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annotate modules/base64/base64.hpp @ 575:0f6501d6df34
Base64: reduce column limit
| author | David Demelier <markand@malikania.fr> |
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| date | Tue, 19 Jul 2016 22:35:42 +0200 |
| parents | f48bb09bccc7 |
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| rev | line source |
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| 517 | 1 /* |
| 2 * base64.hpp -- base64 encoding and decoding | |
| 3 * | |
| 4 * Copyright (c) 2013-2016 David Demelier <markand@malikania.fr> | |
| 5 * | |
| 6 * Permission to use, copy, modify, and/or distribute this software for any | |
| 7 * purpose with or without fee is hereby granted, provided that the above | |
| 8 * copyright notice and this permission notice appear in all copies. | |
| 9 * | |
| 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
| 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
| 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
| 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
| 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
| 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
| 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
| 17 */ | |
| 18 | |
| 19 #ifndef BASE64_HPP | |
| 20 #define BASE64_HPP | |
| 21 | |
| 22 /** | |
| 23 * \file base64.hpp | |
| 24 * \brief Base64 encoding and decoding. | |
| 25 * \author David Demelier <markand@malikania.fr> | |
| 26 */ | |
| 27 | |
| 28 /** | |
| 29 * \page Base64 Base64 | |
| 30 * \brief Base64 encoding and decoding. | |
| 31 * | |
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32 * The %base64 library let you encode and decode %base64 data from std::string |
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33 * and iterators. |
| 517 | 34 * |
| 35 * ## Encoding | |
| 36 * | |
| 37 * You can encode like this: | |
| 38 * | |
| 39 * ````cpp | |
| 40 * std::string b64 = base64::encode("Hello world!"); | |
| 41 * ```` | |
| 42 * | |
| 43 * ## Decoding | |
| 44 * | |
| 45 * And you can decode like this: | |
| 46 * | |
| 47 * ```` | |
| 48 * try { | |
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49 * std::string text = base64::decode(msg); |
| 517 | 50 * } catch (const std::exception &ex) { |
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51 * std::cerr << ex.what() << std::endl; |
| 517 | 52 * } |
| 53 * ```` | |
| 54 */ | |
| 55 | |
| 56 #include <cassert> | |
| 57 #include <cctype> | |
| 58 #include <stdexcept> | |
| 59 #include <string> | |
| 60 | |
| 61 /** | |
| 62 * \brief main %base64 namespace. | |
| 63 */ | |
| 64 namespace base64 { | |
| 65 | |
| 66 /** | |
| 67 * Check if the character is a %base64 character, A-Za-z0-9 and +/. | |
| 68 * | |
| 69 * \param ch the character to test | |
| 70 * \return true if valid | |
| 71 */ | |
| 72 inline bool isBase64(char ch) noexcept | |
| 73 { | |
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74 return std::isalnum(ch) != 0 || ch == '+' || ch == '/'; |
| 517 | 75 } |
| 76 | |
| 77 /** | |
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78 * Check if the given character is a valid character in %base64 string, |
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79 * including '='. |
| 517 | 80 * |
| 81 * \param ch the character | |
| 82 * \return true if the character is valid | |
| 83 */ | |
| 84 inline bool isValid(char ch) noexcept | |
| 85 { | |
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86 return isBase64(ch) || ch == '='; |
| 517 | 87 } |
| 88 | |
| 89 /** | |
| 90 * Get the %base64 character from the 6-bits value. | |
| 91 * | |
| 92 * \pre value must be valid (< 64) | |
| 93 * \param value the value | |
| 94 * \return the %base64 character for value | |
| 95 */ | |
| 96 inline char lookup(unsigned char value) noexcept | |
| 97 { | |
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98 static const char *table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| 517 | 99 |
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100 assert(value < 64); |
| 517 | 101 |
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102 return table[value]; |
| 517 | 103 } |
| 104 | |
| 105 /** | |
| 106 * Get the integer value from the %base64 character. | |
| 107 * | |
| 108 * \pre isBase64(ch) | |
| 109 * \param ch the %base64 character | |
| 110 * \return the integer value for the %base64 character ch | |
| 111 * ```` | |
| 112 * auto b64 = base64::rlookup('D') // 3 | |
| 113 * ```` | |
| 114 */ | |
| 115 inline unsigned char rlookup(char ch) noexcept | |
| 116 { | |
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117 assert(isBase64(ch)); |
| 517 | 118 |
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119 if (ch >= '0' && ch <= '9') |
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120 return static_cast<unsigned char>(ch + 4); |
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121 if (ch >= 'A' && ch <= 'Z') |
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122 return static_cast<unsigned char>(ch - 65); |
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123 if (ch >= 'a' && ch <= 'z') |
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124 return static_cast<unsigned char>(ch - 71); |
| 517 | 125 |
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126 return (ch == '+') ? 62U : 63U; |
| 517 | 127 } |
| 128 | |
| 129 /** | |
| 130 * Encode the input to the output. | |
| 131 * | |
| 132 * Requirements: | |
| 133 * - **InputIt** must be [InputIterator](http://en.cppreference.com/w/cpp/concept/InputIterator) | |
| 134 * - **OutputIt** must be [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator) | |
| 135 * | |
| 136 * \param input the beginning | |
| 137 * \param end the end of the data | |
| 138 * \param output the output destination | |
| 139 * \return output | |
| 140 */ | |
| 141 template <typename InputIt, typename OutputIt> | |
| 142 OutputIt encode(InputIt input, InputIt end, OutputIt output) | |
| 143 { | |
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144 while (input != end) { |
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145 char inputbuf[3] = { 0, 0, 0 }; |
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146 int count; |
| 517 | 147 |
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148 for (count = 0; count < 3 && input != end; ++count) |
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149 inputbuf[count] = *input++; |
| 517 | 150 |
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151 *output++ = lookup(inputbuf[0] >> 2 & 0x3f); |
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152 *output++ = lookup((inputbuf[0] << 4 & 0x3f) | (inputbuf[1] >> 4 & 0x0f)); |
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153 *output++ = (count < 2) ? '=' : lookup((inputbuf[1] << 2 & 0x3c) | (inputbuf[2] >> 6 & 0x03)); |
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154 *output++ = (count < 3) ? '=' : lookup(inputbuf[2] & 0x3f); |
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155 } |
| 517 | 156 |
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157 return output; |
| 517 | 158 } |
| 159 | |
| 160 /** | |
| 161 * Decode the input to the output. | |
| 162 * | |
| 163 * Requirements: | |
| 164 * - **InputIt** must be [InputIterator](http://en.cppreference.com/w/cpp/concept/InputIterator) | |
| 165 * - **OutputIt** must be [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator) | |
| 166 * | |
| 167 * \param input the beginning | |
| 168 * \param end the end of the data | |
| 169 * \param output the output destination | |
| 170 * \return output | |
| 171 * \throw std::invalid_argument on bad %base64 string | |
| 172 */ | |
| 173 template <typename InputIt, typename OutputIt> | |
| 174 OutputIt decode(InputIt input, InputIt end, OutputIt output) | |
| 175 { | |
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176 while (input != end) { |
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177 char inputbuf[4] = { -1, -1, -1, -1 }; |
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178 int count; |
| 517 | 179 |
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180 for (count = 0; count < 4 && input != end; ++count) { |
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181 // Check if the character is valid and get its value. |
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182 if ((*input == '=' && count <= 1) || !isValid(*input)) |
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183 throw std::invalid_argument("invalid base64 string"); |
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184 if (isBase64(*input)) |
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185 inputbuf[count] = static_cast<char>(rlookup(*input)); |
| 517 | 186 |
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187 input++; |
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188 } |
| 517 | 189 |
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190 if (count != 4) |
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191 throw std::invalid_argument("truncated string"); |
| 517 | 192 |
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193 *output++ = static_cast<char>(((inputbuf[0] << 2) & 0xfc) | ((inputbuf[1] >> 4) & 0x03)); |
| 517 | 194 |
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195 if (inputbuf[2] != -1) |
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196 *output++ = static_cast<char>(((inputbuf[1] << 4) & 0xf0) | ((inputbuf[2] >> 2) & 0x0f)); |
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197 if (inputbuf[3] != -1) { |
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198 // "XY=Z" is not allowed. |
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199 if (inputbuf[2] == -1) |
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200 throw std::invalid_argument("invalid base64 string"); |
| 517 | 201 |
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202 *output++ = static_cast<char>(((inputbuf[2] << 6) & 0xc0) | (inputbuf[3] & 0x3f)); |
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203 } |
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204 } |
| 517 | 205 |
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206 return output; |
| 517 | 207 } |
| 208 | |
| 209 /** | |
| 210 * Encode a string. | |
| 211 * | |
| 212 * \param input the input string | |
| 213 * \return the %base64 formatted string | |
| 214 */ | |
| 215 inline std::string encode(const std::string &input) | |
| 216 { | |
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217 std::string result; |
| 517 | 218 |
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219 encode(input.begin(), input.end(), std::back_inserter(result)); |
| 517 | 220 |
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221 return result; |
| 517 | 222 } |
| 223 | |
| 224 /** | |
| 225 * Decode a string. | |
| 226 * | |
| 227 * \param input the %base64 formatted string | |
| 228 * \return the original string | |
| 229 * \throw std::invalid_argument on bad %base64 string | |
| 230 */ | |
| 231 inline std::string decode(const std::string &input) | |
| 232 { | |
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233 std::string result; |
| 517 | 234 |
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235 decode(input.begin(), input.end(), std::back_inserter(result)); |
| 517 | 236 |
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237 return result; |
| 517 | 238 } |
| 239 | |
| 240 } // !base64 | |
| 241 | |
| 242 #endif // !BASE64_HPP |