Add first ip-to-country code for testing.

Also add testing code to the sitemap (which
is not a publicly linked page, so can be used for
testing I assume)

include/ip-to-country.inc

@@ -0,0 +1,175 @@
+<?php // -*- C++ -*-
+
+// $Id$
+
+/*
+
+ This script uses the local copy of the ip-to-country.com
+ database available on all php.net mirror sites to find
+ out what country the user is in. This data is stored in
+ a cookie for future usage, and another check is only done,
+ if the cookie is expired.
+ 
+ We have an index to speed up the search. The first line of
+ the index file contains the step value used to create the
+ index. The IP should be divided by this number, when an
+ appropriate index entry is searched for. Then CSV formatted
+ lines are placed in the file with the division results and 
+ starting indexes (pointing to the data file).
+ 
+ The data file has a fixed record size format to ease
+ fseek()ing. The format of the database is:
+     
+  n records representing IP range and country relations
+  the format of a record is:
+      
+   - starting IP number [10 bytes, padded with zeros from left]
+   - ending IP number   [10 bytes, padded with zeros from left]
+   - ISO country code   [3 bytes / letters]
+   - newline            [1 byte: \n]
+       
+ IP numbers can be created with i2c_ip2num().
+ 
+ Some things to consider:
+ 
+  - Now 'NA' is stored in the cookie (no country detected).
+    This is partly for safety reasons, not to bog down the
+    server with country detection in case the data files are
+    not there, or they are bogus, or the user has a non listed
+    IP.
+  - The cookie may contain the IP address too in the future
+    for automatic detection of new IP usage, and searching
+    again in the DB, but this may lead to 'interesting
+    results' for users with dynamic IP
+
+*/
+
+// Start the detection
+i2c_go();
+
+// Try to find out the country of the user and 
+// set a cookie in the browser (in case there is no
+// cookie already storing this information)
+function i2c_go()
+{
+    global $_SERVER, $_COOKIE;
+    
+    // User already has a country detected
+    if (!empty($_COOKIE['COUNTRY'])) { return TRUE; }
+    
+    // User is behind a proxy
+    if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
+        $ipnum = i2c_ip2num($_SERVER['HTTP_X_FORWARDED_FOR']);
+    }
+     
+    // This is the real IP of the user
+    else {
+        $ipnum = i2c_ip2num($_SERVER['REMOTE_ADDR']);
+    }
+    
+    // Find the index to start search from
+    $idx = i2c_search_in_index($ipnum);
+    
+    // Search in the database from the given index
+    $country = i2c_search_in_db($ipnum, $idx);
+    
+    // Set the country in a cookie for a week and for all *.php.net servers
+    return setcookie("COUNTRY", $country, time() + 60*60*24*7, '/', '.php.net');
+}
+
+// Convert a dotted IP address to a number.
+// (float) is important, as otherwise we would
+// get a signed value, which is not appropriate
+function i2c_ip2num($dotted)
+{
+    $dotted = preg_split("/[.]+/", $dotted);
+    return (float) ($dotted[0] * 16777216) +
+                   ($dotted[1] * 65536) +
+                   ($dotted[2] * 256) +
+                   ($dotted[3]);
+}
+
+// Find nearest index entry for IP number 
+function i2c_search_in_index($ip)
+{
+    global $_SERVER;
+
+    // Indexed part and record number to jump to
+    $idxpart = 0; $recnum = 0;
+    
+    // Open the index file for reading
+    $dbidx = fopen(
+        $_SERVER['DOCUMENT_ROOT'] . "/backend/ip-to-country.idx",
+        "r"
+    );
+    if (!$dbidx) { return 0; }
+
+    // Read in granularity from index file and
+    // convert current IP to something useful
+    $granularity = intval(fgets($dbidx));
+    $ip_chunk = intval($ip / $granularity);
+
+    // Loop till we can read the file
+    while (!feof($dbidx)) {
+
+        // Get CSV data from index file
+        $data = fgetcsv($dbidx, 100);
+
+        // Compare current index part with our IP
+        if ($ip_chunk >= $idxpart && $ip_chunk <= (int) $data[0]) {
+            return $recnum;
+        }
+
+        // Store for next compare
+        $idxpart = (int) $data[0];
+        $recnum  = (int) $data[1];
+    }
+
+    // Return record number found
+    return $recnum;
+}
+
+// Find the country searching from record $idx
+// $ip should be an IP number and not an IP address
+function i2c_search_in_db($ip, $idx = 0)
+{
+    global $_SERVER;
+
+    // Default range and country
+    $range_start = 0; $range_end = 0;
+    $country = "NA";
+
+    // Open DB for reading
+    $ipdb = fopen(
+        $_SERVER['DOCUMENT_ROOT'] . "/backend/ip-to-country.db",
+        "r"
+    );
+
+    // Return with "NA" in case of we cannot open the db
+    if (!$ipdb) { return $country; }
+
+    // Jump to record $idx
+    fseek($ipdb, $idx*24);
+
+    // Read records until we hit the end of the file,
+    // or we find the range where this IP is
+    while (!feof($ipdb) && !($range_start <= $ip && $range_end >= $ip)) {
+            
+        // Try to read record
+        $record = fread($ipdb, 24);
+
+        // Unable to read the record => error
+        if (strlen($record) != 24) { $country = "NA"; break; }
+
+        // Split the record to it's parts
+        $range_start = (float) substr($record, 0, 10);
+        $range_end   = (float) substr($record, 10, 10);
+        $country     = substr($record, 20, 3);
+    }
+
+    // Close datafile
+    fclose($ipdb);
+
+    // Return with the country found
+    return $country;
+}

sitemap.php

@@ -1,8 +1,11 @@
 <?php
 include_once "prepend.inc";
+include_once "ip-to-country.inc";
 commonHeader("Sitemap");
 ?>
 
+<!-- <?php echo $_COOKIE["COUNTRY"]; ?> -->
+
 <h1>PHP.net Sitemap</h1>
 
 <h2>News</h2>