git: 9front

ref: 46dc0c56b3e24cf04c7f699bd8f01ee24d3f63c9
dir: /sys/src/ape/lib/ap/gen/strstr.c/

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#include <string.h>

/* Return pointer to first occurrence of s2 in s1, NULL if none */

char*
strstr(const char *s1, const char *s2)
{
	char *p, *pa, *pb;
	int c0, c;

	c0 = *s2;
	if(c0 == 0)
		return (char *)s1;
	s2++;
	for(p=strchr(s1, c0); p; p=strchr(p+1, c0)) {
		pa = p;
		for(pb=(char*)s2;; pb++) {
			c = *pb;
			if(c == 0)
				return p;
			if(c != *++pa)
				break;
		}
	}
	return 0;
}