<?
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 ;
}
?>
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