lzo.c
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1 /*
2  * LZO 1x decompression
3  * Copyright (c) 2006 Reimar Doeffinger
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "avutil.h"
23 #include "common.h"
25 #undef memcpy
26 #include <string.h>
27 #include "lzo.h"
28 
30 #define OUTBUF_PADDED 1
31 #define INBUF_PADDED 1
33 typedef struct LZOContext {
34  const uint8_t *in, *in_end;
35  uint8_t *out_start, *out, *out_end;
36  int error;
37 } LZOContext;
38 
43 static inline int get_byte(LZOContext *c) {
44  if (c->in < c->in_end)
45  return *c->in++;
47  return 1;
48 }
49 
50 #ifdef INBUF_PADDED
51 #define GETB(c) (*(c).in++)
52 #else
53 #define GETB(c) get_byte(&(c))
54 #endif
55 
62 static inline int get_len(LZOContext *c, int x, int mask) {
63  int cnt = x & mask;
64  if (!cnt) {
65  while (!(x = get_byte(c))) cnt += 255;
66  cnt += mask + x;
67  }
68  return cnt;
69 }
70 
71 //#define UNALIGNED_LOADSTORE
72 #define BUILTIN_MEMCPY
73 #ifdef UNALIGNED_LOADSTORE
74 #define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s);
75 #define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s);
76 #elif defined(BUILTIN_MEMCPY)
77 #define COPY2(d, s) memcpy(d, s, 2);
78 #define COPY4(d, s) memcpy(d, s, 4);
79 #else
80 #define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1];
81 #define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3];
82 #endif
83 
88 static inline void copy(LZOContext *c, int cnt) {
89  register const uint8_t *src = c->in;
90  register uint8_t *dst = c->out;
91  if (cnt > c->in_end - src) {
92  cnt = FFMAX(c->in_end - src, 0);
94  }
95  if (cnt > c->out_end - dst) {
96  cnt = FFMAX(c->out_end - dst, 0);
98  }
99 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
100  COPY4(dst, src);
101  src += 4;
102  dst += 4;
103  cnt -= 4;
104  if (cnt > 0)
105 #endif
106  memcpy(dst, src, cnt);
107  c->in = src + cnt;
108  c->out = dst + cnt;
109 }
110 
111 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
112 
121 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
122  register uint8_t *dst = c->out;
123  if (dst - c->out_start < back) {
125  return;
126  }
127  if (cnt > c->out_end - dst) {
128  cnt = FFMAX(c->out_end - dst, 0);
130  }
131  memcpy_backptr(dst, back, cnt);
132  c->out = dst + cnt;
133 }
134 
135 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
136  const uint8_t *src = &dst[-back];
137  if (back == 1) {
138  memset(dst, *src, cnt);
139  } else {
140 #ifdef OUTBUF_PADDED
141  COPY2(dst, src);
142  COPY2(dst + 2, src + 2);
143  src += 4;
144  dst += 4;
145  cnt -= 4;
146  if (cnt > 0) {
147  COPY2(dst, src);
148  COPY2(dst + 2, src + 2);
149  COPY2(dst + 4, src + 4);
150  COPY2(dst + 6, src + 6);
151  src += 8;
152  dst += 8;
153  cnt -= 8;
154  }
155 #endif
156  if (cnt > 0) {
157  int blocklen = back;
158  while (cnt > blocklen) {
159  memcpy(dst, src, blocklen);
160  dst += blocklen;
161  cnt -= blocklen;
162  blocklen <<= 1;
163  }
164  memcpy(dst, src, cnt);
165  }
166  }
167 }
168 
169 void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
170  memcpy_backptr(dst, back, cnt);
171 }
172 
173 int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
174  int state= 0;
175  int x;
176  LZOContext c;
177  if (!*outlen || !*inlen) {
178  int res = 0;
179  if (!*outlen)
180  res |= AV_LZO_OUTPUT_FULL;
181  if (!*inlen)
182  res |= AV_LZO_INPUT_DEPLETED;
183  return res;
184  }
185  c.in = in;
186  c.in_end = (const uint8_t *)in + *inlen;
187  c.out = c.out_start = out;
188  c.out_end = (uint8_t *)out + * outlen;
189  c.error = 0;
190  x = GETB(c);
191  if (x > 17) {
192  copy(&c, x - 17);
193  x = GETB(c);
194  if (x < 16) c.error |= AV_LZO_ERROR;
195  }
196  if (c.in > c.in_end)
198  while (!c.error) {
199  int cnt, back;
200  if (x > 15) {
201  if (x > 63) {
202  cnt = (x >> 5) - 1;
203  back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
204  } else if (x > 31) {
205  cnt = get_len(&c, x, 31);
206  x = GETB(c);
207  back = (GETB(c) << 6) + (x >> 2) + 1;
208  } else {
209  cnt = get_len(&c, x, 7);
210  back = (1 << 14) + ((x & 8) << 11);
211  x = GETB(c);
212  back += (GETB(c) << 6) + (x >> 2);
213  if (back == (1 << 14)) {
214  if (cnt != 1)
215  c.error |= AV_LZO_ERROR;
216  break;
217  }
218  }
219  } else if(!state){
220  cnt = get_len(&c, x, 15);
221  copy(&c, cnt + 3);
222  x = GETB(c);
223  if (x > 15)
224  continue;
225  cnt = 1;
226  back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
227  } else {
228  cnt = 0;
229  back = (GETB(c) << 2) + (x >> 2) + 1;
230  }
231  copy_backptr(&c, back, cnt + 2);
232  state=
233  cnt = x & 3;
234  copy(&c, cnt);
235  x = GETB(c);
236  }
237  *inlen = c.in_end - c.in;
238  if (c.in > c.in_end)
239  *inlen = 0;
240  *outlen = c.out_end - c.out;
241  return c.error;
242 }
243 
244 #ifdef TEST
245 #include <stdio.h>
246 #include <lzo/lzo1x.h>
247 #include "log.h"
248 #define MAXSZ (10*1024*1024)
249 
250 /* Define one of these to 1 if you wish to benchmark liblzo
251  * instead of our native implementation. */
252 #define BENCHMARK_LIBLZO_SAFE 0
253 #define BENCHMARK_LIBLZO_UNSAFE 0
254 
255 int main(int argc, char *argv[]) {
256  FILE *in = fopen(argv[1], "rb");
257  uint8_t *orig = av_malloc(MAXSZ + 16);
258  uint8_t *comp = av_malloc(2*MAXSZ + 16);
259  uint8_t *decomp = av_malloc(MAXSZ + 16);
260  size_t s = fread(orig, 1, MAXSZ, in);
261  lzo_uint clen = 0;
262  long tmp[LZO1X_MEM_COMPRESS];
263  int inlen, outlen;
264  int i;
266  lzo1x_999_compress(orig, s, comp, &clen, tmp);
267  for (i = 0; i < 300; i++) {
269  inlen = clen; outlen = MAXSZ;
270 #if BENCHMARK_LIBLZO_SAFE
271  if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
272 #elif BENCHMARK_LIBLZO_UNSAFE
273  if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
274 #else
275  if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
276 #endif
277  av_log(NULL, AV_LOG_ERROR, "decompression error\n");
278 STOP_TIMER("lzod")
279  }
280  if (memcmp(orig, decomp, s))
281  av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
282  else
283  av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
284  return 0;
285 }
286 #endif