1 #include <u.h> 2 #include <libc.h> 3 4 #define N 256 5 6 strspn(char *s, char *b) 7 { 8 char map[N], *os; 9 10 memset(map, 0, N); 11 while(*b) 12 map[*(uchar *)b++] = 1; 13 os = s; 14 while(map[*(uchar *)s++]) 15 ; 16 return s - os - 1; 17 } 18