ref: 433b9cd26eb5d27977eb8cde6bb1c019606e0ffa
dir: /src/libc/string/strspn.c/
#include <string.h> #undef strspn size_t strspn(const char *s1, const char *s2) { const unsigned char *s = s1; const unsigned char *accept = s2; size_t n; unsigned ch; char map[__NUMCHARS] = {0}; while ((ch = *accept++) != '\0') map[ch] = 1; for (n = 0; (ch = *s++) != '\0' && map[ch]; ++n) ; return n; }