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 strspn(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)] = { 0 };
15 for (; *s == *c; s++);
19 for (; *c && BITOP(byteset, *c, |=); c++);
20 for (; *s && BITOP(byteset, *s, &); s++);