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
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
|
/*
* LZO 1x decompression
* Copyright (c) 2006 Reimar Doeffinger
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
//! avoid e.g. MPlayers fast_memcpy, it slows things down here
#undef memcpy
#include <string.h>
#include "lzo.h"
//! define if we may write up to 12 bytes beyond the output buffer
#define OUTBUF_PADDED 1
//! define if we may read up to 4 bytes beyond the input buffer
#define INBUF_PADDED 1
typedef struct LZOContext {
uint8_t *in, *in_end;
uint8_t *out_start, *out, *out_end;
int error;
} LZOContext;
/**
* \brief read one byte from input buffer, avoiding overrun
* \return byte read
*/
static inline int get_byte(LZOContext *c) {
if (c->in < c->in_end)
return *c->in++;
c->error |= LZO_INPUT_DEPLETED;
return 1;
}
/**
* \brief decode a length value in the coding used by lzo
* \param x previous byte value
* \param mask bits used from x
* \return decoded length value
*/
static inline int get_len(LZOContext *c, int x, int mask) {
int cnt = x & mask;
if (!cnt) {
while (!(x = get_byte(c))) cnt += 255;
cnt += mask + x;
}
return cnt;
}
/**
* \brief copy bytes from input to output buffer with checking
* \param cnt number of bytes to copy, must be > 0
*/
static inline void copy(LZOContext *c, int cnt) {
register uint8_t *src = c->in;
register uint8_t *dst = c->out;
if (src + cnt > c->in_end) {
cnt = c->in_end - src;
c->error |= LZO_INPUT_DEPLETED;
}
if (dst + cnt > c->out_end) {
cnt = c->out_end - dst;
c->error |= LZO_OUTPUT_FULL;
}
#if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
src += 4;
dst += 4;
cnt -= 4;
if (cnt > 0)
#endif
memcpy(dst, src, cnt);
c->in = src + cnt;
c->out = dst + cnt;
}
/**
* \brief copy previously decoded bytes to current position
* \param back how many bytes back we start
* \param cnt number of bytes to copy, must be > 0
*
* cnt > back is valid, this will copy the bytes we just copied,
* thus creating a repeating pattern with a period length of back.
*/
static inline void copy_backptr(LZOContext *c, int back, int cnt) {
register uint8_t *src = &c->out[-back];
register uint8_t *dst = c->out;
if (src < c->out_start) {
c->error |= LZO_INVALID_BACKPTR;
return;
}
if (dst + cnt > c->out_end) {
cnt = c->out_end - dst;
c->error |= LZO_OUTPUT_FULL;
}
if (back == 1) {
memset(dst, *src, cnt);
dst += cnt;
} else {
#ifdef OUTBUF_PADDED
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
src += 4;
dst += 4;
cnt -= 4;
if (cnt > 0) {
dst[0] = src[0];
dst[1] = src[1];
dst[2] = src[2];
dst[3] = src[3];
dst[4] = src[4];
dst[5] = src[5];
dst[6] = src[6];
dst[7] = src[7];
src += 8;
dst += 8;
cnt -= 8;
}
#endif
if (cnt > 0) {
int blocklen = back;
while (cnt > blocklen) {
memcpy(dst, src, blocklen);
dst += blocklen;
cnt -= blocklen;
blocklen <<= 1;
}
memcpy(dst, src, cnt);
}
dst += cnt;
}
c->out = dst;
}
/**
* \brief decode LZO 1x compressed data
* \param out output buffer
* \param outlen size of output buffer, number of bytes left are returned here
* \param in input buffer
* \param inlen size of input buffer, number of bytes left are returned here
* \return 0 on success, otherwise error flags, see lzo.h
*
* make sure all buffers are appropriately padded, in must provide
* LZO_INPUT_PADDING, out must provide LZO_OUTPUT_PADDING additional bytes
*/
int lzo1x_decode(void *out, int *outlen, void *in, int *inlen) {
enum {COPY, BACKPTR} state = COPY;
int x;
LZOContext c;
c.in = in;
c.in_end = (uint8_t *)in + *inlen;
c.out = c.out_start = out;
c.out_end = (uint8_t *)out + * outlen;
c.error = 0;
x = get_byte(&c);
if (x > 17) {
copy(&c, x - 17);
x = get_byte(&c);
if (x < 16) c.error |= LZO_ERROR;
}
while (!c.error) {
int cnt, back;
if (x >> 4) {
if (x >> 6) {
cnt = (x >> 5) - 1;
back = (get_byte(&c) << 3) + ((x >> 2) & 7) + 1;
} else if (x >> 5) {
cnt = get_len(&c, x, 31);
x = get_byte(&c);
back = (get_byte(&c) << 6) + (x >> 2) + 1;
} else {
cnt = get_len(&c, x, 7);
back = (1 << 14) + ((x & 8) << 11);
x = get_byte(&c);
back += (get_byte(&c) << 6) + (x >> 2);
if (back == (1 << 14)) {
if (cnt != 1)
c.error |= LZO_ERROR;
break;
}
}
} else
switch (state) {
case COPY:
cnt = get_len(&c, x, 15);
copy(&c, cnt + 3);
x = get_byte(&c);
if (x >> 4)
continue;
cnt = 1;
back = (1 << 11) + (get_byte(&c) << 2) + (x >> 2) + 1;
break;
case BACKPTR:
cnt = 0;
back = (get_byte(&c) << 2) + (x >> 2) + 1;
break;
}
copy_backptr(&c, back, cnt + 2);
cnt = x & 3;
state = cnt ? BACKPTR : COPY;
if (cnt)
copy(&c, cnt);
x = get_byte(&c);
}
*inlen = c.in_end - c.in;
*outlen = c.out_end - c.out;
return c.error;
}
#ifdef TEST
#include <stdio.h>
#include <lzo/lzo1x.h>
#include "log.h"
#define MAXSZ (10*1024*1024)
int main(int argc, char *argv[]) {
FILE *in = fopen(argv[1], "rb");
uint8_t *orig = av_malloc(MAXSZ + 16);
uint8_t *comp = av_malloc(2*MAXSZ + 16);
uint8_t *decomp = av_malloc(MAXSZ + 16);
size_t s = fread(orig, 1, MAXSZ, in);
lzo_uint clen = 0;
long tmp[LZO1X_MEM_COMPRESS];
int inlen, outlen;
int i;
av_log_level = AV_LOG_DEBUG;
lzo1x_999_compress(orig, s, comp, &clen, tmp);
for (i = 0; i < 300; i++) {
START_TIMER
inlen = clen; outlen = MAXSZ;
if (lzo1x_decode(decomp, &outlen, comp, &inlen))
av_log(NULL, AV_LOG_ERROR, "decompression error\n");
STOP_TIMER("lzod")
}
if (memcmp(orig, decomp, s))
av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
else
av_log(NULL, AV_LOG_ERROR, "decompression ok\n");
return 0;
}
#endif
|
