summaryrefslogtreecommitdiffstats
path: root/include/import/slz.h
blob: d7d4863509fa35ef41bd2c398bac665de4cd4866 (plain)
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
/*
 * Copyright (C) 2013-2015 Willy Tarreau <w@1wt.eu>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef _SLZ_H
#define _SLZ_H

#include <inttypes.h>

/* We have two macros UNALIGNED_LE_OK and UNALIGNED_FASTER. The latter indicates
 * that using unaligned data is faster than a simple shift. On x86 32-bit at
 * least it is not the case as the per-byte access is 30% faster. A core2-duo on
 * x86_64 is 7% faster to read one byte + shifting by 8 than to read one word,
 * but a core i5 is 7% faster doing the unaligned read, so we privilege more
 * recent implementations here.
 */
#if defined(__x86_64__)
#define UNALIGNED_LE_OK
#define UNALIGNED_FASTER
#define USE_64BIT_QUEUE
#elif defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
#define UNALIGNED_LE_OK
//#define UNALIGNED_FASTER
#elif defined(__ARMEL__) && defined(__ARM_ARCH_7A__)
#define UNALIGNED_LE_OK
#define UNALIGNED_FASTER
#elif defined(__ARM_ARCH_8A) || defined(__ARM_FEATURE_UNALIGNED)
#define UNALIGNED_LE_OK
#define UNALIGNED_FASTER
#endif

/* Log2 of the size of the hash table used for the references table. */
#define HASH_BITS 13

enum slz_state {
	SLZ_ST_INIT,  /* stream initialized */
	SLZ_ST_EOB,   /* header or end of block already sent */
	SLZ_ST_FIXED, /* inside a fixed huffman sequence */
	SLZ_ST_LAST,  /* last block, BFINAL sent */
	SLZ_ST_DONE,  /* BFINAL+EOB sent BFINAL */
	SLZ_ST_END    /* end sent (BFINAL, EOB, CRC + len) */
};

enum {
	SLZ_FMT_GZIP,    /* RFC1952: gzip envelope and crc32 for CRC */
	SLZ_FMT_ZLIB,    /* RFC1950: zlib envelope and adler-32 for CRC */
	SLZ_FMT_DEFLATE, /* RFC1951: raw deflate, and no crc */
};

struct slz_stream {
#ifdef USE_64BIT_QUEUE
	uint64_t queue; /* last pending bits, LSB first */
#else
	uint32_t queue; /* last pending bits, LSB first */
#endif
	uint32_t qbits; /* number of bits in queue, < 8 on 32-bit, < 32 on 64-bit */
	unsigned char *outbuf; /* set by encode() */
	uint16_t state; /* one of slz_state */
	uint8_t level:1; /* 0 = no compression, 1 = compression */
	uint8_t format:2; /* SLZ_FMT_* */
	uint8_t unused1; /* unused for now */
	uint32_t crc32;
	uint32_t ilen;
};

/* Functions specific to rfc1951 (deflate) */
long slz_rfc1951_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
int slz_rfc1951_init(struct slz_stream *strm, int level);
int slz_rfc1951_finish(struct slz_stream *strm, unsigned char *buf);

/* Functions specific to rfc1952 (gzip) */
uint32_t slz_crc32_by1(uint32_t crc, const unsigned char *buf, int len);
uint32_t slz_crc32_by4(uint32_t crc, const unsigned char *buf, int len);
long slz_rfc1952_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
int slz_rfc1952_send_header(struct slz_stream *strm, unsigned char *buf);
int slz_rfc1952_init(struct slz_stream *strm, int level);
int slz_rfc1952_finish(struct slz_stream *strm, unsigned char *buf);

/* Functions specific to rfc1950 (zlib) */
uint32_t slz_adler32_by1(uint32_t crc, const unsigned char *buf, int len);
uint32_t slz_adler32_block(uint32_t crc, const unsigned char *buf, long len);
long slz_rfc1950_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
int slz_rfc1950_send_header(struct slz_stream *strm, unsigned char *buf);
int slz_rfc1950_init(struct slz_stream *strm, int level);
int slz_rfc1950_finish(struct slz_stream *strm, unsigned char *buf);

/* generic functions */

/* Initializes stream <strm>. It will configure the stream to use format
 * <format> for the data, which must be one of SLZ_FMT_*. The compression level
 * passed in <level> is set. This value can only be 0 (no compression) or 1
 * (compression) and other values will lead to unpredictable behaviour. The
 * function should always return 0.
 */
static inline int slz_init(struct slz_stream *strm, int level, int format)
{
	int ret;

	if (format == SLZ_FMT_GZIP)
		ret = slz_rfc1952_init(strm, level);
	else if (format == SLZ_FMT_ZLIB)
		ret = slz_rfc1950_init(strm, level);
	else { /* deflate for anything else */
		ret = slz_rfc1951_init(strm, level);
		strm->format = format;
	}
	return ret;
}

/* Encodes the block according to the format used by the stream. This means
 * that the CRC of the input block may be computed according to the CRC32 or
 * adler-32 algorithms. The number of output bytes is returned.
 */
static inline long slz_encode(struct slz_stream *strm, void *out,
                              const void *in, long ilen, int more)
{
	long ret;

	if (strm->format == SLZ_FMT_GZIP)
		ret = slz_rfc1952_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
	else if (strm->format == SLZ_FMT_ZLIB)
		ret = slz_rfc1950_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
	else /* deflate for other ones */
		ret = slz_rfc1951_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);

	return ret;
}

/* Flushes pending bits and sends the trailer for stream <strm> into buffer
 * <buf> if needed. When it's done, the stream state is updated to SLZ_ST_END.
 * It returns the number of bytes emitted. The trailer consists in flushing the
 * possibly pending bits from the queue (up to 24 bits), rounding to the next
 * byte, then 4 bytes for the CRC when doing zlib/gzip, then another 4 bytes
 * for the input length for gzip. That may about to 4+4+4 = 12 bytes, that the
 * caller must ensure are available before calling the function.
 */
static inline int slz_finish(struct slz_stream *strm, void *buf)
{
	int ret;

	if (strm->format == SLZ_FMT_GZIP)
		ret = slz_rfc1952_finish(strm, (unsigned char *) buf);
	else if (strm->format == SLZ_FMT_ZLIB)
		ret = slz_rfc1950_finish(strm, (unsigned char *) buf);
	else /* deflate for other ones */
		ret = slz_rfc1951_finish(strm, (unsigned char *) buf);

	return ret;
}

#endif