xref: /openbmc/linux/lib/lz4/lz4defs.h (revision 22c03398)
1 #ifndef __LZ4DEFS_H__
2 #define __LZ4DEFS_H__
3 
4 /*
5  * lz4defs.h -- common and architecture specific defines for the kernel usage
6 
7  * LZ4 - Fast LZ compression algorithm
8  * Copyright (C) 2011-2016, Yann Collet.
9  * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions are
12  * met:
13  *	* Redistributions of source code must retain the above copyright
14  *	  notice, this list of conditions and the following disclaimer.
15  *	* Redistributions in binary form must reproduce the above
16  * copyright notice, this list of conditions and the following disclaimer
17  * in the documentation and/or other materials provided with the
18  * distribution.
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  * You can contact the author at :
31  *	- LZ4 homepage : http://www.lz4.org
32  *	- LZ4 source repository : https://github.com/lz4/lz4
33  *
34  *	Changed for kernel usage by:
35  *	Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
36  */
37 
38 #include <asm/unaligned.h>
39 
40 #include <linux/bitops.h>
41 #include <linux/string.h>	 /* memset, memcpy */
42 
43 #define FORCE_INLINE __always_inline
44 
45 /*-************************************
46  *	Basic Types
47  **************************************/
48 #include <linux/types.h>
49 
50 typedef	uint8_t BYTE;
51 typedef uint16_t U16;
52 typedef uint32_t U32;
53 typedef	int32_t S32;
54 typedef uint64_t U64;
55 typedef uintptr_t uptrval;
56 
57 /*-************************************
58  *	Architecture specifics
59  **************************************/
60 #if defined(CONFIG_64BIT)
61 #define LZ4_ARCH64 1
62 #else
63 #define LZ4_ARCH64 0
64 #endif
65 
66 #if defined(__LITTLE_ENDIAN)
67 #define LZ4_LITTLE_ENDIAN 1
68 #else
69 #define LZ4_LITTLE_ENDIAN 0
70 #endif
71 
72 /*-************************************
73  *	Constants
74  **************************************/
75 #define MINMATCH 4
76 
77 #define WILDCOPYLENGTH 8
78 #define LASTLITERALS 5
79 #define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
80 /*
81  * ensure it's possible to write 2 x wildcopyLength
82  * without overflowing output buffer
83  */
84 #define MATCH_SAFEGUARD_DISTANCE  ((2 * WILDCOPYLENGTH) - MINMATCH)
85 
86 /* Increase this value ==> compression run slower on incompressible data */
87 #define LZ4_SKIPTRIGGER 6
88 
89 #define HASH_UNIT sizeof(size_t)
90 
91 #define KB (1 << 10)
92 #define MB (1 << 20)
93 #define GB (1U << 30)
94 
95 #define MAXD_LOG 16
96 #define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
97 #define STEPSIZE sizeof(size_t)
98 
99 #define ML_BITS	4
100 #define ML_MASK	((1U << ML_BITS) - 1)
101 #define RUN_BITS (8 - ML_BITS)
102 #define RUN_MASK ((1U << RUN_BITS) - 1)
103 
104 /*-************************************
105  *	Reading and writing into memory
106  **************************************/
LZ4_read16(const void * ptr)107 static FORCE_INLINE U16 LZ4_read16(const void *ptr)
108 {
109 	return get_unaligned((const U16 *)ptr);
110 }
111 
LZ4_read32(const void * ptr)112 static FORCE_INLINE U32 LZ4_read32(const void *ptr)
113 {
114 	return get_unaligned((const U32 *)ptr);
115 }
116 
LZ4_read_ARCH(const void * ptr)117 static FORCE_INLINE size_t LZ4_read_ARCH(const void *ptr)
118 {
119 	return get_unaligned((const size_t *)ptr);
120 }
121 
LZ4_write16(void * memPtr,U16 value)122 static FORCE_INLINE void LZ4_write16(void *memPtr, U16 value)
123 {
124 	put_unaligned(value, (U16 *)memPtr);
125 }
126 
LZ4_write32(void * memPtr,U32 value)127 static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
128 {
129 	put_unaligned(value, (U32 *)memPtr);
130 }
131 
LZ4_readLE16(const void * memPtr)132 static FORCE_INLINE U16 LZ4_readLE16(const void *memPtr)
133 {
134 	return get_unaligned_le16(memPtr);
135 }
136 
LZ4_writeLE16(void * memPtr,U16 value)137 static FORCE_INLINE void LZ4_writeLE16(void *memPtr, U16 value)
138 {
139 	return put_unaligned_le16(value, memPtr);
140 }
141 
142 /*
143  * LZ4 relies on memcpy with a constant size being inlined. In freestanding
144  * environments, the compiler can't assume the implementation of memcpy() is
145  * standard compliant, so apply its specialized memcpy() inlining logic. When
146  * possible, use __builtin_memcpy() to tell the compiler to analyze memcpy()
147  * as-if it were standard compliant, so it can inline it in freestanding
148  * environments. This is needed when decompressing the Linux Kernel, for example.
149  */
150 #define LZ4_memcpy(dst, src, size) __builtin_memcpy(dst, src, size)
151 #define LZ4_memmove(dst, src, size) __builtin_memmove(dst, src, size)
152 
LZ4_copy8(void * dst,const void * src)153 static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
154 {
155 #if LZ4_ARCH64
156 	U64 a = get_unaligned((const U64 *)src);
157 
158 	put_unaligned(a, (U64 *)dst);
159 #else
160 	U32 a = get_unaligned((const U32 *)src);
161 	U32 b = get_unaligned((const U32 *)src + 1);
162 
163 	put_unaligned(a, (U32 *)dst);
164 	put_unaligned(b, (U32 *)dst + 1);
165 #endif
166 }
167 
168 /*
169  * customized variant of memcpy,
170  * which can overwrite up to 7 bytes beyond dstEnd
171  */
LZ4_wildCopy(void * dstPtr,const void * srcPtr,void * dstEnd)172 static FORCE_INLINE void LZ4_wildCopy(void *dstPtr,
173 	const void *srcPtr, void *dstEnd)
174 {
175 	BYTE *d = (BYTE *)dstPtr;
176 	const BYTE *s = (const BYTE *)srcPtr;
177 	BYTE *const e = (BYTE *)dstEnd;
178 
179 	do {
180 		LZ4_copy8(d, s);
181 		d += 8;
182 		s += 8;
183 	} while (d < e);
184 }
185 
LZ4_NbCommonBytes(register size_t val)186 static FORCE_INLINE unsigned int LZ4_NbCommonBytes(register size_t val)
187 {
188 #if LZ4_LITTLE_ENDIAN
189 	return __ffs(val) >> 3;
190 #else
191 	return (BITS_PER_LONG - 1 - __fls(val)) >> 3;
192 #endif
193 }
194 
LZ4_count(const BYTE * pIn,const BYTE * pMatch,const BYTE * pInLimit)195 static FORCE_INLINE unsigned int LZ4_count(
196 	const BYTE *pIn,
197 	const BYTE *pMatch,
198 	const BYTE *pInLimit)
199 {
200 	const BYTE *const pStart = pIn;
201 
202 	while (likely(pIn < pInLimit - (STEPSIZE - 1))) {
203 		size_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
204 
205 		if (!diff) {
206 			pIn += STEPSIZE;
207 			pMatch += STEPSIZE;
208 			continue;
209 		}
210 
211 		pIn += LZ4_NbCommonBytes(diff);
212 
213 		return (unsigned int)(pIn - pStart);
214 	}
215 
216 #if LZ4_ARCH64
217 	if ((pIn < (pInLimit - 3))
218 		&& (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
219 		pIn += 4;
220 		pMatch += 4;
221 	}
222 #endif
223 
224 	if ((pIn < (pInLimit - 1))
225 		&& (LZ4_read16(pMatch) == LZ4_read16(pIn))) {
226 		pIn += 2;
227 		pMatch += 2;
228 	}
229 
230 	if ((pIn < pInLimit) && (*pMatch == *pIn))
231 		pIn++;
232 
233 	return (unsigned int)(pIn - pStart);
234 }
235 
236 typedef enum { noLimit = 0, limitedOutput = 1 } limitedOutput_directive;
237 typedef enum { byPtr, byU32, byU16 } tableType_t;
238 
239 typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
240 typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
241 
242 typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
243 typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
244 
245 #define LZ4_STATIC_ASSERT(c)	BUILD_BUG_ON(!(c))
246 
247 #endif
248