diff --git a/ChangeLog b/ChangeLog
index 32c869c77c..d2a6dc56a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Tue Dec 25 19:01:04 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* encoding.h (rb_enc_mbc_to_codepoint): wrapper for
+	  ONIGENC_MBC_TO_CODE().
+
+	* string.c (rb_str_succ): deal with invalid sequence as binary.
+
 Tue Dec 25 18:40:46 2007  Koichi Sasada  <ko1@atdot.net>
 
 	* iseq.c: all methods need $SAFE < 1.
diff --git a/encoding.c b/encoding.c
index ee0fdadb39..ea00deb9e2 100644
--- a/encoding.c
+++ b/encoding.c
@@ -660,14 +660,15 @@ rb_enc_ascget(const char *p, const char *e, int *len, rb_encoding *enc)
     return c;
 }
 
-int rb_enc_codepoint(const char *p, const char *e, rb_encoding *enc)
+int
+rb_enc_codepoint(const char *p, const char *e, rb_encoding *enc)
 {
     int r;
     if (e <= p)
         rb_raise(rb_eArgError, "empty string");
     r = rb_enc_precise_mbclen(p, e, enc);
     if (MBCLEN_CHARFOUND(r))
-        return ONIGENC_MBC_TO_CODE(enc,(UChar*)p,(UChar*)e);
+        return rb_enc_mbc_to_codepoint(p, e, enc);
     else
 	rb_raise(rb_eArgError, "invalid mbstring sequence");
 }
diff --git a/include/ruby/encoding.h b/include/ruby/encoding.h
index 49df3b22a8..1b1e3d7c59 100644
--- a/include/ruby/encoding.h
+++ b/include/ruby/encoding.h
@@ -85,18 +85,19 @@ int rb_enc_ascget(const char *p, const char *e, int *len, rb_encoding *enc);
 
 /* -> code or raise exception */
 int rb_enc_codepoint(const char *p, const char *e, rb_encoding *enc);
+#define rb_enc_mbc_to_codepoint(p, e, enc) ONIGENC_MBC_TO_CODE(enc,(UChar*)(p),(UChar*)(e))
 
 /* -> codelen or raise exception */
 int rb_enc_codelen(int code, rb_encoding *enc);
 
 /* code,ptr,encoding -> write buf */
-#define rb_enc_mbcput(c,buf,enc) ONIGENC_CODE_TO_MBC(enc,c,(UChar*)buf)
+#define rb_enc_mbcput(c,buf,enc) ONIGENC_CODE_TO_MBC(enc,c,(UChar*)(buf))
 
 /* ptr, ptr, encoding -> prev_char */
-#define rb_enc_prev_char(s,p,enc) (char *)onigenc_get_prev_char_head(enc,(UChar*)s,(UChar*)p)
+#define rb_enc_prev_char(s,p,enc) (char *)onigenc_get_prev_char_head(enc,(UChar*)(s),(UChar*)(p))
 /* ptr, ptr, encoding -> next_char */
-#define rb_enc_left_char_head(s,p,enc) (char *)onigenc_get_left_adjust_char_head(enc,(UChar*)s,(UChar*)p)
-#define rb_enc_right_char_head(s,p,enc) (char *)onigenc_get_right_adjust_char_head(enc,(UChar*)s,(UChar*)p)
+#define rb_enc_left_char_head(s,p,enc) (char *)onigenc_get_left_adjust_char_head(enc,(UChar*)(s),(UChar*)(p))
+#define rb_enc_right_char_head(s,p,enc) (char *)onigenc_get_right_adjust_char_head(enc,(UChar*)(s),(UChar*)(p))
 
 #define rb_enc_isctype(c,t,enc) ONIGENC_IS_CODE_CTYPE(enc,c,t)
 #define rb_enc_isascii(c,enc) ONIGENC_IS_CODE_ASCII(c)
@@ -110,9 +111,11 @@ int rb_enc_codelen(int code, rb_encoding *enc);
 
 #define rb_enc_asciicompat(enc) (rb_enc_mbminlen(enc)==1)
 
+int rb_enc_casefold(char *to, const char *p, const char *e, rb_encoding *enc);
 int rb_enc_toupper(int c, rb_encoding *enc);
 int rb_enc_tolower(int c, rb_encoding *enc);
 ID rb_intern3(const char*, long, rb_encoding*);
+ID rb_interned_id_p(const char *, long, rb_encoding *);
 int rb_enc_symname_p(const char*, rb_encoding*);
 int rb_enc_str_coderange(VALUE);
 int rb_enc_str_asciionly_p(VALUE);
diff --git a/string.c b/string.c
index aaf14468af..9dc6a13109 100644
--- a/string.c
+++ b/string.c
@@ -1876,7 +1876,8 @@ rb_str_succ(VALUE orig)
     s = e = sbeg + RSTRING_LEN(str);
 
     while ((s = rb_enc_prev_char(sbeg, s, enc)) != 0) {
-	cc = rb_enc_codepoint(s, e, enc);
+	if ((l = rb_enc_precise_mbclen(s, e, enc)) <= 0) continue;
+	cc = rb_enc_mbc_to_codepoint(s, e, enc);
 	if (rb_enc_isalnum(cc, enc)) {
 	    if (rb_enc_isascii(cc, enc)) {
 		if ((c = succ_char(s)) == 0) break;
@@ -1892,7 +1893,8 @@ rb_str_succ(VALUE orig)
 	s = e;
 	while ((s = rb_enc_prev_char(sbeg, s, enc)) != 0) {
 	    int limit = 256;
-	    cc = rb_enc_codepoint(s, e, enc);
+	    if ((l = rb_enc_precise_mbclen(s, e, enc)) <= 0) continue;
+	    cc = rb_enc_mbc_to_codepoint(s, e, enc);
 	    while ((l = rb_enc_mbcput(++cc, carry, enc)) < 0 && --limit);
 	    if (l > 0) {
 		if (l == (o = e - s)) goto overlay;