<?php
/*************************  
  Copyright (c) 2004-2010 TinyWebGallery
  written by Michael Dempfle
 
  This program is free software; you can redistribute it and/or modify 
  it under the terms of the TinyWebGallery license (based on the GNU  
  General Public License as published by the Free Software Foundation;  
  either version 2 of the License, or (at your option) any later version. 
  See license.txt for details.
 
  TWG version: 1.8
 
  $Date: 2009-06-17 22:57:10 +0200 (Mi, 17 Jun 2009) $
  $Revision: 73 $
**********************************************/

defined('_VALID_TWG') or die('Direct Access to this location is not allowed.');

if (!function_exists('str_split')) {
	function str_split($string, $split_length = 1)
	{
		$r = array();

		if ($split_length < 1) {
			return false;
		}
		if ($split_length > strlen($string)) {
			return array($string);
		}
		for($i = 0; $i < strlen($string); $i += $split_length) {
			$r[] = substr($string, $i, $split_length);
		}
		return $r;
	}
}
// shift right
function shr($x, $n)
{
	return (0x80000000 &$x) ? (($x >> 1) &~0x80000000 | 0x40000000) >> ($n - 1) : ($x >> $n);
}
// rotate left
function rotl($x, $n)
{
	return ($x << $n) | shr($x, (32 - $n));
}
// rotate right
function rotr($x, $n)
{
	return shr($x, $n) | ($x << (32 - $n));
}
function sha2($str, $raw_output = false)
{
	$h0 = 0x6a09e667;
	$h1 = 0xbb67ae85;
	$h2 = 0x3c6ef372;
	$h3 = 0xa54ff53a;
	$h4 = 0x510e527f;
	$h5 = 0x9b05688c;
	$h6 = 0x1f83d9ab;
	$h7 = 0x5be0cd19;
	$k = array
	(0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
		0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
		0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
		0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
		0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
		0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
		0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
		0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
		);
	$l = strlen($str);
	$str = str_pad("$str\x80\x0\x0\x0\x0", ($l &~ 63) + ((($l &63) < 56) ? 60 : 124), "\x0") . pack('N', $l << 3);
	$chunks = str_split($str, 64);

	foreach($chunks as $chunk) {
		$w = array_values(unpack('N16', $chunk));

		for($i = 16; $i <= 63; $i++) {
			$s0 = rotr($w[$i - 15], 7) ^ rotr($w[$i - 15], 18) ^ shr($w[$i - 15], 3);
			$s1 = rotr($w[$i - 2], 17) ^ rotr($w[$i - 2], 19) ^ shr($w[$i - 2], 10);
			$w[$i] = $s1 + $w[$i - 7] + $s0 + $w[$i - 16];
		}
		$a = $h0;
		$b = $h1;
		$c = $h2;
		$d = $h3;
		$e = $h4;
		$f = $h5;
		$g = $h6;
		$h = $h7;

		for($i = 0; $i <= 63; $i++) {
			$s0 = rotr($a, 2) ^ rotr($a, 13) ^ rotr($a, 22);
			$s1 = rotr($e, 6) ^ rotr($e, 11) ^ rotr($e, 25);
			$ch = ($e &$f) ^ (~$e &$g);
			$t1 = (int) ($h + $s1 + $ch + $k[$i] + $w[$i]);
			$maj = ($a &$b) ^ ($b &$c) ^ ($c &$a);
			$t2 = (int) ($s0 + $maj);

			$h = $g;
			$g = $f;
			$f = $e;
			$e = $d + $t1;
			$d = $c;
			$c = $b;
			$b = $a;
			$a = $t1 + $t2;
		}
		$h0 = $h0 + $a;
		$h1 = $h1 + $b;
		$h2 = $h2 + $c;
		$h3 = $h3 + $d;
		$h4 = $h4 + $e;
		$h5 = $h5 + $f;
		$h6 = $h6 + $g;
		$h7 = $h7 + $h;
	}
	$hash = pack('N*', $h0, $h1, $h2, $h3, $h4, $h5, $h6, $h7);

	if ($raw_output) {
		return $hash;
	}
	return bin2hex($hash);
}

?>