze if h.is_a? String }
-
-      # handle extra headers or fields
-      @row = if headers.size >= fields.size
-        headers.zip(fields)
-      else
-        fields.zip(headers).each(&:reverse!)
-      end
-    end
-
-    # Internal data format used to compare equality.
-    attr_reader :row
-    protected   :row
-
-    ### Array Delegation ###
-
-    extend Forwardable
-    def_delegators :@row, :empty?, :length, :size
-
-    # :call-seq:
-    #   row.initialize_copy(other_row) -> self
-    #
-    # Calls superclass method.
-    def initialize_copy(other)
-      super_return_value = super
-      @row = @row.collect(&:dup)
-      super_return_value
-    end
-
-    # :call-seq:
-    #   row.header_row? -> true or false
-    #
-    # Returns +true+ if this is a header row, +false+ otherwise.
-    def header_row?
-      @header_row
-    end
-
-    # :call-seq:
-    #   row.field_row? -> true or false
-    #
-    # Returns +true+ if this is a field row, +false+ otherwise.
-    def field_row?
-      not header_row?
-    end
-
-    # :call-seq:
-    #    row.headers -> array_of_headers
-    #
-    # Returns the headers for this row:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table.first
-    #   row.headers # => ["Name", "Value"]
-    def headers
-      @row.map(&:first)
-    end
-
-    # :call-seq:
-    #   field(index) -> value
-    #   field(header) -> value
-    #   field(header, offset) -> value
-    #
-    # Returns the field value for the given +index+ or +header+.
-    #
-    # ---
-    #
-    # Fetch field value by \Integer index:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.field(0) # => "foo"
-    #   row.field(1) # => "bar"
-    #
-    # Counts backward from the last column if +index+ is negative:
-    #   row.field(-1) # => "0"
-    #   row.field(-2) # => "foo"
-    #
-    # Returns +nil+ if +index+ is out of range:
-    #   row.field(2) # => nil
-    #   row.field(-3) # => nil
-    #
-    # ---
-    #
-    # Fetch field value by header (first found):
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.field('Name') # => "Foo"
-    #
-    # Fetch field value by header, ignoring +offset+ leading fields:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.field('Name', 2) # => "Baz"
-    #
-    # Returns +nil+ if the header does not exist.
-    def field(header_or_index, minimum_index = 0)
-      # locate the pair
-      finder = (header_or_index.is_a?(Integer) || header_or_index.is_a?(Range)) ? :[] : :assoc
-      pair   = @row[minimum_index..-1].public_send(finder, header_or_index)
-
-      # return the field if we have a pair
-      if pair.nil?
-        nil
-      else
-        header_or_index.is_a?(Range) ? pair.map(&:last) : pair.last
-      end
-    end
-    alias_method :[], :field
-
-    #
-    # :call-seq:
-    #   fetch(header) -> value
-    #   fetch(header, default) -> value
-    #   fetch(header) {|row| ... } -> value
-    #
-    # Returns the field value as specified by +header+.
-    #
-    # ---
-    #
-    # With the single argument +header+, returns the field value
-    # for that header (first found):
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.fetch('Name') # => "Foo"
-    #
-    # Raises exception +KeyError+ if the header does not exist.
-    #
-    # ---
-    #
-    # With arguments +header+ and +default+ given,
-    # returns the field value for the header (first found)
-    # if the header exists, otherwise returns +default+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.fetch('Name', '') # => "Foo"
-    #   row.fetch(:nosuch, '') # => ""
-    #
-    # ---
-    #
-    # With argument +header+ and a block given,
-    # returns the field value for the header (first found)
-    # if the header exists; otherwise calls the block
-    # and returns its return value:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.fetch('Name') {|header| fail 'Cannot happen' } # => "Foo"
-    #   row.fetch(:nosuch) {|header| "Header '#{header} not found'" } # => "Header 'nosuch not found'"
-    def fetch(header, *varargs)
-      raise ArgumentError, "Too many arguments" if varargs.length > 1
-      pair = @row.assoc(header)
-      if pair
-        pair.last
-      else
-        if block_given?
-          yield header
-        elsif varargs.empty?
-          raise KeyError, "key not found: #{header}"
-        else
-          varargs.first
-        end
-      end
-    end
-
-    # :call-seq:
-    #   row.has_key?(header) -> true or false
-    #
-    # Returns +true+ if there is a field with the given +header+,
-    # +false+ otherwise.
-    def has_key?(header)
-      [email protected](header)
-    end
-    alias_method :include?, :has_key?
-    alias_method :key?,     :has_key?
-    alias_method :member?,  :has_key?
-    alias_method :header?,  :has_key?
-
-    #
-    # :call-seq:
-    #   row[index] = value -> value
-    #   row[header, offset] = value -> value
-    #   row[header] = value -> value
-    #
-    # Assigns the field value for the given +index+ or +header+;
-    # returns +value+.
-    #
-    # ---
-    #
-    # Assign field value by \Integer index:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row[0] = 'Bat'
-    #   row[1] = 3
-    #   row # => #<CSV::Row "Name":"Bat" "Value":3>
-    #
-    # Counts backward from the last column if +index+ is negative:
-    #   row[-1] = 4
-    #   row[-2] = 'Bam'
-    #   row # => #<CSV::Row "Name":"Bam" "Value":4>
-    #
-    # Extends the row with <tt>nil:nil</tt> if positive +index+ is not in the row:
-    #   row[4] = 5
-    #   row # => #<CSV::Row "Name":"bad" "Value":4 nil:nil nil:nil nil:5>
-    #
-    # Raises IndexError if negative +index+ is too small (too far from zero).
-    #
-    # ---
-    #
-    # Assign field value by header (first found):
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row['Name'] = 'Bat'
-    #   row # => #<CSV::Row "Name":"Bat" "Name":"Bar" "Name":"Baz">
-    #
-    # Assign field value by header, ignoring +offset+ leading fields:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row['Name', 2] = 4
-    #   row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":4>
-    #
-    # Append new field by (new) header:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row['New'] = 6
-    #   row# => #<CSV::Row "Name":"foo" "Value":"0" "New":6>
-    def []=(*args)
-      value = args.pop
-
-      if args.first.is_a? Integer
-        if @row[args.first].nil?  # extending past the end with index
-          @row[args.first] = [nil, value]
-          @row.map! { |pair| pair.nil? ? [nil, nil] : pair }
-        else                      # normal index assignment
-          @row[args.first][1] = value
-        end
-      else
-        index = index(*args)
-        if index.nil?             # appending a field
-          self << [args.first, value]
-        else                      # normal header assignment
-          @row[index][1] = value
-        end
-      end
-    end
-
-    #
-    # :call-seq:
-    #   row << [header, value] -> self
-    #   row << hash -> self
-    #   row << value -> self
-    #
-    # Adds a field to +self+; returns +self+:
-    #
-    # If the argument is a 2-element \Array <tt>[header, value]</tt>,
-    # a field is added with the given +header+ and +value+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row << ['NAME', 'Bat']
-    #   row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" "NAME":"Bat">
-    #
-    # If the argument is a \Hash, each <tt>key-value</tt> pair is added
-    # as a field with header +key+ and value +value+.
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row << {NAME: 'Bat', name: 'Bam'}
-    #   row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" NAME:"Bat" name:"Bam">
-    #
-    # Otherwise, the given +value+ is added as a field with no header.
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row << 'Bag'
-    #   row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" nil:"Bag">
-    def <<(arg)
-      if arg.is_a?(Array) and arg.size == 2  # appending a header and name
-        @row << arg
-      elsif arg.is_a?(Hash)                  # append header and name pairs
-        arg.each { |pair| @row << pair }
-      else                                   # append field value
-        @row << [nil, arg]
-      end
-
-      self  # for chaining
-    end
-
-    # :call-seq:
-    #   row.push(*values) -> self
-    #
-    # Appends each of the given +values+ to +self+ as a field; returns +self+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.push('Bat', 'Bam')
-    #   row # => #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz" nil:"Bat" nil:"Bam">
-    def push(*args)
-      args.each { |arg| self << arg }
-
-      self  # for chaining
-    end
-
-    #
-    # :call-seq:
-    #   delete(index) -> [header, value] or nil
-    #   delete(header) -> [header, value] or empty_array
-    #   delete(header, offset) -> [header, value] or empty_array
-    #
-    # Removes a specified field from +self+; returns the 2-element \Array
-    # <tt>[header, value]</tt> if the field exists.
-    #
-    # If an \Integer argument +index+ is given,
-    # removes and returns the field at offset +index+,
-    # or returns +nil+ if the field does not exist:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.delete(1) # => ["Name", "Bar"]
-    #   row.delete(50) # => nil
-    #
-    # Otherwise, if the single argument +header+ is given,
-    # removes and returns the first-found field with the given header,
-    # of returns a new empty \Array if the field does not exist:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.delete('Name') # => ["Name", "Foo"]
-    #   row.delete('NAME') # => []
-    #
-    # If argument +header+ and \Integer argument +offset+ are given,
-    # removes and returns the first-found field with the given header
-    # whose +index+ is at least as large as +offset+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.delete('Name', 1) # => ["Name", "Bar"]
-    #   row.delete('NAME', 1) # => []
-    def delete(header_or_index, minimum_index = 0)
-      if header_or_index.is_a? Integer                 # by index
-        @row.delete_at(header_or_index)
-      elsif i = index(header_or_index, minimum_index)  # by header
-        @row.delete_at(i)
-      else
-        [ ]
-      end
-    end
-
-    # :call-seq:
-    #   row.delete_if {|header, value| ... } -> self
-    #
-    # Removes fields from +self+ as selected by the block; returns +self+.
-    #
-    # Removes each field for which the block returns a truthy value:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.delete_if {|header, value| value.start_with?('B') } # => true
-    #   row # => #<CSV::Row "Name":"Foo">
-    #   row.delete_if {|header, value| header.start_with?('B') } # => false
-    #
-    # If no block is given, returns a new Enumerator:
-    #   row.delete_if # => #<Enumerator: #<CSV::Row "Name":"Foo">:delete_if>
-    def delete_if(&block)
-      return enum_for(__method__) { size } unless block_given?
-
-      @row.delete_if(&block)
-
-      self  # for chaining
-    end
-
-    # :call-seq:
-    #   self.fields(*specifiers) -> array_of_fields
-    #
-    # Returns field values per the given +specifiers+, which may be any mixture of:
-    # - \Integer index.
-    # - \Range of \Integer indexes.
-    # - 2-element \Array containing a header and offset.
-    # - Header.
-    # - \Range of headers.
-    #
-    # For +specifier+ in one of the first four cases above,
-    # returns the result of <tt>self.field(specifier)</tt>;  see #field.
-    #
-    # Although there may be any number of +specifiers+,
-    # the examples here will illustrate one at a time.
-    #
-    # When the specifier is an \Integer +index+,
-    # returns <tt>self.field(index)</tt>L
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.fields(1) # => ["Bar"]
-    #
-    # When the specifier is a \Range of \Integers +range+,
-    # returns <tt>self.field(range)</tt>:
-    #   row.fields(1..2) # => ["Bar", "Baz"]
-    #
-    # When the specifier is a 2-element \Array +array+,
-    # returns <tt>self.field(array)</tt>L
-    #   row.fields('Name', 1) # => ["Foo", "Bar"]
-    #
-    # When the specifier is a header +header+,
-    # returns <tt>self.field(header)</tt>L
-    #   row.fields('Name') # => ["Foo"]
-    #
-    # When the specifier is a \Range of headers +range+,
-    # forms a new \Range +new_range+ from the indexes of
-    # <tt>range.start</tt> and <tt>range.end</tt>,
-    # and returns <tt>self.field(new_range)</tt>:
-    #   source = "Name,NAME,name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.fields('Name'..'NAME') # => ["Foo", "Bar"]
-    #
-    # Returns all fields if no argument given:
-    #   row.fields # => ["Foo", "Bar", "Baz"]
-    def fields(*headers_and_or_indices)
-      if headers_and_or_indices.empty?  # return all fields--no arguments
-        @row.map(&:last)
-      else                              # or work like values_at()
-        all = []
-        headers_and_or_indices.each do |h_or_i|
-          if h_or_i.is_a? Range
-            index_begin = h_or_i.begin.is_a?(Integer) ? h_or_i.begin :
-                                                        index(h_or_i.begin)
-            index_end   = h_or_i.end.is_a?(Integer)   ? h_or_i.end :
-                                                        index(h_or_i.end)
-            new_range   = h_or_i.exclude_end? ? (index_begin...index_end) :
-                                                (index_begin..index_end)
-            all.concat(fields.values_at(new_range))
-          else
-            all << field(*Array(h_or_i))
-          end
-        end
-        return all
-      end
-    end
-    alias_method :values_at, :fields
-
-    # :call-seq:
-    #   index(header) -> index
-    #   index(header, offset) -> index
-    #
-    # Returns the index for the given header, if it exists;
-    # otherwise returns +nil+.
-    #
-    # With the single argument +header+, returns the index
-    # of the first-found field with the given +header+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.index('Name') # => 0
-    #   row.index('NAME') # => nil
-    #
-    # With arguments +header+ and +offset+,
-    # returns the index of the first-found field with given +header+,
-    # but ignoring the first +offset+ fields:
-    #   row.index('Name', 1) # => 1
-    #   row.index('Name', 3) # => nil
-    def index(header, minimum_index = 0)
-      # find the pair
-      index = headers[minimum_index..-1].index(header)
-      # return the index at the right offset, if we found one
-      index.nil? ? nil : index + minimum_index
-    end
-
-    # :call-seq:
-    #   row.field?(value) -> true or false
-    #
-    # Returns +true+ if +value+ is a field in this row, +false+ otherwise:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.field?('Bar') # => true
-    #   row.field?('BAR') # => false
-    def field?(data)
-      fields.include? data
-    end
-
-    include Enumerable
-
-    # :call-seq:
-    #   row.each {|header, value| ... } -> self
-    #
-    # Calls the block with each header-value pair; returns +self+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.each {|header, value| p [header, value] }
-    # Output:
-    #   ["Name", "Foo"]
-    #   ["Name", "Bar"]
-    #   ["Name", "Baz"]
-    #
-    # If no block is given, returns a new Enumerator:
-    #   row.each # => #<Enumerator: #<CSV::Row "Name":"Foo" "Name":"Bar" "Name":"Baz">:each>
-    def each(&block)
-      return enum_for(__method__) { size } unless block_given?
-
-      @row.each(&block)
-
-      self  # for chaining
-    end
-
-    alias_method :each_pair, :each
-
-    # :call-seq:
-    #   row == other -> true or false
-    #
-    # Returns +true+ if +other+ is a /CSV::Row that has the same
-    # fields (headers and values) in the same order as +self+;
-    # otherwise returns +false+:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   other_row = table[0]
-    #   row == other_row # => true
-    #   other_row = table[1]
-    #   row == other_row # => false
-    def ==(other)
-      return @row == other.row if other.is_a? CSV::Row
-      @row == other
-    end
-
-    # :call-seq:
-    #   row.to_h -> hash
-    #
-    # Returns the new \Hash formed by adding each header-value pair in +self+
-    # as a key-value pair in the \Hash.
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.to_h # => {"Name"=>"foo", "Value"=>"0"}
-    #
-    # Header order is preserved, but repeated headers are ignored:
-    #   source = "Name,Name,Name\nFoo,Bar,Baz\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.to_h # => {"Name"=>"Foo"}
-    def to_h
-      hash = {}
-      each do |key, _value|
-        hash[key] = self[key] unless hash.key?(key)
-      end
-      hash
-    end
-    alias_method :to_hash, :to_h
-
-    # :call-seq:
-    #   row.deconstruct_keys(keys) -> hash
-    #
-    # Returns the new \Hash suitable for pattern matching containing only the
-    # keys specified as an argument.
-    def deconstruct_keys(keys)
-      if keys.nil?
-        to_h
-      else
-        keys.to_h { |key| [key, self[key]] }
-      end
-    end
-
-    alias_method :to_ary, :to_a
-
-    # :call-seq:
-    #   row.deconstruct -> array
-    #
-    # Returns the new \Array suitable for pattern matching containing the values
-    # of the row.
-    def deconstruct
-      fields
-    end
-
-    # :call-seq:
-    #   row.to_csv -> csv_string
-    #
-    # Returns the row as a \CSV String. Headers are not included:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.to_csv # => "foo,0\n"
-    def to_csv(**options)
-      fields.to_csv(**options)
-    end
-    alias_method :to_s, :to_csv
-
-    # :call-seq:
-    #   row.dig(index_or_header, *identifiers) -> object
-    #
-    # Finds and returns the object in nested object that is specified
-    # by +index_or_header+ and +specifiers+.
-    #
-    # The nested objects may be instances of various classes.
-    # See {Dig Methods}[rdoc-ref:dig_methods.rdoc].
-    #
-    # Examples:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.dig(1) # => "0"
-    #   row.dig('Value') # => "0"
-    #   row.dig(5) # => nil
-    def dig(index_or_header, *indexes)
-      value = field(index_or_header)
-      if value.nil?
-        nil
-      elsif indexes.empty?
-        value
-      else
-        unless value.respond_to?(:dig)
-          raise TypeError, "#{value.class} does not have \#dig method"
-        end
-        value.dig(*indexes)
-      end
-    end
-
-    # :call-seq:
-    #   row.inspect -> string
-    #
-    # Returns an ASCII-compatible \String showing:
-    # - Class \CSV::Row.
-    # - Header-value pairs.
-    # Example:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   row = table[0]
-    #   row.inspect # => "#<CSV::Row \"Name\":\"foo\" \"Value\":\"0\">"
-    def inspect
-      str = ["#<", self.class.to_s]
-      each do |header, field|
-        str << " " << (header.is_a?(Symbol) ? header.to_s : header.inspect) <<
-               ":" << field.inspect
-      end
-      str << ">"
-      begin
-        str.join('')
-      rescue  # any encoding error
-        str.map do |s|
-          e = Encoding::Converter.asciicompat_encoding(s.encoding)
-          e ? s.encode(e) : s.force_encoding("ASCII-8BIT")
-        end.join('')
-      end
-    end
-  end
-end
diff --git a/lib/csv/table.rb b/lib/csv/table.rb
deleted file mode 100644
index fb19f5453f..0000000000
--- a/lib/csv/table.rb
+++ /dev/null
@@ -1,1055 +0,0 @@
-# frozen_string_literal: true
-
-require "forwardable"
-
-class CSV
-  # = \CSV::Table
-  # A \CSV::Table instance represents \CSV data.
-  # (see {class CSV}[../CSV.html]).
-  #
-  # The instance may have:
-  # - Rows: each is a Table::Row object.
-  # - Headers: names for the columns.
-  #
-  # === Instance Methods
-  #
-  # \CSV::Table has three groups of instance methods:
-  # - Its own internally defined instance methods.
-  # - Methods included by module Enumerable.
-  # - Methods delegated to class Array.:
-  #   * Array#empty?
-  #   * Array#length
-  #   * Array#size
-  #
-  # == Creating a \CSV::Table Instance
-  #
-  # Commonly, a new \CSV::Table instance is created by parsing \CSV source
-  # using headers:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.class # => CSV::Table
-  #
-  # You can also create an instance directly. See ::new.
-  #
-  # == Headers
-  #
-  # If a table has headers, the headers serve as labels for the columns of data.
-  # Each header serves as the label for its column.
-  #
-  # The headers for a \CSV::Table object are stored as an \Array of Strings.
-  #
-  # Commonly, headers are defined in the first row of \CSV source:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.headers # => ["Name", "Value"]
-  #
-  # If no headers are defined, the \Array is empty:
-  #   table = CSV::Table.new([])
-  #   table.headers # => []
-  #
-  # == Access Modes
-  #
-  # \CSV::Table provides three modes for accessing table data:
-  # - \Row mode.
-  # - Column mode.
-  # - Mixed mode (the default for a new table).
-  #
-  # The access mode for a\CSV::Table instance affects the behavior
-  # of some of its instance methods:
-  # - #[]
-  # - #[]=
-  # - #delete
-  # - #delete_if
-  # - #each
-  # - #values_at
-  #
-  # === \Row Mode
-  #
-  # Set a table to row mode with method #by_row!:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-  #
-  # Specify a single row by an \Integer index:
-  #   # Get a row.
-  #   table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
-  #   # Set a row, then get it.
-  #   table[1] = CSV::Row.new(['Name', 'Value'], ['bam', 3])
-  #   table[1] # => #<CSV::Row "Name":"bam" "Value":3>
-  #
-  # Specify a sequence of rows by a \Range:
-  #   # Get rows.
-  #   table[1..2] # => [#<CSV::Row "Name":"bam" "Value":3>, #<CSV::Row "Name":"baz" "Value":"2">]
-  #   # Set rows, then get them.
-  #   table[1..2] = [
-  #     CSV::Row.new(['Name', 'Value'], ['bat', 4]),
-  #     CSV::Row.new(['Name', 'Value'], ['bad', 5]),
-  #   ]
-  #   table[1..2] # => [["Name", #<CSV::Row "Name":"bat" "Value":4>], ["Value", #<CSV::Row "Name":"bad" "Value":5>]]
-  #
-  # === Column Mode
-  #
-  # Set a table to column mode with method #by_col!:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-  #
-  # Specify a column by an \Integer index:
-  #   # Get a column.
-  #   table[0]
-  #   # Set a column, then get it.
-  #   table[0] = ['FOO', 'BAR', 'BAZ']
-  #   table[0] # => ["FOO", "BAR", "BAZ"]
-  #
-  # Specify a column by its \String header:
-  #   # Get a column.
-  #   table['Name'] # => ["FOO", "BAR", "BAZ"]
-  #   # Set a column, then get it.
-  #   table['Name'] = ['Foo', 'Bar', 'Baz']
-  #   table['Name'] # => ["Foo", "Bar", "Baz"]
-  #
-  # === Mixed Mode
-  #
-  # In mixed mode, you can refer to either rows or columns:
-  # - An \Integer index refers to a row.
-  # - A \Range index refers to multiple rows.
-  # - A \String index refers to a column.
-  #
-  # Set a table to mixed mode with method #by_col_or_row!:
-  #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-  #   table = CSV.parse(source, headers: true)
-  #   table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
-  #
-  # Specify a single row by an \Integer index:
-  #   # Get a row.
-  #   table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
-  #   # Set a row, then get it.
-  #   table[1] = CSV::Row.new(['Name', 'Value'], ['bam', 3])
-  #   table[1] # => #<CSV::Row "Name":"bam" "Value":3>
-  #
-  # Specify a sequence of rows by a \Range:
-  #   # Get rows.
-  #   table[1..2] # => [#<CSV::Row "Name":"bam" "Value":3>, #<CSV::Row "Name":"baz" "Value":"2">]
-  #   # Set rows, then get them.
-  #   table[1] = CSV::Row.new(['Name', 'Value'], ['bat', 4])
-  #   table[2] = CSV::Row.new(['Name', 'Value'], ['bad', 5])
-  #   table[1..2] # => [["Name", #<CSV::Row "Name":"bat" "Value":4>], ["Value", #<CSV::Row "Name":"bad" "Value":5>]]
-  #
-  # Specify a column by its \String header:
-  #   # Get a column.
-  #   table['Name'] # => ["foo", "bat", "bad"]
-  #   # Set a column, then get it.
-  #   table['Name'] = ['Foo', 'Bar', 'Baz']
-  #   table['Name'] # => ["Foo", "Bar", "Baz"]
-  class Table
-    # :call-seq:
-    #   CSV::Table.new(array_of_rows, headers = nil) -> csv_table
-    #
-    # Returns a new \CSV::Table object.
-    #
-    # - Argument +array_of_rows+ must be an \Array of CSV::Row objects.
-    # - Argument +headers+, if given, may be an \Array of Strings.
-    #
-    # ---
-    #
-    # Create an empty \CSV::Table object:
-    #   table = CSV::Table.new([])
-    #   table # => #<CSV::Table mode:col_or_row row_count:1>
-    #
-    # Create a non-empty \CSV::Table object:
-    #   rows = [
-    #     CSV::Row.new([], []),
-    #     CSV::Row.new([], []),
-    #     CSV::Row.new([], []),
-    #   ]
-    #   table  = CSV::Table.new(rows)
-    #   table # => #<CSV::Table mode:col_or_row row_count:4>
-    #
-    # ---
-    #
-    # If argument +headers+ is an \Array of Strings,
-    # those Strings become the table's headers:
-    #   table = CSV::Table.new([], headers: ['Name', 'Age'])
-    #   table.headers # => ["Name", "Age"]
-    #
-    # If argument +headers+ is not given and the table has rows,
-    # the headers are taken from the first row:
-    #   rows = [
-    #     CSV::Row.new(['Foo', 'Bar'], []),
-    #     CSV::Row.new(['foo', 'bar'], []),
-    #     CSV::Row.new(['FOO', 'BAR'], []),
-    #   ]
-    #   table  = CSV::Table.new(rows)
-    #   table.headers # => ["Foo", "Bar"]
-    #
-    # If argument +headers+ is not given and the table is empty (has no rows),
-    # the headers are also empty:
-    #   table  = CSV::Table.new([])
-    #   table.headers # => []
-    #
-    # ---
-    #
-    # Raises an exception if argument +array_of_rows+ is not an \Array object:
-    #   # Raises NoMethodError (undefined method `first' for :foo:Symbol):
-    #   CSV::Table.new(:foo)
-    #
-    # Raises an exception if an element of +array_of_rows+ is not a \CSV::Table object:
-    #   # Raises NoMethodError (undefined method `headers' for :foo:Symbol):
-    #   CSV::Table.new([:foo])
-    def initialize(array_of_rows, headers: nil)
-      @table = array_of_rows
-      @headers = headers
-      unless @headers
-        if @table.empty?
-          @headers = []
-        else
-          @headers = @table.first.headers
-        end
-      end
-
-      @mode  = :col_or_row
-    end
-
-    # The current access mode for indexing and iteration.
-    attr_reader :mode
-
-    # Internal data format used to compare equality.
-    attr_reader :table
-    protected   :table
-
-    ### Array Delegation ###
-
-    extend Forwardable
-    def_delegators :@table, :empty?, :length, :size
-
-    # :call-seq:
-    #   table.by_col -> table_dup
-    #
-    # Returns a duplicate of +self+, in column mode
-    # (see {Column Mode}[#class-CSV::Table-label-Column+Mode]):
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.mode # => :col_or_row
-    #   dup_table = table.by_col
-    #   dup_table.mode # => :col
-    #   dup_table.equal?(table) # => false # It's a dup
-    #
-    # This may be used to chain method calls without changing the mode
-    # (but also will affect performance and memory usage):
-    #   dup_table.by_col['Name']
-    #
-    # Also note that changes to the duplicate table will not affect the original.
-    def by_col
-      self.class.new(@table.dup).by_col!
-    end
-
-    # :call-seq:
-    #   table.by_col! -> self
-    #
-    # Sets the mode for +self+ to column mode
-    # (see {Column Mode}[#class-CSV::Table-label-Column+Mode]); returns +self+:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.mode # => :col_or_row
-    #   table1 = table.by_col!
-    #   table.mode # => :col
-    #   table1.equal?(table) # => true # Returned self
-    def by_col!
-      @mode = :col
-
-      self
-    end
-
-    # :call-seq:
-    #   table.by_col_or_row -> table_dup
-    #
-    # Returns a duplicate of +self+, in mixed mode
-    # (see {Mixed Mode}[#class-CSV::Table-label-Mixed+Mode]):
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true).by_col!
-    #   table.mode # => :col
-    #   dup_table = table.by_col_or_row
-    #   dup_table.mode # => :col_or_row
-    #   dup_table.equal?(table) # => false # It's a dup
-    #
-    # This may be used to chain method calls without changing the mode
-    # (but also will affect performance and memory usage):
-    #   dup_table.by_col_or_row['Name']
-    #
-    # Also note that changes to the duplicate table will not affect the original.
-    def by_col_or_row
-      self.class.new(@table.dup).by_col_or_row!
-    end
-
-    # :call-seq:
-    #   table.by_col_or_row! -> self
-    #
-    # Sets the mode for +self+ to mixed mode
-    # (see {Mixed Mode}[#class-CSV::Table-label-Mixed+Mode]); returns +self+:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true).by_col!
-    #   table.mode # => :col
-    #   table1 = table.by_col_or_row!
-    #   table.mode # => :col_or_row
-    #   table1.equal?(table) # => true # Returned self
-    def by_col_or_row!
-      @mode = :col_or_row
-
-      self
-    end
-
-    # :call-seq:
-    #   table.by_row -> table_dup
-    #
-    # Returns a duplicate of +self+, in row mode
-    # (see {Row Mode}[#class-CSV::Table-label-Row+Mode]):
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.mode # => :col_or_row
-    #   dup_table = table.by_row
-    #   dup_table.mode # => :row
-    #   dup_table.equal?(table) # => false # It's a dup
-    #
-    # This may be used to chain method calls without changing the mode
-    # (but also will affect performance and memory usage):
-    #   dup_table.by_row[1]
-    #
-    # Also note that changes to the duplicate table will not affect the original.
-    def by_row
-      self.class.new(@table.dup).by_row!
-    end
-
-    # :call-seq:
-    #   table.by_row! -> self
-    #
-    # Sets the mode for +self+ to row mode
-    # (see {Row Mode}[#class-CSV::Table-label-Row+Mode]); returns +self+:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.mode # => :col_or_row
-    #   table1 = table.by_row!
-    #   table.mode # => :row
-    #   table1.equal?(table) # => true # Returned self
-    def by_row!
-      @mode = :row
-
-      self
-    end
-
-    # :call-seq:
-    #   table.headers -> array_of_headers
-    #
-    # Returns a new \Array containing the \String headers for the table.
-    #
-    # If the table is not empty, returns the headers from the first row:
-    #   rows = [
-    #     CSV::Row.new(['Foo', 'Bar'], []),
-    #     CSV::Row.new(['FOO', 'BAR'], []),
-    #     CSV::Row.new(['foo', 'bar'], []),
-    #   ]
-    #   table  = CSV::Table.new(rows)
-    #   table.headers # => ["Foo", "Bar"]
-    #   table.delete(0)
-    #   table.headers # => ["FOO", "BAR"]
-    #   table.delete(0)
-    #   table.headers # => ["foo", "bar"]
-    #
-    # If the table is empty, returns a copy of the headers in the table itself:
-    #   table.delete(0)
-    #   table.headers # => ["Foo", "Bar"]
-    def headers
-      if @table.empty?
-        @headers.dup
-      else
-        @table.first.headers
-      end
-    end
-
-    # :call-seq:
-    #   table[n] -> row or column_data
-    #   table[range] -> array_of_rows or array_of_column_data
-    #   table[header] -> array_of_column_data
-    #
-    # Returns data from the table;  does not modify the table.
-    #
-    # ---
-    #
-    # Fetch a \Row by Its \Integer Index::
-    # - Form: <tt>table[n]</tt>, +n+ an integer.
-    # - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
-    # - Return value: _nth_ row of the table, if that row exists;
-    #   otherwise +nil+.
-    #
-    # Returns the _nth_ row of the table if that row exists:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
-    #   table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
-    #   table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
-    #
-    # Counts backward from the last row if +n+ is negative:
-    #   table[-1] # => #<CSV::Row "Name":"baz" "Value":"2">
-    #
-    # Returns +nil+ if +n+ is too large or too small:
-    #   table[4] # => nil
-    #   table[-4] # => nil
-    #
-    # Raises an exception if the access mode is <tt>:row</tt>
-    # and +n+ is not an \Integer:
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   # Raises TypeError (no implicit conversion of String into Integer):
-    #   table['Name']
-    #
-    # ---
-    #
-    # Fetch a Column by Its \Integer Index::
-    # - Form: <tt>table[n]</tt>, +n+ an \Integer.
-    # - Access mode: <tt>:col</tt>.
-    # - Return value: _nth_ column of the table, if that column exists;
-    #   otherwise an \Array of +nil+ fields of length <tt>self.size</tt>.
-    #
-    # Returns the _nth_ column of the table if that column exists:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   table[1] # => ["0", "1", "2"]
-    #
-    # Counts backward from the last column if +n+ is negative:
-    #   table[-2] # => ["foo", "bar", "baz"]
-    #
-    # Returns an \Array of +nil+ fields if +n+ is too large or too small:
-    #   table[4] # => [nil, nil, nil]
-    #   table[-4] # => [nil, nil, nil]
-    #
-    # ---
-    #
-    # Fetch Rows by \Range::
-    # - Form: <tt>table[range]</tt>, +range+ a \Range object.
-    # - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
-    # - Return value: rows from the table, beginning at row <tt>range.start</tt>,
-    #   if those rows exists.
-    #
-    # Returns rows from the table, beginning at row <tt>range.first</tt>,
-    # if those rows exist:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   rows = table[1..2] # => #<CSV::Row "Name":"bar" "Value":"1">
-    #   rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
-    #   table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
-    #   rows = table[1..2] # => #<CSV::Row "Name":"bar" "Value":"1">
-    #   rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # If there are too few rows, returns all from <tt>range.start</tt> to the end:
-    #   rows = table[1..50] # => #<CSV::Row "Name":"bar" "Value":"1">
-    #   rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # Special case: if <tt>range.start == table.size</tt>, returns an empty \Array:
-    #   table[table.size..50] # => []
-    #
-    # If <tt>range.end</tt> is negative, calculates the ending index from the end:
-    #   rows = table[0..-1]
-    #   rows # => [#<CSV::Row "Name":"foo" "Value":"0">, #<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # If <tt>range.start</tt> is negative, calculates the starting index from the end:
-    #   rows = table[-1..2]
-    #   rows # => [#<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # If <tt>range.start</tt> is larger than <tt>table.size</tt>, returns +nil+:
-    #   table[4..4] # => nil
-    #
-    # ---
-    #
-    # Fetch Columns by \Range::
-    # - Form: <tt>table[range]</tt>, +range+ a \Range object.
-    # - Access mode: <tt>:col</tt>.
-    # - Return value: column data from the table, beginning at column <tt>range.start</tt>,
-    #   if those columns exist.
-    #
-    # Returns column values from the table, if the column exists;
-    # the values are arranged by row:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_col!
-    #   table[0..1] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # Special case: if <tt>range.start == headers.size</tt>,
-    # returns an \Array (size: <tt>table.size</tt>) of empty \Arrays:
-    #   table[table.headers.size..50] # => [[], [], []]
-    #
-    # If <tt>range.end</tt> is negative, calculates the ending index from the end:
-    #   table[0..-1] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # If <tt>range.start</tt> is negative, calculates the starting index from the end:
-    #   table[-2..2] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    #
-    # If <tt>range.start</tt> is larger than <tt>table.size</tt>,
-    # returns an \Array of +nil+ values:
-    #   table[4..4] # => [nil, nil, nil]
-    #
-    # ---
-    #
-    # Fetch a Column by Its \String Header::
-    # - Form: <tt>table[header]</tt>, +header+ a \String header.
-    # - Access mode: <tt>:col</tt> or <tt>:col_or_row</tt>
-    # - Return value: column data from the table, if that +header+ exists.
-    #
-    # Returns column values from the table, if the column exists:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   table['Name'] # => ["foo", "bar", "baz"]
-    #   table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
-    #   col = table['Name']
-    #   col # => ["foo", "bar", "baz"]
-    #
-    # Modifying the returned column values does not modify the table:
-    #   col[0] = 'bat'
-    #   col # => ["bat", "bar", "baz"]
-    #   table['Name'] # => ["foo", "bar", "baz"]
-    #
-    # Returns an \Array of +nil+ values if there is no such column:
-    #   table['Nosuch'] # => [nil, nil, nil]
-    def [](index_or_header)
-      if @mode == :row or  # by index
-         (@mode == :col_or_row and (index_or_header.is_a?(Integer) or index_or_header.is_a?(Range)))
-        @table[index_or_header]
-      else                 # by header
-        @table.map { |row| row[index_or_header] }
-      end
-    end
-
-    # :call-seq:
-    #   table[n] = row -> row
-    #   table[n] = field_or_array_of_fields -> field_or_array_of_fields
-    #   table[header] = field_or_array_of_fields -> field_or_array_of_fields
-    #
-    # Puts data onto the table.
-    #
-    # ---
-    #
-    # Set a \Row by Its \Integer Index::
-    # - Form: <tt>table[n] = row</tt>, +n+ an \Integer,
-    #   +row+ a \CSV::Row instance or an \Array of fields.
-    # - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
-    # - Return value: +row+.
-    #
-    # If the row exists, it is replaced:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   new_row = CSV::Row.new(['Name', 'Value'], ['bat', 3])
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   return_value = table[0] = new_row
-    #   return_value.equal?(new_row) # => true # Returned the row
-    #   table[0].to_h # => {"Name"=>"bat", "Value"=>3}
-    #
-    # With access mode <tt>:col_or_row</tt>:
-    #   table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
-    #   table[0] = CSV::Row.new(['Name', 'Value'], ['bam', 4])
-    #   table[0].to_h # => {"Name"=>"bam", "Value"=>4}
-    #
-    # With an \Array instead of a \CSV::Row, inherits headers from the table:
-    #   array = ['bad', 5]
-    #   return_value = table[0] = array
-    #   return_value.equal?(array) # => true # Returned the array
-    #   table[0].to_h # => {"Name"=>"bad", "Value"=>5}
-    #
-    # If the row does not exist, extends the table by adding rows:
-    # assigns rows with +nil+ as needed:
-    #   table.size # => 3
-    #   table[5] = ['bag', 6]
-    #   table.size # => 6
-    #   table[3] # => nil
-    #   table[4]# => nil
-    #   table[5].to_h # => {"Name"=>"bag", "Value"=>6}
-    #
-    # Note that the +nil+ rows are actually +nil+, not a row of +nil+ fields.
-    #
-    # ---
-    #
-    # Set a Column by Its \Integer Index::
-    # - Form: <tt>table[n] = array_of_fields</tt>, +n+ an \Integer,
-    #   +array_of_fields+ an \Array of \String fields.
-    # - Access mode: <tt>:col</tt>.
-    # - Return value: +array_of_fields+.
-    #
-    # If the column exists, it is replaced:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   new_col = [3, 4, 5]
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   return_value = table[1] = new_col
-    #   return_value.equal?(new_col) # => true # Returned the column
-    #   table[1] # => [3, 4, 5]
-    #   # The rows, as revised:
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   table[0].to_h # => {"Name"=>"foo", "Value"=>3}
-    #   table[1].to_h # => {"Name"=>"bar", "Value"=>4}
-    #   table[2].to_h # => {"Name"=>"baz", "Value"=>5}
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #
-    # If there are too few values, fills with +nil+ values:
-    #   table[1] = [0]
-    #   table[1] # => [0, nil, nil]
-    #
-    # If there are too many values, ignores the extra values:
-    #   table[1] = [0, 1, 2, 3, 4]
-    #   table[1] # => [0, 1, 2]
-    #
-    # If a single value is given, replaces all fields in the column with that value:
-    #   table[1] = 'bat'
-    #   table[1] # => ["bat", "bat", "bat"]
-    #
-    # ---
-    #
-    # Set a Column by Its \String Header::
-    # - Form: <tt>table[header] = field_or_array_of_fields</tt>,
-    #   +header+ a \String header, +field_or_array_of_fields+ a field value
-    #   or an \Array of \String fields.
-    # - Access mode: <tt>:col</tt> or <tt>:col_or_row</tt>.
-    # - Return value: +field_or_array_of_fields+.
-    #
-    # If the column exists, it is replaced:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   new_col = [3, 4, 5]
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   return_value = table['Value'] = new_col
-    #   return_value.equal?(new_col) # => true # Returned the column
-    #   table['Value'] # => [3, 4, 5]
-    #   # The rows, as revised:
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   table[0].to_h # => {"Name"=>"foo", "Value"=>3}
-    #   table[1].to_h # => {"Name"=>"bar", "Value"=>4}
-    #   table[2].to_h # => {"Name"=>"baz", "Value"=>5}
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #
-    # If there are too few values, fills with +nil+ values:
-    #   table['Value'] = [0]
-    #   table['Value'] # => [0, nil, nil]
-    #
-    # If there are too many values, ignores the extra values:
-    #   table['Value'] = [0, 1, 2, 3, 4]
-    #   table['Value'] # => [0, 1, 2]
-    #
-    # If the column does not exist, extends the table by adding columns:
-    #   table['Note'] = ['x', 'y', 'z']
-    #   table['Note'] # => ["x", "y", "z"]
-    #   # The rows, as revised:
-    #   table.by_row!
-    #   table[0].to_h # => {"Name"=>"foo", "Value"=>0, "Note"=>"x"}
-    #   table[1].to_h # => {"Name"=>"bar", "Value"=>1, "Note"=>"y"}
-    #   table[2].to_h # => {"Name"=>"baz", "Value"=>2, "Note"=>"z"}
-    #   table.by_col!
-    #
-    # If a single value is given, replaces all fields in the column with that value:
-    #   table['Value'] = 'bat'
-    #   table['Value'] # => ["bat", "bat", "bat"]
-    def []=(index_or_header, value)
-      if @mode == :row or  # by index
-         (@mode == :col_or_row and index_or_header.is_a? Integer)
-        if value.is_a? Array
-          @table[index_or_header] = Row.new(headers, value)
-        else
-          @table[index_or_header] = value
-        end
-      else                 # set column
-        unless index_or_header.is_a? Integer
-          index = @headers.index(index_or_header) || @headers.size
-          @headers[index] = index_or_header
-        end
-        if value.is_a? Array  # multiple values
-          @table.each_with_index do |row, i|
-            if row.header_row?
-              row[index_or_header] = index_or_header
-            else
-              row[index_or_header] = value[i]
-            end
-          end
-        else                  # repeated value
-          @table.each do |row|
-            if row.header_row?
-              row[index_or_header] = index_or_header
-            else
-              row[index_or_header] = value
-            end
-          end
-        end
-      end
-    end
-
-    # :call-seq:
-    #   table.values_at(*indexes) -> array_of_rows
-    #   table.values_at(*headers) -> array_of_columns_data
-    #
-    # If the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
-    # and each argument is either an \Integer or a \Range,
-    # returns rows.
-    # Otherwise, returns columns data.
-    #
-    # In either case, the returned values are in the order
-    # specified by the arguments.  Arguments may be repeated.
-    #
-    # ---
-    #
-    # Returns rows as an \Array of \CSV::Row objects.
-    #
-    # No argument:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.values_at # => []
-    #
-    # One index:
-    #   values = table.values_at(0)
-    #   values # => [#<CSV::Row "Name":"foo" "Value":"0">]
-    #
-    # Two indexes:
-    #   values = table.values_at(2, 0)
-    #   values # => [#<CSV::Row "Name":"baz" "Value":"2">, #<CSV::Row "Name":"foo" "Value":"0">]
-    #
-    # One \Range:
-    #   values = table.values_at(1..2)
-    #   values # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # \Ranges and indexes:
-    #   values = table.values_at(0..1, 1..2, 0, 2)
-    #   pp values
-    # Output:
-    #   [#<CSV::Row "Name":"foo" "Value":"0">,
-    #    #<CSV::Row "Name":"bar" "Value":"1">,
-    #    #<CSV::Row "Name":"bar" "Value":"1">,
-    #    #<CSV::Row "Name":"baz" "Value":"2">,
-    #    #<CSV::Row "Name":"foo" "Value":"0">,
-    #    #<CSV::Row "Name":"baz" "Value":"2">]
-    #
-    # ---
-    #
-    # Returns columns data as row Arrays,
-    # each consisting of the specified columns data for that row:
-    #   values = table.values_at('Name')
-    #   values # => [["foo"], ["bar"], ["baz"]]
-    #   values = table.values_at('Value', 'Name')
-    #   values # => [["0", "foo"], ["1", "bar"], ["2", "baz"]]
-    def values_at(*indices_or_headers)
-      if @mode == :row or  # by indices
-         ( @mode == :col_or_row and indices_or_headers.all? do |index|
-                                      index.is_a?(Integer)         or
-                                      ( index.is_a?(Range)         and
-                                        index.first.is_a?(Integer) and
-                                        index.last.is_a?(Integer) )
-                                    end )
-        @table.values_at(*indices_or_headers)
-      else                 # by headers
-        @table.map { |row| row.values_at(*indices_or_headers) }
-      end
-    end
-
-    # :call-seq:
-    #   table << row_or_array -> self
-    #
-    # If +row_or_array+ is a \CSV::Row object,
-    # it is appended to the table:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table << CSV::Row.new(table.headers, ['bat', 3])
-    #   table[3] # => #<CSV::Row "Name":"bat" "Value":3>
-    #
-    # If +row_or_array+ is an \Array, it is used to create a new
-    # \CSV::Row object which is then appended to the table:
-    #   table << ['bam', 4]
-    #   table[4] # => #<CSV::Row "Name":"bam" "Value":4>
-    def <<(row_or_array)
-      if row_or_array.is_a? Array  # append Array
-        @table << Row.new(headers, row_or_array)
-      else                         # append Row
-        @table << row_or_array
-      end
-
-      self # for chaining
-    end
-
-    #
-    # :call-seq:
-    #   table.push(*rows_or_arrays) -> self
-    #
-    # A shortcut for appending multiple rows. Equivalent to:
-    #   rows.each {|row| self << row }
-    #
-    # Each argument may be either a \CSV::Row object or an \Array:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   rows = [
-    #     CSV::Row.new(table.headers, ['bat', 3]),
-    #     ['bam', 4]
-    #   ]
-    #   table.push(*rows)
-    #   table[3..4] # => [#<CSV::Row "Name":"bat" "Value":3>, #<CSV::Row "Name":"bam" "Value":4>]
-    def push(*rows)
-      rows.each { |row| self << row }
-
-      self # for chaining
-    end
-
-    # :call-seq:
-    #   table.delete(*indexes) -> deleted_values
-    #   table.delete(*headers) -> deleted_values
-    #
-    # If the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
-    # and each argument is either an \Integer or a \Range,
-    # returns deleted rows.
-    # Otherwise, returns deleted columns data.
-    #
-    # In either case, the returned values are in the order
-    # specified by the arguments.  Arguments may be repeated.
-    #
-    # ---
-    #
-    # Returns rows as an \Array of \CSV::Row objects.
-    #
-    # One index:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   deleted_values = table.delete(0)
-    #   deleted_values # => [#<CSV::Row "Name":"foo" "Value":"0">]
-    #
-    # Two indexes:
-    #   table = CSV.parse(source, headers: true)
-    #   deleted_values = table.delete(2, 0)
-    #   deleted_values # => [#<CSV::Row "Name":"baz" "Value":"2">, #<CSV::Row "Name":"foo" "Value":"0">]
-    #
-    # ---
-    #
-    # Returns columns data as column Arrays.
-    #
-    # One header:
-    #   table = CSV.parse(source, headers: true)
-    #   deleted_values = table.delete('Name')
-    #   deleted_values # => ["foo", "bar", "baz"]
-    #
-    # Two headers:
-    #   table = CSV.parse(source, headers: true)
-    #   deleted_values = table.delete('Value', 'Name')
-    #   deleted_values # => [["0", "1", "2"], ["foo", "bar", "baz"]]
-    def delete(*indexes_or_headers)
-      if indexes_or_headers.empty?
-        raise ArgumentError, "wrong number of arguments (given 0, expected 1+)"
-      end
-      deleted_values = indexes_or_headers.map do |index_or_header|
-        if @mode == :row or  # by index
-            (@mode == :col_or_row and index_or_header.is_a? Integer)
-          @table.delete_at(index_or_header)
-        else                 # by header
-          if index_or_header.is_a? Integer
-            @headers.delete_at(index_or_header)
-          else
-            @headers.delete(index_or_header)
-          end
-          @table.map { |row| row.delete(index_or_header).last }
-        end
-      end
-      if indexes_or_headers.size == 1
-        deleted_values[0]
-      else
-        deleted_values
-      end
-    end
-
-    # :call-seq:
-    #   table.delete_if {|row_or_column| ... } -> self
-    #
-    # Removes rows or columns for which the block returns a truthy value;
-    # returns +self+.
-    #
-    # Removes rows when the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>;
-    # calls the block with each \CSV::Row object:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   table.size # => 3
-    #   table.delete_if {|row| row['Name'].start_with?('b') }
-    #   table.size # => 1
-    #
-    # Removes columns when the access mode is <tt>:col</tt>;
-    # calls the block with each column as a 2-element array
-    # containing the header and an \Array of column fields:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   table.headers.size # => 2
-    #   table.delete_if {|column_data| column_data[1].include?('2') }
-    #   table.headers.size # => 1
-    #
-    # Returns a new \Enumerator if no block is given:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.delete_if # => #<Enumerator: #<CSV::Table mode:col_or_row row_count:4>:delete_if>
-    def delete_if(&block)
-      return enum_for(__method__) { @mode == :row or @mode == :col_or_row ? size : headers.size } unless block_given?
-
-      if @mode == :row or @mode == :col_or_row  # by index
-        @table.delete_if(&block)
-      else                                      # by header
-        headers.each do |header|
-          delete(header) if yield([header, self[header]])
-        end
-      end
-
-      self # for chaining
-    end
-
-    include Enumerable
-
-    # :call-seq:
-    #  table.each {|row_or_column| ... ) -> self
-    #
-    # Calls the block with each row or column; returns +self+.
-    #
-    # When the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
-    # calls the block with each \CSV::Row object:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.by_row! # => #<CSV::Table mode:row row_count:4>
-    #   table.each {|row| p row }
-    # Output:
-    #   #<CSV::Row "Name":"foo" "Value":"0">
-    #   #<CSV::Row "Name":"bar" "Value":"1">
-    #   #<CSV::Row "Name":"baz" "Value":"2">
-    #
-    # When the access mode is <tt>:col</tt>,
-    # calls the block with each column as a 2-element array
-    # containing the header and an \Array of column fields:
-    #   table.by_col! # => #<CSV::Table mode:col row_count:4>
-    #   table.each {|column_data| p column_data }
-    # Output:
-    #   ["Name", ["foo", "bar", "baz"]]
-    #   ["Value", ["0", "1", "2"]]
-    #
-    # Returns a new \Enumerator if no block is given:
-    #   table.each # => #<Enumerator: #<CSV::Table mode:col row_count:4>:each>
-    def each(&block)
-      return enum_for(__method__) { @mode == :col ? headers.size : size } unless block_given?
-
-      if @mode == :col
-        headers.each.with_index do |header, i|
-          yield([header, @table.map {|row| row[header, i]}])
-        end
-      else
-        @table.each(&block)
-      end
-
-      self # for chaining
-    end
-
-    # :call-seq:
-    #   table == other_table -> true or false
-    #
-    # Returns +true+ if all each row of +self+ <tt>==</tt>
-    # the corresponding row of +other_table+, otherwise, +false+.
-    #
-    # The access mode does no affect the result.
-    #
-    # Equal tables:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   other_table = CSV.parse(source, headers: true)
-    #   table == other_table # => true
-    #
-    # Different row count:
-    #   other_table.delete(2)
-    #   table == other_table # => false
-    #
-    # Different last row:
-    #   other_table << ['bat', 3]
-    #   table == other_table # => false
-    def ==(other)
-      return @table == other.table if other.is_a? CSV::Table
-      @table == other
-    end
-
-    # :call-seq:
-    #   table.to_a -> array_of_arrays
-    #
-    # Returns the table as an \Array of \Arrays;
-    # the headers are in the first row:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.to_a # => [["Name", "Value"], ["foo", "0"], ["bar", "1"], ["baz", "2"]]
-    def to_a
-      array = [headers]
-      @table.each do |row|
-        array.push(row.fields) unless row.header_row?
-      end
-
-      array
-    end
-
-    # :call-seq:
-    #   table.to_csv(**options) -> csv_string
-    #
-    # Returns the table as \CSV string.
-    # See {Options for Generating}[../CSV.html#class-CSV-label-Options+for+Generating].
-    #
-    # Defaults option +write_headers+ to +true+:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.to_csv # => "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #
-    # Omits the headers if option +write_headers+ is given as +false+
-    # (see {Option +write_headers+}[../CSV.html#class-CSV-label-Option+write_headers]):
-    #   table.to_csv(write_headers: false) # => "foo,0\nbar,1\nbaz,2\n"
-    #
-    # Limit rows if option +limit+ is given like +2+:
-    #   table.to_csv(limit: 2) # => "Name,Value\nfoo,0\nbar,1\n"
-    def to_csv(write_headers: true, limit: nil, **options)
-      array = write_headers ? [headers.to_csv(**options)] : []
-      limit ||= @table.size
-      limit = @table.size + 1 + limit if limit < 0
-      limit = 0 if limit < 0
-      @table.first(limit).each do |row|
-        array.push(row.fields.to_csv(**options)) unless row.header_row?
-      end
-
-      array.join("")
-    end
-    alias_method :to_s, :to_csv
-
-    #
-    # Extracts the nested value specified by the sequence of +index+ or +header+ objects by calling dig at each step,
-    # returning nil if any intermediate step is nil.
-    #
-    def dig(index_or_header, *index_or_headers)
-      value = self[index_or_header]
-      if value.nil?
-        nil
-      elsif index_or_headers.empty?
-        value
-      else
-        unless value.respond_to?(:dig)
-          raise TypeError, "#{value.class} does not have \#dig method"
-        end
-        value.dig(*index_or_headers)
-      end
-    end
-
-    # :call-seq:
-    #   table.inspect => string
-    #
-    # Returns a <tt>US-ASCII</tt>-encoded \String showing table:
-    # - Class: <tt>CSV::Table</tt>.
-    # - Access mode: <tt>:row</tt>, <tt>:col</tt>, or <tt>:col_or_row</tt>.
-    # - Size:  Row count, including the header row.
-    #
-    # Example:
-    #   source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #   table = CSV.parse(source, headers: true)
-    #   table.inspect # => "#<CSV::Table mode:col_or_row row_count:4>\nName,Value\nfoo,0\nbar,1\nbaz,2\n"
-    #
-    def inspect
-      inspected = +"#<#{self.class} mode:#{@mode} row_count:#{to_a.size}>"
-      summary = to_csv(limit: 5)
-      inspected << "\n" << summary if summary.encoding.ascii_compatible?
-      inspected
-    end
-  end
-end
diff --git a/lib/csv/version.rb b/lib/csv/version.rb
deleted file mode 100644
index 100c684ac4..0000000000
--- a/lib/csv/version.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-# frozen_string_literal: true
-
-class CSV
-  # The version of the installed library.
-  VERSION = "3.2.9"
-end
diff --git a/lib/csv/writer.rb b/lib/csv/writer.rb
deleted file mode 100644
index 030a295bc9..0000000000
--- a/lib/csv/writer.rb
+++ /dev/null
@@ -1,210 +0,0 @@
-# frozen_string_literal: true
-
-require_relative "input_record_separator"
-require_relative "row"
-
-class CSV
-  # Note: Don't use this class directly. This is an internal class.
-  class Writer
-    #
-    # A CSV::Writer receives an output, prepares the header, format and output.
-    # It allows us to write new rows in the object and rewind it.
-    #
-    attr_reader :lineno
-    attr_reader :headers
-
-    def initialize(output, options)
-      @output = output
-      @options = options
-      @lineno = 0
-      @fields_converter = nil
-      prepare
-      if @options[:write_headers] and @headers
-        self << @headers
-      end
-      @fields_converter = @options[:fields_converter]
-    end
-
-    #
-    # Adds a new row
-    #
-    def <<(row)
-      case row
-      when Row
-        row = row.fields
-      when Hash
-        row = @headers.collect {|header| row[header]}
-      end
-
-      @headers ||= row if @use_headers
-      @lineno += 1
-
-      if @fields_converter
-        quoted_fields = [false] * row.size
-        row = @fields_converter.convert(row, nil, lineno, quoted_fields)
-      end
-
-      i = -1
-      converted_row = row.collect do |field|
-        i += 1
-        quote(field, i)
-      end
-      line = converted_row.join(@column_separator) + @row_separator
-      if @output_encoding
-        line = line.encode(@output_encoding)
-      end
-      @output << line
-
-      self
-    end
-
-    #
-    # Winds back to the beginning
-    #
-    def rewind
-      @lineno = 0
-      @headers = nil if @options[:headers].nil?
-    end
-
-    private
-    def prepare
-      @encoding = @options[:encoding]
-
-      prepare_header
-      prepare_format
-      prepare_output
-    end
-
-    def prepare_header
-      headers = @options[:headers]
-      case headers
-      when Array
-        @headers = headers
-        @use_headers = true
-      when String
-        @headers = CSV.parse_line(headers,
-                                  col_sep: @options[:column_separator],
-                                  row_sep: @options[:row_separator],
-                                  quote_char: @options[:quote_character])
-        @use_headers = true
-      when true
-        @headers = nil
-        @use_headers = true
-      else
-        @headers = nil
-        @use_headers = false
-      end
-      return unless @headers
-
-      converter = @options[:header_fields_converter]
-      @headers = converter.convert(@headers, nil, 0, [])
-      @headers.each do |header|
-        header.freeze if header.is_a?(String)
-      end
-    end
-
-    def prepare_force_quotes_fields(force_quotes)
-      @force_quotes_fields = {}
-      force_quotes.each do |name_or_index|
-        case name_or_index
-        when Integer
-          index = name_or_index
-          @force_quotes_fields[index] = true
-        when String, Symbol
-          name = name_or_index.to_s
-          if @headers.nil?
-            message = ":headers is required when you use field name " +
-                      "in :force_quotes: " +
-                      "#{name_or_index.inspect}: #{force_quotes.inspect}"
-            raise ArgumentError, message
-          end
-          index = @headers.index(name)
-          next if index.nil?
-          @force_quotes_fields[index] = true
-        else
-          message = ":force_quotes element must be " +
-                    "field index or field name: " +
-                    "#{name_or_index.inspect}: #{force_quotes.inspect}"
-          raise ArgumentError, message
-        end
-      end
-    end
-
-    def prepare_format
-      @column_separator = @options[:column_separator].to_s.encode(@encoding)
-      row_separator = @options[:row_separator]
-      if row_separator == :auto
-        @row_separator = InputRecordSeparator.value.encode(@encoding)
-      else
-        @row_separator = row_separator.to_s.encode(@encoding)
-      end
-      @quote_character = @options[:quote_character]
-      force_quotes = @options[:force_quotes]
-      if force_quotes.is_a?(Array)
-        prepare_force_quotes_fields(force_quotes)
-        @force_quotes = false
-      elsif force_quotes
-        @force_quotes_fields = nil
-        @force_quotes = true
-      else
-        @force_quotes_fields = nil
-        @force_quotes = false
-      end
-      unless @force_quotes
-        @quotable_pattern =
-          Regexp.new("[\r\n".encode(@encoding) +
-                     Regexp.escape(@column_separator) +
-                     Regexp.escape(@quote_character.encode(@encoding)) +
-                     "]".encode(@encoding))
-      end
-      @quote_empty = @options.fetch(:quote_empty, true)
-    end
-
-    def prepare_output
-      @output_encoding = nil
-      return unless @output.is_a?(StringIO)
-
-      output_encoding = @output.internal_encoding || @output.external_encoding
-      if @encoding != output_encoding
-        if @options[:force_encoding]
-          @output_encoding = output_encoding
-        else
-          compatible_encoding = Encoding.compatible?(@encoding, output_encoding)
-          if compatible_encoding
-            @output.set_encoding(compatible_encoding)
-            @output.seek(0, IO::SEEK_END)
-          end
-        end
-      end
-    end
-
-    def quote_field(field)
-      field = String(field)
-      encoded_quote_character = @quote_character.encode(field.encoding)
-      encoded_quote_character +
-        field.gsub(encoded_quote_character,
-                   encoded_quote_character * 2) +
-        encoded_quote_character
-    end
-
-    def quote(field, i)
-      if @force_quotes
-        quote_field(field)
-      elsif @force_quotes_fields and @force_quotes_fields[i]
-        quote_field(field)
-      else
-        if field.nil?  # represent +nil+ fields as empty unquoted fields
-          ""
-        else
-          field = String(field)  # Stringify fields
-          # represent empty fields as empty quoted fields
-          if (@quote_empty and field.empty?) or (field.valid_encoding? and @quotable_pattern.match?(field))
-            quote_field(field)
-          else
-            field  # unquoted field
-          end
-        end
-      end
-    end
-  end
-end