ref: 853049c3b9a3c84b6de4eaa5edab039c4d3df98c
dir: /sys/src/libc/port/strspn.c/
#include <u.h> #include <libc.h> #define N 256 long strspn(char *s, char *b) { char map[N], *os; memset(map, 0, N); while(*b) map[*(uchar *)b++] = 1; os = s; while(map[*(uchar *)s++]) ; return s - os - 1; }