判断IP地址是否正确

 

int os_sock_ipv4_is_valied(const char *addr) {

  uint32_t seg[4] = {0};

  const char *start, *end;

  int cnt = 0;



  if (!addr || (!*addr)) {

    error("not invalid value");

    return -1;

  }

  start = addr;



  do {

    end = start;

    // 判断是否'\0'

    while (*start) {

      if (!((*start >= '0') && (*start <= '9'))) break;  // 正常退出循环

      seg[cnt] *= 10;

      seg[cnt] += (*start++) - '0';

      if (seg[cnt] > 255) {

        error("num(%d) is too big", seg[cnt]);

        return -1;

      }

    }

    if (start == end) {

      error("not one can be do");

      return -1;  // 判断是否至少执行一个字节解析

    }

    cnt++;

  } while ((*start++));



  if (cnt < 4) {

    error("Failed to next item, cnt = %d", cnt);

    return -1;

  } else if (cnt > 4) {

    error("Failed to more item, cnt = %d", cnt);

    return -1;

  }

  debug("seg = %d.%d.%d.%d", seg[0], seg[1], seg[2], seg[3]);

  return 0;

}