ref: fe2b29d13bac3ab3c16490b859f452201c6b4c77
dir: /src/libc/string/strcspn.c/
#include <string.h> #undef strcspn size_t strcspn(const char *s1, const char *s2) { const unsigned char *s = s1; const unsigned char *reject = s2; size_t n; unsigned ch; char map[__NUMCHARS] = {0}; while (ch = *reject++) map[ch] = 1; for (n = 0; (ch = *s++) && !map[ch]; ++n) ; return n; }