utfutf.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

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


/*
 * Return pointer to first occurrence of s2 in s1,
 * 0 if none
 */
char*
utfutf(char *s1, char *s2)
{
	char *p;
	long f, n1, n2;
	Rune r;

	n1 = chartorune(&r, s2);
	f = r;
	if(f <= Runesync)		/* represents self */
		return strstr(s1, s2);

	n2 = strlen(s2);
	for(p=s1; (p=utfrune(p, f)); p+=n1)
		if(strncmp(p, s2, n2) == 0)
			return p;
	return 0;
}