* ext/stringio/stringio.c (strio_write): insufficiently filled string

being extended when overwriting.  [ruby-core:03836]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@7417 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Nov 29 16:06:04 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/stringio/stringio.c (strio_write): insufficiently filled string
+	  being extended when overwriting.  [ruby-core:03836]
+
 Mon Nov 29 15:22:28 2004  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* test/io/nonblock/test_flush.rb: abandon tests when io/nonblock is

ext/stringio/stringio.c

@@ -794,7 +794,7 @@ strio_write(self, str)
     else {
 	if (ptr->pos + len > olen) {
 	    rb_str_resize(ptr->string, ptr->pos + len);
-	    MEMZERO(RSTRING(ptr->string)->ptr + olen, char, ptr->pos - olen);
+	    MEMZERO(RSTRING(ptr->string)->ptr + olen, char, ptr->pos + len - olen);
 	}
 	else {
 	    rb_str_modify(ptr->string);

test/stringio/test_stringio.rb

@@ -30,4 +30,14 @@ class TestStringIO < Test::Unit::TestCase
     io.print "last"
     assert_equal("\0" * n + "last", io.string)
   end
+
+  def test_overwrite # [ruby-core:03836]
+    stringio = StringIO.new
+    responses = ['', 'just another ruby', 'hacker']
+    responses.each do |resp|
+      stringio.puts(resp)
+      stringio.rewind
+    end
+    assert_equal("hacker\nother ruby\n", stringio.string)
+  end
 end