EVOLUTION-MANAGER
Edit File: Hash.php
<?php /** * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions. * * Uses hash() or mhash() if available and an internal implementation, otherwise. Currently supports the following: * * md2, md5, md5-96, sha1, sha1-96, sha256, sha256-96, sha384, and sha512, sha512-96 * * If {@link \phpseclib\Crypt\Hash::setKey() setKey()} is called, {@link \phpseclib\Crypt\Hash::hash() hash()} will return the HMAC as opposed to * the hash. If no valid algorithm is provided, sha1 will be used. * * PHP version 5 * * {@internal The variable names are the same as those in * {@link http://tools.ietf.org/html/rfc2104#section-2 RFC2104}.}} * * Here's a short example of how to use this library: * <code> * <?php * include 'vendor/autoload.php'; * * $hash = new \phpseclib\Crypt\Hash('sha1'); * * $hash->setKey('abcdefg'); * * echo base64_encode($hash->hash('abcdefg')); * ?> * </code> * * @category Crypt * @package Hash * @author Jim Wigginton <terrafrost@php.net> * @copyright 2007 Jim Wigginton * @license http://www.opensource.org/licenses/mit-license.html MIT License * @link http://phpseclib.sourceforge.net */ namespace phpseclib\Crypt; defined("ABSPATH") or die(""); use phpseclib\Math\BigInteger; /** * Pure-PHP implementations of keyed-hash message authentication codes (HMACs) and various cryptographic hashing functions. * * @package Hash * @author Jim Wigginton <terrafrost@php.net> * @access public */ class Hash { /**#@+ * @access private * @see \phpseclib\Crypt\Hash::__construct() */ /** * Toggles the internal implementation */ const MODE_INTERNAL = 1; /** * Toggles the mhash() implementation, which has been deprecated on PHP 5.3.0+. */ const MODE_MHASH = 2; /** * Toggles the hash() implementation, which works on PHP 5.1.2+. */ const MODE_HASH = 3; /**#@-*/ /** * Hash Parameter * * @see \phpseclib\Crypt\Hash::setHash() * @var Integer * @access private */ var $hashParam; /** * Byte-length of compression blocks / key (Internal HMAC) * * @see \phpseclib\Crypt\Hash::setAlgorithm() * @var Integer * @access private */ var $b; /** * Byte-length of hash output (Internal HMAC) * * @see \phpseclib\Crypt\Hash::setHash() * @var Integer * @access private */ var $l = false; /** * Hash Algorithm * * @see \phpseclib\Crypt\Hash::setHash() * @var String * @access private */ var $hash; /** * Key * * @see \phpseclib\Crypt\Hash::setKey() * @var String * @access private */ var $key = false; /** * Outer XOR (Internal HMAC) * * @see \phpseclib\Crypt\Hash::setKey() * @var String * @access private */ var $opad; /** * Inner XOR (Internal HMAC) * * @see \phpseclib\Crypt\Hash::setKey() * @var String * @access private */ var $ipad; /** * Default Constructor. * * @param optional String $hash * @return \phpseclib\Crypt\Hash * @access public */ function __construct($hash = 'sha1') { if (!defined('CRYPT_HASH_MODE')) { switch (true) { case extension_loaded('hash'): define('CRYPT_HASH_MODE', self::MODE_HASH); break; case extension_loaded('mhash'): define('CRYPT_HASH_MODE', self::MODE_MHASH); break; default: define('CRYPT_HASH_MODE', self::MODE_INTERNAL); } } $this->setHash($hash); } /** * Sets the key for HMACs * * Keys can be of any length. * * @access public * @param optional String $key */ function setKey($key = false) { $this->key = $key; } /** * Gets the hash function. * * As set by the constructor or by the setHash() method. * * @access public * @return String */ function getHash() { return $this->hashParam; } /** * Sets the hash function. * * @access public * @param String $hash */ function setHash($hash) { $this->hashParam = $hash = strtolower($hash); switch ($hash) { case 'md5-96': case 'sha1-96': case 'sha256-96': case 'sha512-96': $hash = substr($hash, 0, -3); $this->l = 12; // 96 / 8 = 12 break; case 'md2': case 'md5': $this->l = 16; break; case 'sha1': $this->l = 20; break; case 'sha256': $this->l = 32; break; case 'sha384': $this->l = 48; break; case 'sha512': $this->l = 64; } switch ($hash) { case 'md2': $mode = CRYPT_HASH_MODE == self::MODE_HASH && in_array('md2', hash_algos()) ? self::MODE_HASH : self::MODE_INTERNAL; break; case 'sha384': case 'sha512': $mode = CRYPT_HASH_MODE == self::MODE_MHASH ? self::MODE_INTERNAL : CRYPT_HASH_MODE; break; default: $mode = CRYPT_HASH_MODE; } switch ($mode) { case self::MODE_MHASH: switch ($hash) { case 'md5': $this->hash = MHASH_MD5; break; case 'sha256': $this->hash = MHASH_SHA256; break; case 'sha1': default: $this->hash = MHASH_SHA1; } return; case self::MODE_HASH: switch ($hash) { case 'md5': $this->hash = 'md5'; return; case 'md2': case 'sha256': case 'sha384': case 'sha512': $this->hash = $hash; return; case 'sha1': default: $this->hash = 'sha1'; } return; } switch ($hash) { case 'md2': $this->b = 16; $this->hash = array($this, '_md2'); break; case 'md5': $this->b = 64; $this->hash = array($this, '_md5'); break; case 'sha256': $this->b = 64; $this->hash = array($this, '_sha256'); break; case 'sha384': case 'sha512': $this->b = 128; $this->hash = array($this, '_sha512'); break; case 'sha1': default: $this->b = 64; $this->hash = array($this, '_sha1'); } $this->ipad = str_repeat(chr(0x36), $this->b); $this->opad = str_repeat(chr(0x5C), $this->b); } /** * Compute the HMAC. * * @access public * @param String $text * @return String */ function hash($text) { $mode = is_array($this->hash) ? self::MODE_INTERNAL : CRYPT_HASH_MODE; if (!empty($this->key) || is_string($this->key)) { switch ($mode) { case self::MODE_MHASH: $output = mhash($this->hash, $text, $this->key); break; case self::MODE_HASH: $output = hash_hmac($this->hash, $text, $this->key, true); break; case self::MODE_INTERNAL: /* "Applications that use keys longer than B bytes will first hash the key using H and then use the resultant L byte string as the actual key to HMAC." -- http://tools.ietf.org/html/rfc2104#section-2 */ $key = strlen($this->key) > $this->b ? call_user_func($this->hash, $this->key) : $this->key; $key = str_pad($key, $this->b, chr(0)); // step 1 $temp = $this->ipad ^ $key; // step 2 $temp .= $text; // step 3 $temp = call_user_func($this->hash, $temp); // step 4 $output = $this->opad ^ $key; // step 5 $output.= $temp; // step 6 $output = call_user_func($this->hash, $output); // step 7 } } else { switch ($mode) { case self::MODE_MHASH: $output = mhash($this->hash, $text); break; case self::MODE_HASH: $output = hash($this->hash, $text, true); break; case self::MODE_INTERNAL: $output = call_user_func($this->hash, $text); } } return substr($output, 0, $this->l); } /** * Returns the hash length (in bytes) * * @access public * @return Integer */ function getLength() { return $this->l; } /** * Wrapper for MD5 * * @access private * @param String $m */ function _md5($m) { return pack('H*', md5($m)); } /** * Wrapper for SHA1 * * @access private * @param String $m */ function _sha1($m) { return pack('H*', sha1($m)); } /** * Pure-PHP implementation of MD2 * * See {@link http://tools.ietf.org/html/rfc1319 RFC1319}. * * @access private * @param String $m */ function _md2($m) { static $s = array( 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24, 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251, 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63, 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50, 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165, 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210, 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157, 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27, 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15, 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197, 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65, 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123, 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233, 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228, 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237, 31, 26, 219, 153, 141, 51, 159, 17, 131, 20 ); // Step 1. Append Padding Bytes $pad = 16 - (strlen($m) & 0xF); $m.= str_repeat(chr($pad), $pad); $length = strlen($m); // Step 2. Append Checksum $c = str_repeat(chr(0), 16); $l = chr(0); for ($i = 0; $i < $length; $i+= 16) { for ($j = 0; $j < 16; $j++) { // RFC1319 incorrectly states that C[j] should be set to S[c xor L] //$c[$j] = chr($s[ord($m[$i + $j] ^ $l)]); // per <http://www.rfc-editor.org/errata_search.php?rfc=1319>, however, C[j] should be set to S[c xor L] xor C[j] $c[$j] = chr($s[ord($m[$i + $j] ^ $l)] ^ ord($c[$j])); $l = $c[$j]; } } $m.= $c; $length+= 16; // Step 3. Initialize MD Buffer $x = str_repeat(chr(0), 48); // Step 4. Process Message in 16-Byte Blocks for ($i = 0; $i < $length; $i+= 16) { for ($j = 0; $j < 16; $j++) { $x[$j + 16] = $m[$i + $j]; $x[$j + 32] = $x[$j + 16] ^ $x[$j]; } $t = chr(0); for ($j = 0; $j < 18; $j++) { for ($k = 0; $k < 48; $k++) { $x[$k] = $t = $x[$k] ^ chr($s[ord($t)]); //$t = $x[$k] = $x[$k] ^ chr($s[ord($t)]); } $t = chr(ord($t) + $j); } } // Step 5. Output return substr($x, 0, 16); } /** * Pure-PHP implementation of SHA256 * * See {@link http://en.wikipedia.org/wiki/SHA_hash_functions#SHA-256_.28a_SHA-2_variant.29_pseudocode SHA-256 (a SHA-2 variant) pseudocode - Wikipedia}. * * @access private * @param String $m */ function _sha256($m) { if (extension_loaded('suhosin')) { return pack('H*', sha256($m)); } // Initialize variables $hash = array( 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 ); // Initialize table of round constants // (first 32 bits of the fractional parts of the cube roots of the first 64 primes 2..311) static $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 ); // Pre-processing $length = strlen($m); // to round to nearest 56 mod 64, we'll add 64 - (length + (64 - 56)) % 64 $m.= str_repeat(chr(0), 64 - (($length + 8) & 0x3F)); $m[$length] = chr(0x80); // we don't support hashing strings 512MB long $m.= pack('N2', 0, $length << 3); // Process the message in successive 512-bit chunks $chunks = str_split($m, 64); foreach ($chunks as $chunk) { $w = array(); for ($i = 0; $i < 16; $i++) { extract(unpack('Ntemp', $this->_string_shift($chunk, 4))); $w[] = $temp; } // Extend the sixteen 32-bit words into sixty-four 32-bit words for ($i = 16; $i < 64; $i++) { // @codingStandardsIgnoreStart $s0 = $this->_rightRotate($w[$i - 15], 7) ^ $this->_rightRotate($w[$i - 15], 18) ^ $this->_rightShift( $w[$i - 15], 3); $s1 = $this->_rightRotate($w[$i - 2], 17) ^ $this->_rightRotate($w[$i - 2], 19) ^ $this->_rightShift( $w[$i - 2], 10); // @codingStandardsIgnoreEnd $w[$i] = $this->_add($w[$i - 16], $s0, $w[$i - 7], $s1); } // Initialize hash value for this chunk list($a, $b, $c, $d, $e, $f, $g, $h) = $hash; // Main loop for ($i = 0; $i < 64; $i++) { $s0 = $this->_rightRotate($a, 2) ^ $this->_rightRotate($a, 13) ^ $this->_rightRotate($a, 22); $maj = ($a & $b) ^ ($a & $c) ^ ($b & $c); $t2 = $this->_add($s0, $maj); $s1 = $this->_rightRotate($e, 6) ^ $this->_rightRotate($e, 11) ^ $this->_rightRotate($e, 25); $ch = ($e & $f) ^ ($this->_not($e) & $g); $t1 = $this->_add($h, $s1, $ch, $k[$i], $w[$i]); $h = $g; $g = $f; $f = $e; $e = $this->_add($d, $t1); $d = $c; $c = $b; $b = $a; $a = $this->_add($t1, $t2); } // Add this chunk's hash to result so far $hash = array( $this->_add($hash[0], $a), $this->_add($hash[1], $b), $this->_add($hash[2], $c), $this->_add($hash[3], $d), $this->_add($hash[4], $e), $this->_add($hash[5], $f), $this->_add($hash[6], $g), $this->_add($hash[7], $h) ); } // Produce the final hash value (big-endian) return pack('N8', $hash[0], $hash[1], $hash[2], $hash[3], $hash[4], $hash[5], $hash[6], $hash[7]); } /** * Pure-PHP implementation of SHA384 and SHA512 * * @access private * @param String $m */ function _sha512($m) { static $init384, $init512, $k; if (!isset($k)) { // Initialize variables $init384 = array( // initial values for SHA384 'cbbb9d5dc1059ed8', '629a292a367cd507', '9159015a3070dd17', '152fecd8f70e5939', '67332667ffc00b31', '8eb44a8768581511', 'db0c2e0d64f98fa7', '47b5481dbefa4fa4' ); $init512 = array( // initial values for SHA512 '6a09e667f3bcc908', 'bb67ae8584caa73b', '3c6ef372fe94f82b', 'a54ff53a5f1d36f1', '510e527fade682d1', '9b05688c2b3e6c1f', '1f83d9abfb41bd6b', '5be0cd19137e2179' ); for ($i = 0; $i < 8; $i++) { $init384[$i] = new BigInteger($init384[$i], 16); $init384[$i]->setPrecision(64); $init512[$i] = new BigInteger($init512[$i], 16); $init512[$i]->setPrecision(64); } // Initialize table of round constants // (first 64 bits of the fractional parts of the cube roots of the first 80 primes 2..409) $k = array( '428a2f98d728ae22', '7137449123ef65cd', 'b5c0fbcfec4d3b2f', 'e9b5dba58189dbbc', '3956c25bf348b538', '59f111f1b605d019', '923f82a4af194f9b', 'ab1c5ed5da6d8118', 'd807aa98a3030242', '12835b0145706fbe', '243185be4ee4b28c', '550c7dc3d5ffb4e2', '72be5d74f27b896f', '80deb1fe3b1696b1', '9bdc06a725c71235', 'c19bf174cf692694', 'e49b69c19ef14ad2', 'efbe4786384f25e3', '0fc19dc68b8cd5b5', '240ca1cc77ac9c65', '2de92c6f592b0275', '4a7484aa6ea6e483', '5cb0a9dcbd41fbd4', '76f988da831153b5', '983e5152ee66dfab', 'a831c66d2db43210', 'b00327c898fb213f', 'bf597fc7beef0ee4', 'c6e00bf33da88fc2', 'd5a79147930aa725', '06ca6351e003826f', '142929670a0e6e70', '27b70a8546d22ffc', '2e1b21385c26c926', '4d2c6dfc5ac42aed', '53380d139d95b3df', '650a73548baf63de', '766a0abb3c77b2a8', '81c2c92e47edaee6', '92722c851482353b', 'a2bfe8a14cf10364', 'a81a664bbc423001', 'c24b8b70d0f89791', 'c76c51a30654be30', 'd192e819d6ef5218', 'd69906245565a910', 'f40e35855771202a', '106aa07032bbd1b8', '19a4c116b8d2d0c8', '1e376c085141ab53', '2748774cdf8eeb99', '34b0bcb5e19b48a8', '391c0cb3c5c95a63', '4ed8aa4ae3418acb', '5b9cca4f7763e373', '682e6ff3d6b2b8a3', '748f82ee5defb2fc', '78a5636f43172f60', '84c87814a1f0ab72', '8cc702081a6439ec', '90befffa23631e28', 'a4506cebde82bde9', 'bef9a3f7b2c67915', 'c67178f2e372532b', 'ca273eceea26619c', 'd186b8c721c0c207', 'eada7dd6cde0eb1e', 'f57d4f7fee6ed178', '06f067aa72176fba', '0a637dc5a2c898a6', '113f9804bef90dae', '1b710b35131c471b', '28db77f523047d84', '32caab7b40c72493', '3c9ebe0a15c9bebc', '431d67c49c100d4c', '4cc5d4becb3e42b6', '597f299cfc657e2a', '5fcb6fab3ad6faec', '6c44198c4a475817' ); for ($i = 0; $i < 80; $i++) { $k[$i] = new BigInteger($k[$i], 16); } } $hash = $this->l == 48 ? $init384 : $init512; // Pre-processing $length = strlen($m); // to round to nearest 112 mod 128, we'll add 128 - (length + (128 - 112)) % 128 $m.= str_repeat(chr(0), 128 - (($length + 16) & 0x7F)); $m[$length] = chr(0x80); // we don't support hashing strings 512MB long $m.= pack('N4', 0, 0, 0, $length << 3); // Process the message in successive 1024-bit chunks $chunks = str_split($m, 128); foreach ($chunks as $chunk) { $w = array(); for ($i = 0; $i < 16; $i++) { $temp = new BigInteger($this->_string_shift($chunk, 8), 256); $temp->setPrecision(64); $w[] = $temp; } // Extend the sixteen 32-bit words into eighty 32-bit words for ($i = 16; $i < 80; $i++) { $temp = array( $w[$i - 15]->bitwise_rightRotate(1), $w[$i - 15]->bitwise_rightRotate(8), $w[$i - 15]->bitwise_rightShift(7) ); $s0 = $temp[0]->bitwise_xor($temp[1]); $s0 = $s0->bitwise_xor($temp[2]); $temp = array( $w[$i - 2]->bitwise_rightRotate(19), $w[$i - 2]->bitwise_rightRotate(61), $w[$i - 2]->bitwise_rightShift(6) ); $s1 = $temp[0]->bitwise_xor($temp[1]); $s1 = $s1->bitwise_xor($temp[2]); $w[$i] = $w[$i - 16]->copy(); $w[$i] = $w[$i]->add($s0); $w[$i] = $w[$i]->add($w[$i - 7]); $w[$i] = $w[$i]->add($s1); } // Initialize hash value for this chunk $a = $hash[0]->copy(); $b = $hash[1]->copy(); $c = $hash[2]->copy(); $d = $hash[3]->copy(); $e = $hash[4]->copy(); $f = $hash[5]->copy(); $g = $hash[6]->copy(); $h = $hash[7]->copy(); // Main loop for ($i = 0; $i < 80; $i++) { $temp = array( $a->bitwise_rightRotate(28), $a->bitwise_rightRotate(34), $a->bitwise_rightRotate(39) ); $s0 = $temp[0]->bitwise_xor($temp[1]); $s0 = $s0->bitwise_xor($temp[2]); $temp = array( $a->bitwise_and($b), $a->bitwise_and($c), $b->bitwise_and($c) ); $maj = $temp[0]->bitwise_xor($temp[1]); $maj = $maj->bitwise_xor($temp[2]); $t2 = $s0->add($maj); $temp = array( $e->bitwise_rightRotate(14), $e->bitwise_rightRotate(18), $e->bitwise_rightRotate(41) ); $s1 = $temp[0]->bitwise_xor($temp[1]); $s1 = $s1->bitwise_xor($temp[2]); $temp = array( $e->bitwise_and($f), $g->bitwise_and($e->bitwise_not()) ); $ch = $temp[0]->bitwise_xor($temp[1]); $t1 = $h->add($s1); $t1 = $t1->add($ch); $t1 = $t1->add($k[$i]); $t1 = $t1->add($w[$i]); $h = $g->copy(); $g = $f->copy(); $f = $e->copy(); $e = $d->add($t1); $d = $c->copy(); $c = $b->copy(); $b = $a->copy(); $a = $t1->add($t2); } // Add this chunk's hash to result so far $hash = array( $hash[0]->add($a), $hash[1]->add($b), $hash[2]->add($c), $hash[3]->add($d), $hash[4]->add($e), $hash[5]->add($f), $hash[6]->add($g), $hash[7]->add($h) ); } // Produce the final hash value (big-endian) // (\phpseclib\Crypt\Hash::hash() trims the output for hashes but not for HMACs. as such, we trim the output here) $temp = $hash[0]->toBytes() . $hash[1]->toBytes() . $hash[2]->toBytes() . $hash[3]->toBytes() . $hash[4]->toBytes() . $hash[5]->toBytes(); if ($this->l != 48) { $temp.= $hash[6]->toBytes() . $hash[7]->toBytes(); } return $temp; } /** * Right Rotate * * @access private * @param Integer $int * @param Integer $amt * @see _sha256() * @return Integer */ function _rightRotate($int, $amt) { $invamt = 32 - $amt; $mask = (1 << $invamt) - 1; return (($int << $invamt) & 0xFFFFFFFF) | (($int >> $amt) & $mask); } /** * Right Shift * * @access private * @param Integer $int * @param Integer $amt * @see _sha256() * @return Integer */ function _rightShift($int, $amt) { $mask = (1 << (32 - $amt)) - 1; return ($int >> $amt) & $mask; } /** * Not * * @access private * @param Integer $int * @see _sha256() * @return Integer */ function _not($int) { return ~$int & 0xFFFFFFFF; } /** * Add * * _sha256() adds multiple unsigned 32-bit integers. Since PHP doesn't support unsigned integers and since the * possibility of overflow exists, care has to be taken. BigInteger could be used but this should be faster. * * @param Integer $... * @return Integer * @see _sha256() * @access private */ function _add() { static $mod; if (!isset($mod)) { $mod = pow(2, 32); } $result = 0; $arguments = func_get_args(); foreach ($arguments as $argument) { $result+= $argument < 0 ? ($argument & 0x7FFFFFFF) + 0x80000000 : $argument; } return fmod($result, $mod); } /** * String Shift * * Inspired by array_shift * * @param String $string * @param optional Integer $index * @return String * @access private */ function _string_shift(&$string, $index = 1) { $substr = substr($string, 0, $index); $string = substr($string, $index); return $substr; } }