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@@ -0,0 +1,193 @@
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+/*
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+ * Author: Patrick-Christopher Mattulat
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+ * Company: Lynar Studios
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+ * E-Mail: webmaster@lynarstudios.com
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+ * Created: 2022-01-03
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+ * Changed: 2022-05-20
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+ *
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+ * */
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+
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+#include <ls_std/encoding/Base64.hpp>
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+#include <bitset>
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+
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+std::string ls::std::encoding::Base64::encode(const ::std::string &_sequence)
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+{
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+ ::std::string encodedString{};
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+
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+ for(size_t index = 0 ; index < _sequence.size() ; index += 3)
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+ {
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+ ::std::string byteTriple = ls::std::encoding::Base64::_getNextByteTriple(_sequence, index);
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+ encodedString += ls::std::encoding::Base64::_encodeByteTriple(byteTriple);
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+ }
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+
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+ return ls::std::encoding::Base64::_applyEndingRule(encodedString, _sequence.size());
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+}
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+
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+std::string ls::std::encoding::Base64::decode(const ::std::string &_sequence)
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+{
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+ ::std::string decodedString{};
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+
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+ for (int index{} ; index < _sequence.size() ; index += 4)
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+ {
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+ ::std::string quadruple = ls::std::encoding::Base64::_getNextByteQuadruple(_sequence, index);
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+ decodedString += ls::std::encoding::Base64::_decodeByteQuadruple(quadruple);
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+ }
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+
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+ return decodedString;
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+}
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+
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+::std::string ls::std::encoding::Base64::_applyEndingRule(::std::string _encodedString, size_t _sequenceSize)
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+{
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+ size_t size = _encodedString.size();
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+
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+ if (_sequenceSize % 3 == 1)
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+ {
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+ _encodedString[size - 2] = '=';
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+ _encodedString[size - 1] = '=';
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+ }
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+
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+ if (_sequenceSize % 3 == 2)
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+ {
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+ _encodedString[size - 1] = '=';
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+ }
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+
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+ return _encodedString;
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+}
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+
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+std::string ls::std::encoding::Base64::_decodeByteQuadruple(const ::std::string& _quadruple)
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+{
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+ ::std::string decodedText{};
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+ uint8_t shiftValue = 16;
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+ uint32_t bitStorage = ls::std::encoding::Base64::_toDecodingBitStorage(_quadruple);
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+
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+ for (uint8_t index = 0; index < ((uint8_t) _quadruple.size() - 1); index++)
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+ {
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+ uint32_t bitMask = ls::std::encoding::Base64::_generateBitMask(255, shiftValue);
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+ uint32_t bitSequence = ls::std::encoding::Base64::_extractBitSequence(bitMask, bitStorage);
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+ bitSequence = bitSequence >> shiftValue;
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+
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+ decodedText += (char) bitSequence;
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+ shiftValue -= 8;
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+ }
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+
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+ return decodedText;
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+}
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+
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+std::string ls::std::encoding::Base64::_encodeByteTriple(const ::std::string& _byteTriple)
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+{
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+ ::std::string encodedText{};
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+ uint32_t bitStorage = ls::std::encoding::Base64::_toEncodingBitStorage(_byteTriple);
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+ static ::std::vector<uint32_t> bitMaskStorage = {16515072, 258048, 4032, 63};
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+ static ::std::unordered_map<uint8_t, char> encodingMap = ls::std::encoding::Base64::_getEncodingMap();
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+ uint8_t shiftValue = 18;
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+
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+ for (uint8_t bitMaskIndex = 0 ; bitMaskIndex < 4 ; bitMaskIndex++)
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+ {
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+ uint32_t extractedBitSequence = ls::std::encoding::Base64::_extractBitSequence(bitMaskStorage[bitMaskIndex], bitStorage);
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+ extractedBitSequence = extractedBitSequence >> shiftValue;
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+ encodedText += encodingMap[(uint8_t) extractedBitSequence];
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+ shiftValue -= 6;
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+ }
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+
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+ return encodedText;
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+}
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+
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+uint32_t ls::std::encoding::Base64::_extractBitSequence(uint32_t _bitMask, uint32_t _bitStorage)
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+{
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+ return _bitStorage & _bitMask;
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+}
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+
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+uint32_t ls::std::encoding::Base64::_generateBitMask(uint32_t _maskValue, uint8_t _shiftValue)
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+{
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+ if(_shiftValue == 0)
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+ {
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+ return _maskValue;
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+ }
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+
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+ if(_shiftValue < 0)
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+ {
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+ return _maskValue >> _shiftValue;
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+ }
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+
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+ return _maskValue << _shiftValue;
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+}
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+
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+std::unordered_map<char, uint8_t> ls::std::encoding::Base64::_getDecodingMap()
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+{
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+ static ::std::unordered_map<char, uint8_t> decodingMap =
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+ {
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+ {'A', 0}, {'B', 1}, {'C', 2}, {'D', 3}, {'E', 4}, {'F', 5}, {'G', 6}, {'H', 7},
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+ {'I', 8}, {'J', 9}, {'K', 10}, {'L', 11}, {'M', 12}, {'N', 13}, {'O', 14}, {'P', 15},
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+ {'Q', 16}, {'R', 17}, {'S', 18}, {'T', 19}, {'U', 20}, {'V', 21}, {'W', 22}, {'X', 23},
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+ {'Y', 24}, {'Z', 25}, {'a', 26}, {'b', 27}, {'c', 28}, {'d', 29}, {'e', 30}, {'f', 31},
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+ {'g', 32}, {'h', 33}, {'i', 34}, {'j', 35}, {'k', 36}, {'l', 37}, {'m', 38}, {'n', 39},
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+ {'o', 40}, {'p', 41}, {'q', 42}, {'r', 43}, {'s', 44}, {'t', 45}, {'u', 46}, {'v', 47},
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+ {'w', 48}, {'x', 49}, {'y', 50}, {'z', 51}, {'0', 52}, {'1', 53}, {'2', 54}, {'3', 55},
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+ {'4', 56}, {'5', 57}, {'6', 58}, {'7', 59}, {'8', 60}, {'9', 61}, {'+', 62}, {'/', 63}
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+ };
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+
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+ return decodingMap;
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+}
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+
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+std::unordered_map<uint8_t, char> ls::std::encoding::Base64::_getEncodingMap()
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+{
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+ static ::std::unordered_map<uint8_t, char> encodingMap =
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+ {
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+ {0, 'A'}, {1, 'B'}, {2, 'C'}, {3, 'D'}, {4, 'E'}, {5, 'F'}, {6, 'G'}, {7, 'H'},
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+ {8, 'I'}, {9, 'J'}, {10, 'K'}, {11, 'L'}, {12, 'M'}, {13, 'N'}, {14, 'O'}, {15, 'P'},
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+ {16, 'Q'}, {17, 'R'}, {18, 'S'}, {19, 'T'}, {20, 'U'}, {21, 'V'}, {22, 'W'}, {23, 'X'},
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+ {24, 'Y'}, {25, 'Z'}, {26, 'a'}, {27, 'b'}, {28, 'c'}, {29, 'd'}, {30, 'e'}, {31, 'f'},
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+ {32, 'g'}, {33, 'h'}, {34, 'i'}, {35, 'j'}, {36, 'k'}, {37, 'l'}, {38, 'm'}, {39, 'n'},
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+ {40, 'o'}, {41, 'p'}, {42, 'q'}, {43, 'r'}, {44, 's'}, {45, 't'}, {46, 'u'}, {47, 'v'},
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+ {48, 'w'}, {49, 'x'}, {50, 'y'}, {51, 'z'}, {52, '0'}, {53, '1'}, {54, '2'}, {55, '3'},
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+ {56, '4'}, {57, '5'}, {58, '6'}, {59, '7'}, {60, '8'}, {61, '9'}, {62, '+'}, {63, '/'},
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+ };
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+
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+ return encodingMap;
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+}
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+
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+std::string ls::std::encoding::Base64::_getNextByteQuadruple(const ::std::string &_sequence, size_t _index)
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+{
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+ return _sequence.substr(_index, 4);
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+}
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+
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+std::string ls::std::encoding::Base64::_getNextByteTriple(const ::std::string &_sequence, size_t _index)
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+{
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+ return _sequence.substr(_index, 3);
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+}
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+
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+void ls::std::encoding::Base64::_mergeBitSequence(uint32_t &_bitStorage, const uint32_t &_bitMask)
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+{
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+ _bitStorage = _bitStorage | _bitMask;
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+}
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+
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+uint32_t ls::std::encoding::Base64::_toDecodingBitStorage(const ::std::string &_quadruple)
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+{
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+ uint32_t bitStorage{};
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+ uint8_t letterCounter = 1;
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+ ::std::unordered_map<char, uint8_t> decodingMap = ls::std::encoding::Base64::_getDecodingMap();
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+
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+ for(char letter : _quadruple)
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+ {
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+ uint32_t bitMask = ls::std::encoding::Base64::_generateBitMask(decodingMap[(char) letter], (4 - letterCounter) * 6); // must be hardcoded - even in case of less than 4 characters, so that conversion is correct
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+ ls::std::encoding::Base64::_mergeBitSequence(bitStorage, bitMask);
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+ ++letterCounter;
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+ }
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+
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+ return bitStorage;
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+}
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+
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+uint32_t ls::std::encoding::Base64::_toEncodingBitStorage(const ::std::string &_triple)
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+{
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+ uint32_t bitStorage{};
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+ uint8_t shiftValue = 16;
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+
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+ for(char letter : _triple)
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+ {
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+ uint32_t bitMask = ls::std::encoding::Base64::_generateBitMask((uint8_t) letter, shiftValue);
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+ ls::std::encoding::Base64::_mergeBitSequence(bitStorage, bitMask);
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+ shiftValue -= 8;
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+ }
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+
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+ return bitStorage;
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+}
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