CRM/Utils/Array.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.7                                                |
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   6  | Copyright CiviCRM LLC (c) 2004-2017                                |
   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  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
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  17  | See the GNU Affero General Public License for more details.        |
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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) 2004-2017
  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 both the web form layer and the api. Note that
 396    * the api needs the name => value conversion, also the view layer typically
 397    * requires value => name conversion
 398    *
 399    * @param array $defaults
 400    * @param string $property
 401    * @param $lookup
 402    * @param $reverse
 403    *
 404    * @return bool
 405    */
 406   public static function lookupValue(&$defaults, $property, $lookup, $reverse) {
 407     $id = $property . '_id';
 408
 409     $src = $reverse ? $property : $id;
 410     $dst = $reverse ? $id : $property;
 411
 412     if (!array_key_exists(strtolower($src), array_change_key_case($defaults, CASE_LOWER))) {
 413       return FALSE;
 414     }
 415
 416     $look = $reverse ? array_flip($lookup) : $lookup;
 417
 418     // trim lookup array, ignore . ( fix for CRM-1514 ), eg for prefix/suffix make sure Dr. and Dr both are valid
 419     $newLook = array();
 420     foreach ($look as $k => $v) {
 421       $newLook[trim($k, ".")] = $v;
 422     }
 423
 424     $look = $newLook;
 425
 426     if (is_array($look)) {
 427       if (!array_key_exists(trim(strtolower($defaults[strtolower($src)]), '.'), array_change_key_case($look, CASE_LOWER))) {
 428         return FALSE;
 429       }
 430     }
 431
 432     $tempLook = array_change_key_case($look, CASE_LOWER);
 433
 434     $defaults[$dst] = $tempLook[trim(strtolower($defaults[strtolower($src)]), '.')];
 435     return TRUE;
 436   }
 437
 438   /**
 439    * Checks whether an array is empty.
 440    *
 441    * An array is empty if its values consist only of NULL and empty sub-arrays.
 442    * Containing a non-NULL value or non-empty array makes an array non-empty.
 443    *
 444    * If something other than an array is passed, it is considered to be empty.
 445    *
 446    * If nothing is passed at all, the default value provided is empty.
 447    *
 448    * @param array $array
 449    *   (optional) Array to be checked for emptiness.
 450    *
 451    * @return bool
 452    *   True if the array is empty.
 453    */
 454   public static function crmIsEmptyArray($array = array()) {
 455     if (!is_array($array)) {
 456       return TRUE;
 457     }
 458     foreach ($array as $element) {
 459       if (is_array($element)) {
 460         if (!self::crmIsEmptyArray($element)) {
 461           return FALSE;
 462         }
 463       }
 464       elseif (isset($element)) {
 465         return FALSE;
 466       }
 467     }
 468     return TRUE;
 469   }
 470
 471   /**
 472    * Sorts an associative array of arrays by an attribute using strnatcmp().
 473    *
 474    * @param array $array
 475    *   Array to be sorted.
 476    * @param string $field
 477    *   Name of the attribute used for sorting.
 478    *
 479    * @return array
 480    *   Sorted array
 481    */
 482   public static function crmArraySortByField($array, $field) {
 483     $code = "return strnatcmp(\$a['$field'], \$b['$field']);";
 484     uasort($array, create_function('$a,$b', $code));
 485     return $array;
 486   }
 487
 488   /**
 489    * Recursively removes duplicate values from a multi-dimensional array.
 490    *
 491    * @param array $array
 492    *   The input array possibly containing duplicate values.
 493    *
 494    * @return array
 495    *   The input array with duplicate values removed.
 496    */
 497   public static function crmArrayUnique($array) {
 498     $result = array_map("unserialize", array_unique(array_map("serialize", $array)));
 499     foreach ($result as $key => $value) {
 500       if (is_array($value)) {
 501         $result[$key] = self::crmArrayUnique($value);
 502       }
 503     }
 504     return $result;
 505   }
 506
 507   /**
 508    * Sorts an array and maintains index association (with localization).
 509    *
 510    * Uses Collate from the PECL "intl" package, if available, for UTF-8
 511    * sorting (e.g. list of countries). Otherwise calls PHP's asort().
 512    *
 513    * On Debian/Ubuntu: apt-get install php5-intl
 514    *
 515    * @param array $array
 516    *   (optional) Array to be sorted.
 517    *
 518    * @return array
 519    *   Sorted array.
 520    */
 521   public static function asort($array = array()) {
 522     $lcMessages = CRM_Utils_System::getUFLocale();
 523
 524     if ($lcMessages && $lcMessages != 'en_US' && class_exists('Collator')) {
 525       $collator = new Collator($lcMessages . '.utf8');
 526       $collator->asort($array);
 527     }
 528     else {
 529       // This calls PHP's built-in asort().
 530       asort($array);
 531     }
 532
 533     return $array;
 534   }
 535
 536   /**
 537    * Unsets an arbitrary list of array elements from an associative array.
 538    *
 539    * @param array $items
 540    *   The array from which to remove items.
 541    *
 542    * Additional params:
 543    *   When passed a string, unsets $items[$key].
 544    *   When passed an array of strings, unsets $items[$k] for each string $k in the array.
 545    */
 546   public static function remove(&$items) {
 547     foreach (func_get_args() as $n => $key) {
 548       // Skip argument 0 ($items) by testing $n for truth.
 549       if ($n && is_array($key)) {
 550         foreach ($key as $k) {
 551           unset($items[$k]);
 552         }
 553       }
 554       elseif ($n) {
 555         unset($items[$key]);
 556       }
 557     }
 558   }
 559
 560   /**
 561    * Builds an array-tree which indexes the records in an array.
 562    *
 563    * @param string[] $keys
 564    *   Properties by which to index.
 565    * @param object|array $records
 566    *
 567    * @return array
 568    *   Multi-dimensional array, with one layer for each key.
 569    */
 570   public static function index($keys, $records) {
 571     $final_key = array_pop($keys);
 572
 573     $result = array();
 574     foreach ($records as $record) {
 575       $node = &$result;
 576       foreach ($keys as $key) {
 577         if (is_array($record)) {
 578           $keyvalue = isset($record[$key]) ? $record[$key] : NULL;
 579         }
 580         else {
 581           $keyvalue = isset($record->{$key}) ? $record->{$key} : NULL;
 582         }
 583         if (isset($node[$keyvalue]) && !is_array($node[$keyvalue])) {
 584           $node[$keyvalue] = array();
 585         }
 586         $node = &$node[$keyvalue];
 587       }
 588       if (is_array($record)) {
 589         $node[$record[$final_key]] = $record;
 590       }
 591       else {
 592         $node[$record->{$final_key}] = $record;
 593       }
 594     }
 595     return $result;
 596   }
 597
 598   /**
 599    * Iterates over a list of records and returns the value of some property.
 600    *
 601    * @param string $prop
 602    *   Property to retrieve.
 603    * @param array|object $records
 604    *   A list of records.
 605    *
 606    * @return array
 607    *   Keys are the original keys of $records; values are the $prop values.
 608    */
 609   public static function collect($prop, $records) {
 610     $result = array();
 611     if (is_array($records)) {
 612       foreach ($records as $key => $record) {
 613         if (is_object($record)) {
 614           $result[$key] = $record->{$prop};
 615         }
 616         else {
 617           $result[$key] = $record[$prop];
 618         }
 619       }
 620     }
 621     return $result;
 622   }
 623
 624   /**
 625    * Iterates over a list of objects and executes some method on each.
 626    *
 627    * Comparison:
 628    *   - This is like array_map(), except it executes the objects' method
 629    *     instead of a free-form callable.
 630    *   - This is like Array::collect(), except it uses a method
 631    *     instead of a property.
 632    *
 633    * @param string $method
 634    *   The method to execute.
 635    * @param array|Traversable $objects
 636    *   A list of objects.
 637    * @param array $args
 638    *   An optional list of arguments to pass to the method.
 639    *
 640    * @return array
 641    *   Keys are the original keys of $objects; values are the method results.
 642    */
 643   public static function collectMethod($method, $objects, $args = array()) {
 644     $result = array();
 645     if (is_array($objects)) {
 646       foreach ($objects as $key => $object) {
 647         $result[$key] = call_user_func_array(array($object, $method), $args);
 648       }
 649     }
 650     return $result;
 651   }
 652
 653   /**
 654    * Trims delimiters from a string and then splits it using explode().
 655    *
 656    * This method works mostly like PHP's built-in explode(), except that
 657    * surrounding delimiters are trimmed before explode() is called.
 658    *
 659    * Also, if an array or NULL is passed as the $values parameter, the value is
 660    * returned unmodified rather than being passed to explode().
 661    *
 662    * @param array|null|string $values
 663    *   The input string (or an array, or NULL).
 664    * @param string $delim
 665    *   (optional) The boundary string.
 666    *
 667    * @return array|null
 668    *   An array of strings produced by explode(), or the unmodified input
 669    *   array, or NULL.
 670    */
 671   public static function explodePadded($values, $delim = CRM_Core_DAO::VALUE_SEPARATOR) {
 672     if ($values === NULL) {
 673       return NULL;
 674     }
 675     // If we already have an array, no need to continue
 676     if (is_array($values)) {
 677       return $values;
 678     }
 679     // Empty string -> empty array
 680     if ($values === '') {
 681       return array();
 682     }
 683     return explode($delim, trim((string) $values, $delim));
 684   }
 685
 686   /**
 687    * Joins array elements with a string, adding surrounding delimiters.
 688    *
 689    * This method works mostly like PHP's built-in implode(), but the generated
 690    * string is surrounded by delimiter characters. Also, if NULL is passed as
 691    * the $values parameter, NULL is returned.
 692    *
 693    * @param mixed $values
 694    *   Array to be imploded. If a non-array is passed, it will be cast to an
 695    *   array.
 696    * @param string $delim
 697    *   Delimiter to be used for implode() and which will surround the output
 698    *   string.
 699    *
 700    * @return string|NULL
 701    *   The generated string, or NULL if NULL was passed as $values parameter.
 702    */
 703   public static function implodePadded($values, $delim = CRM_Core_DAO::VALUE_SEPARATOR) {
 704     if ($values === NULL) {
 705       return NULL;
 706     }
 707     // If we already have a string, strip $delim off the ends so it doesn't get added twice
 708     if (is_string($values)) {
 709       $values = trim($values, $delim);
 710     }
 711     return $delim . implode($delim, (array) $values) . $delim;
 712   }
 713
 714   /**
 715    * Modifies a key in an array while preserving the key order.
 716    *
 717    * By default when an element is added to an array, it is added to the end.
 718    * This method allows for changing an existing key while preserving its
 719    * position in the array.
 720    *
 721    * The array is both modified in-place and returned.
 722    *
 723    * @param array $elementArray
 724    *   Array to manipulate.
 725    * @param string $oldKey
 726    *   Old key to be replaced.
 727    * @param string $newKey
 728    *   Replacement key string.
 729    *
 730    * @throws Exception
 731    *   Throws a generic Exception if $oldKey is not found in $elementArray.
 732    *
 733    * @return array
 734    *   The manipulated array.
 735    */
 736   public static function crmReplaceKey(&$elementArray, $oldKey, $newKey) {
 737     $keys = array_keys($elementArray);
 738     if (FALSE === $index = array_search($oldKey, $keys)) {
 739       throw new Exception(sprintf('key "%s" does not exit', $oldKey));
 740     }
 741     $keys[$index] = $newKey;
 742     $elementArray = array_combine($keys, array_values($elementArray));
 743     return $elementArray;
 744   }
 745
 746   /**
 747    * Searches array keys by regex, returning the value of the first match.
 748    *
 749    * Given a regular expression and an array, this method searches the keys
 750    * of the array using the regular expression. The first match is then used
 751    * to index into the array, and the associated value is retrieved and
 752    * returned. If no matches are found, or if something other than an array
 753    * is passed, then a default value is returned. Unless otherwise specified,
 754    * the default value is NULL.
 755    *
 756    * @param string $regexKey
 757    *   The regular expression to use when searching for matching keys.
 758    * @param array $list
 759    *   The array whose keys will be searched.
 760    * @param mixed $default
 761    *   (optional) The default value to return if the regex does not match an
 762    *   array key, or if something other than an array is passed.
 763    *
 764    * @return mixed
 765    *   The value found.
 766    */
 767   public static function valueByRegexKey($regexKey, $list, $default = NULL) {
 768     if (is_array($list) && $regexKey) {
 769       $matches = preg_grep($regexKey, array_keys($list));
 770       $key = reset($matches);
 771       return ($key && array_key_exists($key, $list)) ? $list[$key] : $default;
 772     }
 773     return $default;
 774   }
 775
 776   /**
 777    * Generates the Cartesian product of zero or more vectors.
 778    *
 779    * @param array $dimensions
 780    *   List of dimensions to multiply.
 781    *   Each key is a dimension name; each value is a vector.
 782    * @param array $template
 783    *   (optional) A base set of values included in every output.
 784    *
 785    * @return array
 786    *   Each item is a distinct combination of values from $dimensions.
 787    *
 788    *   For example, the product of
 789    *   {
 790    *   fg => {red, blue},
 791    *   bg => {white, black}
 792    *   }
 793    *   would be
 794    *   {
 795    *   {fg => red, bg => white},
 796    *   {fg => red, bg => black},
 797    *   {fg => blue, bg => white},
 798    *   {fg => blue, bg => black}
 799    *   }
 800    */
 801   public static function product($dimensions, $template = array()) {
 802     if (empty($dimensions)) {
 803       return array($template);
 804     }
 805
 806     foreach ($dimensions as $key => $value) {
 807       $firstKey = $key;
 808       $firstValues = $value;
 809       break;
 810     }
 811     unset($dimensions[$key]);
 812
 813     $results = array();
 814     foreach ($firstValues as $firstValue) {
 815       foreach (self::product($dimensions, $template) as $result) {
 816         $result[$firstKey] = $firstValue;
 817         $results[] = $result;
 818       }
 819     }
 820
 821     return $results;
 822   }
 823
 824   /**
 825    * Get the first element of an array.
 826    *
 827    * @param array $array
 828    * @return mixed|NULL
 829    */
 830   public static function first($array) {
 831     foreach ($array as $value) {
 832       return $value;
 833     }
 834     return NULL;
 835   }
 836
 837   /**
 838    * Extract any $keys from $array and copy to a new array.
 839    *
 840    * Note: If a $key does not appear in $array, then it will
 841    * not appear in the result.
 842    *
 843    * @param array $array
 844    * @param array $keys
 845    *   List of keys to copy.
 846    * @return array
 847    */
 848   public static function subset($array, $keys) {
 849     $result = array();
 850     foreach ($keys as $key) {
 851       if (isset($array[$key])) {
 852         $result[$key] = $array[$key];
 853       }
 854     }
 855     return $result;
 856   }
 857
 858   /**
 859    * Transform an associative array of key=>value pairs into a non-associative array of arrays.
 860    * This is necessary to preserve sort order when sending an array through json_encode.
 861    *
 862    * @param array $associative
 863    * @param string $keyName
 864    * @param string $valueName
 865    * @return array
 866    */
 867   public static function makeNonAssociative($associative, $keyName = 'key', $valueName = 'value') {
 868     $output = array();
 869     foreach ($associative as $key => $val) {
 870       $output[] = array($keyName => $key, $valueName => $val);
 871     }
 872     return $output;
 873   }
 874
 875   /**
 876    * Diff multidimensional arrays
 877    * (array_diff does not support multidimensional array)
 878    *
 879    * @param array $array1
 880    * @param array $array2
 881    * @return array
 882    */
 883   public static function multiArrayDiff($array1, $array2) {
 884     $arrayDiff = array();
 885     foreach ($array1 as $mKey => $mValue) {
 886       if (array_key_exists($mKey, $array2)) {
 887         if (is_array($mValue)) {
 888           $recursiveDiff = self::multiArrayDiff($mValue, $array2[$mKey]);
 889           if (count($recursiveDiff)) {
 890             $arrayDiff[$mKey] = $recursiveDiff;
 891           }
 892         }
 893         else {
 894           if ($mValue != $array2[$mKey]) {
 895             $arrayDiff[$mKey] = $mValue;
 896           }
 897         }
 898       }
 899       else {
 900         $arrayDiff[$mKey] = $mValue;
 901       }
 902     }
 903     return $arrayDiff;
 904   }
 905
 906   /**
 907    * Given a 2-dimensional matrix, create a new matrix with a restricted list of columns.
 908    *
 909    * @param array $matrix
 910    *   All matrix data, as a list of rows.
 911    * @param array $columns
 912    *   List of column names.
 913    * @return array
 914    */
 915   public static function filterColumns($matrix, $columns) {
 916     $newRows = array();
 917     foreach ($matrix as $pos => $oldRow) {
 918       $newRow = array();
 919       foreach ($columns as $column) {
 920         $newRow[$column] = CRM_Utils_Array::value($column, $oldRow);
 921       }
 922       $newRows[$pos] = $newRow;
 923     }
 924     return $newRows;
 925   }
 926
 927   /**
 928    * Rewrite the keys in an array.
 929    *
 930    * @param array $array
 931    * @param string|callable $indexBy
 932    *   Either the value to key by, or a function($key, $value) that returns the new key.
 933    * @return array
 934    */
 935   public static function rekey($array, $indexBy) {
 936     $result = array();
 937     foreach ($array as $key => $value) {
 938       $newKey = is_callable($indexBy) ? $indexBy($key, $value) : $value[$indexBy];
 939       $result[$newKey] = $value;
 940     }
 941     return $result;
 942   }
 943
 944   /**
 945    * Copy all properties of $other into $array (recursively).
 946    *
 947    * @param array|ArrayAccess $array
 948    * @param array $other
 949    */
 950   public static function extend(&$array, $other) {
 951     foreach ($other as $key => $value) {
 952       if (is_array($value)) {
 953         self::extend($array[$key], $value);
 954       }
 955       else {
 956         $array[$key] = $value;
 957       }
 958     }
 959   }
 960
 961   /**
 962    * Get a single value from an array-tre.
 963    *
 964    * @param array $arr
 965    *   Ex: array('foo'=>array('bar'=>123)).
 966    * @param array $pathParts
 967    *   Ex: array('foo',bar').
 968    * @return mixed|NULL
 969    *   Ex 123.
 970    */
 971   public static function pathGet($arr, $pathParts) {
 972     $r = $arr;
 973     foreach ($pathParts as $part) {
 974       if (!isset($r[$part])) {
 975         return NULL;
 976       }
 977       $r = $r[$part];
 978     }
 979     return $r;
 980   }
 981
 982   /**
 983    * Set a single value in an array tree.
 984    *
 985    * @param array $arr
 986    *   Ex: array('foo'=>array('bar'=>123)).
 987    * @param array $pathParts
 988    *   Ex: array('foo',bar').
 989    * @param $value
 990    *   Ex: 456.
 991    */
 992   public static function pathSet(&$arr, $pathParts, $value) {
 993     $r = &$arr;
 994     $last = array_pop($pathParts);
 995     foreach ($pathParts as $part) {
 996       if (!isset($r[$part])) {
 997         $r[$part] = array();
 998       }
 999       $r = &$r[$part];
1000     }
1001     $r[$last] = $value;
1002   }
1003
1004   /**
1005    * Convert a simple dictionary into separate key+value records.
1006    *
1007    * @param array $array
1008    *   Ex: array('foo' => 'bar').
1009    * @param string $keyField
1010    *   Ex: 'key'.
1011    * @param string $valueField
1012    *   Ex: 'value'.
1013    * @return array
1014    *   Ex: array(
1015    *     0 => array('key' => 'foo', 'value' => 'bar')
1016    *   ).
1017    */
1018   public static function toKeyValueRows($array, $keyField = 'key', $valueField = 'value') {
1019     $result = array();
1020     foreach ($array as $key => $value) {
1021       $result[] = array(
1022         $keyField => $key,
1023         $valueField => $value,
1024       );
1025     }
1026     return $result;
1027   }
1028
1029   /**
1030    * Convert array where key(s) holds the actual value and value(s) as 1 into array of actual values
1031    *  Ex: array('foobar' => 1, 4 => 1) formatted into array('foobar', 4)
1032    *
1033    * @deprecated use convertCheckboxInputToArray instead (after testing)
1034    * https://github.com/civicrm/civicrm-core/pull/8169
1035    *
1036    * @param array $array
1037    */
1038   public static function formatArrayKeys(&$array) {
1039     if (!is_array($array)) {
1040       return;
1041     }
1042     $keys = array_keys($array, 1);
1043     if (count($keys) > 1 ||
1044       (count($keys) == 1 &&
1045         (current($keys) > 1 ||
1046           is_string(current($keys)) ||
1047           (current($keys) == 1 && $array[1] == 1) // handle (0 => 4), (1 => 1)
1048         )
1049       )
1050     ) {
1051       $array = $keys;
1052     }
1053   }
1054
1055   /**
1056    * Convert the data format coming in from checkboxes to an array of values.
1057    *
1058    * The input format from check boxes looks like
1059    *   array('value1' => 1, 'value2' => 1). This function converts those values to
1060    *   array(''value1', 'value2).
1061    *
1062    * The function will only alter the array if all values are equal to 1.
1063    *
1064    * @param array $input
1065    *
1066    * @return array
1067    */
1068   public static function convertCheckboxFormatToArray($input) {
1069     if (isset($input[0])) {
1070       return $input;
1071     }
1072     $keys = array_keys($input, 1);
1073     if ((count($keys) == count($input))) {
1074       return $keys;
1075     }
1076     return $input;
1077   }
1078
1079   /**
1080    * Ensure that array is encoded in utf8 format.
1081    *
1082    * @param array $array
1083    *
1084    * @return array $array utf8-encoded.
1085    */
1086   public static function encode_items($array) {
1087     foreach ($array as $key => $value) {
1088       if (is_array($value)) {
1089         $array[$key] = self::encode_items($value);
1090       }
1091       elseif (is_string($value)) {
1092         $array[$key] = mb_convert_encoding($value, mb_detect_encoding($value, mb_detect_order(), TRUE), 'UTF-8');
1093       }
1094       else {
1095         $array[$key] = $value;
1096       }
1097     }
1098     return $array;
1099   }
1100
1101   /**
1102    * Build tree of elements.
1103    *
1104    * @param array $elements
1105    * @param int|null $parentId
1106    *
1107    * @return array
1108    */
1109   public static function buildTree($elements, $parentId = NULL) {
1110     $branch = array();
1111
1112     foreach ($elements as $element) {
1113       if ($element['parent_id'] == $parentId) {
1114         $children = self::buildTree($elements, $element['id']);
1115         if ($children) {
1116           $element['children'] = $children;
1117         }
1118         $branch[] = $element;
1119       }
1120     }
1121
1122     return $branch;
1123   }
1124
1125   /**
1126    * Find search string in tree.
1127    *
1128    * @param string $search
1129    * @param array $tree
1130    * @param string $field
1131    *
1132    * @return array|null
1133    */
1134   public static function findInTree($search, $tree, $field = 'id') {
1135     foreach ($tree as $item) {
1136       if ($item[$field] == $search) {
1137         return $item;
1138       }
1139       if (!empty($item['children'])) {
1140         $found = self::findInTree($search, $item['children']);
1141         if ($found) {
1142           return $found;
1143         }
1144       }
1145     }
1146     return NULL;
1147   }
1148
1149 }