/* 函数名称:ipCity 参数说明:$userip——用户IP地址 函数功能:PHP通过IP地址判断用户所在城市 author:lee contact:xpsem2010@gmail.com */ function ipCity($userip) {     //IP数据库路径,这里用的是QQ IP数据库 20110405 纯真版     $dat_path = 'QQWry.dat';
     //判断IP地址是否有效     if(!ereg("^([0-9]{1,3}.){3}[0-9]{1,3}$", $userip)){         return 'IP Address Invalid';     }     //打开IP数据库     if(!$fd = @fopen($dat_path, 'rb')){         return 'IP data file not exists or access denied';     }     //explode函数分解IP地址,运算得出整数形结果     $userip = explode('.', $userip);     $useripNum = $userip[0] * 16777216 + $userip[1] * 65536 + $userip[2] * 256 + $userip[3];     //获取IP地址索引开始和结束位置     $DataBegin = fread($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 = $useripAllNum;     //使用二分查找法从索引记录中搜索匹配的IP地址记录     while($userip1num>$useripNum || $userip2num<$useripNum) {         $Middle= intval(($EndNum + $BeginNum) / 2);         //偏移指针到索引位置读取4个字节         fseek($fd, $useripbegin + 7 * $Middle);         $useripData1 = fread($fd, 4);         if(strlen($useripData1) < 4) {             fclose($fd);             return 'File Error';         }         //提取出来的数据转换成长整形,如果数据是负数则加上2的32次幂         $userip1num = implode('', unpack('L', $useripData1));         if($userip1num < 0) $userip1num += pow(2, 32);         //提取的长整型数大于我们IP地址则修改结束位置进行下一次循环         if($userip1num > $useripNum) {             $EndNum = $Middle;             continue;         }         //取完上一个索引后取下一个索引         $DataSeek = fread($fd, 3);         if(strlen($DataSeek) < 3) {             fclose($fd);             return 'File Error';         }         $DataSeek = implode('', unpack('L', $DataSeek.chr(0)));         fseek($fd, $DataSeek);         $useripData2 = fread($fd, 4);         if(strlen($useripData2) < 4) {             fclose($fd);             return 'File Error';         }         $userip2num = implode('', unpack('L', $useripData2));         if($userip2num < 0) $userip2num += pow(2, 32);         //找不到IP地址对应城市         if($userip2num < $useripNum) {             if($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)) {             $AddrSeek2 = fread($fd, 3);             if(strlen($AddrSeek2) < 3) {                 fclose($fd);                 return 'System Error';             }             $AddrSeek2 = implode('', unpack('L', $AddrSeek2.chr(0)));             fseek($fd, $AddrSeek2);         } else {             fseek($fd, -1, SEEK_CUR);         }         while(($char = fread($fd, 1)) != chr(0))             $useripAddr2 .= $char;         $AddrSeek = implode('', unpack('L', $AddrSeek.chr(0)));         fseek($fd, $AddrSeek);         while(($char = fread($fd, 1)) != chr(0))             $useripAddr1 .= $char;     } else {         fseek($fd, -1, SEEK_CUR);         while(($char = fread($fd, 1)) != chr(0))             $useripAddr1 .= $char;         $useripFlag = fread($fd, 1);         if($useripFlag == chr(2)) {             $AddrSeek2 = fread($fd, 3);             if(strlen($AddrSeek2) < 3) {                 fclose($fd);                 return 'System Error';             }             $AddrSeek2 = implode('', unpack('L', $AddrSeek2.chr(0)));             fseek($fd, $AddrSeek2);         } else {             fseek($fd, -1, SEEK_CUR);         }         while(($char = fread($fd, 1)) != chr(0)){             $useripAddr2 .= $char;         }     }     fclose($fd);     //返回IP地址对应的城市结果     if(preg_match('/http/i', $useripAddr2)) {         $useripAddr2 = '';     }     $useripaddr = "$useripAddr1 $useripAddr2";     $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';     }     return $useripaddr; } ?>  |