char linebuf[LINEBUFSIZE];
char readbuf[READBUFSIZE];

void grep(char* s, char *cur, char *buf, FILE *f, char* filename) {
  goto next_line(s, cur, buf, f, filename);
  return;
}

void grepmain(int argc, char* argv[]) {
  int i;
  char *buf = linebuf;
  char *cur = buf;
  char *s   = cur;
  char *filename;
  FILE *f;

  if (argc < 2) {
    fprintf(stderr, "usage: grep regexp [file ...]");
    exit(0);
  }
  if (argc == 2) {
    grep(s, cur, buf, stdin, NULL);
  } else {
    for (i = 2; i < argc; i++) {
      filename = argv[i];
      f = fopen(filename, "r");
      if (f == NULL) {
        fprintf(stderr, "can't open %s:", filename);
        continue;
      }
      if (READBUFSIZE > 0)
        setvbuf(f, readbuf, _IOFBF, READBUFSIZE);
      grep(s, cur, buf, f, filename);
      fclose(f);
    }
  }

  return;
}