diff --git a/ChangeLog b/ChangeLog
index 7189913f6b..0236af24a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Sat Mar  1 10:01:30 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* string.c (rb_str_coderange_scan_restartable): should not return
+	  offset in the middle of a character.
+
+	* string.c (rb_str_coderange_scan_restartable): should not return
+	  invalid cr value.
+
 Sat Mar  1 09:36:08 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* sprintf.c (rb_str_format): "%#.0o" should keep prefix where
diff --git a/string.c b/string.c
index ee8641e9b2..e8a34b7de0 100644
--- a/string.c
+++ b/string.c
@@ -224,8 +224,8 @@ rb_str_coderange_scan_restartable(const char *s, const char *e, rb_encoding *enc
 	while (p < e) {
 	    int ret = rb_enc_precise_mbclen(p, e, enc);
 	    if (!MBCLEN_CHARFOUND_P(ret)) {
-		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ret;
-		return e - s;
+		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_UNKNOWN;
+		return p - s;
 	    }
 	    p += MBCLEN_CHARFOUND_LEN(ret);
 	    if (p < e) {
@@ -243,7 +243,7 @@ rb_str_coderange_scan_restartable(const char *s, const char *e, rb_encoding *enc
 	while (p < e) {
 	    int ret = rb_enc_precise_mbclen(p, e, enc);
 	    if (!MBCLEN_CHARFOUND_P(ret)) {
-		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ret;
+		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_UNKNOWN;
 		return p - s;
 	    }
 	    p += MBCLEN_CHARFOUND_LEN(ret);