#include "byte.h"unsigned int byte_rchr(s,n,c)char *s;register unsigned int n;int c;{  register char ch;  register char *t;  register char *u;  ch = c;  t = s;  u = 0;  for (;;) {    if (!n) break; if (*t == ch) u = t; ++t; --n;    if (!n) break; if (*t == ch) u = t; ++t; --n;    if (!n) break; if (*t == ch) u = t; ++t; --n;    if (!n) break; if (*t == ch) u = t; ++t; --n;  }  if (!u) u = t;  return u - s;}