yii/framework/utils/CDateParser.php

<?php
/**
 * CDateParser class file
 *
 * @author Wei Zhuo <weizhuo[at]gamil[dot]com>
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CDateParser converts a date string to a UNIX timestamp according to the specified pattern.
 *
 * The following pattern characters are recognized:
 * <pre>
 * Pattern |      Description
 * ----------------------------------------------------
 * d       | Day of month 1 to 31, no padding
 * dd      | Day of monath 01 to 31, zero leading
 * M       | Month digit 1 to 12, no padding
 * MM      | Month digit 01 to 12, zero leading
 * yy      | 2 year digit, e.g., 96, 05
 * yyyy    | 4 year digit, e.g., 2005
 * ----------------------------------------------------
 * </pre>
 * All other characters must appear in the date string at the corresponding positions.
 *
 * For example, to parse a date string '21/10/2008', use the following:
 * <pre>
 * $timestamp=CDateParser::parse('dd/MM/yyyy','21/10/2008');
 * </pre>
 *
 * To format a timestamp to a date string, please use {@link CDateFormatter}.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id$
 * @package system.utils
 * @since 1.0
 */
class CDateParser
{
	/**
	 * Converts a date string to a timestamp.
	 * @param string the date string to be parsed
	 * @param string the pattern that the date string is following
	 * @return integer timestamp for the date string. False if parsing fails.
	 */
	public static function parse($value,$pattern='MM/dd/yyyy')
	{
		$tokens=self::tokenize($pattern);
		$i=0;
		$n=strlen($value);
		foreach($tokens as $token)
		{
			switch($token)
			{
				case 'yyyy':
				{
					if(($year=self::parseInteger($value,$i,4,4))===false)
						return false;
					$i+=4;
					break;
				}
				case 'yy':
				{
					if(($year=self::parseInteger($value,$i,1,2))===false)
						return false;
					$i+=strlen($year);
					break;
				}
				case 'MM':
				{
					if(($month=self::parseInteger($value,$i,2,2))===false)
						return false;
					$i+=2;
					break;
				}
				case 'M':
				{
					if(($month=self::parseInteger($value,$i,1,2))===false)
						return false;
					$i+=strlen($month);
					break;
				}
				case 'dd':
				{
					if(($day=self::parseInteger($value,$i,2,2))===false)
						return false;
					$i+=2;
					break;
				}
				case 'd':
				{
					if(($day=self::parseInteger($value,$i,1,2))===false)
						return false;
					$i+=strlen($day);
					break;
				}
				default:
				{
					$tn=strlen($token);
					if($i>=$n || substr($value,$i,$tn)!==$token)
						return false;
					$i+=$tn;
					break;
				}
			}
		}
		if($i<$n)
			return false;

		if(!isset($year))
			$year=date('Y');
		if(!isset($month))
			$month=date('n');
		if(!isset($day))
			$day=date('j');

		if(strlen($year)===2)
		{
			if($year>70)
				$year+=1900;
			else
				$year+=2000;
		}
		$year=(int)$year;
		$month=(int)$month;
		$day=(int)$day;

		if(CTimestamp::isValidDate($year,$month,$day))
			return CTimestamp::getTimestamp(0,0,0,$month,$day,$year);
		else
			return false;
	}

	private static function tokenize($pattern)
	{
		if(!($n=strlen($pattern)))
			return array();
		$tokens=array();
		for($c0=$pattern[0],$start=0,$i=1;$i<$n;++$i)
		{
			if(($c=$pattern[$i])!==$c0)
			{
				$tokens[]=substr($pattern,$start,$i-$start);
				$c0=$c;
				$start=$i;
			}
		}
		$tokens[]=substr($pattern,$start,$n-$start);
		return $tokens;
	}

	protected static function parseInteger($value,$offset,$minLength,$maxLength)
	{
		for($len=$maxLength;$len>=$minLength;--$len)
		{
			$v=substr($value,$offset,$len);
			if(ctype_digit($v))
				return $v;
		}
		return false;
	}
}