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