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llvm-mirror/include/llvm/Support/SHA1.h
Rui Ueyama e33d058f16 Add convenient functions to compute hashes of byte vectors.
In many sitautions, you just want to compute a hash for one chunk
of data. This patch adds convenient functions for that purpose.

Differential Revision: https://reviews.llvm.org/D26988

llvm-svn: 287726
2016-11-23 00:46:09 +00:00

90 lines
2.5 KiB
C++

//==- SHA1.h - SHA1 implementation for LLVM --*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// This code is taken from public domain
// (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
// and modified by wrapping it in a C++ interface for LLVM,
// and removing unnecessary code.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_SHA1_H
#define LLVM_SUPPORT_SHA1_H
#include "llvm/ADT/ArrayRef.h"
#include <array>
#include <cstdint>
namespace llvm {
template <typename T> class ArrayRef;
class StringRef;
/// A class that wrap the SHA1 algorithm.
class SHA1 {
public:
SHA1() { init(); }
/// Reinitialize the internal state
void init();
/// Digest more data.
void update(ArrayRef<uint8_t> Data);
/// Digest more data.
void update(StringRef Str) {
update(ArrayRef<uint8_t>((uint8_t *)const_cast<char *>(Str.data()),
Str.size()));
}
/// Return a reference to the current raw 160-bits SHA1 for the digested data
/// since the last call to init(). This call will add data to the internal
/// state and as such is not suited for getting an intermediate result
/// (see result()).
StringRef final();
/// Return a reference to the current raw 160-bits SHA1 for the digested data
/// since the last call to init(). This is suitable for getting the SHA1 at
/// any time without invalidating the internal state so that more calls can be
/// made into update.
StringRef result();
/// Returns a raw 160-bit SHA1 hash for the given data.
static std::array<uint8_t, 20> hash(ArrayRef<uint8_t> Data);
private:
/// Define some constants.
/// "static constexpr" would be cleaner but MSVC does not support it yet.
enum { BLOCK_LENGTH = 64 };
enum { HASH_LENGTH = 20 };
// Internal State
struct {
union {
uint8_t C[BLOCK_LENGTH];
uint32_t L[BLOCK_LENGTH / 4];
} Buffer;
uint32_t State[HASH_LENGTH / 4];
uint32_t ByteCount;
uint8_t BufferOffset;
} InternalState;
// Internal copy of the hash, populated and accessed on calls to result()
uint32_t HashResult[HASH_LENGTH / 4];
// Helper
void writebyte(uint8_t data);
void hashBlock();
void addUncounted(uint8_t data);
void pad();
};
} // end llvm namespace
#endif