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comparison weight/probability/ad_weight_probability.inc @ 1:948362c2a207 ad

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update advertisement
author pierre
date Thu, 02 Apr 2009 15:28:21 +0000
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0:d8a3998dac8e 1:948362c2a207
1 <?php
2 // $Id: ad_weight_probability.inc,v 1.1.4.3 2009/02/28 05:48:42 jeremy Exp $
3
4 /**
5 * @file
6 * A plug in for the ad.module, allowing an admin to set the probability that
7 * a given advertisement will be displayed.
8 *
9 * Copyright (c) 2008-2009.
10 * Jeremy Andrews <jeremy@tag1consulting.com>.
11 */
12
13 function ad_weight_probability_cache_filter($ads) {
14 $display = array();
15 if (is_array($ads)) {
16 $probability = array();
17 $cache = adserve_cache('get_cache', 'weight');
18 foreach ($ads as $aid) {
19 $probability[] = isset($cache['probability'][$aid]) ? $cache['probability'][$aid] : 0;
20 }
21 $gcd = ad_weight_probability_gcd($probability);
22 _debug_echo("ad_weight_probability cache_filter gcd($gcd)");
23 foreach ($ads as $aid) {
24 $weight = (isset($cache['probability'][$aid]) && $gcd) ? $cache['probability'][$aid] / $gcd : 0;
25 _debug_echo("ad_weight_probability cache_filter aid($aid) weight($weight)");
26 for ($i = 1; $i <= $weight; $i++) {
27 $display[] = $aid;
28 }
29 }
30 }
31 return $display;
32 }
33
34 /**
35 * Returns the greatest common divisor of an array of integers.
36 */
37 function ad_weight_probability_gcd($integers) {
38 $gcd = array_shift($integers);
39
40 while (!empty($integers)) {
41 $gcd = _ad_weight_probability_gcd($gcd, array_shift($integers));
42 }
43 return $gcd;
44 }
45
46 /**
47 * Helper function to calculate the greatest common divisor using the Euclidean
48 * algorithm (http://en.wikipedia.org/wiki/Euclidean_algorithm).
49 */
50 function _ad_weight_probability_gcd($a, $b) {
51 if ($b == 0) {
52 return $a;
53 }
54 else {
55 return _ad_weight_probability_gcd($b, $a % $b);
56 }
57 }