3 files changed, 11 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index 4af7f3e423..1c99e620c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Sep  7 17:22:59 2009  Nobuyoshi Nakada  <[email protected]>
+
+	* io.c (rb_io_tell): adjustment for ungotten data.
+
 Mon Sep  7 17:13:53 2009  Nobuyoshi Nakada  <[email protected]>
 
 	* io.c (io_encname_bom_p): removed magic number.
diff --git a/io.c b/io.c
index 31a86da6b9..1e6b26b5e4 100644
--- a/io.c
+++ b/io.c
@@ -1042,6 +1042,7 @@ rb_io_tell(VALUE io)
     GetOpenFile(io, fptr);
     pos = io_tell(fptr);
     if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
+    pos -= fptr->rbuf_len;
     return OFFT2NUM(pos);
 }
 
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 7a0ecc0cf1..8b1714b01e 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -121,16 +121,22 @@ class TestIO < Test::Unit::TestCase
   def test_ungetbyte
     t = make_tempfile
     t.open
+    t.binmode
     t.ungetbyte(0x41)
+    assert_equal(-1, t.pos)
     assert_equal(0x41, t.getbyte)
     t.rewind
+    assert_equal(0, t.pos)
     t.ungetbyte("qux")
+    assert_equal(-3, t.pos)
     assert_equal("quxfoo\n", t.gets)
+    assert_equal(4, t.pos)
     t.set_encoding("utf-8")
     t.ungetbyte(0x89)
     t.ungetbyte(0x8e)
     t.ungetbyte("\xe7")
     t.ungetbyte("\xe7\xb4\x85")
+    assert_equal(-2, t.pos)
     assert_equal("\u7d05\u7389bar\n", t.gets)
   end