1 /*
2  * File:  crc.h
3  *
4  * Copyright (c) Freescale Semiconductor, Inc. All rights reserved.
5  * See included license file for license details.
6  */
7 #if !defined(_crc_h_)
8 #define CRYPTOPP_CRC32_H
9 
10 #include "stdafx.h"
11 
12 const uint32_t CRC32_NEGL = 0xffffffffL;
13 
14 #ifdef __LITTLE_ENDIAN__
15           #define CRC32_INDEX(c) (c & 0xff)
16           #define CRC32_SHIFTED(c) (c >> 8)
17 #else
18           #define CRC32_INDEX(c) (c >> 24)
19           #define CRC32_SHIFTED(c) (c << 8)
20 #endif
21 
22 //! CRC Checksum Calculation
23 class CRC32
24 {
25 public:
26           enum
27           {
28                     DIGESTSIZE = 4
29           };
30 
31           CRC32();
32 
33           void update(const uint8_t * input, unsigned length);
34 
35           void truncatedFinal(uint8_t * hash, unsigned size);
36 
updateByte(uint8_t b)37           void updateByte(uint8_t b) { m_crc = m_tab[CRC32_INDEX(m_crc) ^ b] ^ CRC32_SHIFTED(m_crc); }
getCrcByte(unsigned i)38           uint8_t getCrcByte(unsigned i) const { return ((uint8_t *)&(m_crc))[i]; }
39 
40 private:
reset()41           void reset() { m_crc = CRC32_NEGL; m_count = 0; }
42 
43           static const uint32_t m_tab[256];
44           uint32_t m_crc;
45     unsigned m_count;
46 };
47 
48 #endif // _crc_h_
49