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FFmpeg/libavcodec/cdxl.c
Paul B Mahol b2e2287c04 cdxl: disable checked bitstream reader 
Overreads should not be possible.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
2012-06-20 21:07:27 +00:00

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/*
* CDXL video decoder
* Copyright (c) 2011-2012 Paul B Mahol
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define UNCHECKED_BITSTREAM_READER 1
#include "libavutil/intreadwrite.h"
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "get_bits.h"
#define BIT_PLANAR 0x00
#define CHUNKY 0x20
#define BYTE_PLANAR 0x40
#define BIT_LINE 0x80
#define BYTE_LINE 0xC0
typedef struct {
AVCodecContext *avctx;
AVFrame frame;
int bpp;
int format;
int padded_bits;
const uint8_t *palette;
int palette_size;
const uint8_t *video;
int video_size;
uint8_t *new_video;
int new_video_size;
} CDXLVideoContext;
static av_cold int cdxl_decode_init(AVCodecContext *avctx)
{
CDXLVideoContext *c = avctx->priv_data;
avcodec_get_frame_defaults(&c->frame);
c->new_video_size = 0;
c->avctx = avctx;
return 0;
}
static void import_palette(CDXLVideoContext *c, uint32_t *new_palette)
{
int i;
for (i = 0; i < c->palette_size / 2; i++) {
unsigned rgb = AV_RB16(&c->palette[i * 2]);
unsigned r = ((rgb >> 8) & 0xF) * 0x11;
unsigned g = ((rgb >> 4) & 0xF) * 0x11;
unsigned b = (rgb & 0xF) * 0x11;
AV_WN32(&new_palette[i], (0xFFU << 24) | (r << 16) | (g << 8) | b);
}
}
static void bitplanar2chunky(CDXLVideoContext *c, int linesize, uint8_t *out)
{
GetBitContext gb;
int x, y, plane;
init_get_bits(&gb, c->video, c->video_size * 8);
for (plane = 0; plane < c->bpp; plane++) {
for (y = 0; y < c->avctx->height; y++) {
for (x = 0; x < c->avctx->width; x++)
out[linesize * y + x] |= get_bits1(&gb) << plane;
skip_bits(&gb, c->padded_bits);
}
}
}
static void bitline2chunky(CDXLVideoContext *c, int linesize, uint8_t *out)
{
GetBitContext gb;
int x, y, plane;
init_get_bits(&gb, c->video, c->video_size * 8);
for (y = 0; y < c->avctx->height; y++) {
for (plane = 0; plane < c->bpp; plane++) {
for (x = 0; x < c->avctx->width; x++)
out[linesize * y + x] |= get_bits1(&gb) << plane;
skip_bits(&gb, c->padded_bits);
}
}
}
static void import_format(CDXLVideoContext *c, int linesize, uint8_t *out)
{
memset(out, 0, linesize * c->avctx->height);
switch (c->format) {
case BIT_PLANAR:
bitplanar2chunky(c, linesize, out);
break;
case BIT_LINE:
bitline2chunky(c, linesize, out);
break;
}
}
static void cdxl_decode_rgb(CDXLVideoContext *c)
{
uint32_t *new_palette = (uint32_t *)c->frame.data[1];
import_palette(c, new_palette);
import_format(c, c->frame.linesize[0], c->frame.data[0]);
}
static void cdxl_decode_ham6(CDXLVideoContext *c)
{
AVCodecContext *avctx = c->avctx;
uint32_t new_palette[16], r, g, b;
uint8_t *ptr, *out, index, op;
int x, y;
ptr = c->new_video;
out = c->frame.data[0];
import_palette(c, new_palette);
import_format(c, avctx->width, c->new_video);
for (y = 0; y < avctx->height; y++) {
r = new_palette[0] & 0xFF0000;
g = new_palette[0] & 0xFF00;
b = new_palette[0] & 0xFF;
for (x = 0; x < avctx->width; x++) {
index = *ptr++;
op = index >> 4;
index &= 15;
switch (op) {
case 0:
r = new_palette[index] & 0xFF0000;
g = new_palette[index] & 0xFF00;
b = new_palette[index] & 0xFF;
break;
case 1:
b = index * 0x11;
break;
case 2:
r = index * 0x11 << 16;
break;
case 3:
g = index * 0x11 << 8;
break;
}
AV_WL24(out + x * 3, r | g | b);
}
out += c->frame.linesize[0];
}
}
static void cdxl_decode_ham8(CDXLVideoContext *c)
{
AVCodecContext *avctx = c->avctx;
uint32_t new_palette[64], r, g, b;
uint8_t *ptr, *out, index, op;
int x, y;
ptr = c->new_video;
out = c->frame.data[0];
import_palette(c, new_palette);
import_format(c, avctx->width, c->new_video);
for (y = 0; y < avctx->height; y++) {
r = new_palette[0] & 0xFF0000;
g = new_palette[0] & 0xFF00;
b = new_palette[0] & 0xFF;
for (x = 0; x < avctx->width; x++) {
index = *ptr++;
op = index >> 6;
index &= 63;
switch (op) {
case 0:
r = new_palette[index] & 0xFF0000;
g = new_palette[index] & 0xFF00;
b = new_palette[index] & 0xFF;
break;
case 1:
b = (index << 2) | (b & 3);
break;
case 2:
r = (index << 18) | (r & (3 << 16));
break;
case 3:
g = (index << 10) | (g & (3 << 8));
break;
}
AV_WL24(out + x * 3, r | g | b);
}
out += c->frame.linesize[0];
}
}
static int cdxl_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *pkt)
{
CDXLVideoContext *c = avctx->priv_data;
AVFrame * const p = &c->frame;
int ret, w, h, encoding, aligned_width, buf_size = pkt->size;
const uint8_t *buf = pkt->data;
if (buf_size < 32)
return AVERROR_INVALIDDATA;
encoding = buf[1] & 7;
c->format = buf[1] & 0xE0;
w = AV_RB16(&buf[14]);
h = AV_RB16(&buf[16]);
c->bpp = buf[19];
c->palette_size = AV_RB16(&buf[20]);
c->palette = buf + 32;
c->video = c->palette + c->palette_size;
c->video_size = buf_size - c->palette_size - 32;
if (c->palette_size > 512)
return AVERROR_INVALIDDATA;
if (buf_size < c->palette_size + 32)
return AVERROR_INVALIDDATA;
if (c->bpp < 1)
return AVERROR_INVALIDDATA;
if (c->format != BIT_PLANAR && c->format != BIT_LINE) {
av_log_ask_for_sample(avctx, "unsupported pixel format: 0x%0x\n", c->format);
return AVERROR_PATCHWELCOME;
}
if ((ret = av_image_check_size(w, h, 0, avctx)) < 0)
return ret;
if (w != avctx->width || h != avctx->height)
avcodec_set_dimensions(avctx, w, h);
aligned_width = FFALIGN(c->avctx->width, 16);
c->padded_bits = aligned_width - c->avctx->width;
if (c->video_size < aligned_width * avctx->height * c->bpp / 8)
return AVERROR_INVALIDDATA;
if (!encoding && c->palette_size && c->bpp <= 8) {
avctx->pix_fmt = PIX_FMT_PAL8;
} else if (encoding == 1 && (c->bpp == 6 || c->bpp == 8)) {
if (c->palette_size != (1 << (c->bpp - 1)))
return AVERROR_INVALIDDATA;
avctx->pix_fmt = PIX_FMT_BGR24;
} else {
av_log_ask_for_sample(avctx, "unsupported encoding %d and bpp %d\n",
encoding, c->bpp);
return AVERROR_PATCHWELCOME;
}
if (p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
if ((ret = avctx->get_buffer(avctx, p)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
p->pict_type = AV_PICTURE_TYPE_I;
if (encoding) {
av_fast_padded_malloc(&c->new_video, &c->new_video_size,
h * w + FF_INPUT_BUFFER_PADDING_SIZE);
if (!c->new_video)
return AVERROR(ENOMEM);
if (c->bpp == 8)
cdxl_decode_ham8(c);
else
cdxl_decode_ham6(c);
} else {
cdxl_decode_rgb(c);
}
*data_size = sizeof(AVFrame);
*(AVFrame*)data = c->frame;
return buf_size;
}
static av_cold int cdxl_decode_end(AVCodecContext *avctx)
{
CDXLVideoContext *c = avctx->priv_data;
av_free(c->new_video);
if (c->frame.data[0])
avctx->release_buffer(avctx, &c->frame);
return 0;
}
AVCodec ff_cdxl_decoder = {
.name = "cdxl",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_CDXL,
.priv_data_size = sizeof(CDXLVideoContext),
.init = cdxl_decode_init,
.close = cdxl_decode_end,
.decode = cdxl_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Commodore CDXL video"),
};
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