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 
32 #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 const uint8_t *src = &c->out[-back];
123  register uint8_t *dst = c->out;
124  if (src < c->out_start || src > dst) {
126  return;
127  }
128  if (cnt > c->out_end - dst) {
129  cnt = FFMAX(c->out_end - dst, 0);
131  }
132  memcpy_backptr(dst, back, cnt);
133  c->out = dst + cnt;
134 }
135 
136 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
137  const uint8_t *src = &dst[-back];
138  if (back == 1) {
139  memset(dst, *src, cnt);
140  } else {
141 #ifdef OUTBUF_PADDED
142  COPY2(dst, src);
143  COPY2(dst + 2, src + 2);
144  src += 4;
145  dst += 4;
146  cnt -= 4;
147  if (cnt > 0) {
148  COPY2(dst, src);
149  COPY2(dst + 2, src + 2);
150  COPY2(dst + 4, src + 4);
151  COPY2(dst + 6, src + 6);
152  src += 8;
153  dst += 8;
154  cnt -= 8;
155  }
156 #endif
157  if (cnt > 0) {
158  int blocklen = back;
159  while (cnt > blocklen) {
160  memcpy(dst, src, blocklen);
161  dst += blocklen;
162  cnt -= blocklen;
163  blocklen <<= 1;
164  }
165  memcpy(dst, src, cnt);
166  }
167  }
168 }
169 
170 void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
171  memcpy_backptr(dst, back, cnt);
172 }
173 
174 int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
175  int state= 0;
176  int x;
177  LZOContext c;
178  if (!*outlen || !*inlen) {
179  int res = 0;
180  if (!*outlen)
181  res |= AV_LZO_OUTPUT_FULL;
182  if (!*inlen)
183  res |= AV_LZO_INPUT_DEPLETED;
184  return res;
185  }
186  c.in = in;
187  c.in_end = (const uint8_t *)in + *inlen;
188  c.out = c.out_start = out;
189  c.out_end = (uint8_t *)out + * outlen;
190  c.error = 0;
191  x = GETB(c);
192  if (x > 17) {
193  copy(&c, x - 17);
194  x = GETB(c);
195  if (x < 16) c.error |= AV_LZO_ERROR;
196  }
197  if (c.in > c.in_end)
199  while (!c.error) {
200  int cnt, back;
201  if (x > 15) {
202  if (x > 63) {
203  cnt = (x >> 5) - 1;
204  back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
205  } else if (x > 31) {
206  cnt = get_len(&c, x, 31);
207  x = GETB(c);
208  back = (GETB(c) << 6) + (x >> 2) + 1;
209  } else {
210  cnt = get_len(&c, x, 7);
211  back = (1 << 14) + ((x & 8) << 11);
212  x = GETB(c);
213  back += (GETB(c) << 6) + (x >> 2);
214  if (back == (1 << 14)) {
215  if (cnt != 1)
216  c.error |= AV_LZO_ERROR;
217  break;
218  }
219  }
220  } else if(!state){
221  cnt = get_len(&c, x, 15);
222  copy(&c, cnt + 3);
223  x = GETB(c);
224  if (x > 15)
225  continue;
226  cnt = 1;
227  back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
228  } else {
229  cnt = 0;
230  back = (GETB(c) << 2) + (x >> 2) + 1;
231  }
232  copy_backptr(&c, back, cnt + 2);
233  state=
234  cnt = x & 3;
235  copy(&c, cnt);
236  x = GETB(c);
237  }
238  *inlen = c.in_end - c.in;
239  if (c.in > c.in_end)
240  *inlen = 0;
241  *outlen = c.out_end - c.out;
242  return c.error;
243 }
244 
245 #ifdef TEST
246 #include <stdio.h>
247 #include <lzo/lzo1x.h>
248 #include "log.h"
249 #define MAXSZ (10*1024*1024)
250 
251 /* Define one of these to 1 if you wish to benchmark liblzo
252  * instead of our native implementation. */
253 #define BENCHMARK_LIBLZO_SAFE 0
254 #define BENCHMARK_LIBLZO_UNSAFE 0
255 
256 int main(int argc, char *argv[]) {
257  FILE *in = fopen(argv[1], "rb");
258  uint8_t *orig = av_malloc(MAXSZ + 16);
259  uint8_t *comp = av_malloc(2*MAXSZ + 16);
260  uint8_t *decomp = av_malloc(MAXSZ + 16);
261  size_t s = fread(orig, 1, MAXSZ, in);
262  lzo_uint clen = 0;
263  long tmp[LZO1X_MEM_COMPRESS];
264  int inlen, outlen;
265  int i;
267  lzo1x_999_compress(orig, s, comp, &clen, tmp);
268  for (i = 0; i < 300; i++) {
270  inlen = clen; outlen = MAXSZ;
271 #if BENCHMARK_LIBLZO_SAFE
272  if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
273 #elif BENCHMARK_LIBLZO_UNSAFE
274  if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
275 #else
276  if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
277 #endif
278  av_log(NULL, AV_LOG_ERROR, "decompression error\n");
279 STOP_TIMER("lzod")
280  }
281  if (memcmp(orig, decomp, s))
282  av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
283  else
284  av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
285  return 0;
286 }
287 #endif