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- <?php
- /**
- * @package Grav\Common\Helpers
- *
- * @copyright Copyright (c) 2015 - 2021 Trilby Media, LLC. All rights reserved.
- * @license MIT License; see LICENSE file for details.
- */
- namespace Grav\Common\Helpers;
- use function chr;
- use function count;
- use function ord;
- use function strlen;
- /**
- * Class Base32
- * @package Grav\Common\Helpers
- */
- class Base32
- {
- /** @var string */
- protected static $base32Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';
- /** @var array */
- protected static $base32Lookup = [
- 0xFF,0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F, // '0', '1', '2', '3', '4', '5', '6', '7'
- 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, // '8', '9', ':', ';', '<', '=', '>', '?'
- 0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06, // '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G'
- 0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E, // 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O'
- 0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16, // 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W'
- 0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF, // 'X', 'Y', 'Z', '[', '\', ']', '^', '_'
- 0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06, // '`', 'a', 'b', 'c', 'd', 'e', 'f', 'g'
- 0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E, // 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o'
- 0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16, // 'p', 'q', 'r', 's', 't', 'u', 'v', 'w'
- 0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF // 'x', 'y', 'z', '{', '|', '}', '~', 'DEL'
- ];
- /**
- * Encode in Base32
- *
- * @param string $bytes
- * @return string
- */
- public static function encode($bytes)
- {
- $i = 0;
- $index = 0;
- $base32 = '';
- $bytesLen = strlen($bytes);
- while ($i < $bytesLen) {
- $currByte = ord($bytes[$i]);
- /* Is the current digit going to span a byte boundary? */
- if ($index > 3) {
- if (($i + 1) < $bytesLen) {
- $nextByte = ord($bytes[$i+1]);
- } else {
- $nextByte = 0;
- }
- $digit = $currByte & (0xFF >> $index);
- $index = ($index + 5) % 8;
- $digit <<= $index;
- $digit |= $nextByte >> (8 - $index);
- $i++;
- } else {
- $digit = ($currByte >> (8 - ($index + 5))) & 0x1F;
- $index = ($index + 5) % 8;
- if ($index === 0) {
- $i++;
- }
- }
- $base32 .= self::$base32Chars[$digit];
- }
- return $base32;
- }
- /**
- * Decode in Base32
- *
- * @param string $base32
- * @return string
- */
- public static function decode($base32)
- {
- $bytes = [];
- $base32Len = strlen($base32);
- $base32LookupLen = count(self::$base32Lookup);
- for ($i = $base32Len * 5 / 8 - 1; $i >= 0; --$i) {
- $bytes[] = 0;
- }
- for ($i = 0, $index = 0, $offset = 0; $i < $base32Len; $i++) {
- $lookup = ord($base32[$i]) - ord('0');
- /* Skip chars outside the lookup table */
- if ($lookup < 0 || $lookup >= $base32LookupLen) {
- continue;
- }
- $digit = self::$base32Lookup[$lookup];
- /* If this digit is not in the table, ignore it */
- if ($digit === 0xFF) {
- continue;
- }
- if ($index <= 3) {
- $index = ($index + 5) % 8;
- if ($index === 0) {
- $bytes[$offset] |= $digit;
- $offset++;
- if ($offset >= count($bytes)) {
- break;
- }
- } else {
- $bytes[$offset] |= $digit << (8 - $index);
- }
- } else {
- $index = ($index + 5) % 8;
- $bytes[$offset] |= ($digit >> $index);
- $offset++;
- if ($offset >= count($bytes)) {
- break;
- }
- $bytes[$offset] |= $digit << (8 - $index);
- }
- }
- $bites = '';
- foreach ($bytes as $byte) {
- $bites .= chr($byte);
- }
- return $bites;
- }
- }
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