* @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."
*
*
* $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"
*
*
* 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.
*
* Since version 3.1.2 the following set notation is also possible.
*
* # {n: n % 10 > 1 && n % 10 < 5} -- matches numbers like 2, 3, 4, 22, 23, 24
*
* Where set is defined by the expression after n:. In particular, the expression
* accepts the following mathematical/logical operators to form a set of logical conditions
* on the value given by n:
* # < -- less than.
* # <= -- less than equals.
* # > -- greater than.
* # >= -- greater than equals.
* # == -- of equal value.
* # % -- modulo, e.g., 1 % 10 equals 1, 11 % 10 equals 1.
* # - -- minus, negative.
* # + -- addition.
* # & -- conditional AND.
* # && -- condition AND with short circuit.
* # | -- conditional OR.
* # || -- conditional OR with short circuit.
* # ! -- negation.
*
* Additional round brackets can also be used to perform grouping.
*
* @author Xiang Wei Zhuo
* @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;
}
}
?>