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 "avutil.h"
23#include "common.h"
24//! Avoid e.g. MPlayers fast_memcpy, it slows things down here.
25#undef memcpy
26#include <string.h>
27#include "lzo.h"
28
29//! Define if we may write up to 12 bytes beyond the output buffer.
30#define OUTBUF_PADDED 1
31//! Define if we may read up to 8 bytes beyond the input buffer.
32#define INBUF_PADDED 1
33typedef struct LZOContext {
34    const uint8_t *in, *in_end;
35    uint8_t *out_start, *out, *out_end;
36    int error;
37} LZOContext;
38
39/**
40 * \brief Reads one byte from the input buffer, avoiding an overrun.
41 * \return byte read
42 */
43static inline int get_byte(LZOContext *c) {
44    if (c->in < c->in_end)
45        return *c->in++;
46    c->error |= AV_LZO_INPUT_DEPLETED;
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
56/**
57 * \brief Decodes a length value in the coding used by lzo.
58 * \param x previous byte value
59 * \param mask bits used from x
60 * \return decoded length value
61 */
62static 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
84/**
85 * \brief Copies bytes from input to output buffer with checking.
86 * \param cnt number of bytes to copy, must be >= 0
87 */
88static 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);
93        c->error |= AV_LZO_INPUT_DEPLETED;
94    }
95    if (cnt > c->out_end - dst) {
96        cnt = FFMAX(c->out_end - dst, 0);
97        c->error |= AV_LZO_OUTPUT_FULL;
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
111static inline void memcpy_backptr(uint8_t *dst, int back, int cnt);
112
113/**
114 * \brief Copies previously decoded bytes to current position.
115 * \param back how many bytes back we start
116 * \param cnt number of bytes to copy, must be >= 0
117 *
118 * cnt > back is valid, this will copy the bytes we just copied,
119 * thus creating a repeating pattern with a period length of back.
120 */
121static 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) {
125        c->error |= AV_LZO_INVALID_BACKPTR;
126        return;
127    }
128    if (cnt > c->out_end - dst) {
129        cnt = FFMAX(c->out_end - dst, 0);
130        c->error |= AV_LZO_OUTPUT_FULL;
131    }
132    memcpy_backptr(dst, back, cnt);
133    c->out = dst + cnt;
134}
135
136static 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
170void av_memcpy_backptr(uint8_t *dst, int back, int cnt) {
171    memcpy_backptr(dst, back, cnt);
172}
173
174int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen) {
175    int state= 0;
176    int x;
177    LZOContext c;
178    c.in = in;
179    c.in_end = (const uint8_t *)in + *inlen;
180    c.out = c.out_start = out;
181    c.out_end = (uint8_t *)out + * outlen;
182    c.error = 0;
183    x = GETB(c);
184    if (x > 17) {
185        copy(&c, x - 17);
186        x = GETB(c);
187        if (x < 16) c.error |= AV_LZO_ERROR;
188    }
189    if (c.in > c.in_end)
190        c.error |= AV_LZO_INPUT_DEPLETED;
191    while (!c.error) {
192        int cnt, back;
193        if (x > 15) {
194            if (x > 63) {
195                cnt = (x >> 5) - 1;
196                back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
197            } else if (x > 31) {
198                cnt = get_len(&c, x, 31);
199                x = GETB(c);
200                back = (GETB(c) << 6) + (x >> 2) + 1;
201            } else {
202                cnt = get_len(&c, x, 7);
203                back = (1 << 14) + ((x & 8) << 11);
204                x = GETB(c);
205                back += (GETB(c) << 6) + (x >> 2);
206                if (back == (1 << 14)) {
207                    if (cnt != 1)
208                        c.error |= AV_LZO_ERROR;
209                    break;
210                }
211            }
212        } else if(!state){
213                cnt = get_len(&c, x, 15);
214                copy(&c, cnt + 3);
215                x = GETB(c);
216                if (x > 15)
217                    continue;
218                cnt = 1;
219                back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
220        } else {
221                cnt = 0;
222                back = (GETB(c) << 2) + (x >> 2) + 1;
223        }
224        copy_backptr(&c, back, cnt + 2);
225        state=
226        cnt = x & 3;
227        copy(&c, cnt);
228        x = GETB(c);
229    }
230    *inlen = c.in_end - c.in;
231    if (c.in > c.in_end)
232        *inlen = 0;
233    *outlen = c.out_end - c.out;
234    return c.error;
235}
236
237#ifdef TEST
238#include <stdio.h>
239#include <lzo/lzo1x.h>
240#include "log.h"
241#define MAXSZ (10*1024*1024)
242
243/* Define one of these to 1 if you wish to benchmark liblzo
244 * instead of our native implementation. */
245#define BENCHMARK_LIBLZO_SAFE   0
246#define BENCHMARK_LIBLZO_UNSAFE 0
247
248int main(int argc, char *argv[]) {
249    FILE *in = fopen(argv[1], "rb");
250    uint8_t *orig = av_malloc(MAXSZ + 16);
251    uint8_t *comp = av_malloc(2*MAXSZ + 16);
252    uint8_t *decomp = av_malloc(MAXSZ + 16);
253    size_t s = fread(orig, 1, MAXSZ, in);
254    lzo_uint clen = 0;
255    long tmp[LZO1X_MEM_COMPRESS];
256    int inlen, outlen;
257    int i;
258    av_log_set_level(AV_LOG_DEBUG);
259    lzo1x_999_compress(orig, s, comp, &clen, tmp);
260    for (i = 0; i < 300; i++) {
261START_TIMER
262        inlen = clen; outlen = MAXSZ;
263#if BENCHMARK_LIBLZO_SAFE
264        if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
265#elif BENCHMARK_LIBLZO_UNSAFE
266        if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
267#else
268        if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
269#endif
270            av_log(NULL, AV_LOG_ERROR, "decompression error\n");
271STOP_TIMER("lzod")
272    }
273    if (memcmp(orig, decomp, s))
274        av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
275    else
276        av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
277    return 0;
278}
279#endif
280