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FFmpeg/libavcodec/sgidec.c

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/*
* SGI image decoder
* Todd Kirby <doubleshot@pacbell.net>
*
* 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 "avcodec.h"
#include "bytestream.h"
#include "sgi.h"
typedef struct SgiState {
AVFrame picture;
unsigned int width;
unsigned int height;
unsigned int depth;
int linesize;
} SgiState;
/**
* Expand an RLE row into a channel.
* @param in_buf input buffer
* @param in_end end of input buffer
* @param out_buf Points to one line after the output buffer.
* @param out_end end of line in output buffer
* @param pixelstride pixel stride of input buffer
* @return size of output in bytes, -1 if buffer overflows
*/
static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,
unsigned char *out_buf, uint8_t* out_end, int pixelstride)
{
unsigned char pixel, count;
unsigned char *orig = out_buf;
while (1) {
if(in_buf + 1 > in_end) return -1;
pixel = bytestream_get_byte(&in_buf);
if (!(count = (pixel & 0x7f))) {
return (out_buf - orig) / pixelstride;
}
/* Check for buffer overflow. */
if(out_buf + pixelstride * count >= out_end) return -1;
if (pixel & 0x80) {
while (count--) {
*out_buf = bytestream_get_byte(&in_buf);
out_buf += pixelstride;
}
} else {
pixel = bytestream_get_byte(&in_buf);
while (count--) {
*out_buf = pixel;
out_buf += pixelstride;
}
}
}
}
/**
* Read a run length encoded SGI image.
* @param out_buf output buffer
* @param in_buf input buffer
* @param in_end end of input buffer
* @param s the current image state
* @return 0 if no error, else return error number.
*/
static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
const uint8_t *in_end, SgiState* s)
{
uint8_t *dest_row;
unsigned int len = s->height * s->depth * 4;
const uint8_t *start_table = in_buf;
unsigned int y, z;
unsigned int start_offset;
/* size of RLE offset and length tables */
if(len * 2 > in_end - in_buf) {
return AVERROR_INVALIDDATA;
}
in_buf -= SGI_HEADER_SIZE;
for (z = 0; z < s->depth; z++) {
dest_row = out_buf;
for (y = 0; y < s->height; y++) {
dest_row -= s->linesize;
start_offset = bytestream_get_be32(&start_table);
if(start_offset > in_end - in_buf) {
return AVERROR_INVALIDDATA;
}
if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
dest_row + FFABS(s->linesize), s->depth) != s->width)
return AVERROR_INVALIDDATA;
}
}
return 0;
}
/**
* Read an uncompressed SGI image.
* @param out_buf output buffer
* @param out_end end ofoutput buffer
* @param in_buf input buffer
* @param in_end end of input buffer
* @param s the current image state
* @return 0 if read success, otherwise return -1.
*/
static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)
{
int x, y, z;
const uint8_t *ptr;
unsigned int offset = s->height * s->width;
/* Test buffer size. */
if (offset * s->depth > in_end - in_buf) {
return -1;
}
for (y = s->height - 1; y >= 0; y--) {
out_end = out_buf + (y * s->linesize);
for (x = s->width; x > 0; x--) {
ptr = in_buf++;
for(z = 0; z < s->depth; z ++) {
bytestream_put_byte(&out_end, *ptr);
ptr += offset;
}
}
}
return 0;
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *in_buf, int buf_size)
{
SgiState *s = avctx->priv_data;
AVFrame *picture = data;
AVFrame *p = &s->picture;
const uint8_t *in_end = in_buf + buf_size;
unsigned int dimension, bytes_per_channel, rle;
int ret = 0;
uint8_t *out_buf, *out_end;
if (buf_size < SGI_HEADER_SIZE){
av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
return -1;
}
/* Test for SGI magic. */
if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
return -1;
}
rle = bytestream_get_byte(&in_buf);
bytes_per_channel = bytestream_get_byte(&in_buf);
dimension = bytestream_get_be16(&in_buf);
s->width = bytestream_get_be16(&in_buf);
s->height = bytestream_get_be16(&in_buf);
s->depth = bytestream_get_be16(&in_buf);
if (bytes_per_channel != 1) {
av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
return -1;
}
/* Check for supported image dimensions. */
if (dimension != 2 && dimension != 3) {
av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
return -1;
}
if (s->depth == SGI_GRAYSCALE) {
avctx->pix_fmt = PIX_FMT_GRAY8;
} else if (s->depth == SGI_RGB) {
avctx->pix_fmt = PIX_FMT_RGB24;
} else if (s->depth == SGI_RGBA) {
avctx->pix_fmt = PIX_FMT_RGBA;
} else {
av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
return -1;
}
if (avcodec_check_dimensions(avctx, s->width, s->height))
return -1;
avcodec_set_dimensions(avctx, s->width, s->height);
if (p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
if (avctx->get_buffer(avctx, p) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
return -1;
}
p->pict_type = FF_I_TYPE;
p->key_frame = 1;
out_buf = p->data[0];
out_end = out_buf + p->linesize[0] * s->height;
s->linesize = p->linesize[0];
/* Skip header. */
in_buf += SGI_HEADER_SIZE - 12;
if (rle) {
ret = read_rle_sgi(out_end, in_buf, in_end, s);
} else {
ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
}
if (ret == 0) {
*picture = s->picture;
*data_size = sizeof(AVPicture);
return buf_size;
} else {
return -1;
}
}
static av_cold int sgi_init(AVCodecContext *avctx){
SgiState *s = avctx->priv_data;
avcodec_get_frame_defaults(&s->picture);
avctx->coded_frame = &s->picture;
return 0;
}
static av_cold int sgi_end(AVCodecContext *avctx)
{
SgiState * const s = avctx->priv_data;
if (s->picture.data[0])
avctx->release_buffer(avctx, &s->picture);
return 0;
}
AVCodec sgi_decoder = {
"sgi",
CODEC_TYPE_VIDEO,
CODEC_ID_SGI,
sizeof(SgiState),
sgi_init,
NULL,
sgi_end,
decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("SGI image"),
};