1 //===-- llvm/Support/JamCRC.h - Cyclic Redundancy Check ---------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains an implementation of JamCRC. 11 // 12 // We will use the "Rocksoft^tm Model CRC Algorithm" to describe the properties 13 // of this CRC: 14 // Width : 32 15 // Poly : 04C11DB7 16 // Init : FFFFFFFF 17 // RefIn : True 18 // RefOut : True 19 // XorOut : 00000000 20 // Check : 340BC6D9 (result of CRC for "123456789") 21 // 22 // N.B. We permit flexibility of the "Init" value. Some consumers of this need 23 // it to be zero. 24 // 25 //===----------------------------------------------------------------------===// 26 27 #ifndef LLVM_SUPPORT_JAMCRC_H 28 #define LLVM_SUPPORT_JAMCRC_H 29 30 #include "llvm/Support/DataTypes.h" 31 32 namespace llvm { 33 template <typename T> class ArrayRef; 34 35 class JamCRC { 36 public: 37 JamCRC(uint32_t Init = 0xFFFFFFFFU) : CRC(Init) {} 38 39 // \brief Update the CRC calculation with Data. 40 void update(ArrayRef<char> Data); 41 42 uint32_t getCRC() const { return CRC; } 43 44 private: 45 uint32_t CRC; 46 }; 47 } // End of namespace llvm 48 49 #endif 50
