git: 9front

ref: b16cb451cd39f8c553a63d9999d7a8a0a90c3aa3
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;
}