Recommit [NFC] Better encapsulation of llvm::Optional Storage
[llvm-complete.git] / include / llvm / Support / JamCRC.h
blobb6fc4e7b9b033995a7f66aca66666be3686d3efb
1 //===-- llvm/Support/JamCRC.h - Cyclic Redundancy Check ---------*- 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 contains an implementation of JamCRC.
11 // We will use the "Rocksoft^tm Model CRC Algorithm" to describe the properties
12 // of this CRC:
13 // Width : 32
14 // Poly : 04C11DB7
15 // Init : FFFFFFFF
16 // RefIn : True
17 // RefOut : True
18 // XorOut : 00000000
19 // Check : 340BC6D9 (result of CRC for "123456789")
21 // N.B. We permit flexibility of the "Init" value. Some consumers of this need
22 // it to be zero.
24 //===----------------------------------------------------------------------===//
26 #ifndef LLVM_SUPPORT_JAMCRC_H
27 #define LLVM_SUPPORT_JAMCRC_H
29 #include "llvm/Support/DataTypes.h"
31 namespace llvm {
32 template <typename T> class ArrayRef;
34 class JamCRC {
35 public:
36 JamCRC(uint32_t Init = 0xFFFFFFFFU) : CRC(Init) {}
38 // Update the CRC calculation with Data.
39 void update(ArrayRef<char> Data);
41 uint32_t getCRC() const { return CRC; }
43 private:
44 uint32_t CRC;
46 } // End of namespace llvm
48 #endif