mirror of
https://github.com/RetroShare/RetroShare.git
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145 lines
6.5 KiB
C++
145 lines
6.5 KiB
C++
/*******************************************************************************
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* *
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* libretroshare base64 encoding utilities *
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* *
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* Copyright (C) 2015 Retroshare Team <contact@retroshare.cc> *
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* Copyright (C) 2020 Gioacchino Mazzurco <gio@eigenlab.org> *
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* Copyright (C) 2020 Asociación Civil Altermundi <info@altermundi.net> *
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* *
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* This program is free software: you can redistribute it and/or modify *
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* it under the terms of the GNU Lesser General Public License as *
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* published by the Free Software Foundation, either version 3 of the *
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* License, or (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU Lesser General Public License for more details. *
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* *
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* You should have received a copy of the GNU Lesser General Public License *
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* along with this program. If not, see <https://www.gnu.org/licenses/>. *
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* *
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*******************************************************************************/
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#pragma once
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#include <string>
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#include <vector>
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#include <cstdint>
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#include <system_error>
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#include <tuple>
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#include "util/rsmemory.h"
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/**
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* Implement methods to encode e decode to base64 format as per RFC 4648
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* This implementation support also the file name and URL safe base64url format
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* @see https://tools.ietf.org/html/rfc4648#section-5
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*/
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class RsBase64
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{
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public:
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/// Enable base64url by default
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static constexpr bool DEFAULT_URL_SAFE = true;
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/// Disable padding by default
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static constexpr bool DEFAULT_PADDING = false;
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/**
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* @brief Encode arbitrary data to base64
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* @param[in] data pointer to the input data buffer
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* @param[in] len lenght of the input buffer
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* @param[out] outString storage for the resulting base64 encoded string
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* @param[in] padding set to true to enable padding to 32 bits
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* @param[in] urlSafe pass true for base64url format, false for base64 format
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*/
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static void encode(
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rs_view_ptr<const uint8_t> data, size_t len,
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std::string& outString,
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bool padding = DEFAULT_PADDING, bool urlSafe = DEFAULT_URL_SAFE );
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/**
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* @brief Decode data from a base64 encoded string
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* @param[in] encoded encoded string
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* @param[out] decoded storage for decoded data
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* @return success or error details
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*/
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static std::error_condition decode(
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const std::string& encoded, std::vector<uint8_t>& decoded );
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/**
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* Remove invalid characters from base64 encoded string.
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* Often when copy and pasting from one progam to another long base64
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* strings, new lines, spaces or other characters end up polluting the
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* original text. This function is useful to cleanup the pollution before
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* attempting to decode the message.
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* @param in input string
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* @param out storage for cleaned string. In-place operation in supported so
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* the same input string may be passed.
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* @return count of stripped invalid characters
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*/
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static size_t stripInvalid(const std::string& in, std::string& out);
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/**
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* Calculate how much bytes are needed to store the base64 encoded version
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* of some data.
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* @param decodedSize size of the original decoded data
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* @param padding true to enable base64 padding
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* @return how much bytes would take to store the encoded version
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*/
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static size_t encodedSize(
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size_t decodedSize, bool padding = DEFAULT_PADDING );
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/**
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* @brief Calculate how much space is needed to store the decoded version of
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* a base64 encoded string
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* @param input encoded string
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* @return decoded size, plus error information on failure
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*/
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static std::tuple<size_t, std::error_condition> decodedSize(
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const std::string& input );
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private:
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/// base64 conversion table
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static constexpr char bDict[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/// base64url conversion table
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static constexpr char uDict[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
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/// This reverse table supports both base64 and base64url
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static constexpr int8_t rDict[256] = {
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/* index +0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 */
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/* 0 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 16 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 32 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, 62, -1, 63,
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/* 48 */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 0, -1, -1,
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/* 64 */ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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/* 80 */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63,
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/* 96 */ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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/* 112 */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
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/* 128 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 144 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 160 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 176 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 192 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 208 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 224 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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/* 240 */ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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};
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/// base64 padding character
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static constexpr char sPad = '=';
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/** Check if given character is valid either for base64 or for base64url
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* @param c character to check
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* @return true if valid false otherwise
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*/
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static inline bool isBase64Char(char c)
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{ return rDict[static_cast<uint8_t>(c)] >= 0; }
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/** Perform ceil division without floating point operations */
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static inline size_t ceilDivision(size_t dividend, size_t divisor)
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{ return (dividend + divisor - 1) / divisor; }
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};
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