1. sfChoiceFormat.class.php
  2. /**
 * sfChoiceFormat class.
 * 
 * sfChoiceFormat converts between ranges of numeric values and string 
 * names for those ranges.
 *
 * A sfChoiceFormat splits the real number line -Inf to +Inf into two or 
 * more contiguous ranges. Each range is mapped to a string. 
 * sfChoiceFormat is generally used in a MessageFormat for displaying 
 * grammatically correct plurals such as "There are 2 files."
 *
 * 
 *  $string = '[0] are no files |[1] is one file |(1,Inf] are {number} files';
 *  
 *  $formatter = new sfMessageFormat(...); //init for a source
 *  $translated = $formatter->format($string);
 *
 *  $choice = new sfChoiceFormat();
 *  echo $choice->format($translated, 0); //shows "are no files"
 * 
 *
 * The message/string choices are separated by the pipe "|" followed
 * by a set notation of the form
 *  # [1,2] -- accepts values between 1 and 2, inclusive.
 *  # (1,2) -- accepts values between 1 and 2, excluding 1 and 2.
 *  # {1,2,3,4} -- only values defined in the set are accepted.
 *  # [-Inf,0) -- 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.
 *
 * @author Xiang Wei Zhuo 
 * @version v1.0, last update on Fri Dec 24 20:46:16 EST 2004
 * @package    symfony
 * @subpackage i18n
 */
  3. class sfChoiceFormat
  4. {
  5.   /**
  6.    * The pattern to validate a set notation
  7.    */
  8.   protected $validate = '/[\(\[\{]|[-Inf\d:\s]+|,|[\+Inf\d\s:\?\-=!><%\|&\(\)]+|[\)\]\}]/ms';
  10.   /**
  11.    * The pattern to parse the formatting string.
  12.    */
  13.   protected $parse = '/\s*\|?([\(\[\{]([-Inf\d:\s]+,?[\+Inf\d\s:\?\-=!><%\|&\(\)]*)+[\)\]\}])\s*/';
  15.   /**
  16.    * The value for positive infinity.
  17.    */
  18.   protected $inf;
  20.   /**
  21.    * Constructor.
  22.    */
  23.   public function __construct()
  24.   {
  25.     $this->inf = -log(0);
  26.   }
  28.   /**
  29.    * Determines if the given number belongs to a given set
  30.    *
  31.    * @param  float  $number the number to test.
  32.    * @param  string $set    the set, in set notation.
  33.    * @return boolean true if number is in the set, false otherwise.
  34.    */
  35.   public function isValid($number, $set)
  36.   {
  37.     $n = preg_match_all($this->validate, $set, $matches, PREG_SET_ORDER);
  39.     if ($n < 3)
  40.     {
  41.       throw new sfException(sprintf('Invalid set "%s".', $set));
  42.     }
  44.     if (preg_match('/\{\s*n:([^\}]+)\}/', $set, $def))
  45.     {
  46.       return $this->isValidSetNotation($number, $def[1]);
  47.     }
  49.     $leftBracket = $matches[0][0];
  50.     $rightBracket = $matches[$n - 1][0];
  52.     $i = 0;
  53.     $elements = array();
  55.     foreach ($matches as $match)
  56.     {
  57.       $string = $match[0];
  58.       if ($i != 0 && $i != $n - 1 && $string !== ',')
  59.       {
  60.         if ($string == '-Inf')
  61.         {
  62.           $elements[] = -1 * $this->inf;
  63.         }
  64.         else if ($string == '+Inf' || $string == 'Inf')
  65.         {
  66.           $elements[] = $this->inf;
  67.         }
  68.         else
  69.         {
  70.           $elements[] = floatval($string);
  71.         }
  72.       }
  73.       $i++;
  74.     }
  75.     $total = count($elements);
  76.     $number = floatval($number);
  78.     if ($leftBracket == '{' && $rightBracket == '}')
  79.     {
  80.       return in_array($number, $elements);
  81.     }
  83.     $left = false;
  84.     if ($leftBracket == '[')
  85.     {
  86.       $left = $number >= $elements[0];
  87.     }
  88.     else if ($leftBracket == '(')
  89.     {
  90.       $left = $number > $elements[0];
  91.     }
  93.     $right = false;
  94.     if ($rightBracket == ']')
  95.     {
  96.       $right = $number <= $elements[$total - 1];
  97.     }
  98.     else if ($rightBracket == ')')
  99.     {
  100.       $right = $number < $elements[$total - 1];
  101.     }
  103.     if ($left && $right)
  104.     {
  105.       return true;
  106.     }
  108.     return false;
  109.   }
  111.   protected function isValidSetNotation($number, $set)
  112.   {
  113.     $str = '$result = '.str_replace('n', '$number', $set).';';
  114.     try
  115.     {
  116.       eval($str);
  117.       return $result;
  118.     }
  119.     catch (Exception $e)
  120.     {
  121.       return false;
  122.     }
  123.   }
  125.   /**
  126.    * Parses a choice string and get a list of sets and a list of strings corresponding to the sets.
  127.    *
  128.    * @param  string $string the string containing the choices
  129.    * @return array array($sets, $strings)
  130.    */
  131.   public function parse($string)
  132.   {
  133.     $n = preg_match_all($this->parse, $string, $matches, PREG_OFFSET_CAPTURE);
  134.     $sets = array();
  135.     foreach ($matches[1] as $match)
  136.     {
  137.       $sets[] = $match[0];
  138.     }
  140.     $offset = $matches[0];
  141.     $strings = array();
  142.     for ($i = 0; $i < $n; $i++)
  143.     {
  144.       $len = strlen($offset[$i][0]);
  145.       $begin = $i == 0 ? $len : $offset[$i][1] + $len;
  146.       $end = $i == $n - 1 ? strlen($string) : $offset[$i + 1][1];
  147.       $strings[] = substr($string, $begin, $end - $begin);
  148.     }
  150.     return array($sets, $strings);
  151.   }
  153.   /**
  154.    * For the choice string, and a number, find and return the string that satisfied the set within the choices.
  155.    *
  156.    * @param  string $string   the choices string.
  157.    * @param  float  $number   the number to test.
  158.    * @return string the choosen string.
  159.    */
  160.   public function format($string, $number)
  161.   {
  162.     list($sets, $strings) = $this->parse($string);
  163.     $total = count($sets);
  164.     for ($i = 0; $i < $total; $i++)
  165.     {
  166.       if ($this->isValid($number, $sets[$i]))
  167.       {
  168.         return $strings[$i];
  169.       }
  170.     }
  172.     return false;
  173.   }
  174. }
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