| 26 | } |
| 27 | |
| 28 | std::string b64decode(const std::string& in) { |
| 29 | std::string out; |
| 30 | std::vector<int> T(256, -1); |
| 31 | for (int i = 0; i < 64; i++) T[(unsigned char)B64[i]] = i; |
| 32 | int val = 0, valb = -8; |
| 33 | for (unsigned char c : in) { |
| 34 | if (T[c] == -1) break; |
| 35 | val = (val << 6) + T[c]; |
| 36 | valb += 6; |
| 37 | if (valb >= 0) { |
| 38 | out += (char)((val >> valb) & 0xFF); |
| 39 | valb -= 8; |
| 40 | } |
| 41 | } |
| 42 | return out; |
| 43 | } |
| 44 | |
| 45 | // ── RLE on raw bytes ────────────────────────────────────────── |
| 46 | // Format: each run = [count(1 byte)][value(1 byte)] |