PHP校验15位和18位身份证号的类封装

class IDCardFilter
{
  /**
   * 身份证号码校验
   *
   * @param string $idCard
   * @return bool
   */
  public function vaild($idCard)
  {
    // 基础的校验，校验身份证格式是否正确
    if (!$this->isCardNumber($idCard)) {
      return false;
    }

    // 将 15 位转换成 18 位
    $idCard = $this->fifteen2Eighteen($idCard);

    // 检查省是否存在
    if (!$this->checkProvince($idCard)) {
      return false;
    }

    // 检查生日是否正确
    if (!$this->checkBirthday($idCard)) {
      return false;
    }

    // 检查校验码
    return $this->checkCode($idCard);
  }
}

/**
 * 检测是否是身份证号码
 *
 * @param string $idCard
 * @return boolean
 */
public function isCardNumber($idCard)
{
  return preg_match(self::REGX, $idCard);
}

/**
 * 15位转18位
 *
 * @param string $idCard
 * @return void
 */
public function fifteen2Eighteen($idCard)
{
  if (strlen($idCard) != 15) {
    return $idCard;
  }

  // 如果身份证顺序码是996 997 998 999，这些是为百岁以上老人的特殊编码
  // $code = array_search(substr($idCard, 12, 3), [996, 997, 998, 999]) !== false ? '18' : '19';
  // 一般 19 就够了
  $code = '19';
  $idCardBase = substr($idCard, 0, 6) . $code . substr($idCard, 6, 9);
  return $idCardBase . $this->genCode($idCardBase);
}

/**
 * 生成校验码
 *
 * @param string $idCardBase
 * @return void
 */
final protected function genCode($idCardBase)
{
  $idCardLength = strlen($idCardBase);
  if ($idCardLength != 17) {
    return false;
  }
  $factor = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
  $verifyNumbers = ['1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'];
  $sum = 0;
  for ($i = 0; $i < $idCardLength; $i++) {
    $sum += substr($idCardBase, $i, 1) * $factor[$i];
  }
  $index = $sum % 11;
  return $verifyNumbers[$index];
}

protected $provinces = [
  11 => "北京", 12 => "天津", 13 => "河北",  14 => "山西", 15 => "内蒙古",
  21 => "辽宁", 22 => "吉林", 23 => "黑龙江", 31 => "上海", 32 => "江苏",
  33 => "浙江", 34 => "安徽", 35 => "福建",  36 => "江西", 37 => "山东", 41 => "河南",
  42 => "湖北", 43 => "湖南", 44 => "广东",  45 => "广西", 46 => "海南", 50 => "重庆",
  51 => "四川", 52 => "贵州", 53 => "云南",  54 => "西藏", 61 => "陕西", 62 => "甘肃",
  63 => "青海", 64 => "宁夏", 65 => "新疆",  71 => "台湾", 81 => "香港", 82 => "澳门", 91 => "国外"
];

/**
 * 检查省份是否正确
 *
 * @param string $idCard
 * @return void
 */
public function checkProvince($idCard)
{
  $provinceNumber = substr($idCard, 0, 2);
  return isset($this->provinces[$provinceNumber]);
}

/**
 * 检测生日是否正确
 *
 * @param string $idCard
 * @return void
 */
public function checkBirthday($idCard)
{
  $regx = '#^\d{6}(\d{4})(\d{2})(\d{2})\d{3}[0-9X]$#';
  if (!preg_match($regx, $idCard, $matches)) {
    return false;
  }
  array_shift($matches);
  list($year, $month, $day) = $matches;
  return checkdate($month, $day, $year);
}

/**
 * 校验码比对
 *
 * @param string $idCard
 * @return void
 */
public function checkCode($idCard)
{
  $idCardBase = substr($idCard, 0, 17);
  $code = $this->genCode($idCardBase);
  return $idCard == ($idCardBase . $code);
}