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   1  <?php
   2  
   3  /**
   4   * ChoiceFormat class file.
   5   *
   6   * This program is free software; you can redistribute it and/or modify
   7   * it under the terms of the BSD License.
   8   *
   9   * Copyright(c) 2004 by Qiang Xue. All rights reserved.
  10   *
  11   * To contact the author write to {@link mailto:qiang.xue@gmail.com Qiang Xue}
  12   * The latest version of PRADO can be obtained from:
  13   * {@link http://prado.sourceforge.net/}
  14   *
  15   * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
  16   * @version $Revision: 1.1 $  $Date: 2005/01/11 07:19:39 $
  17   * @package System.I18N.core
  18   */
  19  
  20  
  21  /**
  22   * ChoiceFormat class.
  23   * 
  24   * ChoiceFormat converts between ranges of numeric values and string 
  25   * names for those ranges.
  26   *
  27   * A ChoiceFormat splits the real number line -Inf to +Inf into two or 
  28   * more contiguous ranges. Each range is mapped to a string. 
  29   * ChoiceFormat is generally used in a MessageFormat for displaying 
  30   * grammatically correct plurals such as "There are 2 files."
  31   *
  32   * <code>
  33   *    $string = '[0] are no files |[1] is one file |(1,Inf] are {number} files';
  34   *  
  35   *  $formatter = new MessageFormat(...); //init for a source
  36   *    $translated = $formatter->format($string);
  37   *
  38   *  $choice = new ChoiceFormat();
  39   *     echo $choice->format($translated, 0); //shows "are no files"
  40   * </code>
  41   *
  42   * The message/string choices are separated by the pipe "|" followed
  43   * by a set notation of the form
  44   *  # <t>[1,2]</t> -- accepts values between 1 and 2, inclusive.
  45   *  # <t>(1,2)</t> -- accepts values between 1 and 2, excluding 1 and 2.
  46   *  # <t>{1,2,3,4}</t> -- only values defined in the set are accepted.
  47   *  # <t>[-Inf,0)</t> -- accepts value greater or equal to negative infinity 
  48   *                       and strictly less than 0
  49   * Any non-empty combinations of the delimiters of square and round brackets
  50   * are acceptable.
  51   *
  52   * @author Xiang Wei Zhuo <weizhuo[at]gmail[dot]com>
  53   * @version v1.0, last update on Fri Dec 24 20:46:16 EST 2004
  54   * @package System.I18N.core
  55   */
  56  class ChoiceFormat
  57  {
  58      /**
  59       * The pattern to validate a set notation
  60       * @var string 
  61       */
  62      protected $validate = '/[\(\[\{]|[-Inf\d]+|,|[\+Inf\d]+|[\)\]\}]/ms';
  63  
  64      /**
  65       * The pattern to parse the formatting string.
  66       * @var string 
  67       */
  68      protected $parse = '/\s?\|?([\(\[\{]([-Inf\d]+,?[\+Inf\d]*)+[\)\]\}])\s?/';
  69  
  70      /**
  71       * The value for positive infinity.
  72       * @var float 
  73       */
  74      protected $inf;
  75  
  76  
  77      /**
  78       * Constructor.
  79       */    
  80  	function __construct()
  81      {
  82          $this->inf = -log(0);
  83      }
  84  
  85  
  86      /**
  87       * Determine if the given number belongs to a given set
  88       * @param float the number to test.
  89       * @param string the set, in set notation.
  90       * @return boolean true if number is in the set, false otherwise.
  91       */    
  92  	function isValid($number, $set)
  93      {
  94          $n = preg_match_all($this->validate,$set,$matches,PREG_SET_ORDER);
  95          
  96          if($n < 3) throw new Exception("Invalid set \"{$set}\"");
  97          
  98          $leftBracket = $matches[0][0];
  99          $rightBracket = $matches[$n-1][0];
 100  
 101          $i = 0;
 102          $elements = array();
 103          
 104          foreach($matches as $match)
 105          {
 106              $string = $match[0];
 107              if($i != 0 && $i != $n-1 && $string !== ',')
 108              {
 109                  if($string == '-Inf')
 110                      $elements[] = -1*$this->inf;
 111                  else if ($string == '+Inf' || $string == 'Inf')
 112                      $elements[] = $this->inf;
 113                  else
 114                      $elements[] = floatval($string);
 115              }
 116              $i++;
 117          }
 118          $total = count($elements);
 119          $number = floatval($number);
 120  
 121          if($leftBracket == '{' && $rightBracket == '}')
 122              return in_array($number, $elements);
 123  
 124          $left = false;
 125          if($leftBracket == '[')
 126              $left = $number >= $elements[0];
 127          else if ($leftBracket == '(')
 128              $left = $number > $elements[0];
 129  
 130          $right = false;
 131          if($rightBracket==']')
 132              $right = $number <= $elements[$total-1];
 133          else if($rightBracket == ')')
 134              $right = $number < $elements[$total-1];
 135          
 136          if($left && $right) return true;    
 137  
 138          return false;
 139      }    
 140  
 141  
 142      /**
 143       * Parse a choice string and get a list of sets and a list of strings 
 144       * corresponding to the sets.
 145       * @param string the string containing the choices
 146       * @return array array($sets, $strings)
 147       */    
 148  	function parse($string)
 149      {
 150          $n = preg_match_all($this->parse,$string,$matches, PREG_OFFSET_CAPTURE);
 151          $sets = array();
 152          foreach($matches[1] as $match)
 153              $sets[] = $match[0];
 154          $offset = $matches[0];
 155          $strings = array();
 156          for($i = 0; $i < $n; $i++)
 157          {
 158              $len = strlen($offset[$i][0]);
 159              $begin = $i == 0? $len : $offset[$i][1] + $len;
 160              $end = $i == $n-1 ? strlen($string) : $offset[$i+1][1];    
 161              $strings[] = substr($string, $begin, $end - $begin);
 162          }
 163          return array($sets, $strings);
 164      }
 165  
 166      /**
 167       * For the choice string, and a number, find and return the 
 168       * string that satisfied the set within the choices.
 169       * @param string the choices string.
 170       * @param float the number to test.
 171       * @return string the choosen string.
 172       */        
 173  	public function format($string, $number)
 174      {
 175          list($sets, $strings) = $this->parse($string);
 176          $total = count($sets);
 177          for($i = 0; $i < $total; $i++)
 178          {
 179              if($this->isValid($number, $sets[$i]))
 180                  return $strings[$i];
 181          }
 182          return false;
 183      }
 184  }
 185  
 186  ?>