From 9874fdbc866f8b504296cdfa75177f01b077f079 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 9 Jan 2008 05:52:20 +0000
Subject: * string.c (rb_enc_cr_str_buf_cat, rb_str_buf_append): deal with self
   appending.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@14963 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 string.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

(limited to 'string.c')

diff --git a/string.c b/string.c
index 57b5cd837b..f2371dcf01 100644
--- a/string.c
+++ b/string.c
@@ -1061,7 +1061,7 @@ static VALUE
 rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
     int ptr_encindex, int ptr_cr, int *ptr_cr_ret)
 {
-    long capa, total;
+    long capa, total, off = -1;
 
     int str_encindex = ENCODING_GET(str);
     int res_encindex;
@@ -1128,7 +1128,13 @@ rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
     if (len < 0) {
 	rb_raise(rb_eArgError, "negative string size (or size too big)");
     }
+    if (ptr >= RSTRING_PTR(str) && ptr <= RSTRING_END(str)) {
+        off = ptr - RSTRING_PTR(str);
+    }
     rb_str_modify(str);
+    if (off != -1) {
+        ptr = RSTRING_PTR(str) + off;
+    }
     if (len == 0) {
         ENCODING_CODERANGE_SET(str, res_encindex, res_cr);
         return str;
@@ -1170,10 +1176,6 @@ rb_str_buf_append(VALUE str, VALUE str2)
 {
     int str2_cr;
 
-    if (str == str2) {
-        str2 = rb_str_dup(str2);
-    }
-
     str2_cr = ENC_CODERANGE(str2);
 
     rb_enc_cr_str_buf_cat(str, RSTRING_PTR(str2), RSTRING_LEN(str2),
-- 
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