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
|
/*
* lz4defs.h -- architecture specific defines
*
* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/*
* Detects 64 bits mode
*/
#if __SIZEOF_POINTER__ == 8
#define LZ4_ARCH64 1
#else
#define LZ4_ARCH64 0
#endif
#include <linux/string.h>
#include <asm/unaligned.h>
#define A32(_p) get_unaligned((u32 *) (_p))
#define A16(_p) get_unaligned((u16 *) (_p))
#define GET_LE16_ADVANCE(_src) \
({ \
u16 _r = get_unaligned_le16(_src); \
(_src) += 2; \
_r; \
})
#define PUT_LE16_ADVANCE(_dst, _v) \
do { \
put_unaligned_le16((_v), (_dst)); \
(_dst) += 2; \
} while (0)
#define LENGTH_LONG 15
#define COPYLENGTH 8
#define ML_BITS 4
#define ML_MASK ((1U << ML_BITS) - 1)
#define RUN_BITS (8 - ML_BITS)
#define RUN_MASK ((1U << RUN_BITS) - 1)
#define MEMORY_USAGE 14
#define MINMATCH 4
#define SKIPSTRENGTH 6
#define LASTLITERALS 5
#define MFLIMIT (COPYLENGTH + MINMATCH)
#define MINLENGTH (MFLIMIT + 1)
#define MAXD_LOG 16
#define MAXD (1 << MAXD_LOG)
#define MAXD_MASK (u32)(MAXD - 1)
#define MAX_DISTANCE (MAXD - 1)
#define HASH_LOG (MAXD_LOG - 1)
#define HASHTABLESIZE (1 << HASH_LOG)
#define MAX_NB_ATTEMPTS 256
#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)
#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT - 1))
#define __HASH_VALUE(p, bits) \
(((A32(p)) * 2654435761U) >> (32 - (bits)))
#define HASH_VALUE(p) __HASH_VALUE(p, HASH_LOG)
#define MEMCPY_ADVANCE(_dst, _src, length) \
do { \
typeof(length) _length = (length); \
memcpy(_dst, _src, _length); \
_src += _length; \
_dst += _length; \
} while (0)
#define MEMCPY_ADVANCE_BYTES(_dst, _src, _length) \
do { \
const u8 *_end = (_src) + (_length); \
while ((_src) < _end) \
*_dst++ = *_src++; \
} while (0)
#define STEPSIZE __SIZEOF_LONG__
#define LZ4_COPYPACKET(_src, _dst) \
do { \
MEMCPY_ADVANCE(_dst, _src, STEPSIZE); \
MEMCPY_ADVANCE(_dst, _src, COPYLENGTH - STEPSIZE);\
} while (0)
/*
* Equivalent to MEMCPY_ADVANCE - except may overrun @_dst and @_src by
* COPYLENGTH:
*
* Note: src and dst may overlap (with src < dst) - we must do the copy in
* STEPSIZE chunks for correctness
*
* Note also: length may be negative - we must not call memcpy if length is
* negative, but still adjust dst and src by length
*/
#define MEMCPY_ADVANCE_CHUNKED(_dst, _src, _length) \
do { \
u8 *_end = (_dst) + (_length); \
while ((_dst) < _end) \
LZ4_COPYPACKET(_src, _dst); \
_src -= (_dst) - _end; \
_dst = _end; \
} while (0)
#define MEMCPY_ADVANCE_CHUNKED_NOFIXUP(_dst, _src, _end)\
do { \
while ((_dst) < (_end)) \
LZ4_COPYPACKET((_src), (_dst)); \
} while (0)
struct lz4_hashtable {
#if LZ4_ARCH64
const u8 * const base;
u32 *table;
#else
const int base;
const u8 *table;
#endif
};
#if LZ4_ARCH64
#define HTYPE u32
#else /* 32-bit */
#define HTYPE const u8*
#endif
#ifdef __BIG_ENDIAN
#define LZ4_NBCOMMONBYTES(val) (__builtin_clzl(val) >> 3)
#else
#define LZ4_NBCOMMONBYTES(val) (__builtin_ctzl(val) >> 3)
#endif
static inline unsigned common_length(const u8 *l, const u8 *r,
const u8 *const l_end)
{
const u8 *l_start = l;
while (likely(l <= l_end - sizeof(long))) {
unsigned long diff =
get_unaligned((unsigned long *) l) ^
get_unaligned((unsigned long *) r);
if (diff)
return l + LZ4_NBCOMMONBYTES(diff) - l_start;
l += sizeof(long);
r += sizeof(long);
}
#if LZ4_ARCH64
if (l <= l_end - 4 && A32(r) == A32(l)) {
l += 4;
r += 4;
}
#endif
if (l <= l_end - 2 && A16(r) == A16(l)) {
l += 2;
r += 2;
}
if (l <= l_end - 1 && *r == *l) {
l++;
r++;
}
return l - l_start;
}
static inline unsigned encode_length(u8 **op, unsigned length)
{
if (length >= LENGTH_LONG) {
length -= LENGTH_LONG;
for (; length > 254 ; length -= 255)
*(*op)++ = 255;
*(*op)++ = length;
return LENGTH_LONG;
} else
return length;
}
|
