text: #ifndef _MACARON_BASE64_H_
  #define _MACARON_BASE64_H_
  
  /**
   * The MIT License (MIT)
   * Copyright (c) 2016 tomykaira
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #include <string>
  
  namespace macaron {
  
      class Base64 {
      public:
  
          static std::string Encode(const std::string data) {
              static constexpr char sEncodingTable[] = {
                      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
                      'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
                      'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
                      'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
                      'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                      'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
                      'w', 'x', 'y', 'z', '0', '1', '2', '3',
                      '4', '5', '6', '7', '8', '9', '+', '/'
              };
  
              size_t in_len = data.size();
              size_t out_len = 4 * ((in_len + 2) / 3);
              std::string ret(out_len, '\0');
              size_t i;
              char *p = const_cast<char*>(ret.c_str());
  
              for (i = 0; i < in_len - 2; i += 3) {
                  *p++ = sEncodingTable[(data[i] >> 2) & 0x3F];
                  *p++ = sEncodingTable[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xF0) >> 4)];
                  *p++ = sEncodingTable[((data[i + 1] & 0xF) << 2) | ((int) (data[i + 2] & 0xC0) >> 6)];
                  *p++ = sEncodingTable[data[i + 2] & 0x3F];
              }
              if (i < in_len) {
                  *p++ = sEncodingTable[(data[i] >> 2) & 0x3F];
                  if (i == (in_len - 1)) {
                      *p++ = sEncodingTable[((data[i] & 0x3) << 4)];
                      *p++ = '=';
                  }
                  else {
                      *p++ = sEncodingTable[((data[i] & 0x3) << 4) | ((int) (data[i + 1] & 0xF0) >> 4)];
                      *p++ = sEncodingTable[((data[i + 1] & 0xF) << 2)];
                  }
                  *p++ = '=';
              }
  
              return ret;
          }
  
          static std::string Decode(const std::string& input, std::string& out) {
              static constexpr unsigned char kDecodingTable[] = {
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
                      52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
                      64,  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, 64, 64, 64, 64, 64,
                      64, 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, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
                      64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
              };
  
              size_t in_len = input.size();
              if (in_len % 4 != 0) return "Input data size is not a multiple of 4";
  
              size_t out_len = in_len / 4 * 3;
              if (input[in_len - 1] == '=') out_len--;
              if (input[in_len - 2] == '=') out_len--;
  
              out.resize(out_len);
  
              for (size_t i = 0, j = 0; i < in_len;) {
                  uint32_t a = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
                  uint32_t b = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
                  uint32_t c = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
                  uint32_t d = input[i] == '=' ? 0 & i++ : kDecodingTable[static_cast<int>(input[i++])];
  
                  uint32_t triple = (a << 3 * 6) + (b << 2 * 6) + (c << 1 * 6) + (d << 0 * 6);
  
                  if (j < out_len) out[j++] = (triple >> 2 * 8) & 0xFF;
                  if (j < out_len) out[j++] = (triple >> 1 * 8) & 0xFF;
                  if (j < out_len) out[j++] = (triple >> 0 * 8) & 0xFF;
              }
  
              return "";
          }
  
      };
  
  }
  
  #endif /* _MACARON_BASE64_H_ */