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Added Base 16 encoded implementation.
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‎source/Jocic/Encoders/Base/Base16.php

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<?php
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/*******************************************************************\
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|* Author: Djordje Jocic *|
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|* Year: 2019 *|
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|* License: MIT License (MIT) *|
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|* =============================================================== *|
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|* Personal Website: http://www.djordjejocic.com/ *|
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|* =============================================================== *|
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|* Permission is hereby granted, free of charge, to any person *|
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|* obtaining a copy of this software and associated documentation *|
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|* files (the "Software"), to deal in the Software without *|
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|* restriction, including without limitation the rights to use, *|
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|* copy, modify, merge, publish, distribute, sublicense, and/or *|
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|* sell copies of the Software, and to permit persons to whom the *|
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|* Software is furnished to do so, subject to the following *|
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|* conditions. *|
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|* --------------------------------------------------------------- *|
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|* The above copyright notice and this permission notice shall be *|
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|* included in all copies or substantial portions of the Software. *|
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|* --------------------------------------------------------------- *|
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|* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, *|
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|* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES *|
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|* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND *|
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|* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *|
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|* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, *|
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|* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, RISING *|
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|* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *|
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|* OTHER DEALINGS IN THE SOFTWARE. *|
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\*******************************************************************/
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namespace Jocic\Encoders\Base;
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use Jocic\Encoders\DefaultInterface;
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/**
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* <i>Base16</i> class is used for encoding data in <i>Base 16</i> format.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*/
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class Base16 extends BaseCore implements DefaultInterface, BaseInterface
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{
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/******************\
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|* CORE CONSTANTS *|
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\******************/
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// CORE CONSTANTS GO HERE
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/******************\
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|* CORE VARIABLES *|
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\******************/
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/**
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* Array containing characters of the encoding table for <i>Base 16</i>
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* encoding per <i>RFC 4648</i> specifications.
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*
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* Note: Review page 10 of the mentioned document for more information.
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*
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* @var array
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* @access private
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*/
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private $baseTable = [
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"0", "1", "2", "3", "4", "5", "6", "7",
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"8", "9", "A", "B", "C", "D", "E", "F"
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];
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/*******************\
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|* MAGIC FUNCTIONS *|
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\*******************/
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// MAGIC FUNCTIONS GO HERE
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/***************\
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|* GET METHODS *|
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\***************/
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/**
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* Returns an array containing characters of the encoding table for
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* <i>Base 16</i> encoding per <i>RFC 4648</i> specifications.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @return array
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* Array containing characters of the encoding table.
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*/
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public function getBaseTable()
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{
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// Logic
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return $this->baseTable;
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}
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/**
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* Returns an empty string as <i>Base 16</i> encoding isn't padded.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @return string
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* String containing a single character used for padding-purposes.
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*/
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public function getBasePadding()
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{
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// Logic
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return "";
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}
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/***************\
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|* SET METHODS *|
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\***************/
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// SET METHODS GO HERE
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/****************\
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|* CORE METHODS *|
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\****************/
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/**
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* Encodes a provided string to <i>Base 16</i> encoding.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @param string $input
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* Input string that needs to be encoded.
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* @return string
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* Encoded input per used specifications.
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*/
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public function encode($input)
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{
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// Core Variables
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$baseTable = $this->getBaseTable();
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$output = "";
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$chunks = [];
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// Step 1 - Handle Empty Input
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if ($input == "")
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{
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return "";
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}
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// Step 2 - Split Input Into 4-bit Chunks
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$chunks = $this->convertInputToChunks($input);
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// Step 3 - Process Chunks
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foreach ($chunks as $chunk)
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{
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$output .= $baseTable[$chunk];
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}
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// Step 4 - Apply Padding & Return Encoding
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return $output;
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}
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/**
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* Decodes a provided string from <i>Base 16</i> encoding.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @param string $input
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* Input string that needs to be decoded.
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* @return string
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* Decoded input per used specifications.
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*/
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public function decode($input)
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{
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// Core Variables
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$chunks = [];
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// Step 1 - Handle Empty Input
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if ($input == "")
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{
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return "";
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}
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// Step 2 - Decode Input Into 4-bit Chunks
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$chunks = $this->convertEncodingToChunks($input);
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// Step 3 - Merge Dervided Chunks
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$input = $this->mergeEncodingChunks($chunks);
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// Step 4 - Return Decoding
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return $input;
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}
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/*****************\
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|* CHECK METHODS *|
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\*****************/
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/**
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* Checks if the <i>Base 16</i> encoding is valid or not.
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*
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* Note: Invalid encodings should be rejected per section <i>3.3</i>
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* in the <i>RFC 4648</i> specifications.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @param string $encoding
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* <i>Base 16</i> encoding that needs to be checked.
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* @return bool
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* Value <i>True</i> if encoding is valid, and vice versa.
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*/
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public function isEncodingValid($encoding)
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{
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// Core Variables
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$baseTable = $this->getBaseTable();
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// Other Variables
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$characters = [];
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// Step 1 - Check If Empty
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if ($encoding == "")
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{
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return true;
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}
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// Step 2 - Check General Form
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if (!preg_match("/^([A-z0-9]+)?$/", $encoding))
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{
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return false;
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}
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// Step 3 - Generate Character Array
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$characters = str_split($encoding);
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// Step 4 - Check Characters
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foreach ($characters as $character)
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{
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if (!in_array($character, $baseTable))
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{
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return false;
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}
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}
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return true;
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}
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/********************\
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|* ENCODING METHODS *|
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\********************/
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/**
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* Converts provided string into chunks - 4-bit values.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @param string $input
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* Input that needs to be converted to chunks.
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* @return array
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* Array containing chunks (4-bit values).
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*/
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public function convertInputToChunks($input)
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{
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// Core Variables
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$characters = null;
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// Chunk Variables
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$chunks = [];
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$byte = null;
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// Logic
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$characters = str_split($input);
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foreach ($characters as $character)
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{
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// Convert Character To Byte
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$byte = ord($character) & 0xFF;
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// Split Byte Into Chunks
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$chunks[] = ($byte & 0xF0) >> 4;
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$chunks[] = ($byte & 0x0F) >> 0;
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}
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return $chunks;
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}
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/********************\
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|* DECODING METHODS *|
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\********************/
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/**
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* Merges encoding chunks into a single string.
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*
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* @author Djordje Jocic <[email protected]>
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* @copyright 2019 All Rights Reserved
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* @version 1.0.0
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*
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* @param array $chunks
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* Encoding chunks that should be merged.
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* @return string
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* Merged encoding chunks - actual decoding.
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*/
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public function mergeEncodingChunks($chunks)
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{
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// Core Variables
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$decoding = "";
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$byte = null;
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// Logic
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for ($i = 0; $i < count($chunks); $i += 2)
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{
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$byte = (($chunks[$i] << 4) | $chunks[$i + 1]) & 0xFF;
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$decoding .= sprintf("%c", $byte);
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}
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return $decoding;
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}
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/*****************\
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|* OTHER METHODS *|
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\*****************/
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// OTHER METHODS GO HERE
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}
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?>

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