130 lines
4.0 KiB
PHP
130 lines
4.0 KiB
PHP
<?php
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/**
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* @package Grav\Common\Helpers
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*
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* @copyright Copyright (C) 2015 - 2019 Trilby Media, LLC. All rights reserved.
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* @license MIT License; see LICENSE file for details.
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*/
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namespace Grav\Common\Helpers;
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class Base32
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{
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protected static $base32Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
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protected static $base32Lookup = [
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0xFF,0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F, // '0', '1', '2', '3', '4', '5', '6', '7'
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0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // '8', '9', ':', ';', '<', '=', '>', '?'
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0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06, // '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G'
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0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E, // 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O'
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0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16, // 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W'
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0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF, // 'X', 'Y', 'Z', '[', '\', ']', '^', '_'
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0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06, // '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g'
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0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E, // 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o'
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0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16, // 'p', 'q', 'r', 's', 't', 'u', 'v', 'w'
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0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF // 'x', 'y', 'z', '{', '|', '}', '~', 'DEL'
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];
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/**
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* Encode in Base32
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*
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* @param string $bytes
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* @return string
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*/
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public static function encode($bytes)
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{
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$i = 0; $index = 0;
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$base32 = '';
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$bytesLen = \strlen($bytes);
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while ($i < $bytesLen) {
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$currByte = \ord($bytes[$i]);
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/* Is the current digit going to span a byte boundary? */
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if ($index > 3) {
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if (($i + 1) < $bytesLen) {
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$nextByte = \ord($bytes[$i+1]);
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} else {
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$nextByte = 0;
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}
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$digit = $currByte & (0xFF >> $index);
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$index = ($index + 5) % 8;
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$digit <<= $index;
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$digit |= $nextByte >> (8 - $index);
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$i++;
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} else {
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$digit = ($currByte >> (8 - ($index + 5))) & 0x1F;
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$index = ($index + 5) % 8;
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if ($index === 0) {
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$i++;
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}
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}
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$base32 .= self::$base32Chars[$digit];
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}
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return $base32;
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}
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/**
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* Decode in Base32
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*
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* @param string $base32
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* @return string
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*/
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public static function decode($base32)
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{
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$bytes = [];
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$base32Len = \strlen($base32);
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$base32LookupLen = \count(self::$base32Lookup);
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for ($i = $base32Len * 5 / 8 - 1; $i >= 0; --$i) {
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$bytes[] = 0;
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}
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for ($i = 0, $index = 0, $offset = 0; $i < $base32Len; $i++) {
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$lookup = \ord($base32[$i]) - \ord('0');
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/* Skip chars outside the lookup table */
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if ($lookup < 0 || $lookup >= $base32LookupLen) {
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continue;
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}
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$digit = self::$base32Lookup[$lookup];
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/* If this digit is not in the table, ignore it */
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if ($digit === 0xFF) {
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continue;
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}
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if ($index <= 3) {
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$index = ($index + 5) % 8;
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if ($index === 0) {
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$bytes[$offset] |= $digit;
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$offset++;
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if ($offset >= \count($bytes)) {
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break;
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}
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} else {
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$bytes[$offset] |= $digit << (8 - $index);
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}
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} else {
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$index = ($index + 5) % 8;
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$bytes[$offset] |= ($digit >> $index);
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$offset++;
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if ($offset >= \count($bytes)) {
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break;
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}
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$bytes[$offset] |= $digit << (8 - $index);
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}
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}
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$bites = '';
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foreach ($bytes as $byte) {
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$bites .= \chr($byte);
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}
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return $bites;
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}
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}
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