// ************************************************************************** // * This file is part of the FreeFileSync project. It is distributed under * // * GNU General Public License: http://www.gnu.org/licenses/gpl.html * // * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved * // ************************************************************************** #ifndef BASE64_HEADER_08473021856321840873021487213453214 #define BASE64_HEADER_08473021856321840873021487213453214 #ifndef NDEBUG //no release build dependencies! #include <iterator> #include <cassert> #endif namespace zen { //http://en.wikipedia.org/wiki/Base64 /* Usage: const std::string input = "Sample text"; std::string output; zen::encodeBase64(input.begin(), input.end(), std::back_inserter(output)); //output contains "U2FtcGxlIHRleHQ=" */ template <class InputIterator, class OutputIterator> OutputIterator encodeBase64(InputIterator first, InputIterator last, OutputIterator result); //nothrow! template <class InputIterator, class OutputIterator> OutputIterator decodeBase64(InputIterator first, InputIterator last, OutputIterator result); //nothrow! //------------------------- implementation ------------------------------- namespace implementation { //64 chars for base64 encoding + padding char const char ENCODING_MIME[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; const signed char DECODING_MIME[] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 64, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 }; const unsigned char INDEX_PAD = 64; //"=" } //http://en.wikipedia.org/wiki/Base64 template <class InputIterator, class OutputIterator> inline OutputIterator encodeBase64(InputIterator first, InputIterator last, OutputIterator result) { using namespace implementation; static_assert(sizeof(typename std::iterator_traits<InputIterator>::value_type) == 1, ""); static_assert(sizeof(ENCODING_MIME) == 65 + 1, ""); while (first != last) { const unsigned char a = static_cast<unsigned char>(*first++); *result++ = ENCODING_MIME[a >> 2]; if (first == last) { *result++ = ENCODING_MIME[((a & 0x3) << 4)]; *result++ = ENCODING_MIME[INDEX_PAD]; *result++ = ENCODING_MIME[INDEX_PAD]; break; } const unsigned char b = static_cast<unsigned char>(*first++); *result++ = ENCODING_MIME[((a & 0x3) << 4) | (b >> 4)]; if (first == last) { *result++ = ENCODING_MIME[((b & 0xf) << 2)]; *result++ = ENCODING_MIME[INDEX_PAD]; break; } const unsigned char c = static_cast<unsigned char>(*first++); *result++ = ENCODING_MIME[((b & 0xf) << 2) | (c >> 6)]; *result++ = ENCODING_MIME[c & 0x3f]; } return result; } template <class InputIterator, class OutputIterator> inline OutputIterator decodeBase64(InputIterator first, InputIterator last, OutputIterator result) { using namespace implementation; static_assert(sizeof(typename std::iterator_traits<InputIterator>::value_type) == 1, ""); static_assert(sizeof(DECODING_MIME) == 128, ""); const unsigned char INDEX_END = INDEX_PAD + 1; auto readIndex = [&]() -> unsigned char //return index within [0, 64] or INDEX_END if end of input { while (true) { if (first == last) return INDEX_END; const unsigned char ch = static_cast<unsigned char>(*first++); if (ch < 128) //we're in lower ASCII table half { const int index = implementation::DECODING_MIME[ch]; if (0 <= index && index <= static_cast<int>(INDEX_PAD)) //skip all unknown characters (including carriage return, line-break, tab) return index; } } }; for (;;) { const unsigned char index1 = readIndex(); const unsigned char index2 = readIndex(); if (index1 >= INDEX_PAD || index2 >= INDEX_PAD) { assert(index1 == INDEX_END && index2 == INDEX_END); break; } *result++ = static_cast<char>((index1 << 2) | (index2 >> 4)); const unsigned char index3 = readIndex(); if (index3 >= INDEX_PAD) //padding { assert(index3 == INDEX_PAD); break; } *result++ = static_cast<char>(((index2 & 0xf) << 4) | (index3 >> 2)); const unsigned char index4 = readIndex(); if (index4 >= INDEX_PAD) //padding { assert(index4 == INDEX_PAD); break; } *result++ = static_cast<char>(((index3 & 0x3) << 6) | index4); } return result; } } #endif //BASE64_HEADER_08473021856321840873021487213453214