diff --git a/ChangeLog b/ChangeLog
index 84d5cc187b..fbc98f9c51 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Jan  9 16:59:54 2008  Tanaka Akira  <akr@fsij.org>
+
+	* string.c (rb_enc_cr_str_buf_cat): fix self appending.
+
 Wed Jan  9 15:54:24 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ruby.c (process_options): give priority command line encoding option
diff --git a/string.c b/string.c
index f2371dcf01..c00fa3cd5c 100644
--- a/string.c
+++ b/string.c
@@ -1132,9 +1132,6 @@ rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
         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;
@@ -1156,6 +1153,9 @@ rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
 	}
 	RESIZE_CAPA(str, capa);
     }
+    if (off != -1) {
+        ptr = RSTRING_PTR(str) + off;
+    }
     memcpy(RSTRING_PTR(str) + RSTRING_LEN(str), ptr, len);
     STR_SET_LEN(str, total);
     RSTRING_PTR(str)[total] = '\0'; // sentinel