Analysis of the function of pure IP database read in Discuz 5.0

function | data | database

Discuz 5.0 do not use their own IP data, but the use of pure IP data format, access to the pure IP database a little trouble, its storage format is more special and interesting, the specific format of the analysis of the following two links, other languages to implement the link at the end of the reference article.

"Pure IP database format detailed"
Link One: http://blog.csdn.net/heiyeshuwu/archive/2006/05/12/725675.aspx
Link two: http://lumaqq.linuxsir.org/article/qqwry_format_detail.html

Pure IP Database official website: http://www.cz88.net/ip/
Pure IP Database Download: Http://update.cz88.net/soft/qqwry.rar

The following function Conrvertip () is located in the discuz!5_gbk/upload/include/misc.func.php path, and you are interested in reading the analysis specifically. (The following code I made a simple change, more convenient to read, the core did not modify)

?
//===================================
//
Function: IP address get real address function
Parameters: $ip-IP Address
Author: [discuz!] (C) Comsenz Inc.
//
//===================================
function Convertip ($IP) {
IP Data File path
$dat _path = ' QQWry.Dat ';

Check IP Address
if (!preg_match ("/^d{1,3}.d{1,3}.d{1,3}.d{1,3}$/", $ip)) {
Return "IP address Error";
}
Open IP Data file
if (! $fd = @fopen ($dat _path, ' RB ')) {
Return ' IP date file not exists or access denied ';
}

Decomposition of IP to calculate the number of plastic
$ip = Explode ('. ', $IP);
$ipNum = $ip [0] * 16777216 + $ip [1] * 65536 + $ip [2] * 256 + $IP [3];

Get IP Data index start and end locations
$DataBegin = Fread ($FD, 4);
$DataEnd = Fread ($FD, 4);
$ipbegin = Implode (', Unpack (' L ', $DataBegin));
if ($ipbegin < 0) $ipbegin + = POW (2, 32);
$ipend = Implode (', Unpack (' L ', $DataEnd));
if ($ipend < 0) $ipend + = POW (2, 32);
$ipAllNum = ($ipend-$ipbegin)/7 + 1;

$BeginNum = 0;
$EndNum = $ipAllNum;

Search for matching IP records from index records using the binary lookup method
while ($ip 1num> $ipNum | | $ip 2num< $ipNum) {
$Middle = Intval (($EndNum + $BeginNum)/2);

Offset pointer reads 4 bytes to index position
Fseek ($FD, $ipbegin + 7 * $Middle);
$ipData 1 = fread ($FD, 4);
if (strlen ($ipData 1) < 4) {
Fclose ($FD);
Return ' System Error ';
}
The extracted data is transformed and shaped, if the data is negative, plus 2 of the 32 power
$ip 1num = Implode (', Unpack (' L ', $ipData 1));
if ($ip 1num < 0) $ip 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 ($ip 1num > $ipNum) {
$EndNum = $Middle;
Continue
}

Remove an index after fetching the previous index
$DataSeek = Fread ($FD, 3);
if (strlen ($DataSeek) < 3) {
Fclose ($FD);
Return ' System Error ';
}
$DataSeek = Implode (', Unpack (' L ', $DataSeek. chr (0)));
Fseek ($FD, $DataSeek);
$ipData 2 = fread ($FD, 4);
if (strlen ($ipData 2) < 4) {
Fclose ($FD);
Return ' System Error ';
}
$ip 2num = Implode (', Unpack (' L ', $ipData 2));
if ($ip 2num < 0) $ip 2num + + POW (2, 32);

I can't find the hint unknown.
if ($ip 2num < $ipNum) {
if ($Middle = = $BeginNum) {
Fclose ($FD);
Return ' Unknown ';
}
$BeginNum = $Middle;
}
}

The following code read dizzy, did not read clearly, interested in slowly read
$ipFlag = Fread ($FD, 1);
if ($ipFlag = = Chr (1)) {
$ipSeek = Fread ($FD, 3);
if (strlen ($ipSeek) < 3) {
Fclose ($FD);
Return ' System Error ';
}
$ipSeek = Implode (', Unpack (' L ', $ipSeek. chr (0)));
Fseek ($FD, $ipSeek);
$ipFlag = Fread ($FD, 1);
}

if ($ipFlag = = Chr (2)) {
$AddrSeek = Fread ($FD, 3);
if (strlen ($AddrSeek) < 3) {
Fclose ($FD);
Return ' System Error ';
}
$ipFlag = Fread ($FD, 1);
if ($ipFlag = = 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))
$ipAddr 2. = $char;

$AddrSeek = Implode (', Unpack (' L ', $AddrSeek. chr (0)));
Fseek ($FD, $AddrSeek);

while (($char = Fread ($FD, 1))!= chr (0))
$ipAddr 1. = $char;
} else {
Fseek ($FD,-1, seek_cur);
while (($char = Fread ($FD, 1))!= chr (0))
$ipAddr 1. = $char;

$ipFlag = Fread ($FD, 1);
if ($ipFlag = = 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)) {
$ipAddr 2. = $char;
}
}
Fclose ($FD);

Finally, the result is returned after the corresponding substitution operation
if (Preg_match ('/http/i ', $ipAddr 2)) {
$ipAddr 2 = ';
}
$IPADDR = "$ipAddr 1 $ipAddr 2";
$IPADDR = preg_replace ('/cz88.net/is ', ', ', $ipaddr);
$IPADDR = preg_replace ('/^s*/is ', ', ', $ipaddr);
$IPADDR = preg_replace ('/s*$/is ', ', ', $ipaddr);
if (Preg_match ('/http/i ', $ipaddr) | | $ipaddr = = ') {
$ipaddr = ' Unknown ';
}

return $ipaddr;
}

//========================
//
Call examples (FAST)
//
//========================

echo convertip (' 219.238.235.10 ');
Output: Beijing Telecom Tong

echo convertip (' 23.56.82.12 ');
Output: IANA

echo convertip (' 250.69.52.0 ');
Output: IANA reserved address

echo convertip (' 238.69.52.0 ');
Output: IANA reserved address for multicast

echo convertip (' 192.168.0.1 ');
Output: Local area network each other and you in the same intranet

echo convertip (' 255.255.255.255 ');
Output: Pure network November 20, 2006 IP data

?>

Attached: (corresponding other implementation procedures)

using QQWry.Dat to achieve efficient IP address retrieval (PHP) (Author: Andot)

Pure IP database (QQWry.Dat) query C source code (Author: Windix)