3 #define BITOP(a,b,op) \
4 ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
6 size_t strcspn(const char *_s, const char *_c)
8 const unsigned char *s = _s;
9 const unsigned char *c = _c;
10 const unsigned char *a = s;
11 size_t byteset[32/sizeof(size_t)];
13 if (!c[0]) return strlen(s);
14 if (!c[1]) return (s=strchr(s, *c)) ? s-a : strlen(a);
16 memset(byteset, 0, sizeof byteset);
17 for (; *c && BITOP(byteset, *c, |=); c++);
18 for (; *s && !BITOP(byteset, *s, &); s++);