boost/beast/core/detail/base64.ipp
// // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // Official repository: https://github.com/boostorg/beast // /* Portions from http://www.adp-gmbh.ch/cpp/common/base64.html Copyright notice: base64.cpp and base64.h Copyright (C) 2004-2008 Rene Nyffenegger This source code is provided 'as-is', without any express or implied warranty. In no event will the author be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this source code must not be misrepresented; you must not claim that you wrote the original source code. If you use this source code in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original source code. 3. This notice may not be removed or altered from any source distribution. Rene Nyffenegger rene.nyffenegger@adp-gmbh.ch */ #ifndef BOOST_BEAST_DETAIL_BASE64_IPP #define BOOST_BEAST_DETAIL_BASE64_IPP #include <boost/beast/core/detail/base64.hpp> #include <boost/beast/core/string.hpp> #include <cctype> #include <string> #include <utility> namespace boost { namespace beast { namespace detail { namespace base64 { char const* get_alphabet() { static char constexpr tab[] = { "ABCDEFGHIJKLMNOP" "QRSTUVWXYZabcdef" "ghijklmnopqrstuv" "wxyz0123456789+/" }; return &tab[0]; } signed char const* get_inverse() { static signed char constexpr tab[] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0-15 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 16-31 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, // 32-47 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, // 48-63 -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 64-79 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, // 80-95 -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, // 96-111 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, // 112-127 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 128-143 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 144-159 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 160-175 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 176-191 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 192-207 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 208-223 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 224-239 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 // 240-255 }; return &tab[0]; } /** Encode a series of octets as a padded, base64 string. The resulting string will not be null terminated. @par Requires The memory pointed to by `out` points to valid memory of at least `encoded_size(len)` bytes. @return The number of characters written to `out`. This will exclude any null termination. */ std::size_t encode(void* dest, void const* src, std::size_t len) { char* out = static_cast<char*>(dest); char const* in = static_cast<char const*>(src); auto const tab = base64::get_alphabet(); for(auto n = len / 3; n--;) { *out++ = tab[ (in[0] & 0xfc) >> 2]; *out++ = tab[((in[0] & 0x03) << 4) + ((in[1] & 0xf0) >> 4)]; *out++ = tab[((in[2] & 0xc0) >> 6) + ((in[1] & 0x0f) << 2)]; *out++ = tab[ in[2] & 0x3f]; in += 3; } switch(len % 3) { case 2: *out++ = tab[ (in[0] & 0xfc) >> 2]; *out++ = tab[((in[0] & 0x03) << 4) + ((in[1] & 0xf0) >> 4)]; *out++ = tab[ (in[1] & 0x0f) << 2]; *out++ = '='; break; case 1: *out++ = tab[ (in[0] & 0xfc) >> 2]; *out++ = tab[((in[0] & 0x03) << 4)]; *out++ = '='; *out++ = '='; break; case 0: break; } return out - static_cast<char*>(dest); } /** Decode a padded base64 string into a series of octets. @par Requires The memory pointed to by `out` points to valid memory of at least `decoded_size(len)` bytes. @return The number of octets written to `out`, and the number of characters read from the input string, expressed as a pair. */ std::pair<std::size_t, std::size_t> decode(void* dest, char const* src, std::size_t len) { char* out = static_cast<char*>(dest); auto in = reinterpret_cast<unsigned char const*>(src); unsigned char c3[3], c4[4]; int i = 0; int j = 0; auto const inverse = base64::get_inverse(); while(len-- && *in != '=') { auto const v = inverse[*in]; if(v == -1) break; ++in; c4[i] = v; if(++i == 4) { c3[0] = (c4[0] << 2) + ((c4[1] & 0x30) >> 4); c3[1] = ((c4[1] & 0xf) << 4) + ((c4[2] & 0x3c) >> 2); c3[2] = ((c4[2] & 0x3) << 6) + c4[3]; for(i = 0; i < 3; i++) *out++ = c3[i]; i = 0; } } if(i) { c3[0] = ( c4[0] << 2) + ((c4[1] & 0x30) >> 4); c3[1] = ((c4[1] & 0xf) << 4) + ((c4[2] & 0x3c) >> 2); c3[2] = ((c4[2] & 0x3) << 6) + c4[3]; for(j = 0; j < i - 1; j++) *out++ = c3[j]; } return {out - static_cast<char*>(dest), in - reinterpret_cast<unsigned char const*>(src)}; } } // base64 } // detail } // beast } // boost #endif