xref: /f-stack/app/redis-5.0.5/src/lzfP.h (revision 572c4311)
1 /*
2  * Copyright (c) 2000-2007 Marc Alexander Lehmann <[email protected]>
3  *
4  * Redistribution and use in source and binary forms, with or without modifica-
5  * tion, are permitted provided that the following conditions are met:
6  *
7  *   1.  Redistributions of source code must retain the above copyright notice,
8  *       this list of conditions and the following disclaimer.
9  *
10  *   2.  Redistributions in binary form must reproduce the above copyright
11  *       notice, this list of conditions and the following disclaimer in the
12  *       documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
15  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
16  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
17  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
18  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
20  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
21  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
22  * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
23  * OF THE POSSIBILITY OF SUCH DAMAGE.
24  *
25  * Alternatively, the contents of this file may be used under the terms of
26  * the GNU General Public License ("GPL") version 2 or any later version,
27  * in which case the provisions of the GPL are applicable instead of
28  * the above. If you wish to allow the use of your version of this file
29  * only under the terms of the GPL and not to allow others to use your
30  * version of this file under the BSD license, indicate your decision
31  * by deleting the provisions above and replace them with the notice
32  * and other provisions required by the GPL. If you do not delete the
33  * provisions above, a recipient may use your version of this file under
34  * either the BSD or the GPL.
35  */
36 
37 #ifndef LZFP_h
38 #define LZFP_h
39 
40 #define STANDALONE 1 /* at the moment, this is ok. */
41 
42 #ifndef STANDALONE
43 # include "lzf.h"
44 #endif
45 
46 /*
47  * Size of hashtable is (1 << HLOG) * sizeof (char *)
48  * decompression is independent of the hash table size
49  * the difference between 15 and 14 is very small
50  * for small blocks (and 14 is usually a bit faster).
51  * For a low-memory/faster configuration, use HLOG == 13;
52  * For best compression, use 15 or 16 (or more, up to 22).
53  */
54 #ifndef HLOG
55 # define HLOG 16
56 #endif
57 
58 /*
59  * Sacrifice very little compression quality in favour of compression speed.
60  * This gives almost the same compression as the default code, and is
61  * (very roughly) 15% faster. This is the preferred mode of operation.
62  */
63 #ifndef VERY_FAST
64 # define VERY_FAST 1
65 #endif
66 
67 /*
68  * Sacrifice some more compression quality in favour of compression speed.
69  * (roughly 1-2% worse compression for large blocks and
70  * 9-10% for small, redundant, blocks and >>20% better speed in both cases)
71  * In short: when in need for speed, enable this for binary data,
72  * possibly disable this for text data.
73  */
74 #ifndef ULTRA_FAST
75 # define ULTRA_FAST 0
76 #endif
77 
78 /*
79  * Unconditionally aligning does not cost very much, so do it if unsure
80  */
81 #ifndef STRICT_ALIGN
82 # if !(defined(__i386) || defined (__amd64))
83 #  define STRICT_ALIGN 1
84 # else
85 #  define STRICT_ALIGN 0
86 # endif
87 #endif
88 
89 /*
90  * You may choose to pre-set the hash table (might be faster on some
91  * modern cpus and large (>>64k) blocks, and also makes compression
92  * deterministic/repeatable when the configuration otherwise is the same).
93  */
94 #ifndef INIT_HTAB
95 # define INIT_HTAB 0
96 #endif
97 
98 /*
99  * Avoid assigning values to errno variable? for some embedding purposes
100  * (linux kernel for example), this is necessary. NOTE: this breaks
101  * the documentation in lzf.h. Avoiding errno has no speed impact.
102  */
103 #ifndef AVOID_ERRNO
104 # define AVOID_ERRNO 0
105 #endif
106 
107 /*
108  * Whether to pass the LZF_STATE variable as argument, or allocate it
109  * on the stack. For small-stack environments, define this to 1.
110  * NOTE: this breaks the prototype in lzf.h.
111  */
112 #ifndef LZF_STATE_ARG
113 # define LZF_STATE_ARG 0
114 #endif
115 
116 /*
117  * Whether to add extra checks for input validity in lzf_decompress
118  * and return EINVAL if the input stream has been corrupted. This
119  * only shields against overflowing the input buffer and will not
120  * detect most corrupted streams.
121  * This check is not normally noticeable on modern hardware
122  * (<1% slowdown), but might slow down older cpus considerably.
123  */
124 #ifndef CHECK_INPUT
125 # define CHECK_INPUT 1
126 #endif
127 
128 /*
129  * Whether to store pointers or offsets inside the hash table. On
130  * 64 bit architetcures, pointers take up twice as much space,
131  * and might also be slower. Default is to autodetect.
132  */
133 /*#define LZF_USER_OFFSETS autodetect */
134 
135 /*****************************************************************************/
136 /* nothing should be changed below */
137 
138 #ifdef __cplusplus
139 # include <cstring>
140 # include <climits>
141 using namespace std;
142 #else
143 # include <string.h>
144 # include <limits.h>
145 #endif
146 
147 #ifndef LZF_USE_OFFSETS
148 # if defined (WIN32)
149 #  define LZF_USE_OFFSETS defined(_M_X64)
150 # else
151 #  if __cplusplus > 199711L
152 #   include <cstdint>
153 #  else
154 #   include <stdint.h>
155 #  endif
156 #  define LZF_USE_OFFSETS (UINTPTR_MAX > 0xffffffffU)
157 # endif
158 #endif
159 
160 typedef unsigned char u8;
161 
162 #if LZF_USE_OFFSETS
163 # define LZF_HSLOT_BIAS ((const u8 *)in_data)
164   typedef unsigned int LZF_HSLOT;
165 #else
166 # define LZF_HSLOT_BIAS 0
167   typedef const u8 *LZF_HSLOT;
168 #endif
169 
170 typedef LZF_HSLOT LZF_STATE[1 << (HLOG)];
171 
172 #if !STRICT_ALIGN
173 /* for unaligned accesses we need a 16 bit datatype. */
174 # if USHRT_MAX == 65535
175     typedef unsigned short u16;
176 # elif UINT_MAX == 65535
177     typedef unsigned int u16;
178 # else
179 #  undef STRICT_ALIGN
180 #  define STRICT_ALIGN 1
181 # endif
182 #endif
183 
184 #if ULTRA_FAST
185 # undef VERY_FAST
186 #endif
187 
188 #endif
189 
190