optimize strchrnul/strcspn not to scan string twice on no-match

[musl] / src / string / strcspn.c

diff --git a/src/string/strcspn.c b/src/string/strcspn.c
index c843ff9..cfdba11 100644 (file)
--- a/src/string/strcspn.c
+++ b/src/string/strcspn.c
@@ -3,13 +3,14 @@
 #define BITOP(a,b,op) \
  ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
 
+char *__strchrnul(const char *, int);
+
 size_t strcspn(const char *s, const char *c)
 {
        const char *a = s;
        size_t byteset[32/sizeof(size_t)];
 
-       if (!c[0]) return strlen(s);
-       if (!c[1]) return (s=strchr(s, *c)) ? s-a : strlen(a);
+       if (!c[0] || !c[1]) return __strchrnul(s, *c)-a;
 
        memset(byteset, 0, sizeof byteset);
        for (; *c && BITOP(byteset, *(unsigned char *)c, |=); c++);