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FFmpeg4/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 "libavutil/imgutils.h"
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "sgi.h"
typedef struct SgiState {
AVCodecContext *avctx;
unsigned int width;
unsigned int height;
unsigned int depth;
unsigned int bytes_per_channel;
int linesize;
GetByteContext g;
} SgiState;
/**
* Expand an RLE row into a channel.
* @param s the current image state
* @param out_buf Points to one line after the output buffer.
* @param len length of out_buf in bytes
* @param pixelstride pixel stride of input buffer
* @return size of output in bytes, else return error code.
*/
static int expand_rle_row8(SgiState *s, uint8_t *out_buf,
int len, int pixelstride)
{
unsigned char pixel, count;
unsigned char *orig = out_buf;
uint8_t *out_end = out_buf + len;
while (out_buf < out_end) {
if (bytestream2_get_bytes_left(&s->g) < 1)
return AVERROR_INVALIDDATA;
pixel = bytestream2_get_byteu(&s->g);
if (!(count = (pixel & 0x7f))) {
break;
}
/* Check for buffer overflow. */
if (out_end - out_buf <= pixelstride * (count - 1)) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
return AVERROR_INVALIDDATA;
}
if (pixel & 0x80) {
while (count--) {
*out_buf = bytestream2_get_byte(&s->g);
out_buf += pixelstride;
}
} else {
pixel = bytestream2_get_byte(&s->g);
while (count--) {
*out_buf = pixel;
out_buf += pixelstride;
}
}
}
return (out_buf - orig) / pixelstride;
}
static int expand_rle_row16(SgiState *s, uint16_t *out_buf,
int len, int pixelstride)
{
unsigned short pixel;
unsigned char count;
unsigned short *orig = out_buf;
uint16_t *out_end = out_buf + len;
while (out_buf < out_end) {
if (bytestream2_get_bytes_left(&s->g) < 2)
return AVERROR_INVALIDDATA;
pixel = bytestream2_get_be16u(&s->g);
if (!(count = (pixel & 0x7f)))
break;
/* Check for buffer overflow. */
if (out_end - out_buf <= pixelstride * (count - 1)) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
return AVERROR_INVALIDDATA;
}
if (pixel & 0x80) {
while (count--) {
pixel = bytestream2_get_ne16(&s->g);
AV_WN16A(out_buf, pixel);
out_buf += pixelstride;
}
} else {
pixel = bytestream2_get_ne16(&s->g);
while (count--) {
AV_WN16A(out_buf, pixel);
out_buf += pixelstride;
}
}
}
return (out_buf - orig) / pixelstride;
}
/**
* Read a run length encoded SGI image.
* @param out_buf output buffer
* @param s the current image state
* @return 0 if no error, else return error code.
*/
static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
{
uint8_t *dest_row;
unsigned int len = s->height * s->depth * 4;
GetByteContext g_table = s->g;
unsigned int y, z;
unsigned int start_offset;
int linesize, ret;
/* size of RLE offset and length tables */
if (len * 2 > bytestream2_get_bytes_left(&s->g)) {
return AVERROR_INVALIDDATA;
}
for (z = 0; z < s->depth; z++) {
dest_row = out_buf;
for (y = 0; y < s->height; y++) {
linesize = s->width * s->depth;
dest_row -= s->linesize;
start_offset = bytestream2_get_be32(&g_table);
bytestream2_seek(&s->g, start_offset, SEEK_SET);
if (s->bytes_per_channel == 1)
ret = expand_rle_row8(s, dest_row + z, linesize, s->depth);
else
ret = expand_rle_row16(s, (uint16_t *)dest_row + z, linesize, s->depth);
if (ret != s->width)
return AVERROR_INVALIDDATA;
}
}
return 0;
}
/**
* Read an uncompressed SGI image.
* @param out_buf output buffer
* @param s the current image state
* @return 0 if read success, else return error code.
*/
static int read_uncompressed_sgi(unsigned char *out_buf, SgiState *s)
{
int x, y, z;
unsigned int offset = s->height * s->width * s->bytes_per_channel;
GetByteContext gp[4];
uint8_t *out_end;
/* Test buffer size. */
if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
return AVERROR_INVALIDDATA;
/* Create a reader for each plane */
for (z = 0; z < s->depth; z++) {
gp[z] = s->g;
bytestream2_skip(&gp[z], z * offset);
}
for (y = s->height - 1; y >= 0; y--) {
out_end = out_buf + (y * s->linesize);
if (s->bytes_per_channel == 1) {
for (x = s->width; x > 0; x--)
for (z = 0; z < s->depth; z++)
*out_end++ = bytestream2_get_byteu(&gp[z]);
} else {
uint16_t *out16 = (uint16_t *)out_end;
for (x = s->width; x > 0; x--)
for (z = 0; z < s->depth; z++)
*out16++ = bytestream2_get_ne16u(&gp[z]);
}
}
return 0;
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
SgiState *s = avctx->priv_data;
AVFrame *p = data;
unsigned int dimension, rle;
int ret = 0;
uint8_t *out_buf, *out_end;
bytestream2_init(&s->g, avpkt->data, avpkt->size);
if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
return AVERROR_INVALIDDATA;
}
/* Test for SGI magic. */
if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {
av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
return AVERROR_INVALIDDATA;
}
rle = bytestream2_get_byteu(&s->g);
s->bytes_per_channel = bytestream2_get_byteu(&s->g);
dimension = bytestream2_get_be16u(&s->g);
s->width = bytestream2_get_be16u(&s->g);
s->height = bytestream2_get_be16u(&s->g);
s->depth = bytestream2_get_be16u(&s->g);
if (s->bytes_per_channel != 1 && s->bytes_per_channel != 2) {
av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
return AVERROR_INVALIDDATA;
}
/* Check for supported image dimensions. */
if (dimension != 2 && dimension != 3) {
av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
return AVERROR_INVALIDDATA;
}
if (s->depth == SGI_GRAYSCALE) {
avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
} else if (s->depth == SGI_RGB) {
avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
} else if (s->depth == SGI_RGBA) {
avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;
} else {
av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
return AVERROR_INVALIDDATA;
}
ret = ff_set_dimensions(avctx, s->width, s->height);
if (ret < 0)
return ret;
if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
return ret;
p->pict_type = AV_PICTURE_TYPE_I;
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. */
bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
if (rle) {
ret = read_rle_sgi(out_end, s);
} else {
ret = read_uncompressed_sgi(out_buf, s);
}
if (ret)
return ret;
*got_frame = 1;
return avpkt->size;
}
static av_cold int sgi_decode_init(AVCodecContext *avctx)
{
SgiState *s = avctx->priv_data;
s->avctx = avctx;
return 0;
}
AVCodec ff_sgi_decoder = {
.name = "sgi",
.long_name = NULL_IF_CONFIG_SMALL("SGI image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_SGI,
.priv_data_size = sizeof(SgiState),
.decode = decode_frame,
.init = sgi_decode_init,
.capabilities = AV_CODEC_CAP_DR1,
};
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