|
| 1 | +// Base64 Originally from René Nyffenegger's public domain base64 code |
| 2 | +// (https://renenyffenegger.ch/notes/development/Base64/Encoding-and-decoding-base-64-with-cpp/) |
| 3 | +// |
| 4 | +// These changes were made: |
| 5 | +// 1. String input/output interface |
| 6 | +// 2. Proper padding handling |
| 7 | +// 3. Explicit character validation |
| 8 | + |
| 9 | +#include <string> |
| 10 | +#include <vector> |
| 11 | + |
| 12 | +static const std::string BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" |
| 13 | + "abcdefghijklmnopqrstuvwxyz" |
| 14 | + "0123456789+/"; |
| 15 | + |
| 16 | +bool is_base64(unsigned char c) { |
| 17 | + return (isalnum(c) || (c == '+') || (c == '/')); |
| 18 | +} |
| 19 | + |
| 20 | +bool base64_encode(std::string &out, const std::string &in) { |
| 21 | + int i = 0, j = 0; |
| 22 | + unsigned char char_array_3[3]; |
| 23 | + unsigned char char_array_4[4]; |
| 24 | + out.clear(); |
| 25 | + |
| 26 | + for (auto c : in) { |
| 27 | + char_array_3[i++] = c; |
| 28 | + if (i == 3) { |
| 29 | + char_array_4[0] = (char_array_3[0] & 0xfc) >> 2; |
| 30 | + char_array_4[1] = |
| 31 | + ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4); |
| 32 | + char_array_4[2] = |
| 33 | + ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6); |
| 34 | + char_array_4[3] = char_array_3[2] & 0x3f; |
| 35 | + |
| 36 | + for (i = 0; i < 4; i++) |
| 37 | + out += BASE64_CHARS[char_array_4[i]]; |
| 38 | + i = 0; |
| 39 | + } |
| 40 | + } |
| 41 | + |
| 42 | + if (i) { |
| 43 | + for (j = i; j < 3; j++) |
| 44 | + char_array_3[j] = '\0'; |
| 45 | + |
| 46 | + char_array_4[0] = (char_array_3[0] & 0xfc) >> 2; |
| 47 | + char_array_4[1] = |
| 48 | + ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4); |
| 49 | + char_array_4[2] = |
| 50 | + ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6); |
| 51 | + |
| 52 | + for (j = 0; j < i + 1; j++) |
| 53 | + out += BASE64_CHARS[char_array_4[j]]; |
| 54 | + |
| 55 | + while (i++ < 3) |
| 56 | + out += '='; |
| 57 | + } |
| 58 | + |
| 59 | + return true; |
| 60 | +} |
| 61 | + |
| 62 | +bool base64_decode(std::string &out, const std::string &in) { |
| 63 | + int i = 0, j = 0; |
| 64 | + unsigned char char_array_4[4], char_array_3[3]; |
| 65 | + out.clear(); |
| 66 | + |
| 67 | + for (auto c : in) { |
| 68 | + if (c == '=') |
| 69 | + break; |
| 70 | + |
| 71 | + if (!is_base64(c)) |
| 72 | + return false; |
| 73 | + |
| 74 | + char_array_4[i++] = c; |
| 75 | + if (i == 4) { |
| 76 | + for (i = 0; i < 4; i++) |
| 77 | + char_array_4[i] = BASE64_CHARS.find(char_array_4[i]); |
| 78 | + |
| 79 | + char_array_3[0] = |
| 80 | + (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4); |
| 81 | + char_array_3[1] = |
| 82 | + ((char_array_4[1] & 0x0f) << 4) + ((char_array_4[2] & 0x3c) >> 2); |
| 83 | + char_array_3[2] = ((char_array_4[2] & 0x03) << 6) + char_array_4[3]; |
| 84 | + |
| 85 | + for (i = 0; i < 3; i++) |
| 86 | + out += char_array_3[i]; |
| 87 | + i = 0; |
| 88 | + } |
| 89 | + } |
| 90 | + |
| 91 | + if (i) { |
| 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] = 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] = |
| 100 | + ((char_array_4[1] & 0x0f) << 4) + ((char_array_4[2] & 0x3c) >> 2); |
| 101 | + |
| 102 | + for (j = 0; j < i - 1; j++) |
| 103 | + out += char_array_3[j]; |
| 104 | + } |
| 105 | + |
| 106 | + return true; |
| 107 | +} |
| 108 | + |
| 109 | +std::string pack_bits_to_string(const std::vector<bool> &vec) { |
| 110 | + std::string packed; |
| 111 | + if (vec.empty()) |
| 112 | + return packed; |
| 113 | + |
| 114 | + packed.reserve((vec.size() + 7) / 8); |
| 115 | + for (size_t i = 0; i < vec.size(); i += 8) { |
| 116 | + unsigned char byte = 0; |
| 117 | + for (size_t j = 0; j < 8 && (i + j) < vec.size(); ++j) { |
| 118 | + if (vec[i + j]) { |
| 119 | + byte |= (1 << (7 - j)); |
| 120 | + } |
| 121 | + } |
| 122 | + packed.push_back(byte); |
| 123 | + } |
| 124 | + return packed; |
| 125 | +} |
| 126 | + |
| 127 | +std::vector<bool> unpack_bits_from_string(const std::string &packed, |
| 128 | + size_t original_size) { |
| 129 | + std::vector<bool> vec; |
| 130 | + vec.reserve(original_size); |
| 131 | + for (size_t i = 0; i < packed.size(); ++i) { |
| 132 | + unsigned char byte = packed[i]; |
| 133 | + for (int j = 7; j >= 0 && vec.size() < original_size; --j) { |
| 134 | + vec.push_back((byte >> j) & 1); |
| 135 | + } |
| 136 | + } |
| 137 | + return vec; |
| 138 | +} |
| 139 | + |
| 140 | +std::string pack_bit_vector_to_base64(const std::vector<bool> &vec) { |
| 141 | + std::string packed = pack_bits_to_string(vec); |
| 142 | + std::string b64; |
| 143 | + base64_encode(b64, packed); |
| 144 | + return b64; |
| 145 | +} |
| 146 | + |
| 147 | +std::vector<bool> unpack_bit_vector_from_base64(const std::string &b64, |
| 148 | + size_t original_size) { |
| 149 | + std::string packed; |
| 150 | + base64_decode(packed, b64); |
| 151 | + return unpack_bits_from_string(packed, original_size); |
| 152 | +} |
0 commit comments