3 * Copyright (c) 2006 Reimar Doeffinger
5 * This file is part of FFmpeg.
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.
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.
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
22 //! Avoid e.g. MPlayers fast_memcpy, it slows things down here.
27 //! Define if we may write up to 12 bytes beyond the output buffer.
28 #define OUTBUF_PADDED 1
29 //! Define if we may read up to 8 bytes beyond the input buffer.
30 #define INBUF_PADDED 1
31 typedef struct LZOContext {
32 const uint8_t *in, *in_end;
33 uint8_t *out_start, *out, *out_end;
38 * \brief Reads one byte from the input buffer, avoiding an overrun.
41 static inline int get_byte(LZOContext *c) {
42 if (c->in < c->in_end)
44 c->error |= LZO_INPUT_DEPLETED;
49 #define GETB(c) (*(c).in++)
51 #define GETB(c) get_byte(&(c))
55 * \brief Decodes a length value in the coding used by lzo.
56 * \param x previous byte value
57 * \param mask bits used from x
58 * \return decoded length value
60 static inline int get_len(LZOContext *c, int x, int mask) {
63 while (!(x = get_byte(c))) cnt += 255;
69 //#define UNALIGNED_LOADSTORE
70 #define BUILTIN_MEMCPY
71 #ifdef UNALIGNED_LOADSTORE
72 #define COPY2(d, s) *(uint16_t *)(d) = *(uint16_t *)(s);
73 #define COPY4(d, s) *(uint32_t *)(d) = *(uint32_t *)(s);
74 #elif defined(BUILTIN_MEMCPY)
75 #define COPY2(d, s) memcpy(d, s, 2);
76 #define COPY4(d, s) memcpy(d, s, 4);
78 #define COPY2(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1];
79 #define COPY4(d, s) (d)[0] = (s)[0]; (d)[1] = (s)[1]; (d)[2] = (s)[2]; (d)[3] = (s)[3];
83 * \brief Copies bytes from input to output buffer with checking.
84 * \param cnt number of bytes to copy, must be >= 0
86 static inline void copy(LZOContext *c, int cnt) {
87 register const uint8_t *src = c->in;
88 register uint8_t *dst = c->out;
89 if (cnt > c->in_end - src) {
90 cnt = FFMAX(c->in_end - src, 0);
91 c->error |= LZO_INPUT_DEPLETED;
93 if (cnt > c->out_end - dst) {
94 cnt = FFMAX(c->out_end - dst, 0);
95 c->error |= LZO_OUTPUT_FULL;
97 #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
104 memcpy(dst, src, cnt);
109 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
112 * \brief Copies previously decoded bytes to current position.
113 * \param back how many bytes back we start
114 * \param cnt number of bytes to copy, must be >= 0
116 * cnt > back is valid, this will copy the bytes we just copied,
117 * thus creating a repeating pattern with a period length of back.
119 static inline void copy_backptr(LZOContext *c, int back, int cnt) {
120 register const uint8_t *src = &c->out[-back];
121 register uint8_t *dst = c->out;
122 if (src < c->out_start || src > dst) {
123 c->error |= LZO_INVALID_BACKPTR;
126 if (cnt > c->out_end - dst) {
127 cnt = FFMAX(c->out_end - dst, 0);
128 c->error |= LZO_OUTPUT_FULL;
130 memcpy_backptr(dst, back, cnt);
134 static inline void memcpy_backptr(uint8_t *dst, int back, int cnt) {
135 const uint8_t *src = &dst[-back];
137 memset(dst, *src, cnt);
141 COPY2(dst + 2, src + 2);
147 COPY2(dst + 2, src + 2);
148 COPY2(dst + 4, src + 4);
149 COPY2(dst + 6, src + 6);
157 while (cnt > blocklen) {
158 memcpy(dst, src, blocklen);
163 memcpy(dst, src, cnt);
169 * \brief deliberately overlapping memcpy implementation
170 * \param dst destination buffer; must be padded with 12 additional bytes
171 * \param back how many bytes back we start (the initial size of the overlapping window)
172 * \param cnt number of bytes to copy, must be >= 0
174 * cnt > back is valid, this will copy the bytes we just copied,
175 * thus creating a repeating pattern with a period length of back.
177 void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
178 memcpy_backptr(dst, back, cnt);
182 * \brief Decodes LZO 1x compressed data.
183 * \param out output buffer
184 * \param outlen size of output buffer, number of bytes left are returned here
185 * \param in input buffer
186 * \param inlen size of input buffer, number of bytes left are returned here
187 * \return 0 on success, otherwise error flags, see lzo.h
189 * Make sure all buffers are appropriately padded, in must provide
190 * LZO_INPUT_PADDING, out must provide LZO_OUTPUT_PADDING additional bytes.
192 int lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
197 c.in_end = (const uint8_t *)in + *inlen;
198 c.out = c.out_start = out;
199 c.out_end = (uint8_t *)out + * outlen;
205 if (x < 16) c.error |= LZO_ERROR;
208 c.error |= LZO_INPUT_DEPLETED;
214 back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
216 cnt = get_len(&c, x, 31);
218 back = (GETB(c) << 6) + (x >> 2) + 1;
220 cnt = get_len(&c, x, 7);
221 back = (1 << 14) + ((x & 8) << 11);
223 back += (GETB(c) << 6) + (x >> 2);
224 if (back == (1 << 14)) {
226 c.error |= LZO_ERROR;
231 cnt = get_len(&c, x, 15);
237 back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
240 back = (GETB(c) << 2) + (x >> 2) + 1;
242 copy_backptr(&c, back, cnt + 2);
248 *inlen = c.in_end - c.in;
251 *outlen = c.out_end - c.out;
257 #include <lzo/lzo1x.h>
259 #define MAXSZ (10*1024*1024)
260 int main(int argc, char *argv[]) {
261 FILE *in = fopen(argv[1], "rb");
262 uint8_t *orig = av_malloc(MAXSZ + 16);
263 uint8_t *comp = av_malloc(2*MAXSZ + 16);
264 uint8_t *decomp = av_malloc(MAXSZ + 16);
265 size_t s = fread(orig, 1, MAXSZ, in);
267 long tmp[LZO1X_MEM_COMPRESS];
270 av_log_level = AV_LOG_DEBUG;
271 lzo1x_999_compress(orig, s, comp, &clen, tmp);
272 for (i = 0; i < 300; i++) {
274 inlen = clen; outlen = MAXSZ;
276 if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
277 #elif defined(LIBLZO_UNSAFE)
278 if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
280 if (lzo1x_decode(decomp, &outlen, comp, &inlen))
282 av_log(NULL, AV_LOG_ERROR, "decompression error\n");
285 if (memcmp(orig, decomp, s))
286 av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
288 av_log(NULL, AV_LOG_ERROR, "decompression OK\n");