byte_diff.c

来自「linux下qmail的源码 本人加了一些注释」· C语言 代码 · 共 17 行

#include "byte.h"

int byte_diff(s,n,t)
register char *s;
register unsigned int n;
register char *t;
{
  for (;;) {
    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;
    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;
    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;
    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;
  }
  return ((int)(unsigned int)(unsigned char) *s)
       - ((int)(unsigned int)(unsigned char) *t);
}