SplEnum.php

<?php
/***************************************************************
 *  Copyright notice
 *
 *  (c) 2013 Thomas Maroschik <tmaroschik@dfau.de>
 *  All rights reserved
 *
 *  This script is part of the TYPO3 project. The TYPO3 project 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.
 *
 *  The GNU General Public License can be found at
 *  http://www.gnu.org/copyleft/gpl.html.
 *  A copy is found in the textfile GPL.txt and important notices to the license
 *  from the author is found in LICENSE.txt distributed with these scripts.
 *
 *
 *  This script 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.
 *
 *  This copyright notice MUST APPEAR in all copies of the script!
 ***************************************************************/

/**
 * Emulates SplEnum in vanilla PHP
 *
 */
abstract class SplEnum extends SplType {

	/**
	 * @var string
	 */
	private $value;

	/**
	 * @var array
	 */
	protected static $enumConstants;

	/**
	 * @param mixed $value
	 */
	public function __construct($value = NULL) {
		if ($value === NULL) {
			$value = static::__default;
		}
		$this->loadValues();
		if (!static::isValid($value)) {
			throw new UnexpectedValueException(sprintf("Invalid enumeration %s for Enum %s", $value, __CLASS__));
		}
		$this->setValue($value);
	}

	/**
	 * @param string $class
	 * @throws Exception
	 */
	protected function loadValues() {
		$class = get_called_class();
		if(!isset(static::$enumConstants[$class])) {
			$reflection = new \ReflectionClass($class);
			$constants  = $reflection->getConstants();
			if (isset($constants['__default'])) {
				unset($constants['__default']);
			}
			if(empty($constants)) {
				throw new \Exception(sprintf(
					'No enumeration constants defined for "%s"', $class
				));
			}
			foreach($constants as $constant => $value) {
				if(!is_int($value) && !is_string($value)) {
					throw new \Exception(sprintf(
						'Constant value must be of type integer or string; constant=%s; type=%s',
						$constant,
						is_object($value) ? get_class($value) : gettype($value)
					));
				}
			}
			$constantValueCounts = array_count_values($constants);
			arsort($constantValueCounts, SORT_NUMERIC);
			$constantValueCount = current($constantValueCounts);
			$constant = key($constantValueCounts);
			if($constantValueCount > 1) {
				throw new \Exception(sprintf(
					'Constant value is not unique; constant=%s; value=%s; enum=%s',
					$constant, $constantValueCount, $class
				));
			}
			static::$enumConstants[$class] = $constants;
		}
	}

	/**
	 * @param mixed $value
	 */
	private function setValue($value) {
		$this->value = $value;
	}

	/**
	 * Check if the value on this enum is a valid value for the enum
	 * @return boolean
	 */
	private function isValid($value) {
		if (!in_array($value, SplEnum::$enumConstants[get_called_class()])) {
			return FALSE;
		}
		return TRUE;
	}

	/**
	 * Get the valid values for this enum
	 * Defaults to constants you define in your subclass
	 * override to provide custom functionality
	 *
	 * @param bool $include_default
	 * @return array
	 */
	public function getConstList($include_default = FALSE) {
		$enumConstants = SplEnum::$enumConstants[get_called_class()];
		if (!$include_default) {
			unset($enumConstants['__default']);
		}
		return $enumConstants;
	}

	/**
	 * @return string
	 */
	public function __toString() {
		return (string) $this->value;
	}
}

abstract class SplType {
	const __default = NULL;
}
?>