Import CSV 3.0.2

This includes performance improvement especially writing. Writing is
about 2 times faster.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66507 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 713 insertions, 0 deletions

diff --git a/lib/csv/parser.rb b/lib/csv/parser.rb
new file mode 100644
index 0000000000..2682c27ea3
--- /dev/null
+++ b/lib/csv/parser.rb
@@ -0,0 +1,713 @@
+# frozen_string_literal: true
+
+require "strscan"
+
+require_relative "match_p"
+require_relative "row"
+require_relative "table"
+
+using CSV::MatchP if CSV.const_defined?(:MatchP)
+
+class CSV
+  class Parser
+    class InvalidEncoding < StandardError
+    end
+
+    class Scanner < StringScanner
+      alias_method :scan_all, :scan
+
+      def initialize(*args)
+        super
+        @keeps = []
+      end
+
+      def keep_start
+        @keeps.push(pos)
+      end
+
+      def keep_end
+        start = @keeps.pop
+        string[start, pos - start]
+      end
+
+      def keep_back
+        self.pos = @keeps.pop
+      end
+
+      def keep_drop
+        @keeps.pop
+      end
+    end
+
+    class InputsScanner
+      def initialize(inputs, encoding, chunk_size: 8192)
+        @inputs = inputs.dup
+        @encoding = encoding
+        @chunk_size = chunk_size
+        @last_scanner = @inputs.empty?
+        @keeps = []
+        read_chunk
+      end
+
+      def scan(pattern)
+        value = @scanner.scan(pattern)
+        return value if @last_scanner
+
+        if value
+          read_chunk if @scanner.eos?
+          return value
+        else
+          nil
+        end
+      end
+
+      def scan_all(pattern)
+        value = @scanner.scan(pattern)
+        return value if @last_scanner
+
+        return nil if value.nil?
+        while @scanner.eos? and read_chunk and (sub_value = @scanner.scan(pattern))
+          value << sub_value
+        end
+        value
+      end
+
+      def eos?
+        @scanner.eos?
+      end
+
+      def keep_start
+        @keeps.push([@scanner.pos, nil])
+      end
+
+      def keep_end
+        start, buffer = @keeps.pop
+        keep = @scanner.string[start, @scanner.pos - start]
+        if buffer
+          buffer << keep
+          keep = buffer
+        end
+        keep
+      end
+
+      def keep_back
+        start, buffer = @keeps.pop
+        if buffer
+          string = @scanner.string
+          keep = string[start, string.size - start]
+          if keep and not keep.empty?
+            @inputs.unshift(StringIO.new(keep))
+            @last_scanner = false
+          end
+          @scanner = StringScanner.new(buffer)
+        else
+          @scanner.pos = start
+        end
+      end
+
+      def keep_drop
+        @keeps.pop
+      end
+
+      def rest
+        @scanner.rest
+      end
+
+      private
+      def read_chunk
+        return false if @last_scanner
+
+        unless @keeps.empty?
+          keep = @keeps.last
+          keep_start = keep[0]
+          string = @scanner.string
+          keep_data = string[keep_start, @scanner.pos - keep_start]
+          if keep_data
+            keep_buffer = keep[1]
+            if keep_buffer
+              keep_buffer << keep_data
+            else
+              keep[1] = keep_data.dup
+            end
+          end
+          keep[0] = 0
+        end
+
+        input = @inputs.first
+        case input
+        when StringIO
+          string = input.string
+          raise InvalidEncoding unless string.valid_encoding?
+          @scanner = StringScanner.new(string)
+          @inputs.shift
+          @last_scanner = @inputs.empty?
+          true
+        else
+          chunk = input.gets(nil, @chunk_size)
+          if chunk
+            raise InvalidEncoding unless chunk.valid_encoding?
+            @scanner = StringScanner.new(chunk)
+            if input.respond_to?(:eof?) and input.eof?
+              @inputs.shift
+              @last_scanner = @inputs.empty?
+            end
+            true
+          else
+            @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
+      @field_size_limit
+    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
+        headers = Row.new(@headers, @raw_headers, true)
+        if @unconverted_fields
+          headers = add_unconverted_fields(headers, [])
+        end
+        yield headers
+      end
+
+      row = []
+      begin
+        @scanner = build_scanner
+        skip_needless_lines
+        start_row
+        while true
+          @quoted_column_value = false
+          @unquoted_column_value = false
+          value = parse_column_value
+          if value and @field_size_limit and value.size >= @field_size_limit
+            raise MalformedCSVError.new("Field size exceeded", @lineno + 1)
+          end
+          if parse_column_end
+            row << value
+          elsif parse_row_end
+            if row.empty? and value.nil?
+              emit_row([], &block) unless @skip_blanks
+            else
+              row << value
+              emit_row(row, &block)
+              row = []
+            end
+            skip_needless_lines
+            start_row
+          elsif @scanner.eos?
+            return if row.empty? and value.nil?
+            row << value
+            emit_row(row, &block)
+            return
+          else
+            if @quoted_column_value
+              message = "Do not allow except col_sep_split_separator " +
+                "after quoted fields"
+              raise MalformedCSVError.new(message, @lineno + 1)
+            elsif @unquoted_column_value and @scanner.scan(@cr_or_lf)
+              message = "Unquoted fields do not allow \\r or \\n"
+              raise MalformedCSVError.new(message, @lineno + 1)
+            elsif @scanner.rest.start_with?(@quote_character)
+              message = "Illegal quoting"
+              raise MalformedCSVError.new(message, @lineno + 1)
+            else
+              raise MalformedCSVError.new("TODO: Meaningful message",
+                                          @lineno + 1)
+            end
+          end
+        end
+      rescue InvalidEncoding
+        message = "Invalid byte sequence in #{@encoding}"
+        raise MalformedCSVError.new(message, @lineno + 1)
+      end
+    end
+
+    private
+    def prepare
+      prepare_variable
+      prepare_regexp
+      prepare_line
+      prepare_header
+      prepare_parser
+    end
+
+    def prepare_variable
+      @encoding = @options[:encoding]
+      @liberal_parsing = @options[:liberal_parsing]
+      @unconverted_fields = @options[:unconverted_fields]
+      @field_size_limit = @options[:field_size_limit]
+      @skip_blanks = @options[:skip_blanks]
+      @fields_converter = @options[:fields_converter]
+      @header_fields_converter = @options[:header_fields_converter]
+    end
+
+    def prepare_regexp
+      @column_separator = @options[:column_separator].to_s.encode(@encoding)
+      @row_separator =
+        resolve_row_separator(@options[:row_separator]).encode(@encoding)
+      @quote_character = @options[:quote_character].to_s.encode(@encoding)
+      if @quote_character.length != 1
+        raise ArgumentError, ":quote_char has to be a single character String"
+      end
+
+      escaped_column_separator = Regexp.escape(@column_separator)
+      escaped_row_separator = Regexp.escape(@row_separator)
+      escaped_quote_character = Regexp.escape(@quote_character)
+
+      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
+
+      @column_end = Regexp.new(escaped_column_separator)
+      if @column_separator.size > 1
+        @column_ends = @column_separator.each_char.collect do |char|
+          Regexp.new(Regexp.escape(char))
+        end
+      else
+        @column_ends = nil
+      end
+      @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
+      @quotes = Regexp.new(escaped_quote_character +
+                           "+".encode(@encoding))
+      @quoted_value = Regexp.new("[^".encode(@encoding) +
+                                 escaped_quote_character +
+                                 "]+".encode(@encoding))
+      if @liberal_parsing
+        @unquoted_value = Regexp.new("[^".encode(@encoding) +
+                                     escaped_column_separator +
+                                     "\r\n]+".encode(@encoding))
+      else
+        @unquoted_value = Regexp.new("[^".encode(@encoding) +
+                                     escaped_quote_character +
+                                     escaped_column_separator +
+                                     "\r\n]+".encode(@encoding))
+      end
+      @cr_or_lf = Regexp.new("[\r\n]".encode(@encoding))
+      @not_line_end = Regexp.new("[^\r\n]+".encode(@encoding))
+    end
+
+    def resolve_row_separator(separator)
+      if separator == :auto
+        cr = "\r".encode(@encoding)
+        lf = "\n".encode(@encoding)
+        if @input.is_a?(StringIO)
+          separator = detect_row_separator(@input.string, cr, lf)
+        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 = $INPUT_RECORD_SEPARATOR 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
+        @use_headers = true
+      when String
+        @raw_headers = 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)
+      else
+        @headers = nil
+      end
+    end
+
+    def parse_headers(row)
+      CSV.parse_line(row,
+                     col_sep:    @column_separator,
+                     row_sep:    @row_separator,
+                     quote_char: @quote_character)
+    end
+
+    def adjust_headers(headers)
+      adjusted_headers = @header_fields_converter.convert(headers, nil, @lineno)
+      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?
+      if @input.is_a?(StringIO)
+        sample = @input.string
+      else
+        return false if @samples.empty?
+        sample = @samples.first
+      end
+      sample[0, 128].index(@quote_character)
+    end
+
+    SCANNER_TEST = (ENV["CSV_PARSER_SCANNER_TEST"] == "yes")
+    if SCANNER_TEST
+      class UnoptimizedStringIO
+        def initialize(string)
+          @io = StringIO.new(string)
+        end
+
+        def gets(*args)
+          @io.gets(*args)
+        end
+
+        def eof?
+          @io.eof?
+        end
+      end
+
+      def build_scanner
+        inputs = @samples.collect do |sample|
+          UnoptimizedStringIO.new(sample)
+        end
+        if @input.is_a?(StringIO)
+          inputs << UnoptimizedStringIO.new(@input.string)
+        else
+          inputs << @input
+        end
+        InputsScanner.new(inputs, @encoding, chunk_size: 1)
+      end
+    else
+      def build_scanner
+        string = nil
+        if @samples.empty? and @input.is_a?(StringIO)
+          string = @input.string
+        elsif @samples.size == 1 and @input.respond_to?(:eof?) and @input.eof?
+          string = @samples[0]
+        end
+        if string
+          unless string.valid_encoding?
+            message = "Invalid byte sequence in #{@encoding}"
+            raise MalformedCSVError.new(message, @lineno + 1)
+          end
+          Scanner.new(string)
+        else
+          inputs = @samples.collect do |sample|
+            StringIO.new(sample)
+          end
+          inputs << @input
+          InputsScanner.new(inputs, @encoding)
+        end
+      end
+    end
+
+    def skip_needless_lines
+      return unless @skip_lines
+
+      while true
+        @scanner.keep_start
+        line = @scanner.scan_all(@not_line_end) || "".encode(@encoding)
+        line << @row_separator if parse_row_end
+        if skip_line?(line)
+          @scanner.keep_drop
+        else
+          @scanner.keep_back
+          return
+        end
+      end
+    end
+
+    def skip_line?(line)
+      case @skip_lines
+      when String
+        line.include?(@skip_lines)
+      when Regexp
+        @skip_lines.match?(line)
+      else
+        @skip_lines.match(line)
+      end
+    end
+
+    def parse_column_value
+      if @liberal_parsing
+        quoted_value = parse_quoted_column_value
+        if quoted_value
+          unquoted_value = parse_unquoted_column_value
+          if unquoted_value
+            @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)
+      @unquoted_column_value = true if value
+      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 - 1) / 2]
+        while true
+          quoted_value = @scanner.scan_all(@quoted_value)
+          value << quoted_value if quoted_value
+          quotes = @scanner.scan_all(@quotes)
+          unless quotes
+            message = "Unclosed quoted field"
+            raise MalformedCSVError.new(message, @lineno + 1)
+          end
+          n_quotes = quotes.size
+          if n_quotes == 1
+            break
+          elsif (n_quotes % 2) == 1
+            value << quotes[0, (n_quotes - 1) / 2]
+            break
+          else
+            value << quotes[0, n_quotes / 2]
+          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 start_row
+      if @last_line
+        @last_line = nil
+      else
+        @scanner.keep_drop
+      end
+      @scanner.keep_start
+    end
+
+    def emit_row(row, &block)
+      @lineno += 1
+
+      raw_row = row
+      if @use_headers
+        if @headers.nil?
+          @headers = adjust_headers(row)
+          return unless @return_headers
+          row = Row.new(@headers, row, true)
+        else
+          row = Row.new(@headers,
+                        @fields_converter.convert(raw_row, @headers, @lineno))
+        end
+      else
+        # convert fields, if needed...
+        row = @fields_converter.convert(raw_row, nil, @lineno)
+      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