* io.c (rb_io_extract_modeenc): plain rb/wb should set ASCII-8BIT

  to the external_encoding.

* io.c (rb_file_open_internal): ditto.

* io.c (NEED_WRITECONV): no conversion when the external_encoding
  is ASCII-8BIT.

* io.c (do_writeconv): skip ASCII-8BIT.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 29 insertions, 7 deletions

diff --git a/ChangeLog b/ChangeLog
index 5089ad3ef5..d7262f988e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Tue Oct 21 01:49:55 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (rb_io_extract_modeenc): plain rb/wb should set ASCII-8BIT
+	  to the external_encoding.
+
+	* io.c (rb_file_open_internal): ditto.
+
+	* io.c (NEED_WRITECONV): no conversion when the external_encoding
+	  is ASCII-8BIT.
+
+	* io.c (do_writeconv): skip ASCII-8BIT.
+
 Tue Oct 21 00:51:59 2008  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (rb_io_ascii8bit_binmode): renamed from rb_io_binmode.
diff --git a/io.c b/io.c
index 3795fb76dc..29b98d0bac 100644
--- a/io.c
+++ b/io.c
@@ -669,7 +669,7 @@ rb_io_wait_writable(int f)
 # define NEED_NEWLINE_DECORATOR_ON_WRITE(fptr) 0
 #endif
 #define NEED_READCONV(fptr) (fptr->encs.enc2 != NULL || NEED_NEWLINE_DECORATOR_ON_READ(fptr))
-#define NEED_WRITECONV(fptr) (fptr->encs.enc != NULL || NEED_NEWLINE_DECORATOR_ON_WRITE(fptr) || (fptr->encs.ecflags & (ECONV_DECORATOR_MASK|ECONV_STATEFUL_DECORATOR_MASK)))
+#define NEED_WRITECONV(fptr) ((fptr->encs.enc != NULL && fptr->encs.enc != rb_ascii8bit_encoding()) || NEED_NEWLINE_DECORATOR_ON_WRITE(fptr) || (fptr->encs.ecflags & (ECONV_DECORATOR_MASK|ECONV_STATEFUL_DECORATOR_MASK)))
 
 static void
 make_writeconv(rb_io_t *fptr)
@@ -689,7 +689,7 @@ make_writeconv(rb_io_t *fptr)
             ecflags |= TEXTMODE_NEWLINE_DECORATOR_ON_WRITE;
 #endif
 
-        if (!fptr->encs.enc) {
+        if (!fptr->encs.enc || (fptr->encs.enc == rb_ascii8bit_encoding() && !fptr->encs.enc2)) {
             /* no encoding conversion */
             fptr->writeconv_pre_ecflags = 0;
             fptr->writeconv_pre_ecopts = Qnil;
@@ -804,6 +804,7 @@ do_writeconv(VALUE str, rb_io_t *fptr)
 {
     if (NEED_WRITECONV(fptr)) {
         VALUE common_encoding = Qnil;
+
         make_writeconv(fptr);
 
         if (fptr->writeconv) {
@@ -817,7 +818,7 @@ do_writeconv(VALUE str, rb_io_t *fptr)
         else {
             if (fptr->encs.enc2)
                 common_encoding = rb_enc_from_encoding(fptr->encs.enc2);
-            else
+            else if (fptr->encs.enc != rb_ascii8bit_encoding())
                 common_encoding = rb_enc_from_encoding(fptr->encs.enc);
         }
 
@@ -3959,6 +3960,12 @@ rb_io_extract_modeenc(VALUE *vmode_p, VALUE *vperm_p, VALUE opthash,
             has_enc = 1;
             parse_mode_enc(p+1, &enc, &enc2);
         }
+	else {
+	    rb_encoding *e;
+
+	    e = (fmode & FMODE_BINMODE) ? rb_ascii8bit_encoding() : NULL;
+	    rb_io_ext_int_to_encs(e, NULL, &enc, &enc2);
+	}
     }
 
     if (NIL_P(opthash)) {
@@ -4151,8 +4158,11 @@ rb_file_open_internal(VALUE io, VALUE filename, const char *modestr)
         parse_mode_enc(p+1, &convconfig.enc, &convconfig.enc2);
     }
     else {
+	rb_encoding *e;
 	/* Set to default encodings */
-	rb_io_ext_int_to_encs(NULL, NULL, &convconfig.enc, &convconfig.enc2);
+
+	e = (fmode & FMODE_BINMODE) ? rb_ascii8bit_encoding() : NULL;
+	rb_io_ext_int_to_encs(e, NULL, &convconfig.enc, &convconfig.enc2);
         convconfig.ecflags = 0;
         convconfig.ecopts = Qnil;
     }
diff --git a/test/ruby/test_io_m17n.rb b/test/ruby/test_io_m17n.rb
index 6d3589580e..8b7c3363d1 100644
--- a/test/ruby/test_io_m17n.rb
+++ b/test/ruby/test_io_m17n.rb
@@ -59,7 +59,7 @@ EOT
     with_tmpdir {
       generate_file('tmp', "")
       open("tmp", "rb") {|f|
-        assert_equal(Encoding.default_external, f.external_encoding)
+        assert_equal(Encoding.find("ASCII-8BIT"), f.external_encoding)
         assert_equal(nil, f.internal_encoding)
       }
     }
@@ -137,7 +137,7 @@ EOT
   def test_open_wb
     with_tmpdir {
       open("tmp", "wb") {|f|
-        assert_equal(nil, f.external_encoding)
+        assert_equal(Encoding.find("ASCII-8BIT"), f.external_encoding)
         assert_equal(nil, f.internal_encoding)
       }
     }
@@ -1314,7 +1314,7 @@ EOT
       #   0xA1F1        0xC2A2          U+00A2
 
       open("t","rt") {|f| assert_equal("a\nb\nc\n\xc2\xa2".force_encoding(Encoding.default_external), f.read) }
-      open("t","rb") {|f| assert_equal("a\rb\r\nc\n\xc2\xa2".force_encoding(Encoding.default_external), f.read) }
+      open("t","rb") {|f| assert_equal("a\rb\r\nc\n\xc2\xa2".force_encoding(Encoding::ASCII_8BIT), f.read) }
 
       open("t","rt:euc-jp") {|f| assert_equal("a\nb\nc\n\xc2\xa2".force_encoding("EUC-JP"), f.read) }
       open("t","rb:euc-jp") {|f| assert_equal("a\rb\r\nc\n\xc2\xa2".force_encoding("EUC-JP"), f.read) }