From 067a85ef854d787b90f02ceec6c3398c3103295b Mon Sep 17 00:00:00 2001
From: =?utf8?q?Andreas=20K=C3=B6nig?= <a.koenig@mind.de>
Date: Tue, 24 Oct 2000 16:01:26 +0200
Subject: [PATCH] Fix the bug reported in Subject: Encode bug? Message-ID:
 <m3lmveqwh5.fsf@ak-71.mind.de>

Also make is_utf8_char() stricter.

p4raw-id: //depot/perl@7425
---
 ext/Encode/Encode.xs |  2 +-
 utf8.c               | 38 ++++++++++++++++++++++++++++----------
 2 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/ext/Encode/Encode.xs b/ext/Encode/Encode.xs
index c231bba..9dea8d0 100644
--- a/ext/Encode/Encode.xs
+++ b/ext/Encode/Encode.xs
@@ -182,7 +182,7 @@ _is_utf8(sv, ...)
 	{
 	  SV *	check = items == 2 ? ST(1) : Nullsv;
 	  if (SvPOK(sv)) {
-	    RETVAL = SvUTF8(sv);
+	    RETVAL = SvUTF8(sv) ? 1 : 0;
 	    if (RETVAL &&
 		SvTRUE(check) &&
 		!is_utf8_string((U8*)SvPVX(sv), SvCUR(sv)))
diff --git a/utf8.c b/utf8.c
index 98236ed..2e48339 100644
--- a/utf8.c
+++ b/utf8.c
@@ -104,27 +104,41 @@ Perl_uv_to_utf8(pTHX_ U8 *d, UV uv)
 /* Tests if some arbitrary number of bytes begins in a valid UTF-8 character.
  * The actual number of bytes in the UTF-8 character will be returned if it
  * is valid, otherwise 0. */
-int
+STRLEN
 Perl_is_utf8_char(pTHX_ U8 *s)
 {
     U8 u = *s;
-    int slen, len;
+    STRLEN slen, len;
+    UV uv, ouv;
 
-    if (!(u & 0x80))
+    if (u <= 0x7f)
 	return 1;
 
-    if (!(u & 0x40))
+    if (u >= 0x80 && u <= 0xbf)
 	return 0;
 
     len = UTF8SKIP(s);
 
+    if (len < 2 || (u >= 0xc0 && u <= 0xfd && s[1] < 0x80))
+	return 0;
+
     slen = len - 1;
     s++;
+    uv = u;
+    ouv = uv;
     while (slen--) {
 	if ((*s & 0xc0) != 0x80)
 	    return 0;
+	uv = (uv << 6) | (*s & 0x3f);
+	if (uv < ouv)
+	    return 0;
+	ouv = uv;
 	s++;
     }
+
+    if (UTF8LEN(uv) < len)
+	return 0;
+
     return len;
 }
 
@@ -140,16 +154,20 @@ string, false otherwise.
 bool
 Perl_is_utf8_string(pTHX_ U8 *s, STRLEN len)
 {
-    U8* x=s;
-    U8* send=s+len;
-    int c;
+    U8* x = s;
+    U8* send = s + len;
+    STRLEN c;
+
     while (x < send) {
         c = is_utf8_char(x);
+	if (!c)
+	    return FALSE;
         x += c;
-        if (!c || x > send)
-            return 0;
+        if (x > send)
+            return FALSE;
     }
-    return 1;
+
+    return TRUE;
 }
 
 /*
-- 
2.7.4