aboutsummaryrefslogtreecommitdiffstats
path: root/lib/lz4/lz4defs.h
blob: 00a0b58a0871bc3c1f0afca8aa9bbd03aab09edd (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
#ifndef __LZ4DEFS_H__
#define __LZ4DEFS_H__

/*
 * lz4defs.h -- common and architecture specific defines for the kernel usage

 * LZ4 - Fast LZ compression algorithm
 * Copyright (C) 2011-2016, Yann Collet.
 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *	* Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 *	* Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * You can contact the author at :
 *	- LZ4 homepage : http://www.lz4.org
 *	- LZ4 source repository : https://github.com/lz4/lz4
 *
 *	Changed for kernel usage by:
 *	Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
 */

#include <asm/unaligned.h>
#include <linux/string.h>	 /* memset, memcpy */

#define FORCE_INLINE __always_inline

/*-************************************
 *	Basic Types
 **************************************/
#include <linux/types.h>

typedef	uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
typedef	int32_t S32;
typedef uint64_t U64;
typedef uintptr_t uptrval;

/*-************************************
 *	Architecture specifics
 **************************************/
#if defined(CONFIG_64BIT)
#define LZ4_ARCH64 1
#else
#define LZ4_ARCH64 0
#endif

#if defined(__LITTLE_ENDIAN)
#define LZ4_LITTLE_ENDIAN 1
#else
#define LZ4_LITTLE_ENDIAN 0
#endif

/*-************************************
 *	Constants
 **************************************/
#define MINMATCH 4

#define WILDCOPYLENGTH 8
#define LASTLITERALS 5
#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)

/* Increase this value ==> compression run slower on incompressible data */
#define LZ4_SKIPTRIGGER 6

#define HASH_UNIT sizeof(size_t)

#define KB (1 << 10)
#define MB (1 << 20)
#define GB (1U << 30)

#define MAXD_LOG 16
#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
#define STEPSIZE sizeof(size_t)

#define ML_BITS	4
#define ML_MASK	((1U << ML_BITS) - 1)
#define RUN_BITS (8 - ML_BITS)
#define RUN_MASK ((1U << RUN_BITS) - 1)

/*-************************************
 *	Reading and writing into memory
 **************************************/
static FORCE_INLINE U16 LZ4_read16(const void *ptr)
{
	return get_unaligned((const U16 *)ptr);
}

static FORCE_INLINE U32 LZ4_read32(const void *ptr)
{
	return get_unaligned((const U32 *)ptr);
}

static FORCE_INLINE size_t LZ4_read_ARCH(const void *ptr)
{
	return get_unaligned((const size_t *)ptr);
}

static FORCE_INLINE void LZ4_write16(void *memPtr, U16 value)
{
	put_unaligned(value, (U16 *)memPtr);
}

static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
{
	put_unaligned(value, (U32 *)memPtr);
}

static FORCE_INLINE U16 LZ4_readLE16(const void *memPtr)
{
	return get_unaligned_le16(memPtr);
}

static FORCE_INLINE void LZ4_writeLE16(void *memPtr, U16 value)
{
	return put_unaligned_le16(value, memPtr);
}

static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
{
#if LZ4_ARCH64
	U64 a = get_unaligned((const U64 *)src);

	put_unaligned(a, (U64 *)dst);
#else
	U32 a = get_unaligned((const U32 *)src);
	U32 b = get_unaligned((const U32 *)src + 1);

	put_unaligned(a, (U32 *)dst);
	put_unaligned(b, (U32 *)dst + 1);
#endif
}

/*
 * customized variant of memcpy,
 * which can overwrite up to 7 bytes beyond dstEnd
 */
static FORCE_INLINE void LZ4_wildCopy(void *dstPtr,
	const void *srcPtr, void *dstEnd)
{
	BYTE *d = (BYTE *)dstPtr;
	const BYTE *s = (const BYTE *)srcPtr;
	BYTE *const e = (BYTE *)dstEnd;

	do {
		LZ4_copy8(d, s);
		d += 8;
		s += 8;
	} while (d < e);
}

static FORCE_INLINE unsigned int LZ4_NbCommonBytes(register size_t val)
{
#if LZ4_LITTLE_ENDIAN
	return __ffs(val) >> 3;
#else
	return (BITS_PER_LONG - 1 - __fls(val)) >> 3;
#endif
}

static FORCE_INLINE unsigned int LZ4_count(
	const BYTE *pIn,
	const BYTE *pMatch,
	const BYTE *pInLimit)
{
	const BYTE *const pStart = pIn;

	while (likely(pIn < pInLimit - (STEPSIZE - 1))) {
		size_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);

		if (!diff) {
			pIn += STEPSIZE;
			pMatch += STEPSIZE;
			continue;
		}

		pIn += LZ4_NbCommonBytes(diff);

		return (unsigned int)(pIn - pStart);
	}

#if LZ4_ARCH64
	if ((pIn < (pInLimit - 3))
		&& (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
		pIn += 4;
		pMatch += 4;
	}
#endif

	if ((pIn < (pInLimit - 1))
		&& (LZ4_read16(pMatch) == LZ4_read16(pIn))) {
		pIn += 2;
		pMatch += 2;
	}

	if ((pIn < pInLimit) && (*pMatch == *pIn))
		pIn++;

	return (unsigned int)(pIn - pStart);
}

typedef enum { noLimit = 0, limitedOutput = 1 } limitedOutput_directive;
typedef enum { byPtr, byU32, byU16 } tableType_t;

typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;

typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
typedef enum { full = 0, partial = 1 } earlyEnd_directive;

#endif