git: 9front

ref: e54b98b92961ba0a3cb4eee7b2da80c8dafbeb57
dir: /sys/src/ape/lib/ap/gen/strspn.c/

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#include <string.h>

#define	N	256

size_t
strspn(const char *s, const char *b)
{
	char map[N], *os;

	memset(map, 0, N);
	while(*b)
		map[*(unsigned char *)b++] = 1;
	os = (char*)s;
	while(map[*(unsigned char *)s++])
		;
	return s - os - 1;
}