fix serious bug in strchr - char signedness

search for bytes with high bit set was giving (potentially dangerous)
wrong results. i've tested, cleaned up, and hopefully sped up this
function now.

diff --git a/src/string/strchr.c b/src/string/strchr.c
index e606f4fee48f3155c22e426f69d9495b60979dd9..2fe033868206cbd31e914de27aa9995f7d92023a 100644 (file)
--- a/src/string/strchr.c
+++ b/src/string/strchr.c
@@ -10,14 +10,16 @@
 
 char *strchr(const char *s, int c)
 {
-       c = (char)c;
+       size_t *w, k;
+
+       c = (unsigned char)c;
        if (!c) return (char *)s + strlen(s);
-       for (; ((uintptr_t)s & ALIGN) && *s && *s != c; s++);
-       if (*s && *s != c) {
-               const size_t *w;
-               size_t k = ONES * c;
-               for (w = (const void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
-               for (s = (const void *)w; *s && *s != c; s++);
-       }
-       return *s ? (char *)s : 0;
+
+       for (; ((uintptr_t)s & ALIGN) && *s; s++)
+               if (*(unsigned char *)s == c) return (char *)s;
+       k = ONES * c;
+       for (w = (void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
+       for (s = (void *)w; *s; s++)
+               if (*(unsigned char *)s == c) return (char *)s;
+       return 0;
 }