crc32c_defs.h revision a378bd5a5a80656ad1782ee80fa301a5ecb10ecb 
1/*
2 * This is the CRC32c polynomial, as outlined by Castagnoli.
3 * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+
4 * x^8+x^6+x^0
5 */
6#define CRCPOLY_LE 0x82F63B78
7#define CRCPOLY_BE 0x1EDC6F41
8
9/* How many bits at a time to use.  Valid values are 1, 2, 4, 8, 32 and 64. */
10/* For less performance-sensitive, use 4 */
11#ifndef CRC_LE_BITS
12# define CRC_LE_BITS 64
13#endif
14#ifndef CRC_BE_BITS
15# define CRC_BE_BITS 64
16#endif
17
18/*
19 * Little-endian CRC computation.  Used with serial bit streams sent
20 * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
21 */
22#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
23	CRC_LE_BITS & CRC_LE_BITS-1
24# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
25#endif
26
27/*
28 * Big-endian CRC computation.  Used with serial bit streams sent
29 * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
30 */
31#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
32	CRC_BE_BITS & CRC_BE_BITS-1
33# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
34#endif
35
36
37#define ___constant_swab32(x) \
38	((uint32_t)( \
39		(((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \
40		(((uint32_t)(x) & (uint32_t)0x0000ff00UL) <<  8) | \
41		(((uint32_t)(x) & (uint32_t)0x00ff0000UL) >>  8) | \
42		(((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24)))
43
44
45#include "ext2fs.h"
46#ifdef WORDS_BIGENDIAN
47#define __constant_cpu_to_le32(x) ___constant_swab32((x))
48#define __constant_cpu_to_be32(x) (x)
49#define __be32_to_cpu(x) (x)
50#define __cpu_to_be32(x) (x)
51#define __cpu_to_le32(x) (ext2fs_cpu_to_le32((x)))
52#define __le32_to_cpu(x) (ext2fs_le32_to_cpu((x)))
53#else
54#define __constant_cpu_to_le32(x) (x)
55#define __constant_cpu_to_be32(x) ___constant_swab32((x))
56#define __be32_to_cpu(x) (ext2fs_be32_to_cpu((x)))
57#define __cpu_to_be32(x) (ext2fs_cpu_to_be32((x)))
58#define __cpu_to_le32(x) (x)
59#define __le32_to_cpu(x) (x)
60#endif
61
62#if (__GNUC__ >= 3)
63#define likely(x)	__builtin_expect(!!(x), 1)
64#define unlikely(x)	__builtin_expect(!!(x), 0)
65#else
66#define likely(x)	(x)
67#define unlikely(x)	(x)
68#endif
69