1 //==- SHA1.h - SHA1 implementation for LLVM                     --*- 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 // This code is taken from public domain
9 // (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
10 // and modified by wrapping it in a C++ interface for LLVM,
11 // and removing unnecessary code.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_SUPPORT_SHA1_H
16 #define LLVM_SUPPORT_SHA1_H
17 
18 #include "llvm/ADT/ArrayRef.h"
19 
20 #include <array>
21 #include <cstdint>
22 
23 namespace llvm {
24 template <typename T> class ArrayRef;
25 class StringRef;
26 
27 /// A class that wrap the SHA1 algorithm.
28 class SHA1 {
29 public:
SHA1()30   SHA1() { init(); }
31 
32   /// Reinitialize the internal state
33   void init();
34 
35   /// Digest more data.
36   void update(ArrayRef<uint8_t> Data);
37 
38   /// Digest more data.
update(StringRef Str)39   void update(StringRef Str) {
40     update(ArrayRef<uint8_t>((uint8_t *)const_cast<char *>(Str.data()),
41                              Str.size()));
42   }
43 
44   /// Return a reference to the current raw 160-bits SHA1 for the digested data
45   /// since the last call to init(). This call will add data to the internal
46   /// state and as such is not suited for getting an intermediate result
47   /// (see result()).
48   StringRef final();
49 
50   /// Return a reference to the current raw 160-bits SHA1 for the digested data
51   /// since the last call to init(). This is suitable for getting the SHA1 at
52   /// any time without invalidating the internal state so that more calls can be
53   /// made into update.
54   StringRef result();
55 
56   /// Returns a raw 160-bit SHA1 hash for the given data.
57   static std::array<uint8_t, 20> hash(ArrayRef<uint8_t> Data);
58 
59 private:
60   /// Define some constants.
61   /// "static constexpr" would be cleaner but MSVC does not support it yet.
62   enum { BLOCK_LENGTH = 64 };
63   enum { HASH_LENGTH = 20 };
64 
65   // Internal State
66   struct {
67     union {
68       uint8_t C[BLOCK_LENGTH];
69       uint32_t L[BLOCK_LENGTH / 4];
70     } Buffer;
71     uint32_t State[HASH_LENGTH / 4];
72     uint32_t ByteCount;
73     uint8_t BufferOffset;
74   } InternalState;
75 
76   // Internal copy of the hash, populated and accessed on calls to result()
77   uint32_t HashResult[HASH_LENGTH / 4];
78 
79   // Helper
80   void writebyte(uint8_t data);
81   void hashBlock();
82   void addUncounted(uint8_t data);
83   void pad();
84 };
85 
86 } // end llvm namespace
87 
88 #endif
89