LLVM  16.0.0git
Base64.h
Go to the documentation of this file.
1 //===--- Base64.h - Base64 Encoder/Decoder ----------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file provides generic base64 encoder/decoder.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_SUPPORT_BASE64_H
14 #define LLVM_SUPPORT_BASE64_H
15 
16 #include "llvm/Support/Error.h"
17 #include <cstdint>
18 #include <string>
19 #include <vector>
20 
21 namespace llvm {
22 
23 template <class InputBytes> std::string encodeBase64(InputBytes const &Bytes) {
24  static const char Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
25  "abcdefghijklmnopqrstuvwxyz"
26  "0123456789+/";
27  std::string Buffer;
28  Buffer.resize(((Bytes.size() + 2) / 3) * 4);
29 
30  size_t i = 0, j = 0;
31  for (size_t n = Bytes.size() / 3 * 3; i < n; i += 3, j += 4) {
32  uint32_t x = ((unsigned char)Bytes[i] << 16) |
33  ((unsigned char)Bytes[i + 1] << 8) |
34  (unsigned char)Bytes[i + 2];
35  Buffer[j + 0] = Table[(x >> 18) & 63];
36  Buffer[j + 1] = Table[(x >> 12) & 63];
37  Buffer[j + 2] = Table[(x >> 6) & 63];
38  Buffer[j + 3] = Table[x & 63];
39  }
40  if (i + 1 == Bytes.size()) {
41  uint32_t x = ((unsigned char)Bytes[i] << 16);
42  Buffer[j + 0] = Table[(x >> 18) & 63];
43  Buffer[j + 1] = Table[(x >> 12) & 63];
44  Buffer[j + 2] = '=';
45  Buffer[j + 3] = '=';
46  } else if (i + 2 == Bytes.size()) {
47  uint32_t x =
48  ((unsigned char)Bytes[i] << 16) | ((unsigned char)Bytes[i + 1] << 8);
49  Buffer[j + 0] = Table[(x >> 18) & 63];
50  Buffer[j + 1] = Table[(x >> 12) & 63];
51  Buffer[j + 2] = Table[(x >> 6) & 63];
52  Buffer[j + 3] = '=';
53  }
54  return Buffer;
55 }
56 
57 llvm::Error decodeBase64(llvm::StringRef Input, std::vector<char> &Output);
58 
59 } // end namespace llvm
60 
61 #endif
i
i
Definition: README.txt:29
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Error.h
llvm::encodeBase64
std::string encodeBase64(InputBytes const &Bytes)
Definition: Base64.h:23
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
uint32_t
j
return j(j<< 16)
llvm::Error
Lightweight error class with error context and mandatory checking.
Definition: Error.h:155
x
TODO unsigned x
Definition: README.txt:10
n
The same transformation can work with an even modulo with the addition of a and shrink the compare RHS by the same amount Unless the target supports that transformation probably isn t worthwhile The transformation can also easily be made to work with non zero equality for n
Definition: README.txt:685
llvm::decodeBase64
llvm::Error decodeBase64(llvm::StringRef Input, std::vector< char > &Output)
Definition: Base64.cpp:37