shithub: plan9front

ref: 5fd2e746e1a2a00d2acbc0c3b1924b1ea22101e8
dir: /sys/src/ape/lib/ap/gen/strcspn.c/

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#include <string.h>

#define	N	256

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

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