From a838eb5c65cd937c36c8e0653ecde78913d47d78 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 8 Sep 2004 09:44:46 +0000
Subject: [PATCH] * ext/stringio/stringio.c (strio_write): zero fill a gap if
 exsts.   [ruby-dev:24190]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@6873 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog                      | 11 ++++++++---
 ext/stringio/stringio.c        | 10 ++++++----
 test/stringio/test_stringio.rb |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8f48217f03..b36952d7ad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,14 +1,19 @@
+Wed Sep  8 18:44:03 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/stringio/stringio.c (strio_write): zero fill a gap if exsts.
+	  [ruby-dev:24190]
+
 Wed Sep  8 15:19:49 2004  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 
 	* ext/tcltklib/tcltklib.c (ip_init): cannot create a IP at level 4
 
-	* ext/tk/lib/multi-tk.rb: improve 'exit' operation, security check, 
+	* ext/tk/lib/multi-tk.rb: improve 'exit' operation, security check,
 	  and error treatment
 
 	* ext/tk/lib/multi-tk.rb: allow a trusted slave IP to create slave IPs
 
-	* ext/tk/lib/tk/listbox.rb: add TkListbox#value, value=, clear,	and 
-	  erase 
+	* ext/tk/lib/tk/listbox.rb: add TkListbox#value, value=, clear,	and
+	  erase
 
 	* ext/tk/lib/tk/text.rb: add TkText#clear and erase
 
diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 706385a0b2..573fc0ea94 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -771,22 +771,24 @@ strio_write(self, str)
     VALUE self, str;
 {
     struct StringIO *ptr = writable(StringIO(self));
-    long len;
+    long len, olen;
 
     if (TYPE(str) != T_STRING)
 	str = rb_obj_as_string(str);
     len = RSTRING(str)->len;
     if (!len) return INT2FIX(0);
     check_modifiable(ptr);
+    olen = RSTRING(ptr->string)->len;
     if (ptr->flags & STRIO_APPEND) {
-	ptr->pos = RSTRING(ptr->string)->len;
+	ptr->pos = olen;
     }
-    if (ptr->pos == RSTRING(ptr->string)->len) {
+    if (ptr->pos == olen) {
 	rb_str_cat(ptr->string, RSTRING(str)->ptr, len);
     }
     else {
-	if (ptr->pos + len > RSTRING(ptr->string)->len) {
+	if (ptr->pos + len > olen) {
 	    rb_str_resize(ptr->string, ptr->pos + len);
+	    MEMZERO(RSTRING(ptr->string)->ptr + olen, char, ptr->pos - olen);
 	}
 	else {
 	    rb_str_modify(ptr->string);
diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index cdb35e6acc..fee305e856 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -20,7 +20,7 @@ class TestStringIO < Test::Unit::TestCase
     io.puts "abc"
     io.truncate(0)
     io.puts "def"
-    assert_equal("\0\0\0def\n", io.string)
+    assert_equal("\0\0\0\0def\n", io.string)
   end
 
   def test_seek_beyond_eof # [ruby-dev:24194]