llvm/Support/Base64.h

0001 //===--- Base64.h - Base64 Encoder/Decoder ----------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 // This file provides generic base64 encoder/decoder.
0010 //
0011 //===----------------------------------------------------------------------===//
0012
0013 #ifndef LLVM_SUPPORT_BASE64_H
0014 #define LLVM_SUPPORT_BASE64_H
0015
0016 #include "llvm/Support/Error.h"
0017 #include <cstdint>
0018 #include <string>
0019 #include <vector>
0020
0021 namespace llvm {
0022
0023 template <class InputBytes> std::string encodeBase64(InputBytes const &Bytes) {
0024   static const char Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
0025                               "abcdefghijklmnopqrstuvwxyz"
0026                               "0123456789+/";
0027   std::string Buffer;
0028   Buffer.resize(((Bytes.size() + 2) / 3) * 4);
0029
0030   size_t i = 0, j = 0;
0031   for (size_t n = Bytes.size() / 3 * 3; i < n; i += 3, j += 4) {
0032     uint32_t x = ((unsigned char)Bytes[i] << 16) |
0033                  ((unsigned char)Bytes[i + 1] << 8) |
0034                  (unsigned char)Bytes[i + 2];
0035     Buffer[j + 0] = Table[(x >> 18) & 63];
0036     Buffer[j + 1] = Table[(x >> 12) & 63];
0037     Buffer[j + 2] = Table[(x >> 6) & 63];
0038     Buffer[j + 3] = Table[x & 63];
0039   }
0040   if (i + 1 == Bytes.size()) {
0041     uint32_t x = ((unsigned char)Bytes[i] << 16);
0042     Buffer[j + 0] = Table[(x >> 18) & 63];
0043     Buffer[j + 1] = Table[(x >> 12) & 63];
0044     Buffer[j + 2] = '=';
0045     Buffer[j + 3] = '=';
0046   } else if (i + 2 == Bytes.size()) {
0047     uint32_t x =
0048         ((unsigned char)Bytes[i] << 16) | ((unsigned char)Bytes[i + 1] << 8);
0049     Buffer[j + 0] = Table[(x >> 18) & 63];
0050     Buffer[j + 1] = Table[(x >> 12) & 63];
0051     Buffer[j + 2] = Table[(x >> 6) & 63];
0052     Buffer[j + 3] = '=';
0053   }
0054   return Buffer;
0055 }
0056
0057 llvm::Error decodeBase64(llvm::StringRef Input, std::vector<char> &Output);
0058
0059 } // end namespace llvm
0060
0061 #endif