CRM/Utils/Array.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 5                                                  |
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   6  | Copyright CiviCRM LLC (c) 2004-2018                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
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  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
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  25  +--------------------------------------------------------------------+
  26  */
  27
  28 /**
  29  * Provides a collection of static methods for array manipulation.
  30  *
  31  * @package CRM
  32  * @copyright CiviCRM LLC (c) 2004-2018
  33  */
  34 class CRM_Utils_Array {
  35
  36   /**
  37    * Returns $list[$key] if such element exists, or a default value otherwise.
  38    *
  39    * If $list is not actually an array at all, then the default value is
  40    * returned.
  41    *
  42    *
  43    * @param string $key
  44    *   Key value to look up in the array.
  45    * @param array $list
  46    *   Array from which to look up a value.
  47    * @param mixed $default
  48    *   (optional) Value to return $list[$key] does not exist.
  49    *
  50    * @return mixed
  51    *   Can return any type, since $list might contain anything.
  52    */
  53   public static function value($key, $list, $default = NULL) {
  54     if (is_array($list)) {
  55       return array_key_exists($key, $list) ? $list[$key] : $default;
  56     }
  57     return $default;
  58   }
  59
  60   /**
  61    * Recursively searches an array for a key, returning the first value found.
  62    *
  63    * If $params[$key] does not exist and $params contains arrays, descend into
  64    * each array in a depth-first manner, in array iteration order.
  65    *
  66    * @param array $params
  67    *   The array to be searched.
  68    * @param string $key
  69    *   The key to search for.
  70    *
  71    * @return mixed
  72    *   The value of the key, or null if the key is not found.
  73    */
  74   public static function retrieveValueRecursive(&$params, $key) {
  75     if (!is_array($params)) {
  76       return NULL;
  77     }
  78     elseif ($value = CRM_Utils_Array::value($key, $params)) {
  79       return $value;
  80     }
  81     else {
  82       foreach ($params as $subParam) {
  83         if (is_array($subParam) &&
  84           $value = self::retrieveValueRecursive($subParam, $key)
  85         ) {
  86           return $value;
  87         }
  88       }
  89     }
  90     return NULL;
  91   }
  92
  93   /**
  94    * Wraps and slightly changes the behavior of PHP's array_search().
  95    *
  96    * This function reproduces the behavior of array_search() from PHP prior to
  97    * version 4.2.0, which was to return NULL on failure. This function also
  98    * checks that $list is an array before attempting to search it.
  99    *
 100    *
 101    * @param mixed $value
 102    *   The value to search for.
 103    * @param array $list
 104    *   The array to be searched.
 105    *
 106    * @return int|string|null
 107    *   Returns the key, which could be an int or a string, or NULL on failure.
 108    */
 109   public static function key($value, $list) {
 110     if (is_array($list)) {
 111       $key = array_search($value, $list);
 112
 113       // array_search returns key if found, false otherwise
 114       // it may return values like 0 or empty string which
 115       // evaluates to false
 116       // hence we must use identical comparison operator
 117       return ($key === FALSE) ? NULL : $key;
 118     }
 119     return NULL;
 120   }
 121
 122   /**
 123    * Builds an XML fragment representing an array.
 124    *
 125    * Depending on the nature of the keys of the array (and its sub-arrays,
 126    * if any) the XML fragment may not be valid.
 127    *
 128    * @param array $list
 129    *   The array to be serialized.
 130    * @param int $depth
 131    *   (optional) Indentation depth counter.
 132    * @param string $seperator
 133    *   (optional) String to be appended after open/close tags.
 134    *
 135    * @return string
 136    *   XML fragment representing $list.
 137    */
 138   public static function &xml(&$list, $depth = 1, $seperator = "\n") {
 139     $xml = '';
 140     foreach ($list as $name => $value) {
 141       $xml .= str_repeat(' ', $depth * 4);
 142       if (is_array($value)) {
 143         $xml .= "<{$name}>{$seperator}";
 144         $xml .= self::xml($value, $depth + 1, $seperator);
 145         $xml .= str_repeat(' ', $depth * 4);
 146         $xml .= "</{$name}>{$seperator}";
 147       }
 148       else {
 149         // make sure we escape value
 150         $value = self::escapeXML($value);
 151         $xml .= "<{$name}>$value</{$name}>{$seperator}";
 152       }
 153     }
 154     return $xml;
 155   }
 156
 157   /**
 158    * Sanitizes a string for serialization in CRM_Utils_Array::xml().
 159    *
 160    * Replaces '&', '<', and '>' with their XML escape sequences. Replaces '^A'
 161    * with a comma.
 162    *
 163    * @param string $value
 164    *   String to be sanitized.
 165    *
 166    * @return string
 167    *   Sanitized version of $value.
 168    */
 169   public static function escapeXML($value) {
 170     static $src = NULL;
 171     static $dst = NULL;
 172
 173     if (!$src) {
 174       $src = array('&', '<', '>', '\ 1');
 175       $dst = array('&amp;', '&lt;', '&gt;', ',');
 176     }
 177
 178     return str_replace($src, $dst, $value);
 179   }
 180
 181   /**
 182    * Converts a nested array to a flat array.
 183    *
 184    * The nested structure is preserved in the string values of the keys of the
 185    * flat array.
 186    *
 187    * Example nested array:
 188    * Array
 189    * (
 190    *     [foo] => Array
 191    *         (
 192    *             [0] => bar
 193    *             [1] => baz
 194    *             [2] => 42
 195    *         )
 196    *
 197    *     [asdf] => Array
 198    *         (
 199    *             [merp] => bleep
 200    *             [quack] => Array
 201    *                 (
 202    *                     [0] => 1
 203    *                     [1] => 2
 204    *                     [2] => 3
 205    *                 )
 206    *
 207    *         )
 208    *
 209    *     [quux] => 999
 210    * )
 211    *
 212    * Corresponding flattened array:
 213    * Array
 214    * (
 215    *     [foo.0] => bar
 216    *     [foo.1] => baz
 217    *     [foo.2] => 42
 218    *     [asdf.merp] => bleep
 219    *     [asdf.quack.0] => 1
 220    *     [asdf.quack.1] => 2
 221    *     [asdf.quack.2] => 3
 222    *     [quux] => 999
 223    * )
 224    *
 225    * @param array $list
 226    *   Array to be flattened.
 227    * @param array $flat
 228    *   Destination array.
 229    * @param string $prefix
 230    *   (optional) String to prepend to keys.
 231    * @param string $seperator
 232    *   (optional) String that separates the concatenated keys.
 233    */
 234   public static function flatten(&$list, &$flat, $prefix = '', $seperator = ".") {
 235     foreach ($list as $name => $value) {
 236       $newPrefix = ($prefix) ? $prefix . $seperator . $name : $name;
 237       if (is_array($value)) {
 238         self::flatten($value, $flat, $newPrefix, $seperator);
 239       }
 240       else {
 241         if (!empty($value)) {
 242           $flat[$newPrefix] = $value;
 243         }
 244       }
 245     }
 246   }
 247
 248   /**
 249    * Converts an array with path-like keys into a tree of arrays.
 250    *
 251    * This function is the inverse of CRM_Utils_Array::flatten().
 252    *
 253    * @param string $delim
 254    *   A path delimiter
 255    * @param array $arr
 256    *   A one-dimensional array indexed by string keys
 257    *
 258    * @return array
 259    *   Array-encoded tree
 260    */
 261   public function unflatten($delim, &$arr) {
 262     $result = array();
 263     foreach ($arr as $key => $value) {
 264       $path = explode($delim, $key);
 265       $node = &$result;
 266       while (count($path) > 1) {
 267         $key = array_shift($path);
 268         if (!isset($node[$key])) {
 269           $node[$key] = array();
 270         }
 271         $node = &$node[$key];
 272       }
 273       // last part of path
 274       $key = array_shift($path);
 275       $node[$key] = $value;
 276     }
 277     return $result;
 278   }
 279
 280   /**
 281    * Merges two arrays.
 282    *
 283    * If $a1[foo] and $a2[foo] both exist and are both arrays, the merge
 284    * process recurses into those sub-arrays. If $a1[foo] and $a2[foo] both
 285    * exist but they are not both arrays, the value from $a1 overrides the
 286    * value from $a2 and the value from $a2 is discarded.
 287    *
 288    * @param array $a1
 289    *   First array to be merged.
 290    * @param array $a2
 291    *   Second array to be merged.
 292    *
 293    * @return array
 294    *   The merged array.
 295    */
 296   public static function crmArrayMerge($a1, $a2) {
 297     if (empty($a1)) {
 298       return $a2;
 299     }
 300
 301     if (empty($a2)) {
 302       return $a1;
 303     }
 304
 305     $a3 = array();
 306     foreach ($a1 as $key => $value) {
 307       if (array_key_exists($key, $a2) &&
 308         is_array($a2[$key]) && is_array($a1[$key])
 309       ) {
 310         $a3[$key] = array_merge($a1[$key], $a2[$key]);
 311       }
 312       else {
 313         $a3[$key] = $a1[$key];
 314       }
 315     }
 316
 317     foreach ($a2 as $key => $value) {
 318       if (array_key_exists($key, $a1)) {
 319         // already handled in above loop
 320         continue;
 321       }
 322       $a3[$key] = $a2[$key];
 323     }
 324
 325     return $a3;
 326   }
 327
 328   /**
 329    * Determines whether an array contains any sub-arrays.
 330    *
 331    * @param array $list
 332    *   The array to inspect.
 333    *
 334    * @return bool
 335    *   True if $list contains at least one sub-array, false otherwise.
 336    */
 337   public static function isHierarchical(&$list) {
 338     foreach ($list as $n => $v) {
 339       if (is_array($v)) {
 340         return TRUE;
 341       }
 342     }
 343     return FALSE;
 344   }
 345
 346   /**
 347    * Is array A a subset of array B.
 348    *
 349    * @param array $subset
 350    * @param array $superset
 351    *
 352    * @return bool
 353    *   TRUE if $subset is a subset of $superset
 354    */
 355   public static function isSubset($subset, $superset) {
 356     foreach ($subset as $expected) {
 357       if (!in_array($expected, $superset)) {
 358         return FALSE;
 359       }
 360     }
 361     return TRUE;
 362   }
 363
 364   /**
 365    * Searches an array recursively in an optionally case-insensitive manner.
 366    *
 367    * @param string $value
 368    *   Value to search for.
 369    * @param array $params
 370    *   Array to search within.
 371    * @param bool $caseInsensitive
 372    *   (optional) Whether to search in a case-insensitive manner.
 373    *
 374    * @return bool
 375    *   True if $value was found, false otherwise.
 376    */
 377   public static function crmInArray($value, $params, $caseInsensitive = TRUE) {
 378     foreach ($params as $item) {
 379       if (is_array($item)) {
 380         $ret = crmInArray($value, $item, $caseInsensitive);
 381       }
 382       else {
 383         $ret = ($caseInsensitive) ? strtolower($item) == strtolower($value) : $item == $value;
 384         if ($ret) {
 385           return $ret;
 386         }
 387       }
 388     }
 389     return FALSE;
 390   }
 391
 392   /**
 393    * Convert associative array names to values and vice-versa.
 394    *
 395    * This function is used by by import functions and some webforms.
 396    *
 397    * @param array $defaults
 398    * @param string $property
 399    * @param $lookup
 400    * @param $reverse
 401    *
 402    * @return bool
 403    */
 404   public static function lookupValue(&$defaults, $property, $lookup, $reverse) {
 405     $id = $property . '_id';
 406
 407     $src = $reverse ? $property : $id;
 408     $dst = $reverse ? $id : $property;
 409
 410     if (!array_key_exists(strtolower($src), array_change_key_case($defaults, CASE_LOWER))) {
 411       return FALSE;
 412     }
 413
 414     $look = $reverse ? array_flip($lookup) : $lookup;
 415
 416     // trim lookup array, ignore . ( fix for CRM-1514 ), eg for prefix/suffix make sure Dr. and Dr both are valid
 417     $newLook = array();
 418     foreach ($look as $k => $v) {
 419       $newLook[trim($k, ".")] = $v;
 420     }
 421
 422     $look = $newLook;
 423
 424     if (is_array($look)) {
 425       if (!array_key_exists(trim(strtolower($defaults[strtolower($src)]), '.'), array_change_key_case($look, CASE_LOWER))) {
 426         return FALSE;
 427       }
 428     }
 429
 430     $tempLook = array_change_key_case($look, CASE_LOWER);
 431
 432     $defaults[$dst] = $tempLook[trim(strtolower($defaults[strtolower($src)]), '.')];
 433     return TRUE;
 434   }
 435
 436   /**
 437    * Checks whether an array is empty.
 438    *
 439    * An array is empty if its values consist only of NULL and empty sub-arrays.
 440    * Containing a non-NULL value or non-empty array makes an array non-empty.
 441    *
 442    * If something other than an array is passed, it is considered to be empty.
 443    *
 444    * If nothing is passed at all, the default value provided is empty.
 445    *
 446    * @param array $array
 447    *   (optional) Array to be checked for emptiness.
 448    *
 449    * @return bool
 450    *   True if the array is empty.
 451    */
 452   public static function crmIsEmptyArray($array = array()) {
 453     if (!is_array($array)) {
 454       return TRUE;
 455     }
 456     foreach ($array as $element) {
 457       if (is_array($element)) {
 458         if (!self::crmIsEmptyArray($element)) {
 459           return FALSE;
 460         }
 461       }
 462       elseif (isset($element)) {
 463         return FALSE;
 464       }
 465     }
 466     return TRUE;
 467   }
 468
 469   /**
 470    * Sorts an associative array of arrays by an attribute using strnatcmp().
 471    *
 472    * @param array $array
 473    *   Array to be sorted.
 474    * @param string|array $field
 475    *   Name of the attribute used for sorting.
 476    *
 477    * @return array
 478    *   Sorted array
 479    */
 480   public static function crmArraySortByField($array, $field) {
 481     $fields = (array) $field;
 482     uasort($array, function ($a, $b) use ($fields) {
 483       foreach ($fields as $f) {
 484         $v = strnatcmp($a[$f], $b[$f]);
 485         if ($v !== 0) {
 486           return $v;
 487         }
 488       }
 489       return 0;
 490     });
 491     return $array;
 492   }
 493
 494   /**
 495    * Recursively removes duplicate values from a multi-dimensional array.
 496    *
 497    * @param array $array
 498    *   The input array possibly containing duplicate values.
 499    *
 500    * @return array
 501    *   The input array with duplicate values removed.
 502    */
 503   public static function crmArrayUnique($array) {
 504     $result = array_map("unserialize", array_unique(array_map("serialize", $array)));
 505     foreach ($result as $key => $value) {
 506       if (is_array($value)) {
 507         $result[$key] = self::crmArrayUnique($value);
 508       }
 509     }
 510     return $result;
 511   }
 512
 513   /**
 514    * Sorts an array and maintains index association (with localization).
 515    *
 516    * Uses Collate from the PECL "intl" package, if available, for UTF-8
 517    * sorting (e.g. list of countries). Otherwise calls PHP's asort().
 518    *
 519    * On Debian/Ubuntu: apt-get install php5-intl
 520    *
 521    * @param array $array
 522    *   (optional) Array to be sorted.
 523    *
 524    * @return array
 525    *   Sorted array.
 526    */
 527   public static function asort($array = array()) {
 528     $lcMessages = CRM_Utils_System::getUFLocale();
 529
 530     if ($lcMessages && $lcMessages != 'en_US' && class_exists('Collator')) {
 531       $collator = new Collator($lcMessages . '.utf8');
 532       $collator->asort($array);
 533     }
 534     else {
 535       // This calls PHP's built-in asort().
 536       asort($array);
 537     }
 538
 539     return $array;
 540   }
 541
 542   /**
 543    * Unsets an arbitrary list of array elements from an associative array.
 544    *
 545    * @param array $items
 546    *   The array from which to remove items.
 547    *
 548    * Additional params:
 549    *   When passed a string, unsets $items[$key].
 550    *   When passed an array of strings, unsets $items[$k] for each string $k in the array.
 551    */
 552   public static function remove(&$items) {
 553     foreach (func_get_args() as $n => $key) {
 554       // Skip argument 0 ($items) by testing $n for truth.
 555       if ($n && is_array($key)) {
 556         foreach ($key as $k) {
 557           unset($items[$k]);
 558         }
 559       }
 560       elseif ($n) {
 561         unset($items[$key]);
 562       }
 563     }
 564   }
 565
 566   /**
 567    * Builds an array-tree which indexes the records in an array.
 568    *
 569    * @param string[] $keys
 570    *   Properties by which to index.
 571    * @param object|array $records
 572    *
 573    * @return array
 574    *   Multi-dimensional array, with one layer for each key.
 575    */
 576   public static function index($keys, $records) {
 577     $final_key = array_pop($keys);
 578
 579     $result = array();
 580     foreach ($records as $record) {
 581       $node = &$result;
 582       foreach ($keys as $key) {
 583         if (is_array($record)) {
 584           $keyvalue = isset($record[$key]) ? $record[$key] : NULL;
 585         }
 586         else {
 587           $keyvalue = isset($record->{$key}) ? $record->{$key} : NULL;
 588         }
 589         if (isset($node[$keyvalue]) && !is_array($node[$keyvalue])) {
 590           $node[$keyvalue] = array();
 591         }
 592         $node = &$node[$keyvalue];
 593       }
 594       if (is_array($record)) {
 595         $node[$record[$final_key]] = $record;
 596       }
 597       else {
 598         $node[$record->{$final_key}] = $record;
 599       }
 600     }
 601     return $result;
 602   }
 603
 604   /**
 605    * Iterates over a list of records and returns the value of some property.
 606    *
 607    * @param string $prop
 608    *   Property to retrieve.
 609    * @param array|object $records
 610    *   A list of records.
 611    *
 612    * @return array
 613    *   Keys are the original keys of $records; values are the $prop values.
 614    */
 615   public static function collect($prop, $records) {
 616     $result = array();
 617     if (is_array($records)) {
 618       foreach ($records as $key => $record) {
 619         if (is_object($record)) {
 620           $result[$key] = $record->{$prop};
 621         }
 622         else {
 623           $result[$key] = self::value($prop, $record);
 624         }
 625       }
 626     }
 627     return $result;
 628   }
 629
 630   /**
 631    * Iterates over a list of objects and executes some method on each.
 632    *
 633    * Comparison:
 634    *   - This is like array_map(), except it executes the objects' method
 635    *     instead of a free-form callable.
 636    *   - This is like Array::collect(), except it uses a method
 637    *     instead of a property.
 638    *
 639    * @param string $method
 640    *   The method to execute.
 641    * @param array|Traversable $objects
 642    *   A list of objects.
 643    * @param array $args
 644    *   An optional list of arguments to pass to the method.
 645    *
 646    * @return array
 647    *   Keys are the original keys of $objects; values are the method results.
 648    */
 649   public static function collectMethod($method, $objects, $args = array()) {
 650     $result = array();
 651     if (is_array($objects)) {
 652       foreach ($objects as $key => $object) {
 653         $result[$key] = call_user_func_array(array($object, $method), $args);
 654       }
 655     }
 656     return $result;
 657   }
 658
 659   /**
 660    * Trims delimiters from a string and then splits it using explode().
 661    *
 662    * This method works mostly like PHP's built-in explode(), except that
 663    * surrounding delimiters are trimmed before explode() is called.
 664    *
 665    * Also, if an array or NULL is passed as the $values parameter, the value is
 666    * returned unmodified rather than being passed to explode().
 667    *
 668    * @param array|null|string $values
 669    *   The input string (or an array, or NULL).
 670    * @param string $delim
 671    *   (optional) The boundary string.
 672    *
 673    * @return array|null
 674    *   An array of strings produced by explode(), or the unmodified input
 675    *   array, or NULL.
 676    */
 677   public static function explodePadded($values, $delim = CRM_Core_DAO::VALUE_SEPARATOR) {
 678     if ($values === NULL) {
 679       return NULL;
 680     }
 681     // If we already have an array, no need to continue
 682     if (is_array($values)) {
 683       return $values;
 684     }
 685     // Empty string -> empty array
 686     if ($values === '') {
 687       return array();
 688     }
 689     return explode($delim, trim((string) $values, $delim));
 690   }
 691
 692   /**
 693    * Joins array elements with a string, adding surrounding delimiters.
 694    *
 695    * This method works mostly like PHP's built-in implode(), but the generated
 696    * string is surrounded by delimiter characters. Also, if NULL is passed as
 697    * the $values parameter, NULL is returned.
 698    *
 699    * @param mixed $values
 700    *   Array to be imploded. If a non-array is passed, it will be cast to an
 701    *   array.
 702    * @param string $delim
 703    *   Delimiter to be used for implode() and which will surround the output
 704    *   string.
 705    *
 706    * @return string|NULL
 707    *   The generated string, or NULL if NULL was passed as $values parameter.
 708    */
 709   public static function implodePadded($values, $delim = CRM_Core_DAO::VALUE_SEPARATOR) {
 710     if ($values === NULL) {
 711       return NULL;
 712     }
 713     // If we already have a string, strip $delim off the ends so it doesn't get added twice
 714     if (is_string($values)) {
 715       $values = trim($values, $delim);
 716     }
 717     return $delim . implode($delim, (array) $values) . $delim;
 718   }
 719
 720   /**
 721    * Modifies a key in an array while preserving the key order.
 722    *
 723    * By default when an element is added to an array, it is added to the end.
 724    * This method allows for changing an existing key while preserving its
 725    * position in the array.
 726    *
 727    * The array is both modified in-place and returned.
 728    *
 729    * @param array $elementArray
 730    *   Array to manipulate.
 731    * @param string $oldKey
 732    *   Old key to be replaced.
 733    * @param string $newKey
 734    *   Replacement key string.
 735    *
 736    * @throws Exception
 737    *   Throws a generic Exception if $oldKey is not found in $elementArray.
 738    *
 739    * @return array
 740    *   The manipulated array.
 741    */
 742   public static function crmReplaceKey(&$elementArray, $oldKey, $newKey) {
 743     $keys = array_keys($elementArray);
 744     if (FALSE === $index = array_search($oldKey, $keys)) {
 745       throw new Exception(sprintf('key "%s" does not exit', $oldKey));
 746     }
 747     $keys[$index] = $newKey;
 748     $elementArray = array_combine($keys, array_values($elementArray));
 749     return $elementArray;
 750   }
 751
 752   /**
 753    * Searches array keys by regex, returning the value of the first match.
 754    *
 755    * Given a regular expression and an array, this method searches the keys
 756    * of the array using the regular expression. The first match is then used
 757    * to index into the array, and the associated value is retrieved and
 758    * returned. If no matches are found, or if something other than an array
 759    * is passed, then a default value is returned. Unless otherwise specified,
 760    * the default value is NULL.
 761    *
 762    * @param string $regexKey
 763    *   The regular expression to use when searching for matching keys.
 764    * @param array $list
 765    *   The array whose keys will be searched.
 766    * @param mixed $default
 767    *   (optional) The default value to return if the regex does not match an
 768    *   array key, or if something other than an array is passed.
 769    *
 770    * @return mixed
 771    *   The value found.
 772    */
 773   public static function valueByRegexKey($regexKey, $list, $default = NULL) {
 774     if (is_array($list) && $regexKey) {
 775       $matches = preg_grep($regexKey, array_keys($list));
 776       $key = reset($matches);
 777       return ($key && array_key_exists($key, $list)) ? $list[$key] : $default;
 778     }
 779     return $default;
 780   }
 781
 782   /**
 783    * Generates the Cartesian product of zero or more vectors.
 784    *
 785    * @param array $dimensions
 786    *   List of dimensions to multiply.
 787    *   Each key is a dimension name; each value is a vector.
 788    * @param array $template
 789    *   (optional) A base set of values included in every output.
 790    *
 791    * @return array
 792    *   Each item is a distinct combination of values from $dimensions.
 793    *
 794    *   For example, the product of
 795    *   {
 796    *   fg => {red, blue},
 797    *   bg => {white, black}
 798    *   }
 799    *   would be
 800    *   {
 801    *   {fg => red, bg => white},
 802    *   {fg => red, bg => black},
 803    *   {fg => blue, bg => white},
 804    *   {fg => blue, bg => black}
 805    *   }
 806    */
 807   public static function product($dimensions, $template = array()) {
 808     if (empty($dimensions)) {
 809       return array($template);
 810     }
 811
 812     foreach ($dimensions as $key => $value) {
 813       $firstKey = $key;
 814       $firstValues = $value;
 815       break;
 816     }
 817     unset($dimensions[$key]);
 818
 819     $results = array();
 820     foreach ($firstValues as $firstValue) {
 821       foreach (self::product($dimensions, $template) as $result) {
 822         $result[$firstKey] = $firstValue;
 823         $results[] = $result;
 824       }
 825     }
 826
 827     return $results;
 828   }
 829
 830   /**
 831    * Get the first element of an array.
 832    *
 833    * @param array $array
 834    * @return mixed|NULL
 835    */
 836   public static function first($array) {
 837     foreach ($array as $value) {
 838       return $value;
 839     }
 840     return NULL;
 841   }
 842
 843   /**
 844    * Extract any $keys from $array and copy to a new array.
 845    *
 846    * Note: If a $key does not appear in $array, then it will
 847    * not appear in the result.
 848    *
 849    * @param array $array
 850    * @param array $keys
 851    *   List of keys to copy.
 852    * @return array
 853    */
 854   public static function subset($array, $keys) {
 855     $result = array();
 856     foreach ($keys as $key) {
 857       if (isset($array[$key])) {
 858         $result[$key] = $array[$key];
 859       }
 860     }
 861     return $result;
 862   }
 863
 864   /**
 865    * Transform an associative array of key=>value pairs into a non-associative array of arrays.
 866    * This is necessary to preserve sort order when sending an array through json_encode.
 867    *
 868    * @param array $associative
 869    * @param string $keyName
 870    * @param string $valueName
 871    * @return array
 872    */
 873   public static function makeNonAssociative($associative, $keyName = 'key', $valueName = 'value') {
 874     $output = array();
 875     foreach ($associative as $key => $val) {
 876       $output[] = array($keyName => $key, $valueName => $val);
 877     }
 878     return $output;
 879   }
 880
 881   /**
 882    * Diff multidimensional arrays
 883    * (array_diff does not support multidimensional array)
 884    *
 885    * @param array $array1
 886    * @param array $array2
 887    * @return array
 888    */
 889   public static function multiArrayDiff($array1, $array2) {
 890     $arrayDiff = array();
 891     foreach ($array1 as $mKey => $mValue) {
 892       if (array_key_exists($mKey, $array2)) {
 893         if (is_array($mValue)) {
 894           $recursiveDiff = self::multiArrayDiff($mValue, $array2[$mKey]);
 895           if (count($recursiveDiff)) {
 896             $arrayDiff[$mKey] = $recursiveDiff;
 897           }
 898         }
 899         else {
 900           if ($mValue != $array2[$mKey]) {
 901             $arrayDiff[$mKey] = $mValue;
 902           }
 903         }
 904       }
 905       else {
 906         $arrayDiff[$mKey] = $mValue;
 907       }
 908     }
 909     return $arrayDiff;
 910   }
 911
 912   /**
 913    * Given a 2-dimensional matrix, create a new matrix with a restricted list of columns.
 914    *
 915    * @param array $matrix
 916    *   All matrix data, as a list of rows.
 917    * @param array $columns
 918    *   List of column names.
 919    * @return array
 920    */
 921   public static function filterColumns($matrix, $columns) {
 922     $newRows = array();
 923     foreach ($matrix as $pos => $oldRow) {
 924       $newRow = array();
 925       foreach ($columns as $column) {
 926         $newRow[$column] = CRM_Utils_Array::value($column, $oldRow);
 927       }
 928       $newRows[$pos] = $newRow;
 929     }
 930     return $newRows;
 931   }
 932
 933   /**
 934    * Rewrite the keys in an array.
 935    *
 936    * @param array $array
 937    * @param string|callable $indexBy
 938    *   Either the value to key by, or a function($key, $value) that returns the new key.
 939    * @return array
 940    */
 941   public static function rekey($array, $indexBy) {
 942     $result = array();
 943     foreach ($array as $key => $value) {
 944       $newKey = is_callable($indexBy) ? $indexBy($key, $value) : $value[$indexBy];
 945       $result[$newKey] = $value;
 946     }
 947     return $result;
 948   }
 949
 950   /**
 951    * Copy all properties of $other into $array (recursively).
 952    *
 953    * @param array|ArrayAccess $array
 954    * @param array $other
 955    */
 956   public static function extend(&$array, $other) {
 957     foreach ($other as $key => $value) {
 958       if (is_array($value)) {
 959         self::extend($array[$key], $value);
 960       }
 961       else {
 962         $array[$key] = $value;
 963       }
 964     }
 965   }
 966
 967   /**
 968    * Get a single value from an array-tre.
 969    *
 970    * @param array $arr
 971    *   Ex: array('foo'=>array('bar'=>123)).
 972    * @param array $pathParts
 973    *   Ex: array('foo',bar').
 974    * @return mixed|NULL
 975    *   Ex 123.
 976    */
 977   public static function pathGet($arr, $pathParts) {
 978     $r = $arr;
 979     foreach ($pathParts as $part) {
 980       if (!isset($r[$part])) {
 981         return NULL;
 982       }
 983       $r = $r[$part];
 984     }
 985     return $r;
 986   }
 987
 988   /**
 989    * Set a single value in an array tree.
 990    *
 991    * @param array $arr
 992    *   Ex: array('foo'=>array('bar'=>123)).
 993    * @param array $pathParts
 994    *   Ex: array('foo',bar').
 995    * @param $value
 996    *   Ex: 456.
 997    */
 998   public static function pathSet(&$arr, $pathParts, $value) {
 999     $r = &$arr;
1000     $last = array_pop($pathParts);
1001     foreach ($pathParts as $part) {
1002       if (!isset($r[$part])) {
1003         $r[$part] = array();
1004       }
1005       $r = &$r[$part];
1006     }
1007     $r[$last] = $value;
1008   }
1009
1010   /**
1011    * Convert a simple dictionary into separate key+value records.
1012    *
1013    * @param array $array
1014    *   Ex: array('foo' => 'bar').
1015    * @param string $keyField
1016    *   Ex: 'key'.
1017    * @param string $valueField
1018    *   Ex: 'value'.
1019    * @return array
1020    *   Ex: array(
1021    *     0 => array('key' => 'foo', 'value' => 'bar')
1022    *   ).
1023    */
1024   public static function toKeyValueRows($array, $keyField = 'key', $valueField = 'value') {
1025     $result = array();
1026     foreach ($array as $key => $value) {
1027       $result[] = array(
1028         $keyField => $key,
1029         $valueField => $value,
1030       );
1031     }
1032     return $result;
1033   }
1034
1035   /**
1036    * Convert array where key(s) holds the actual value and value(s) as 1 into array of actual values
1037    *  Ex: array('foobar' => 1, 4 => 1) formatted into array('foobar', 4)
1038    *
1039    * @deprecated use convertCheckboxInputToArray instead (after testing)
1040    * https://github.com/civicrm/civicrm-core/pull/8169
1041    *
1042    * @param array $array
1043    */
1044   public static function formatArrayKeys(&$array) {
1045     if (!is_array($array)) {
1046       return;
1047     }
1048     $keys = array_keys($array, 1);
1049     if (count($keys) > 1 ||
1050       (count($keys) == 1 &&
1051         (current($keys) > 1 ||
1052           is_string(current($keys)) ||
1053           (current($keys) == 1 && $array[1] == 1) // handle (0 => 4), (1 => 1)
1054         )
1055       )
1056     ) {
1057       $array = $keys;
1058     }
1059   }
1060
1061   /**
1062    * Convert the data format coming in from checkboxes to an array of values.
1063    *
1064    * The input format from check boxes looks like
1065    *   array('value1' => 1, 'value2' => 1). This function converts those values to
1066    *   array(''value1', 'value2).
1067    *
1068    * The function will only alter the array if all values are equal to 1.
1069    *
1070    * @param array $input
1071    *
1072    * @return array
1073    */
1074   public static function convertCheckboxFormatToArray($input) {
1075     if (isset($input[0])) {
1076       return $input;
1077     }
1078     $keys = array_keys($input, 1);
1079     if ((count($keys) == count($input))) {
1080       return $keys;
1081     }
1082     return $input;
1083   }
1084
1085   /**
1086    * Ensure that array is encoded in utf8 format.
1087    *
1088    * @param array $array
1089    *
1090    * @return array $array utf8-encoded.
1091    */
1092   public static function encode_items($array) {
1093     foreach ($array as $key => $value) {
1094       if (is_array($value)) {
1095         $array[$key] = self::encode_items($value);
1096       }
1097       elseif (is_string($value)) {
1098         $array[$key] = mb_convert_encoding($value, mb_detect_encoding($value, mb_detect_order(), TRUE), 'UTF-8');
1099       }
1100       else {
1101         $array[$key] = $value;
1102       }
1103     }
1104     return $array;
1105   }
1106
1107   /**
1108    * Build tree of elements.
1109    *
1110    * @param array $elements
1111    * @param int|null $parentId
1112    *
1113    * @return array
1114    */
1115   public static function buildTree($elements, $parentId = NULL) {
1116     $branch = array();
1117
1118     foreach ($elements as $element) {
1119       if ($element['parent_id'] == $parentId) {
1120         $children = self::buildTree($elements, $element['id']);
1121         if ($children) {
1122           $element['children'] = $children;
1123         }
1124         $branch[] = $element;
1125       }
1126     }
1127
1128     return $branch;
1129   }
1130
1131   /**
1132    * Find search string in tree.
1133    *
1134    * @param string $search
1135    * @param array $tree
1136    * @param string $field
1137    *
1138    * @return array|null
1139    */
1140   public static function findInTree($search, $tree, $field = 'id') {
1141     foreach ($tree as $item) {
1142       if ($item[$field] == $search) {
1143         return $item;
1144       }
1145       if (!empty($item['children'])) {
1146         $found = self::findInTree($search, $item['children']);
1147         if ($found) {
1148           return $found;
1149         }
1150       }
1151     }
1152     return NULL;
1153   }
1154
1155 }