class ip {
var $fh; //IP数据库文件句柄
var $first; //第一条索引
var $last; //最后一条索引
var $total; //索引总数

//构造函数
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; //每条索引7字节
}

//检查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() {
//读取little-endian编码的4个字节转化为长整型数
$result = unpack('Vlong',fread($this->fh,4));
return $result['long'];
}

function getLong3() {
//读取little-endian编码的3个字节转化为长整型数
$result = unpack('Vlong',3).chr(0));
return $result['long'];
}

//查询信息
function getInfo($data = "") {
$char = fread($this->fh,1);
while (ord($char) != 0) { //国家地区信息以0结束
$data .= $char;
$char = fread($this->fh,1);
}
return $data;
}

//查询地区信息
function getArea() {
$byte = fread($this->fh,1); //标志字节
switch (ord($byte)) {
case 0: $area = ''; break; //没有地区信息
case 1: //地区被重定向
fseek($this->fh,$this->getLong3());
$area = $this->getInfo(); break;
case 2: //地区被重定向
fseek($this->fh,$this->getLong3());
$area = $this->getInfo(); break;
default: $area = $this->getInfo($byte); break; //地区没有被重定向
}
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 + $r) / 2); //计算中间索引
fseek($this->fh,$this->first + $m * 7);
$beginip = strrev(fread($this->fh,4)); //中间索引的开始IP地址
fseek($this->fh,$this->getLong3());
$endip = strrev(fread($this->fh,4)); //中间索引的结束IP地址

if ($ip < $beginip) { //用户的IP小于中间索引的开始IP地址时
$r = $m - 1;
} else {
if ($ip > $endip) { //用户的IP大于中间索引的结束IP地址时
$l = $m + 1;
} else { //用户IP在中间索引的IP范围内时
$findip = $this->first + $m * 7;
break;
}
}
}

//查询国家地区信息
fseek($this->fh,$findip);
$location['beginip'] = long2ip($this->getLong4()); //用户IP所在范围的开始地址
$offset = $this->getlong3();
fseek($this->fh,$offset);
$location['endip'] = long2ip($this->getLong4()); //用户IP所在范围的结束地址
$byte = fread($this->fh,1); //标志字节
switch (ord($byte)) {
case 1: //国家和区域信息都被重定向
$countryOffset = $this->getLong3(); //重定向地址
fseek($this->fh,$countryOffset);
$byte = fread($this->fh,1); //标志字节
switch (ord($byte)) {
case 2: //国家信息被二次重定向
fseek($this->fh,$this->getLong3());
$location['country'] = $this->getInfo();
fseek($this->fh,$countryOffset + 4);
$location['area'] = $this->getArea();
break;
default: //国家信息没有被二次重定向
$location['country'] = $this->getInfo($byte);
$location['area'] = $this->getArea();
break;
}
break;

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

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

//gb2312 to utf-8（去除无信息时显示的CZ88.NET）
foreach ($location as $k => $v) {
$location[$k] = str_replace('CZ88.NET','',iconv('gb2312','utf-8',$v));
}

return $location;
}

//析构函数
function __destruct() {
fclose($this->fh);
}
}

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