| Rich Felker | 0b44a03 | 2011-02-12 00:22:29 -0500 | [diff] [blame] | 1 | #include <string.h> |
| 2 | |
| 3 | #define BITOP(a,b,op) \ |
| 4 | ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a)))) |
| 5 | |
| Rich Felker | 9ae8d5f | 2011-03-25 16:34:03 -0400 | [diff] [blame] | 6 | size_t strspn(const char *s, const char *c) |
| Rich Felker | 0b44a03 | 2011-02-12 00:22:29 -0500 | [diff] [blame] | 7 | { |
| Rich Felker | 9ae8d5f | 2011-03-25 16:34:03 -0400 | [diff] [blame] | 8 | const char *a = s; |
| Rich Felker | 0b44a03 | 2011-02-12 00:22:29 -0500 | [diff] [blame] | 9 | size_t byteset[32/sizeof(size_t)] = { 0 }; |
| 10 | |
| 11 | if (!c[0]) return 0; |
| 12 | if (!c[1]) { |
| 13 | for (; *s == *c; s++); |
| 14 | return s-a; |
| 15 | } |
| 16 | |
| Rich Felker | 9ae8d5f | 2011-03-25 16:34:03 -0400 | [diff] [blame] | 17 | for (; *c && BITOP(byteset, *(unsigned char *)c, |=); c++); |
| 18 | for (; *s && BITOP(byteset, *(unsigned char *)s, &); s++); |
| Rich Felker | 0b44a03 | 2011-02-12 00:22:29 -0500 | [diff] [blame] | 19 | return s-a; |
| 20 | } |