X-Git-Url: https://git.cyclocoop.org/?a=blobdiff_plain;f=includes%2FArrayUtils.php;h=985271f70997ab1e58885e04e0142d194bb7dbae;hb=93cb656139efbe9325cf868dcd4132354f2db99c;hp=d1b72a02b7ace35b2f59bded05cd73948b365062;hpb=1c4587aabfc7e6d00171062214f5887f0e8d7ede;p=lhc%2Fweb%2Fwiklou.git

diff --git a/includes/ArrayUtils.php b/includes/ArrayUtils.php
index d1b72a02b7..985271f709 100644
--- a/includes/ArrayUtils.php
+++ b/includes/ArrayUtils.php
@@ -21,7 +21,7 @@ class ArrayUtils {
 	 *     various consistent hash implementations that existed before this
 	 *     function was introduced.
 	 */
-	static function consistentHashSort( &$array, $key, $separator = "\000" ) {
+	public static function consistentHashSort( &$array, $key, $separator = "\000" ) {
 		$hashes = array();
 		foreach ( $array as $elt ) {
 			$hashes[$elt] = md5( $elt . $separator . $key );
@@ -30,4 +30,40 @@ class ArrayUtils {
 			return strcmp( $hashes[$a], $hashes[$b] );
 		} );
 	}
+
+	/**
+	 * Given an array of non-normalised probabilities, this function will select
+	 * an element and return the appropriate key
+	 *
+	 * @param $weights array
+	 *
+	 * @return bool|int|string
+	 */
+	public static function pickRandom( $weights ) {
+		if ( !is_array( $weights ) || count( $weights ) == 0 ) {
+			return false;
+		}
+
+		$sum = array_sum( $weights );
+		if ( $sum == 0 ) {
+			# No loads on any of them
+			# In previous versions, this triggered an unweighted random selection,
+			# but this feature has been removed as of April 2006 to allow for strict
+			# separation of query groups.
+			return false;
+		}
+		$max = mt_getrandmax();
+		$rand = mt_rand( 0, $max ) / $max * $sum;
+
+		$sum = 0;
+		foreach ( $weights as $i => $w ) {
+			$sum += $w;
+			# Do not return keys if they have 0 weight.
+			# Note that the "all 0 weight" case is handed above
+			if ( $w > 0 && $sum >= $rand ) {
+				break;
+			}
+		}
+		return $i;
+	}
 }