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FFmpeg/libavcodec/dxa.c
Paul B Mahol 586c2528a0 dxa: port to bytestream2 API 
Protects against overreads in input buffer.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
2012-12-06 19:09:48 +00:00

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/*
* Feeble Files/ScummVM DXA decoder
* Copyright (c) 2007 Konstantin Shishkov
*
* 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
*/
/**
* @file
* DXA Video decoder
*/
#include <stdio.h>
#include <stdlib.h>
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"
#include "bytestream.h"
#include "avcodec.h"
#include "internal.h"
#include <zlib.h>
/*
* Decoder context
*/
typedef struct DxaDecContext {
AVFrame pic, prev;
int dsize;
uint8_t *decomp_buf;
uint32_t pal[256];
} DxaDecContext;
static const int shift1[6] = { 0, 8, 8, 8, 4, 4 };
static const int shift2[6] = { 0, 0, 8, 4, 0, 4 };
static int decode_13(AVCodecContext *avctx, DxaDecContext *c, uint8_t* dst, uint8_t *src, uint8_t *ref)
{
uint8_t *code, *data, *mv, *msk, *tmp, *tmp2;
int i, j, k;
int type, x, y, d, d2;
int stride = c->pic.linesize[0];
uint32_t mask;
code = src + 12;
data = code + ((avctx->width * avctx->height) >> 4);
mv = data + AV_RB32(src + 0);
msk = mv + AV_RB32(src + 4);
for(j = 0; j < avctx->height; j += 4){
for(i = 0; i < avctx->width; i += 4){
tmp = dst + i;
tmp2 = ref + i;
type = *code++;
switch(type){
case 4: // motion compensation
x = (*mv) >> 4; if(x & 8) x = 8 - x;
y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
tmp2 += x + y*stride;
case 0: // skip
case 5: // skip in method 12
for(y = 0; y < 4; y++){
memcpy(tmp, tmp2, 4);
tmp += stride;
tmp2 += stride;
}
break;
case 1: // masked change
case 10: // masked change with only half of pixels changed
case 11: // cases 10-15 are for method 12 only
case 12:
case 13:
case 14:
case 15:
if(type == 1){
mask = AV_RB16(msk);
msk += 2;
}else{
type -= 10;
mask = ((msk[0] & 0xF0) << shift1[type]) | ((msk[0] & 0xF) << shift2[type]);
msk++;
}
for(y = 0; y < 4; y++){
for(x = 0; x < 4; x++){
tmp[x] = (mask & 0x8000) ? *data++ : tmp2[x];
mask <<= 1;
}
tmp += stride;
tmp2 += stride;
}
break;
case 2: // fill block
for(y = 0; y < 4; y++){
memset(tmp, data[0], 4);
tmp += stride;
}
data++;
break;
case 3: // raw block
for(y = 0; y < 4; y++){
memcpy(tmp, data, 4);
data += 4;
tmp += stride;
}
break;
case 8: // subblocks - method 13 only
mask = *msk++;
for(k = 0; k < 4; k++){
d = ((k & 1) << 1) + ((k & 2) * stride);
d2 = ((k & 1) << 1) + ((k & 2) * stride);
tmp2 = ref + i + d2;
switch(mask & 0xC0){
case 0x80: // motion compensation
x = (*mv) >> 4; if(x & 8) x = 8 - x;
y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
tmp2 += x + y*stride;
case 0x00: // skip
tmp[d + 0 ] = tmp2[0];
tmp[d + 1 ] = tmp2[1];
tmp[d + 0 + stride] = tmp2[0 + stride];
tmp[d + 1 + stride] = tmp2[1 + stride];
break;
case 0x40: // fill
tmp[d + 0 ] = data[0];
tmp[d + 1 ] = data[0];
tmp[d + 0 + stride] = data[0];
tmp[d + 1 + stride] = data[0];
data++;
break;
case 0xC0: // raw
tmp[d + 0 ] = *data++;
tmp[d + 1 ] = *data++;
tmp[d + 0 + stride] = *data++;
tmp[d + 1 + stride] = *data++;
break;
}
mask <<= 2;
}
break;
case 32: // vector quantization - 2 colors
mask = AV_RB16(msk);
msk += 2;
for(y = 0; y < 4; y++){
for(x = 0; x < 4; x++){
tmp[x] = data[mask & 1];
mask >>= 1;
}
tmp += stride;
tmp2 += stride;
}
data += 2;
break;
case 33: // vector quantization - 3 or 4 colors
case 34:
mask = AV_RB32(msk);
msk += 4;
for(y = 0; y < 4; y++){
for(x = 0; x < 4; x++){
tmp[x] = data[mask & 3];
mask >>= 2;
}
tmp += stride;
tmp2 += stride;
}
data += type - 30;
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown opcode %d\n", type);
return AVERROR_INVALIDDATA;
}
}
dst += stride * 4;
ref += stride * 4;
}
return 0;
}
static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
{
DxaDecContext * const c = avctx->priv_data;
uint8_t *outptr, *srcptr, *tmpptr;
unsigned long dsize;
int i, j, compr, ret;
int stride;
int pc = 0;
GetByteContext gb;
bytestream2_init(&gb, avpkt->data, avpkt->size);
/* make the palette available on the way out */
if (bytestream2_peek_le32(&gb) == MKTAG('C','M','A','P')) {
bytestream2_skip(&gb, 4);
for(i = 0; i < 256; i++){
c->pal[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);
}
pc = 1;
}
if ((ret = ff_get_buffer(avctx, &c->pic)) < 0){
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
c->pic.palette_has_changed = pc;
outptr = c->pic.data[0];
srcptr = c->decomp_buf;
tmpptr = c->prev.data[0];
stride = c->pic.linesize[0];
if (bytestream2_get_le32(&gb) == MKTAG('N','U','L','L'))
compr = -1;
else
compr = bytestream2_get_byte(&gb);
dsize = c->dsize;
if (compr != 4 && compr != -1) {
bytestream2_skip(&gb, 4);
if (uncompress(c->decomp_buf, &dsize, avpkt->data + bytestream2_tell(&gb),
bytestream2_get_bytes_left(&gb)) != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "Uncompress failed!\n");
return AVERROR_INVALIDDATA;
}
}
switch(compr){
case -1:
c->pic.key_frame = 0;
c->pic.pict_type = AV_PICTURE_TYPE_P;
if(c->prev.data[0])
memcpy(c->pic.data[0], c->prev.data[0], c->pic.linesize[0] * avctx->height);
else{ // Should happen only when first frame is 'NULL'
memset(c->pic.data[0], 0, c->pic.linesize[0] * avctx->height);
c->pic.key_frame = 1;
c->pic.pict_type = AV_PICTURE_TYPE_I;
}
break;
case 2:
case 3:
case 4:
case 5:
c->pic.key_frame = !(compr & 1);
c->pic.pict_type = (compr & 1) ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;
for(j = 0; j < avctx->height; j++){
if((compr & 1) && tmpptr){
for(i = 0; i < avctx->width; i++)
outptr[i] = srcptr[i] ^ tmpptr[i];
tmpptr += stride;
}else
memcpy(outptr, srcptr, avctx->width);
outptr += stride;
srcptr += avctx->width;
}
break;
case 12: // ScummVM coding
case 13:
c->pic.key_frame = 0;
c->pic.pict_type = AV_PICTURE_TYPE_P;
if (!c->prev.data[0]) {
av_log(avctx, AV_LOG_ERROR, "Missing reference frame\n");
return AVERROR_INVALIDDATA;
}
decode_13(avctx, c, c->pic.data[0], srcptr, c->prev.data[0]);
break;
default:
av_log(avctx, AV_LOG_ERROR, "Unknown/unsupported compression type %d\n", compr);
return AVERROR_INVALIDDATA;
}
FFSWAP(AVFrame, c->pic, c->prev);
if(c->pic.data[0])
avctx->release_buffer(avctx, &c->pic);
*got_frame = 1;
*(AVFrame*)data = c->prev;
/* always report that the buffer was completely consumed */
return avpkt->size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
DxaDecContext * const c = avctx->priv_data;
avctx->pix_fmt = AV_PIX_FMT_PAL8;
avcodec_get_frame_defaults(&c->pic);
avcodec_get_frame_defaults(&c->prev);
c->dsize = avctx->width * avctx->height * 2;
c->decomp_buf = av_malloc(c->dsize);
if (!c->decomp_buf) {
av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
return AVERROR(ENOMEM);
}
return 0;
}
static av_cold int decode_end(AVCodecContext *avctx)
{
DxaDecContext * const c = avctx->priv_data;
av_freep(&c->decomp_buf);
if(c->prev.data[0])
avctx->release_buffer(avctx, &c->prev);
if(c->pic.data[0])
avctx->release_buffer(avctx, &c->pic);
return 0;
}
AVCodec ff_dxa_decoder = {
.name = "dxa",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_DXA,
.priv_data_size = sizeof(DxaDecContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Feeble Files/ScummVM DXA"),
};
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