llvm/Support/SHA1.h

0001 //==- SHA1.h - SHA1 implementation for LLVM                     --*- 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 // This code is taken from public domain
0009 // (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
0010 // and modified by wrapping it in a C++ interface for LLVM,
0011 // and removing unnecessary code.
0012 //
0013 //===----------------------------------------------------------------------===//
0014
0015 #ifndef LLVM_SUPPORT_SHA1_H
0016 #define LLVM_SUPPORT_SHA1_H
0017
0018 #include <array>
0019 #include <cstdint>
0020
0021 namespace llvm {
0022 template <typename T> class ArrayRef;
0023 class StringRef;
0024
0025 /// A class that wrap the SHA1 algorithm.
0026 class SHA1 {
0027 public:
0028   SHA1() { init(); }
0029
0030   /// Reinitialize the internal state
0031   void init();
0032
0033   /// Digest more data.
0034   void update(ArrayRef<uint8_t> Data);
0035
0036   /// Digest more data.
0037   void update(StringRef Str);
0038
0039   /// Return the current raw 160-bits SHA1 for the digested data
0040   /// since the last call to init(). This call will add data to the internal
0041   /// state and as such is not suited for getting an intermediate result
0042   /// (see result()).
0043   std::array<uint8_t, 20> final();
0044
0045   /// Return the current raw 160-bits SHA1 for the digested data
0046   /// since the last call to init(). This is suitable for getting the SHA1 at
0047   /// any time without invalidating the internal state so that more calls can be
0048   /// made into update.
0049   std::array<uint8_t, 20> result();
0050
0051   /// Returns a raw 160-bit SHA1 hash for the given data.
0052   static std::array<uint8_t, 20> hash(ArrayRef<uint8_t> Data);
0053
0054 private:
0055   /// Define some constants.
0056   /// "static constexpr" would be cleaner but MSVC does not support it yet.
0057   enum { BLOCK_LENGTH = 64 };
0058   enum { HASH_LENGTH = 20 };
0059
0060   // Internal State
0061   struct {
0062     union {
0063       uint8_t C[BLOCK_LENGTH];
0064       uint32_t L[BLOCK_LENGTH / 4];
0065     } Buffer;
0066     uint32_t State[HASH_LENGTH / 4];
0067     uint32_t ByteCount;
0068     uint8_t BufferOffset;
0069   } InternalState;
0070
0071   // Helper
0072   void writebyte(uint8_t data);
0073   void hashBlock();
0074   void addUncounted(uint8_t data);
0075   void pad();
0076
0077   void final(std::array<uint32_t, HASH_LENGTH / 4> &HashResult);
0078 };
0079
0080 } // end llvm namespace
0081
0082 #endif