MyDate

<?php

/*A bit of code to test the function:
echo "This function should be able to make sense of almost any date thrown at it. It will return a Unix timestamp for a date string.";
$testdate = "";
if(isset($_GET["date"])) $testdate = $_GET["date"];
echo "<form action='mydate.php'>Date: <input type='text' name='date' value='$testdate'><input type='submit'></form>";
if(isset($_GET["date"])) $date = mydate($testdate);
else die();
echo "<br>";
if(!$date) echo "<br>Invalid date!";
else echo "<br>Date is ".strftime("%d/%m/%Y",$date)." or in PHP Unix form, $date";*/

function mydate($date){
	// Date may be in Unix format already:
	if($date*1 >= 79200) return $date;
	// Date cannot be shorter than 5 characters:
	if(strlen($date) < 5) return false;

	// Standardise date seperators to "/":
	$date = str_replace(", ","/",$date);
	$date = str_replace(" ,","/",$date);
	$date = str_replace(" , ","/",$date);
	$date = str_replace(" ","/",$date);
	$date = str_replace(",","/",$date);
	$date = str_replace("-","/",$date);

	// Split date into three seperate parts:
	$parts = explode("/",$date);
	if(count($parts) != 3) return false; // Date must have three parts.
	$part1 = $parts[0];
	$part2 = $parts[1];
	$part3 = $parts[2];
	
	// Check if there is a month in text somewhere:
	$longmonths = array("january","february","march","april","may","june",
							"july","august","september","october","november","december");
	$shortmonths = array("jan","feb","mar","apr","may","jun","jul","aug","sep","oct","nov","dec");
	while(list($key,$month) = each($longmonths)){
		if(strtolower($part1) == $month or strtolower($part1) == $shortmonths[$key]){
			$part1 = $key+1;
			$month = "part1";
			break;
		}
		if(strtolower($part2) == $month or strtolower($part2) == $shortmonths[$key]){
			$part2 = $key+1;
			$month = "part2";
			break;
		}
		if(strtolower($part3) == $month or strtolower($part3) == $shortmonths[$key]){
			$part3 = $key+1;
			$month = "part3";
			break;
		}  
	}
	if(!isset($month)){ // Check if two parts are > 12 - the other is probably month, or it is an invalid date.
		if($part1 > 12 and $part2 > 12) $month = "part3";
		if($part1 > 12 and $part3 > 12) $month = "part2";
		if($part2 > 12 and $part3 > 12) $month = "part1";
	}
	if(isset($month)){
		if($$month > 12) return false;
		$m = $$month;
		unset($$month);
		$datearray = false;
		if(isset($part1) and isset($part2)) $datearray = choosedayandyear($m,$part1,$part2);
		if(!$datearray) if(isset($part1) and isset($part2)) $datearray = choosedayandyear($m,$part2,$part1);
		if(!$datearray) if(isset($part1) and isset($part3)) $datearray = choosedayandyear($m,$part1,$part3);
		if(!$datearray) if(isset($part1) and isset($part3)) $datearray = choosedayandyear($m,$part3,$part1);
		if(!$datearray) if(isset($part2) and isset($part3)) $datearray = choosedayandyear($m,$part2,$part3);
		if(!$datearray) if(isset($part2) and isset($part3)) $datearray = choosedayandyear($m,$part3,$part2);
		if(!$datearray) return false;
	}
	
	else{// Deduce format according to the magnitude of each part:
		$datearray = examinedate($part1,$part2,$part3);
		if(!$datearray) $datearray = examinedate($part3,$part1,$part2);
		if(!$datearray) $datearray = examinedate($part2,$part3,$part1);
		
	}
	
	if($datearray){
		$d = $datearray[0];
		$m = $datearray[1];
		$y = $datearray[2];
	}
	else{ // Assume d/m/y if all else fails!
		$d = $part1;
		$m = $part2;
		$y = $part3;
		if(($m == 1 or $m == 3 or $m == 5 or $m == 7 or $m == 8 or $m == 10 or $m == 12) and $d > 31) return false;
		if(($m == 4 or $m == 6 or $m == 9 or $m == 11) and $d > 30) return false;
		if($m == 2 and 0 != fmod($y,4) and $d > 28) return false;
		if($m == 2 and $d > 28) return false;
	}
	if($y < 70) $y += 2000;
	elseif($y < 1900) $y += 1900;
	if($y <= 1969 or $y >= 2038) return false; // Windows can't cope with dates beyond this range - sorry!
	return strtotime($m."/".$d."/".$y);
}

function examinedate($p1,$p2,$p3){
	if($p1 > 31){ // must be year
		if($p2 > 31 or $p3 > 31) return false; // must be invalid
		$y = $p1;
		if($p2 > 12){ // must be day
			$d = $p2;
			if($p3 > 12) return false; // must be invalid
			$m = $p3;
		}
		elseif($p3 > 12){ // 2 must be month!
			$m = $p2;
			$d = $p3;
		}
		else{ // both p2 and p3 are less than 12, so could be either day or month - assume y/m/d
			$d = $p2;
			$m = $p3;
		}
	}
	else return false; // Inconclusive
	return array($d,$m,$y);
	
}

function choosedayandyear($m,$p1,$p2){
	if($m == 1 or $m == 3 or $m == 5 or $m == 7 or $m == 8 or $m == 10 or $m == 12){
		if($p1 > 31 and $p2 <= 31){
			$d = $p2;
			$y = $p1;
			return array($d,$m,$y);
		}
	}
	if($m == 4 or $m == 6 or $m == 9 or $m == 11){
		if($p1 > 30 and $p2 <= 30){
			$d = $p2;
			$y = $p1;
			return array($d,$m,$y);
		}
	}
	if($m == 2){
		if($p1 == 29 and 0 == fmod($p2,4)){
			$d = $p1;
			$y = $p2;
			return array($d,$m,$y);
		}
		elseif($p1 > 28){
			if($p2 > 28) return false;
			$y = $p1;
			$d = $p2;
			return array($d,$m,$y);
		}
	}
	return false;
}
?>