shithub: riscv

ref: 5b81e7de3f1ab3691438878cf1da912a54138d5f
dir: /sys/src/libc/port/strstr.c/

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#include <u.h>
#include <libc.h>

/*
 * Return pointer to first occurrence of s2 in s1,
 * 0 if none
 */
char*
strstr(char *s1, char *s2)
{
	char *p, *pa, *pb;
	int c0, c;

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