FFmpeg: libavutil/lzo.c Source File

FFmpeg
lzo.c
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1 /*
2  * LZO 1x decompression
3  * Copyright (c) 2006 Reimar Doeffinger
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <string.h>
23 
24 #include "avutil.h"
25 #include "avassert.h"
26 #include "common.h"
27 #include "intreadwrite.h"
28 #include "lzo.h"
29 
30 /// Define if we may write up to 12 bytes beyond the output buffer.
31  #define OUTBUF_PADDED 1
32 /// Define if we may read up to 8 bytes beyond the input buffer.
33  #define INBUF_PADDED 1
34 
35  typedef struct LZOContext {
36   const uint8_t *in, *in_end;
37   uint8_t *out_start, *out, *out_end;
38   int error;
39 } LZOContext;
40 
41 /**
42  * @brief Reads one byte from the input buffer, avoiding an overrun.
43  * @return byte read
44  */
45  static inline int get_byte(LZOContext *c)
46 {
47  if (c->in < c->in_end)
48  return *c->in++;
49  c->error |= AV_LZO_INPUT_DEPLETED;
50  return 1;
51 }
52 
53 #ifdef INBUF_PADDED
54  #define GETB(c) (*(c).in++)
55 #else
56 #define GETB(c) get_byte(&(c))
57 #endif
58 
59 /**
60  * @brief Decodes a length value in the coding used by lzo.
61  * @param x previous byte value
62  * @param mask bits used from x
63  * @return decoded length value
64  */
65  static inline int get_len(LZOContext *c, int x, int mask)
66 {
67  int cnt = x & mask;
68  if (!cnt) {
69  while (!(x = get_byte(c))) {
70  if (cnt >= INT_MAX - 1000) {
71  c->error |= AV_LZO_ERROR;
72  break;
73  }
74  cnt += 255;
75  }
76  cnt += mask + x;
77  }
78  return cnt;
79 }
80 
81 /**
82  * @brief Copies bytes from input to output buffer with checking.
83  * @param cnt number of bytes to copy, must be >= 0
84  */
85  static inline void copy(LZOContext *c, int cnt)
86 {
87  register const uint8_t *src = c->in;
88  register uint8_t *dst = c->out;
89  av_assert0(cnt >= 0);
90  if (cnt > c->in_end - src) {
91  cnt = FFMAX(c->in_end - src, 0);
92  c->error |= AV_LZO_INPUT_DEPLETED;
93  }
94  if (cnt > c->out_end - dst) {
95  cnt = FFMAX(c->out_end - dst, 0);
96  c->error |= AV_LZO_OUTPUT_FULL;
97  }
98 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
99  AV_COPY32U(dst, src);
100  src += 4;
101  dst += 4;
102  cnt -= 4;
103  if (cnt > 0)
104 #endif
105  memcpy(dst, src, cnt);
106  c->in = src + cnt;
107  c->out = dst + cnt;
108 }
109 
110 /**
111  * @brief Copies previously decoded bytes to current position.
112  * @param back how many bytes back we start, must be > 0
113  * @param cnt number of bytes to copy, must be > 0
114  *
115  * cnt > back is valid, this will copy the bytes we just copied,
116  * thus creating a repeating pattern with a period length of back.
117  */
118  static inline void copy_backptr(LZOContext *c, int back, int cnt)
119 {
120  register uint8_t *dst = c->out;
121  av_assert0(cnt > 0);
122  if (dst - c->out_start < back) {
123  c->error |= AV_LZO_INVALID_BACKPTR;
124  return;
125  }
126  if (cnt > c->out_end - dst) {
127  cnt = FFMAX(c->out_end - dst, 0);
128  c->error |= AV_LZO_OUTPUT_FULL;
129  }
130  av_memcpy_backptr(dst, back, cnt);
131  c->out = dst + cnt;
132 }
133 
134  int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
135 {
136  int state = 0;
137  int x;
138  LZOContext c;
139  if (*outlen <= 0 || *inlen <= 0) {
140  int res = 0;
141  if (*outlen <= 0)
142  res |= AV_LZO_OUTPUT_FULL;
143  if (*inlen <= 0)
144  res |= AV_LZO_INPUT_DEPLETED;
145  return res;
146  }
147  c.in = in;
148  c.in_end = (const uint8_t *)in + *inlen;
149  c.out = c.out_start = out;
150  c.out_end = (uint8_t *)out + *outlen;
151  c.error = 0;
152  x = GETB(c);
153  if (x > 17) {
154  copy(&c, x - 17);
155  x = GETB(c);
156  if (x < 16)
157  c.error |= AV_LZO_ERROR;
158  }
159  if (c.in > c.in_end)
160  c.error |= AV_LZO_INPUT_DEPLETED;
161  while (!c.error) {
162  int cnt, back;
163  if (x > 15) {
164  if (x > 63) {
165  cnt = (x >> 5) - 1;
166  back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
167  } else if (x > 31) {
168  cnt = get_len(&c, x, 31);
169  x = GETB(c);
170  back = (GETB(c) << 6) + (x >> 2) + 1;
171  } else {
172  cnt = get_len(&c, x, 7);
173  back = (1 << 14) + ((x & 8) << 11);
174  x = GETB(c);
175  back += (GETB(c) << 6) + (x >> 2);
176  if (back == (1 << 14)) {
177  if (cnt != 1)
178  c.error |= AV_LZO_ERROR;
179  break;
180  }
181  }
182  } else if (!state) {
183  cnt = get_len(&c, x, 15);
184  copy(&c, cnt + 3);
185  x = GETB(c);
186  if (x > 15)
187  continue;
188  cnt = 1;
189  back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
190  } else {
191  cnt = 0;
192  back = (GETB(c) << 2) + (x >> 2) + 1;
193  }
194  copy_backptr(&c, back, cnt + 2);
195  state =
196  cnt = x & 3;
197  copy(&c, cnt);
198  x = GETB(c);
199  }
200  *inlen = c.in_end - c.in;
201  if (c.in > c.in_end)
202  *inlen = 0;
203  *outlen = c.out_end - c.out;
204  return c.error;
205 }
AV_LZO_ERROR
#define AV_LZO_ERROR
a non-specific error in the compressed bitstream
Definition: lzo.h:43
get_len
static int get_len(LZOContext *c, int x, int mask)
Decodes a length value in the coding used by lzo.
Definition: lzo.c:65
avutil.h
Convenience header that includes libavutil's core.
src
#define src
Definition: vp8dsp.c:254
AV_LZO_OUTPUT_FULL
#define AV_LZO_OUTPUT_FULL
decoded data did not fit into output buffer
Definition: lzo.h:39
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
uint8_t
Definition: audio_convert.c:194
LZOContext::out_start
uint8_t * out_start
Definition: lzo.c:37
LZOContext::out_end
uint8_t * out_end
Definition: lzo.c:37
LZOContext
Definition: lzo.c:35
av_memcpy_backptr
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
Overlapping memcpy() implementation.
Definition: mem.c:414
copy
static void copy(LZOContext *c, int cnt)
Copies bytes from input to output buffer with checking.
Definition: lzo.c:85
LZOContext::in
const uint8_t * in
Definition: lzo.c:36
LZOContext::out
uint8_t * out
Definition: lzo.c:37
mask
static const uint16_t mask[17]
Definition: lzw.c:38
avassert.h
simple assert() macros that are a bit more flexible than ISO C assert().
FFMAX
#define FFMAX(a, b)
Definition: common.h:94
copy_backptr
static void copy_backptr(LZOContext *c, int back, int cnt)
Copies previously decoded bytes to current position.
Definition: lzo.c:118
LZOContext::error
int error
Definition: lzo.c:38
AV_COPY32U
#define AV_COPY32U(d, s)
Definition: intreadwrite.h:557
av_lzo1x_decode
int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
Decodes LZO 1x compressed data.
Definition: lzo.c:134
state
static struct @271 state
AV_LZO_INPUT_DEPLETED
#define AV_LZO_INPUT_DEPLETED
end of the input buffer reached before decoding finished
Definition: lzo.h:37
LZOContext::in_end
const uint8_t * in_end
Definition: lzo.c:36
in
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(constint16_t *) pi >>8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(constint32_t *) pi >>24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(constfloat *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(constfloat *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(constfloat *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(constdouble *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(constdouble *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(constdouble *) pi *(1U<< 31))))#defineSET_CONV_FUNC_GROUP(ofmt, ifmt) staticvoidset_generic_function(AudioConvert *ac){}voidff_audio_convert_free(AudioConvert **ac){if(!*ac) return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enumAVSampleFormatout_fmt, enumAVSampleFormatin_fmt, intchannels, intsample_rate, intapply_map){AudioConvert *ac;intin_planar, out_planar;ac=av_mallocz(sizeof(*ac));if(!ac) returnNULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt)>2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);returnNULL;}returnac;}in_planar=ff_sample_fmt_is_planar(in_fmt, channels);out_planar=ff_sample_fmt_is_planar(out_fmt, channels);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}elseif(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;elseac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);if(ARCH_AARCH64) ff_audio_convert_init_aarch64(ac);if(ARCH_ARM) ff_audio_convert_init_arm(ac);if(ARCH_X86) ff_audio_convert_init_x86(ac);returnac;}intff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){intuse_generic=1;intlen=in->nb_samples;intp;if(ac->dc){av_log(ac->avr, AV_LOG_TRACE,"%dsamples-audio_convert:%sto%s(dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));returnff_convert_dither(ac-> in
Definition: audio_convert.c:194
common.h
common internal and external API header
c
static double c[64]
Definition: vsrc_mptestsrc.c:87
GETB
#define GETB(c)
Definition: lzo.c:54
out
FILE * out
Definition: movenc.c:54
AV_LZO_INVALID_BACKPTR
#define AV_LZO_INVALID_BACKPTR
a reference to previously decoded data was wrong
Definition: lzo.h:41
get_byte
static int get_byte(LZOContext *c)
Reads one byte from the input buffer, avoiding an overrun.
Definition: lzo.c:45
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