Commit 517840c6 authored by Reimar Döffinger's avatar Reimar Döffinger

Our own LZO (1X) implementation, under LGPL and optimized for readability.

Tested on CamStudio sample files.

Originally committed as revision 4840 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 1015631b
......@@ -169,6 +169,7 @@ ifeq ($(CONFIG_TSCC_DECODER),yes)
endif
ifeq ($(CONFIG_CSCD_DECODER),yes)
OBJS+= cscd.o
OBJS+= lzo.o
endif
ifeq ($(CONFIG_ULTI_DECODER),yes)
OBJS+= ulti.o
......
......@@ -25,9 +25,7 @@
#ifdef CONFIG_ZLIB
#include <zlib.h>
#endif
#ifdef CONFIG_LZO
#include <lzo1x.h>
#endif
#include "lzo.h"
typedef struct {
AVFrame pic;
......@@ -158,16 +156,10 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
// decompress data
switch ((buf[0] >> 1) & 7) {
case 0: { // lzo compression
#ifdef CONFIG_LZO
unsigned int dlen = c->decomp_size;
if (lzo1x_decompress_safe(&buf[2], buf_size - 2,
c->decomp_buf, &dlen, NULL) != LZO_E_OK)
int outlen = c->decomp_size, inlen = buf_size - 2;
if (lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen))
av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");
break;
#else
av_log(avctx, AV_LOG_ERROR, "compiled without lzo (GPL) support\n");
return -1;
#endif
}
case 1: { // zlib compression
#ifdef CONFIG_ZLIB
......
/*
* LZO 1x decompression
* Copyright (c) 2006 Reimar Doeffinger
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
#include "lzo.h"
typedef struct LZOContext {
uint8_t *in, *in_end;
uint8_t *out, *out_end;
int out_size;
int error;
} LZOContext;
/**
* \brief read one byte from input buffer, avoiding overrun
* \return byte read
*/
static inline int get_byte(LZOContext *c) {
if (c->in < c->in_end)
return *c->in++;
c->error |= LZO_INPUT_DEPLETED;
return -1;
}
/**
* \brief decode 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))) cnt += 255;
cnt += mask + x;
}
return cnt;
}
/**
* \brief copy 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) {
if (c->in + cnt > c->in_end) {
cnt = c->in_end - c->in;
c->error |= LZO_INPUT_DEPLETED;
}
if (c->out + cnt > c->out_end) {
cnt = c->out_end - c->out;
c->error |= LZO_OUTPUT_FULL;
}
do {
*c->out++ = *c->in++;
} while (--cnt);
}
/**
* \brief copy previously decoded bytes to current position
* \param back how many bytes back we start
* \param cnt number of bytes to copy, must be > 0
*
* cnt > back is valid, this will copy the bytes we just copied.
*/
static inline void copy_backptr(LZOContext *c, int back, int cnt) {
if (c->out - back < c->out_end - c->out_size) {
c->error |= LZO_INVALID_BACKPTR;
return;
}
if (c->out + cnt > c->out_end) {
cnt = c->out_end - c->out;
c->error |= LZO_OUTPUT_FULL;
}
do {
*c->out++ = c->out[-back];
} while (--cnt);
}
/**
* \brief decode LZO 1x compressed data
* \param out output buffer
* \param outlen size of output buffer, number of bytes left are returned here
* \param in input buffer
* \param inlen size of input buffer, number of bytes left are returned here
* \return 0 on success, otherwise error flags, see lzo.h
*/
int lzo1x_decode(void *out, int *outlen, void *in, int *inlen) {
enum {COPY, BACKPTR} state = COPY;
int x;
LZOContext c;
c.in = in;
c.in_end = in + *inlen;
c.out = out;
c.out_end = out + * outlen;
c.out_size = *outlen;
c.error = 0;
x = get_byte(&c);
if (x > 17) {
copy(&c, x - 17);
x = get_byte(&c);
if (x < 16) c.error |= LZO_ERROR;
}
while (!c.error) {
int cnt, back;
if (x >> 4) {
state = BACKPTR;
if (x >> 6) {
cnt = (x >> 5) - 1;
back = (get_byte(&c) << 3) + ((x >> 2) & 7) + 1;
} else if (x >> 5) {
cnt = get_len(&c, x, 31);
x = get_byte(&c);
back = (get_byte(&c) << 6) + (x >> 2) + 1;
} else {
cnt = get_len(&c, x, 7);
back = (1 << 14) + ((x & 8) << 11);
x = get_byte(&c);
back += (get_byte(&c) << 6) + (x >> 2);
if (back == (1 << 14)) {
if (cnt != 1)
c.error |= LZO_ERROR;
break;
}
}
} else
switch (state) {
case COPY:
cnt = get_len(&c, x, 15);
copy(&c, cnt + 3);
x = get_byte(&c);
if (x >> 4)
continue;
cnt = 1;
back = (1 << 11) + (get_byte(&c) << 2) + (x >> 2) + 1;
break;
case BACKPTR:
cnt = 0;
back = (get_byte(&c) << 2) + (x >> 2) + 1;
break;
}
copy_backptr(&c, back, cnt + 2);
cnt = x & 3;
if (cnt)
copy(&c, cnt);
else
state = (state == COPY) ? BACKPTR : COPY;
x = get_byte(&c);
}
*inlen = c.in_end - c.in;
*outlen = c.out_end - c.out;
return c.error;
}
#ifndef _LZO_H
#define LZO_H
#define LZO_INPUT_DEPLETED 1
#define LZO_OUTPUT_FULL 2
#define LZO_INVALID_BACKPTR 4
#define LZO_ERROR 8
int lzo1x_decode(void *out, int *outlen, void *in, int *inlen);
#endif
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment