From f23f4f6e63b16d443855dde1fd19ed8c5a18960e Mon Sep 17 00:00:00 2001
From: matz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Thu, 7 Sep 2000 06:59:46 +0000
Subject: matz

git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@929 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 string.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'string.c')

diff --git a/string.c b/string.c
index 6343a2af5..5eb5d248e 100644
--- a/string.c
+++ b/string.c
@@ -427,10 +427,18 @@ rb_str_cat(str, ptr, len)
     long len;
 {
     if (len > 0) {
+	int poffset = -1;
+
 	rb_str_modify(str);
+	if (RSTRING(str)->ptr <= ptr &&
+	    ptr < RSTRING(str)->ptr + RSTRING(str)->len) {
+	    poffset = ptr - RSTRING(str)->ptr;
+	}
 	REALLOC_N(RSTRING(str)->ptr, char, RSTRING(str)->len + len + 1);
-	if (ptr)
+	if (ptr) {
+	    if (poffset >= 0) ptr = RSTRING(str)->ptr + poffset;
 	    memcpy(RSTRING(str)->ptr + RSTRING(str)->len, ptr, len);
+	}
 	RSTRING(str)->len += len;
 	RSTRING(str)->ptr[RSTRING(str)->len] = '\0'; /* sentinel */
     }
-- 
cgit