--- /dev/null
+<?php
+/**
+ * Methods to play with arrays.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * A collection of static methods to play with arrays.
+ *
+ * @since 1.21
+ */
+class ArrayUtils {
+ /**
+ * Sort the given array in a pseudo-random order which depends only on the
+ * given key and each element value in $array. This is typically used for load
+ * balancing between servers each with a local cache.
+ *
+ * Keys are preserved. The input array is modified in place.
+ *
+ * Note: Benchmarking on PHP 5.3 and 5.4 indicates that for small
+ * strings, md5() is only 10% slower than hash('joaat',...) etc.,
+ * since the function call overhead dominates. So there's not much
+ * justification for breaking compatibility with installations
+ * compiled with ./configure --disable-hash.
+ *
+ * @param array &$array Array to sort
+ * @param string $key
+ * @param string $separator A separator used to delimit the array elements and the
+ * key. This can be chosen to provide backwards compatibility with
+ * various consistent hash implementations that existed before this
+ * function was introduced.
+ */
+ public static function consistentHashSort( &$array, $key, $separator = "\000" ) {
+ $hashes = [];
+ foreach ( $array as $elt ) {
+ $hashes[$elt] = md5( $elt . $separator . $key );
+ }
+ uasort( $array, function ( $a, $b ) use ( $hashes ) {
+ 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 array $weights
+ * @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;
+ }
+
+ /**
+ * Do a binary search, and return the index of the largest item that sorts
+ * less than or equal to the target value.
+ *
+ * @since 1.23
+ *
+ * @param callable $valueCallback A function to call to get the value with
+ * a given array index.
+ * @param int $valueCount The number of items accessible via $valueCallback,
+ * indexed from 0 to $valueCount - 1
+ * @param callable $comparisonCallback A callback to compare two values, returning
+ * -1, 0 or 1 in the style of strcmp().
+ * @param string $target The target value to find.
+ *
+ * @return int|bool The item index of the lower bound, or false if the target value
+ * sorts before all items.
+ */
+ public static function findLowerBound( $valueCallback, $valueCount,
+ $comparisonCallback, $target
+ ) {
+ if ( $valueCount === 0 ) {
+ return false;
+ }
+
+ $min = 0;
+ $max = $valueCount;
+ do {
+ $mid = $min + ( ( $max - $min ) >> 1 );
+ $item = call_user_func( $valueCallback, $mid );
+ $comparison = call_user_func( $comparisonCallback, $target, $item );
+ if ( $comparison > 0 ) {
+ $min = $mid;
+ } elseif ( $comparison == 0 ) {
+ $min = $mid;
+ break;
+ } else {
+ $max = $mid;
+ }
+ } while ( $min < $max - 1 );
+
+ if ( $min == 0 ) {
+ $item = call_user_func( $valueCallback, $min );
+ $comparison = call_user_func( $comparisonCallback, $target, $item );
+ if ( $comparison < 0 ) {
+ // Before the first item
+ return false;
+ }
+ }
+ return $min;
+ }
+
+ /**
+ * Do array_diff_assoc() on multi-dimensional arrays.
+ *
+ * Note: empty arrays are removed.
+ *
+ * @since 1.23
+ *
+ * @param array $array1 The array to compare from
+ * @param array $array2,... More arrays to compare against
+ * @return array An array containing all the values from array1
+ * that are not present in any of the other arrays.
+ */
+ public static function arrayDiffAssocRecursive( $array1 ) {
+ $arrays = func_get_args();
+ array_shift( $arrays );
+ $ret = [];
+
+ foreach ( $array1 as $key => $value ) {
+ if ( is_array( $value ) ) {
+ $args = [ $value ];
+ foreach ( $arrays as $array ) {
+ if ( isset( $array[$key] ) ) {
+ $args[] = $array[$key];
+ }
+ }
+ $valueret = call_user_func_array( __METHOD__, $args );
+ if ( count( $valueret ) ) {
+ $ret[$key] = $valueret;
+ }
+ } else {
+ foreach ( $arrays as $array ) {
+ if ( isset( $array[$key] ) && $array[$key] === $value ) {
+ continue 2;
+ }
+ }
+ $ret[$key] = $value;
+ }
+ }
+
+ return $ret;
+ }
+}
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