* transcode.c (rb_econv_putback): putback from last byte.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@18966 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Sun Aug 31 04:35:21 2008  Tanaka Akira  <akr@fsij.org>
+
+	* transcode.c (rb_econv_putback): putback from last byte.
+
 Sun Aug 31 04:27:04 2008  Tanaka Akira  <akr@fsij.org>
 
 	* transcode.c (econv_putback): renamed from econv_primitive_putback.

test/ruby/test_econv.rb

@@ -485,6 +485,15 @@ class TestEncodingConverter < Test::Unit::TestCase
     assert_equal(["abcdef", ""], [dst, src])
   end
 
+  def test_putback2
+    ec = Encoding::Converter.new("utf-16le", "euc-jp")
+    ret = ec.primitive_convert(src="\x00\xd8\x21\x00", dst="", nil, nil)
+    assert_equal(:invalid_byte_sequence, ret)
+    assert_equal("\x00", ec.putback(1))
+    assert_equal("\x21", ec.putback(1))
+    assert_equal("", ec.putback(1))
+  end
+
   def test_invalid_replace
     ec = Encoding::Converter.new("UTF-8", "EUC-JP", Encoding::Converter::INVALID_REPLACE)
     ret = ec.primitive_convert(src="abc\x80def", dst="", nil, 100)

transcode.c

@@ -1452,7 +1452,7 @@ rb_econv_putback(rb_econv_t *ec, unsigned char *p, int n)
     if (ec->num_trans == 0 || n == 0)
         return;
     tc = ec->elems[0].tc;
-    memcpy(p, TRANSCODING_READBUF(tc) + tc->recognized_len, n);
+    memcpy(p, TRANSCODING_READBUF(tc) + tc->recognized_len + tc->readagain_len - n, n);
     tc->readagain_len -= n;
 }