Subversion-Projekte lars-tiefland.prado

<?php

/**

 * ChoiceFormat class file.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the BSD License.

 *

 * Copyright(c) 2004 by Qiang Xue. All rights reserved.

 *

 * To contact the author write to {@link mailto:qiang.xue@gmail.com Qiang Xue}

 * The latest version of PRADO can be obtained from:

 * {@link http://prado.sourceforge.net/}

 *

 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>

 * @version $Revision: 1.1 $  $Date: 2005/01/11 07:19:39 $

 * @package System.I18N.core

 */

/**

 * ChoiceFormat class.

 *

 * ChoiceFormat converts between ranges of numeric values and string

 * names for those ranges.

 *

 * A ChoiceFormat splits the real number line -Inf to +Inf into two or

 * more contiguous ranges. Each range is mapped to a string.

 * ChoiceFormat is generally used in a MessageFormat for displaying

 * grammatically correct plurals such as "There are 2 files."

 *

 * <code>

 *	$string = '[0] are no files |[1] is one file |(1,Inf] are {number} files';

 *

 *  $formatter = new MessageFormat(...); //init for a source

 *	$translated = $formatter->format($string);

 *

 *  $choice = new ChoiceFormat();

 * 	echo $choice->format($translated, 0); //shows "are no files"

 * </code>

 *

 * The message/string choices are separated by the pipe "|" followed

 * by a set notation of the form

 *  # <tt>[1,2]</tt> -- accepts values between 1 and 2, inclusive.

 *  # <tt>(1,2)</tt> -- accepts values between 1 and 2, excluding 1 and 2.

 *  # <tt>{1,2,3,4}</tt> -- only values defined in the set are accepted.

 *  # <tt>[-Inf,0)</tt> -- accepts value greater or equal to negative infinity

 *                       and strictly less than 0

 * Any non-empty combinations of the delimiters of square and round brackets

 * are acceptable.

 *

 * Since version 3.1.2 the following set notation is also possible.

 *

 *  # <tt>{n: n % 10 > 1 && n % 10 < 5}</tt> --  matches numbers like 2, 3, 4, 22, 23, 24

 *

 * Where set is defined by the expression after <tt>n:</tt>. In particular, the expression

 * accepts the following mathematical/logical operators to form a set of logical conditions

 * on the value given by <tt>n</tt>:

 *   # <tt>&lt;</tt> -- less than.

 *   # <tt>&lt;=</tt> -- less than equals.

 *   # <tt>&gt;</tt> -- greater than.

 *   # <tt>&gt=</tt> -- greater than equals.

 *   # <tt>==</tt> -- of equal value.

 *   # <tt>%</tt> -- modulo, e.g., 1 % 10 equals 1, 11 % 10 equals 1.

 *   # <tt>-</tt> -- minus, negative.

 *   # <tt>+</tt> -- addition.

 *   # <tt>&amp;</tt> -- conditional AND.

 *   # <tt>&amp;&amp;</tt> -- condition AND with short circuit.

 *   # <tt>|</tt> -- conditional OR.

 *   # <tt>||</tt> -- conditional OR with short circuit.

 *   # <tt>!</tt> -- negation.

 *

 * Additional round brackets can also be used to perform grouping.

 *

 * @author Xiang Wei Zhuo <weizhuo[at]gmail[dot]com>

 * @version v1.0, last update on Fri Dec 24 20:46:16 EST 2004

 * @package System.I18N.core

 */

class ChoiceFormat

{

	/**

	 * The pattern to validate a set notation

	 * @var string

	 */

	protected $validate = '/[\(\[\{]|[-Inf\d:\s]+|,|[\+Inf\d\s:\?\-=!><%\|&\(\)]+|[\)\]\}]/ms';

	/**

	 * The pattern to parse the formatting string.

	 * @var string

	 */

	protected $parse = '/\s*\|?([\(\[\{]([-Inf\d:\s]+,?[\+Inf\d\s:\?\-=!><%\|&\(\)]*)+[\)\]\}])\s*/';

	/**

	 * The value for positive infinity.

	 * @var float

	 */

	protected $inf;

	/**

	 * Constructor.

	 */

	function __construct()

	{

		$this->inf = -log(0);

	}

	/**

	 * Determine if the given number belongs to a given set

	 * @param float the number to test.

	 * @param string the set, in set notation.

	 * @return boolean true if number is in the set, false otherwise.

	 */

	function isValid($number, $set)

	{

		$n = preg_match_all($this->validate,$set,$matches,PREG_SET_ORDER);

		if($n < 3) throw new Exception("Invalid set \"{$set}\"");

		if(preg_match('/\{\s*n:([^\}]+)\}/', $set, $def))

		{

			return $this->isValidSetNotation($number, $def[1]);

		}

		$leftBracket = $matches[0][0];

		$rightBracket = $matches[$n-1][0];

		$i = 0;

		$elements = array();

		foreach($matches as $match)

		{

			$string = $match[0];

			if($i != 0 && $i != $n-1 && $string !== ',')

			{

				if($string == '-Inf')

					$elements[] = -1*$this->inf;

				else if ($string == '+Inf' || $string == 'Inf')

					$elements[] = $this->inf;

				else

					$elements[] = floatval($string);

			}

			$i++;

		}

		$total = count($elements);

		$number = floatval($number);

		if($leftBracket == '{' && $rightBracket == '}')

			return in_array($number, $elements);

		$left = false;

		if($leftBracket == '[')

			$left = $number >= $elements[0];

		else if ($leftBracket == '(')

			$left = $number > $elements[0];

		$right = false;

		if($rightBracket==']')

			$right = $number <= $elements[$total-1];

		else if($rightBracket == ')')

			$right = $number < $elements[$total-1];

		if($left && $right) return true;

		return false;

	}

	protected function isValidSetNotation($number, $set)

	{

		$str = '$result = '.str_replace('n', '$number', $set).';';

		try

		{

			eval($str);

			return $result;

		}

		catch(Exception $e)

		{

			return false;

		}

	}

	/**

	 * Parse a choice string and get a list of sets and a list of strings

	 * corresponding to the sets.

	 * @param string the string containing the choices

	 * @return array array($sets, $strings)

	 */

	function parse($string)

	{

		$n = preg_match_all($this->parse,$string,$matches, PREG_OFFSET_CAPTURE);

		$sets = array();

		foreach($matches[1] as $match)

			$sets[] = $match[0];

		$offset = $matches[0];

		$strings = array();

		for($i = 0; $i < $n; $i++)

		{

			$len = strlen($offset[$i][0]);

			$begin = $i == 0? $len : $offset[$i][1] + $len;

			$end = $i == $n-1 ? strlen($string) : $offset[$i+1][1];

			$strings[] = substr($string, $begin, $end - $begin);

		}

		return array($sets, $strings);

	}

	/**

	 * For the choice string, and a number, find and return the

	 * string that satisfied the set within the choices.

	 * @param string the choices string.

	 * @param float the number to test.

	 * @return string the choosen string.

	 */

	public function format($string, $number)

	{

		list($sets, $strings) = $this->parse($string);

		$total = count($sets);

		for($i = 0; $i < $total; $i++)

		{

			if($this->isValid($number, $sets[$i]))

				return $strings[$i];

		}

		return false;

	}

}

?>