| 60 | } |
| 61 | |
| 62 | std::string Decode(const std::string& encoded_string) |
| 63 | { |
| 64 | size_t in_len = encoded_string.size(); |
| 65 | size_t i = 0; |
| 66 | int in = 0; |
| 67 | unsigned char char_array_4[4], char_array_3[3]; |
| 68 | std::string ret; |
| 69 | |
| 70 | while (in_len-- && encoded_string[in] != '=' && is_base64(encoded_string[in])) |
| 71 | { |
| 72 | char_array_4[i++] = encoded_string[in]; |
| 73 | in++; |
| 74 | if (i == 4) |
| 75 | { |
| 76 | for (i = 0; i < 4; i++) |
| 77 | char_array_4[i] = static_cast<unsigned char>(base64_chars.find(char_array_4[i])); |
| 78 | |
| 79 | char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4); |
| 80 | char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2); |
| 81 | char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3]; |
| 82 | |
| 83 | for (i = 0; i < 3; i++) |
| 84 | ret += char_array_3[i]; |
| 85 | i = 0; |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | if (i) |
| 90 | { |
| 91 | size_t j; |
| 92 | for (j = i; j < 4; j++) |
| 93 | char_array_4[j] = 0; |
| 94 | |
| 95 | for (j = 0; j < 4; j++) |
| 96 | char_array_4[j] = static_cast<unsigned char>(base64_chars.find(char_array_4[j])); |
| 97 | |
| 98 | char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4); |
| 99 | char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2); |
| 100 | char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3]; |
| 101 | |
| 102 | for (j = 0; j < i - 1; j++) |
| 103 | ret += char_array_3[j]; |
| 104 | } |
| 105 | |
| 106 | return ret; |
| 107 | } |
| 108 | }; |