src/util/base64.cpp

   1 /*
   2 base64.cpp and base64.h
   3
   4 Copyright (C) 2004-2008 René Nyffenegger
   5
   6 This source code is provided 'as-is', without any express or implied
   7 warranty. In no event will the author be held liable for any damages
   8 arising from the use of this software.
   9
  10 Permission is granted to anyone to use this software for any purpose,
  11 including commercial applications, and to alter it and redistribute it
  12 freely, subject to the following restrictions:
  13
  14 1. The origin of this source code must not be misrepresented; you must not
  15    claim that you wrote the original source code. If you use this source code
  16    in a product, an acknowledgment in the product documentation would be
  17    appreciated but is not required.
  18
  19 2. Altered source versions must be plainly marked as such, and must not be
  20    misrepresented as being the original source code.
  21
  22 3. This notice may not be removed or altered from any source distribution.
  23
  24 René Nyffenegger rene.nyffenegger@adp-gmbh.ch
  25
  26 */
  27
  28 #include "base64.h"
  29 #include <iostream>
  30
  31 static const std::string base64_chars =
  32                 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  33                 "abcdefghijklmnopqrstuvwxyz"
  34                 "0123456789+/";
  35
  36
  37 static inline bool is_base64(unsigned char c)
  38 {
  39         return isalnum(c) || c == '+' || c == '/' || c == '=';
  40 }
  41
  42 bool base64_is_valid(std::string const& s)
  43 {
  44         for (char i : s)
  45                 if (!is_base64(i))
  46                         return false;
  47         return true;
  48 }
  49
  50 std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {
  51         std::string ret;
  52         int i = 0;
  53         int j = 0;
  54         unsigned char char_array_3[3];
  55         unsigned char char_array_4[4];
  56
  57         while (in_len--) {
  58                 char_array_3[i++] = *(bytes_to_encode++);
  59                 if (i == 3) {
  60                         char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
  61                         char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
  62                         char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
  63                         char_array_4[3] = char_array_3[2] & 0x3f;
  64
  65                         for(i = 0; (i <4) ; i++)
  66                                 ret += base64_chars[char_array_4[i]];
  67                         i = 0;
  68                 }
  69         }
  70
  71         if (i)
  72         {
  73                 for(j = i; j < 3; j++)
  74                         char_array_3[j] = '\0';
  75
  76                 char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
  77                 char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
  78                 char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
  79                 char_array_4[3] = char_array_3[2] & 0x3f;
  80
  81                 for (j = 0; (j < i + 1); j++)
  82                         ret += base64_chars[char_array_4[j]];
  83
  84         // Don't pad it with =
  85                 /*while((i++ < 3))
  86                         ret += '=';*/
  87
  88         }
  89
  90         return ret;
  91
  92 }
  93
  94 std::string base64_decode(std::string const& encoded_string) {
  95         int in_len = encoded_string.size();
  96         int i = 0;
  97         int j = 0;
  98         int in_ = 0;
  99         unsigned char char_array_4[4], char_array_3[3];
 100         std::string ret;
 101
 102         while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
 103                 char_array_4[i++] = encoded_string[in_]; in_++;
 104                 if (i ==4) {
 105                         for (i = 0; i <4; i++)
 106                                 char_array_4[i] = base64_chars.find(char_array_4[i]);
 107
 108                         char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
 109                         char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
 110                         char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
 111
 112                         for (i = 0; (i < 3); i++)
 113                                 ret += char_array_3[i];
 114                         i = 0;
 115                 }
 116         }
 117
 118         if (i) {
 119                 for (j = i; j <4; j++)
 120                         char_array_4[j] = 0;
 121
 122                 for (j = 0; j <4; j++)
 123                         char_array_4[j] = base64_chars.find(char_array_4[j]);
 124
 125                 char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
 126                 char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
 127                 char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
 128
 129                 for (j = 0; (j < i - 1); j++) ret += char_array_3[j];
 130         }
 131
 132         return ret;
 133 }