PHP: Get the city by IP address

File directory:   iplocation-----qqwry----------QQWry.Dat-----ipCity.class.php     ipCity.class.php file code:    

<?php class IpCity {/** * based on IP address to obtain the corresponding city * @param type $userip User IP address * @return Strin  
        G */Public function getcity ($userip, $dat _path = ') {//IP database path, here is the QQ IP database 20110405 Pure version Empty ($dat _path) && $dat _path = Fcpath.  
        ' Plugin/iplocation/qqwry/qqwry.dat '; Determine if the IP address is valid if (Preg_match ("/^" ([0-9]{1,3}.) {3} [0-9]  
        {1,3}$/", $userip) = = 0) {return ' IP address Invalid ';  //Open IP database if (! $fd = @fopen ($dat _path, ' RB ')) {return ' IP data file not exists or  
        Access Denied ';  
        The//explode function decomposes the IP address, and the result of the integer shape is calculated $userip = Explode ('. ', $userip);  
        $useripNum = $userip [0] * 16777216 + $userip [1] * 65536 + $userip [2] * 256 + $userip [3];  
        Gets the IP address index start and end position $DataBegin = Fread ($FD, 4);  
        $DataEnd = Fread ($FD, 4);  $useripbegin = Implode (', Unpack (' L ', $DataBegin));
        if ($useripbegin < 0) $useripbegin + = POW (2, 32);  
        $useripend = Implode (', Unpack (' L ', $DataEnd));  
        if ($useripend < 0) $useripend + = POW (2, 32);  
        $useripAllNum = ($useripend-$useripbegin)/7 + 1;  
        $BeginNum = 0;  
        $EndNum = $useripAllNum; Use the binary lookup method to search for a matching IP address record from the index record while ($userip 1num > $useripNum $userip 2num < $useripNum) {$M  
            Iddle = Intval (($EndNum + $BeginNum)/2);  
            The offset pointer reads 4 bytes to the index position fseek ($FD, $useripbegin + 7 * $Middle);  
            $useripData 1 = fread ($FD, 4);  
                if (strlen ($useripData 1) < 4) {fclose ($FD);  
            Return ' File Error ';  
            ///Extract Data conversion growth shaping, if the data is negative then add 2 of the 32 power $userip 1num = implode (', Unpack (' L ', $useripData 1)); if ($userip 1num < 0) $userip 1num + + POW (2, 32);  
            The number of long integers fetched is greater than our IP address to modify the end position for the next loop if ($userip 1num > $useripNum) {$EndNu  
                m = $Middle;  
            Continue  
            After the previous index is taken, remove an index $DataSeek = fread ($FD, 3);  
                if (strlen ($DataSeek) < 3) {fclose ($FD);  
            Return ' File Error ';  
            $DataSeek = Implode (', Unpack (' L ', $DataSeek. chr (0)));  
            Fseek ($FD, $DataSeek);  
            $useripData 2 = fread ($FD, 4);  
                if (strlen ($useripData 2) < 4) {fclose ($FD);  
            Return ' File Error ';  
            $userip 2num = Implode (', Unpack (' L ', $useripData 2));  
            if ($userip 2num < 0) $userip 2num + + POW (2, 32);  
                 Could not find IP address corresponding city if ($userip 2num < $useripNum) {if ($Middle = = $BeginNum) {   Fclose ($FD);  
                Return ' No Data ';  
            } $BeginNum = $Middle;  
        }} $useripFlag = Fread ($FD, 1);  
            if ($useripFlag = = Chr (1)) {$useripSeek = Fread ($FD, 3);  
                if (strlen ($useripSeek) < 3) {fclose ($FD);  
            Return ' System Error ';  
            $useripSeek = Implode (', Unpack (' L ', $useripSeek. chr (0)));  
            Fseek ($FD, $useripSeek);  
        $useripFlag = Fread ($FD, 1);  
            } if ($useripFlag = = Chr (2)) {$AddrSeek = Fread ($FD, 3);  
                if (strlen ($AddrSeek) < 3) {fclose ($FD);  
            Return ' System Error ';  
            $useripFlag = Fread ($FD, 1);  
                if ($useripFlag = = Chr (2)) {$AddrSeek 2 = fread ($FD, 3); if (strlen ($AddrSeEK2) < 3) {fclose ($FD);  
                Return ' System Error ';  
                $AddrSeek 2 = implode (', Unpack (' L ', $AddrSeek 2 chr (0)));  
            Fseek ($FD, $AddrSeek 2);  
            else {fseek ($FD,-1, seek_cur);  
            while ($char = Fread ($FD, 1))!= chr (0)) $useripAddr 2. = $char;  
            $AddrSeek = Implode (', Unpack (' L ', $AddrSeek. chr (0)));  
            Fseek ($FD, $AddrSeek);  
        while ($char = Fread ($FD, 1))!= chr (0)) $useripAddr 1. = $char;  
            else {fseek ($FD,-1, seek_cur);  
            while ($char = Fread ($FD, 1))!= chr (0)) $useripAddr 1. = $char;  
            $useripFlag = Fread ($FD, 1);  
                if ($useripFlag = = Chr (2)) {$AddrSeek 2 = fread ($FD, 3); if (Strlen ($AddrSeek 2 ) < 3) {fclose ($FD);  
                Return ' System Error ';  
                $AddrSeek 2 = implode (', Unpack (' L ', $AddrSeek 2 chr (0)));  
            Fseek ($FD, $AddrSeek 2);  
            else {fseek ($FD,-1, seek_cur);  
            while ($char = Fread ($FD, 1))!= chr (0)) {$useripAddr 2. = $char;  
        } fclose ($FD);  
        Returns the city result of the IP address if (preg_match ('/http/i ', $useripAddr 2)) {$useripAddr 2 = ';  
        $USERIPADDR = "$useripAddr 1 $useripAddr 2";  
        $USERIPADDR = preg_replace ('/cz88.net/is ', ', ', $useripaddr);  
        $USERIPADDR = preg_replace ('/^s*/is ', ', ', $useripaddr);  
        $USERIPADDR = preg_replace ('/s*$/is ', ', ', $useripaddr);  
       if (Preg_match ('/http/i ', $useripaddr) $useripaddr = = ') {$useripaddr = ' No Data '; } elseif (! $this->is_utf8 ($useripaddr)) {$useripaddr = Iconv (' GBK ', ' UTF-8 ', $useripaddr);  
    return $useripaddr; /** * To determine if I utf-8 encoded string * @param type $string * @return Boolean/private Functio n Is_utf8 ($string) {if (Preg_match) ("/^". Chr (228). "-" . Chr (233). "]{1}[". Chr (128). "-" . Chr (191). "]{1}[". Chr (128). "-" . Chr (191). ']{1} ' {1}/', $string) = = True Preg_match ("/". Chr (228). "-" . Chr (233). "]{1}[". Chr (128). "-" . Chr (191). "]{1}[". Chr (128). "-" . Chr (191). ']{1} ' {1}$/', $string) = = True Preg_match ("/". Chr (228). "-" . Chr (233). "]{1}[". Chr (128). "-" . Chr (191). "]{1}[". Chr (128). "-" . Chr (191).  
        ']{1} ' {2,}/', $string) = = True) {return true;  
        else {return false;   }  
    }  
  
}

QQWry.Dat files can be searched on Baidu or need to send your mailbox, I sent you through the mailbox. Use Demo:

Include Fcpath. ' plugin/iplocation/ipcity.class.php ';  
$city = new IpCity ();  
$ADDR = $city->getcity (' 172.0.0.1 ');  
Echo $addr; Echo Local Address