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- /*
- * LZO 1x decompression
- * Copyright (c) 2006 Reimar Doeffinger
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
- #include <string.h>
- #include "avutil.h"
- #include "avassert.h"
- #include "common.h"
- #include "intreadwrite.h"
- #include "lzo.h"
- /// Define if we may write up to 12 bytes beyond the output buffer.
- #define OUTBUF_PADDED 1
- /// Define if we may read up to 8 bytes beyond the input buffer.
- #define INBUF_PADDED 1
- typedef struct LZOContext {
- const uint8_t *in, *in_end;
- uint8_t *out_start, *out, *out_end;
- int error;
- } LZOContext;
- /**
- * @brief Reads one byte from the input buffer, avoiding an overrun.
- * @return byte read
- */
- static inline int get_byte(LZOContext *c)
- {
- if (c->in < c->in_end)
- return *c->in++;
- c->error |= AV_LZO_INPUT_DEPLETED;
- return 1;
- }
- #ifdef INBUF_PADDED
- #define GETB(c) (*(c).in++)
- #else
- #define GETB(c) get_byte(&(c))
- #endif
- /**
- * @brief Decodes a length value in the coding used by lzo.
- * @param x previous byte value
- * @param mask bits used from x
- * @return decoded length value
- */
- static inline int get_len(LZOContext *c, int x, int mask)
- {
- int cnt = x & mask;
- if (!cnt) {
- while (!(x = get_byte(c))) {
- if (cnt >= INT_MAX - 1000) {
- c->error |= AV_LZO_ERROR;
- break;
- }
- cnt += 255;
- }
- cnt += mask + x;
- }
- return cnt;
- }
- /**
- * @brief Copies bytes from input to output buffer with checking.
- * @param cnt number of bytes to copy, must be >= 0
- */
- static inline void copy(LZOContext *c, int cnt)
- {
- register const uint8_t *src = c->in;
- register uint8_t *dst = c->out;
- av_assert0(cnt >= 0);
- if (cnt > c->in_end - src) {
- cnt = FFMAX(c->in_end - src, 0);
- c->error |= AV_LZO_INPUT_DEPLETED;
- }
- if (cnt > c->out_end - dst) {
- cnt = FFMAX(c->out_end - dst, 0);
- c->error |= AV_LZO_OUTPUT_FULL;
- }
- #if defined(INBUF_PADDED) && defined(OUTBUF_PADDED)
- AV_COPY32U(dst, src);
- src += 4;
- dst += 4;
- cnt -= 4;
- if (cnt > 0)
- #endif
- memcpy(dst, src, cnt);
- c->in = src + cnt;
- c->out = dst + cnt;
- }
- /**
- * @brief Copies previously decoded bytes to current position.
- * @param back how many bytes back we start, must be > 0
- * @param cnt number of bytes to copy, must be >= 0
- *
- * cnt > back is valid, this will copy the bytes we just copied,
- * thus creating a repeating pattern with a period length of back.
- */
- static inline void copy_backptr(LZOContext *c, int back, int cnt)
- {
- register uint8_t *dst = c->out;
- av_assert0(cnt > 0);
- if (dst - c->out_start < back) {
- c->error |= AV_LZO_INVALID_BACKPTR;
- return;
- }
- if (cnt > c->out_end - dst) {
- cnt = FFMAX(c->out_end - dst, 0);
- c->error |= AV_LZO_OUTPUT_FULL;
- }
- av_memcpy_backptr(dst, back, cnt);
- c->out = dst + cnt;
- }
- int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen)
- {
- int state = 0;
- int x;
- LZOContext c;
- if (*outlen <= 0 || *inlen <= 0) {
- int res = 0;
- if (*outlen <= 0)
- res |= AV_LZO_OUTPUT_FULL;
- if (*inlen <= 0)
- res |= AV_LZO_INPUT_DEPLETED;
- return res;
- }
- c.in = in;
- c.in_end = (const uint8_t *)in + *inlen;
- c.out = c.out_start = out;
- c.out_end = (uint8_t *)out + *outlen;
- c.error = 0;
- x = GETB(c);
- if (x > 17) {
- copy(&c, x - 17);
- x = GETB(c);
- if (x < 16)
- c.error |= AV_LZO_ERROR;
- }
- if (c.in > c.in_end)
- c.error |= AV_LZO_INPUT_DEPLETED;
- while (!c.error) {
- int cnt, back;
- if (x > 15) {
- if (x > 63) {
- cnt = (x >> 5) - 1;
- back = (GETB(c) << 3) + ((x >> 2) & 7) + 1;
- } else if (x > 31) {
- cnt = get_len(&c, x, 31);
- x = GETB(c);
- back = (GETB(c) << 6) + (x >> 2) + 1;
- } else {
- cnt = get_len(&c, x, 7);
- back = (1 << 14) + ((x & 8) << 11);
- x = GETB(c);
- back += (GETB(c) << 6) + (x >> 2);
- if (back == (1 << 14)) {
- if (cnt != 1)
- c.error |= AV_LZO_ERROR;
- break;
- }
- }
- } else if (!state) {
- cnt = get_len(&c, x, 15);
- copy(&c, cnt + 3);
- x = GETB(c);
- if (x > 15)
- continue;
- cnt = 1;
- back = (1 << 11) + (GETB(c) << 2) + (x >> 2) + 1;
- } else {
- cnt = 0;
- back = (GETB(c) << 2) + (x >> 2) + 1;
- }
- copy_backptr(&c, back, cnt + 2);
- state =
- cnt = x & 3;
- copy(&c, cnt);
- x = GETB(c);
- }
- *inlen = c.in_end - c.in;
- if (c.in > c.in_end)
- *inlen = 0;
- *outlen = c.out_end - c.out;
- return c.error;
- }
- #ifdef TEST
- #include <stdio.h>
- #include <lzo/lzo1x.h>
- #include "log.h"
- #define MAXSZ (10*1024*1024)
- /* Define one of these to 1 if you wish to benchmark liblzo
- * instead of our native implementation. */
- #define BENCHMARK_LIBLZO_SAFE 0
- #define BENCHMARK_LIBLZO_UNSAFE 0
- int main(int argc, char *argv[]) {
- FILE *in = fopen(argv[1], "rb");
- uint8_t *orig = av_malloc(MAXSZ + 16);
- uint8_t *comp = av_malloc(2*MAXSZ + 16);
- uint8_t *decomp = av_malloc(MAXSZ + 16);
- size_t s = fread(orig, 1, MAXSZ, in);
- lzo_uint clen = 0;
- long tmp[LZO1X_MEM_COMPRESS];
- int inlen, outlen;
- int i;
- av_log_set_level(AV_LOG_DEBUG);
- lzo1x_999_compress(orig, s, comp, &clen, tmp);
- for (i = 0; i < 300; i++) {
- START_TIMER
- inlen = clen; outlen = MAXSZ;
- #if BENCHMARK_LIBLZO_SAFE
- if (lzo1x_decompress_safe(comp, inlen, decomp, &outlen, NULL))
- #elif BENCHMARK_LIBLZO_UNSAFE
- if (lzo1x_decompress(comp, inlen, decomp, &outlen, NULL))
- #else
- if (av_lzo1x_decode(decomp, &outlen, comp, &inlen))
- #endif
- av_log(NULL, AV_LOG_ERROR, "decompression error\n");
- STOP_TIMER("lzod")
- }
- if (memcmp(orig, decomp, s))
- av_log(NULL, AV_LOG_ERROR, "decompression incorrect\n");
- else
- av_log(NULL, AV_LOG_ERROR, "decompression OK\n");
- return 0;
- }
- #endif
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