class ip {
 var $fh; //IP數(shù)據(jù)庫文件句柄
 var $first; //第一條索引
 var $last; //最后一條索引
 var $total; //索引總數(shù)

 //構造函數(shù)
 function __construct() {
  $this->fh = fopen('qqwry.dat', 'rb'); //qqwry.dat文件
  $this->first = $this->getLong4();
  $this->last = $this->getLong4();
  $this->total = ($this->last - $this->first) / 7; //每條索引7字節(jié)
 }

 //檢查IP合法性
 function checkIp($ip) {
  $arr = explode('.',$ip);
  if(count($arr) !=4 ) {
   return false;
  } else {
   for ($i=0; $i < 4; $i++) {
    if ($arr[$i] <'0' || $arr[$i] > '255') {
     return false;
    }
   }
  }
  return true;
 }

 function getLong4() {
  //讀取little-endian編碼的4個字節(jié)轉化為長整型數(shù)
  $result = unpack('Vlong', fread($this->fh, 4));
  return $result['long'];
 }

 function getLong3() {
  //讀取little-endian編碼的3個字節(jié)轉化為長整型數(shù)
  $result = unpack('Vlong', fread($this->fh, 3).chr(0));
  return $result['long'];
 }

 //查詢信息
 function getInfo($data = "") {
  $char = fread($this->fh, 1);
  while (ord($char) != 0) { //國家地區(qū)信息以0結束
   $data .= $char;
   $char = fread($this->fh, 1);
  }
  return $data;
 }

 //查詢地區(qū)信息
 function getArea() {
  $byte = fread($this->fh, 1); //標志字節(jié)
  switch (ord($byte)) {
   case 0: $area = ''; break; //沒有地區(qū)信息
   case 1: //地區(qū)被重定向
    fseek($this->fh, $this->getLong3());
    $area = $this->getInfo(); break;
   case 2: //地區(qū)被重定向
   fseek($this->fh, $this->getLong3());
   $area = $this->getInfo(); break;
   default: $area = $this->getInfo($byte);  break; //地區(qū)沒有被重定向
  }
  return $area;
 }

 function ip2addr($ip) {
  if(!$this -> checkIp($ip)){
   return false;
  }

  $ip = pack('N', intval(ip2long($ip)));

  //二分查找
  $l = 0;
  $r = $this->total;

  while($l <= $r) {
   $m = floor(($l + $r) / 2); //計算中間索引
   fseek($this->fh, $this->first + $m * 7);
   $beginip = strrev(fread($this->fh, 4)); //中間索引的開始IP地址
   fseek($this->fh, $this->getLong3());
   $endip = strrev(fread($this->fh, 4)); //中間索引的結束IP地址

   if ($ip < $beginip) { //用戶的IP小于中間索引的開始IP地址時
    $r = $m - 1;
   } else {
    if ($ip > $endip) { //用戶的IP大于中間索引的結束IP地址時
     $l = $m + 1;
    } else { //用戶IP在中間索引的IP范圍內時
     $findip = $this->first + $m * 7;
     break;
    }
   }
  }

  //查詢國家地區(qū)信息
  fseek($this->fh, $findip);
  $location['beginip'] = long2ip($this->getLong4()); //用戶IP所在范圍的開始地址
  $offset = $this->getlong3();
  fseek($this->fh, $offset);
  $location['endip'] = long2ip($this->getLong4()); //用戶IP所在范圍的結束地址
  $byte = fread($this->fh, 1); //標志字節(jié)
  switch (ord($byte)) {
   case 1:  //國家和區(qū)域信息都被重定向
    $countryOffset = $this->getLong3(); //重定向地址
    fseek($this->fh, $countryOffset);
    $byte = fread($this->fh, 1); //標志字節(jié)
    switch (ord($byte)) {
     case 2: //國家信息被二次重定向
      fseek($this->fh, $this->getLong3());
      $location['country'] = $this->getInfo();
      fseek($this->fh, $countryOffset + 4);
      $location['area'] = $this->getArea();
      break;
     default: //國家信息沒有被二次重定向
      $location['country'] = $this->getInfo($byte);
      $location['area'] = $this->getArea();
      break;
    }
    break;

   case 2: //國家信息被重定向
    fseek($this->fh, $this->getLong3());
    $location['country'] = $this->getInfo();
    fseek($this->fh, $offset + 8);
    $location['area'] = $this->getArea();
    break;

   default: //國家信息沒有被重定向
    $location['country'] = $this->getInfo($byte);
    $location['area'] = $this->getArea();
    break;
  }

  //gb2312 to utf-8（去除無信息時顯示的CZ88.NET）
  foreach ($location as $k => $v) {
   $location[$k] = str_replace('CZ88.NET','',iconv('gb2312', 'utf-8', $v));
  }

  return $location;
 }

 //析構函數(shù)
 function __destruct() {
  fclose($this->fh);
 }
}

$ip = new ip();
$addr = $ip -> ip2addr('IP地址');
print_r($addr);
?>