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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 "codec_internal.h"
#include "decode.h"
#include "sgi.h"
/**
* Expand an RLE row into a channel.
* @param logctx a logcontext
* @param out_buf Points to one line after the output buffer.
* @param g GetByteContext used to read input from
* @param width length of out_buf in nb of elements
* @return nb of elements written, else return error code.
*/
static int expand_rle_row8(void *logctx, uint8_t *out_buf,
GetByteContext *g, unsigned width)
{
unsigned char pixel, count;
unsigned char *orig = out_buf;
uint8_t *out_end = out_buf + width;
while (out_buf < out_end) {
if (bytestream2_get_bytes_left(g) < 1)
return AVERROR_INVALIDDATA;
pixel = bytestream2_get_byteu(g);
if (!(count = (pixel & 0x7f))) {
break;
}
/* Check for buffer overflow. */
if (out_end - out_buf < count) {
av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
return AVERROR_INVALIDDATA;
}
if (pixel & 0x80) {
while (count--)
*out_buf++ = bytestream2_get_byte(g);
} else {
pixel = bytestream2_get_byte(g);
while (count--)
*out_buf++ = pixel;
}
}
return out_buf - orig;
}
static int expand_rle_row16(void *logctx, uint16_t *out_buf,
GetByteContext *g, unsigned width)
{
unsigned short pixel;
unsigned char count;
unsigned short *orig = out_buf;
uint16_t *out_end = out_buf + width;
while (out_buf < out_end) {
if (bytestream2_get_bytes_left(g) < 2)
return AVERROR_INVALIDDATA;
pixel = bytestream2_get_be16u(g);
if (!(count = (pixel & 0x7f)))
break;
/* Check for buffer overflow. */
if (out_end - out_buf < count) {
av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
return AVERROR_INVALIDDATA;
}
if (pixel & 0x80) {
while (count--) {
pixel = bytestream2_get_ne16(g);
AV_WN16A(out_buf, pixel);
out_buf++;
}
} else {
pixel = bytestream2_get_ne16(g);
while (count--) {
AV_WN16A(out_buf, pixel);
out_buf++;
}
}
}
return out_buf - orig;
}
/**
* 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(void *logctx, uint8_t *out[4], ptrdiff_t stride[4],
GetByteContext *g, unsigned width, int height,
unsigned nb_components, unsigned bytes_per_channel)
{
unsigned int len = height * nb_components * 4;
GetByteContext g_table = *g;
unsigned int start_offset;
int ret;
/* size of RLE offset and length tables */
if (len * 2 > bytestream2_get_bytes_left(g)) {
return AVERROR_INVALIDDATA;
}
for (unsigned z = 0; z < nb_components; z++) {
uint8_t *dest_row = out[z] + (height - 1) * stride[z];
while (1) {
start_offset = bytestream2_get_be32(&g_table);
bytestream2_seek(g, start_offset, SEEK_SET);
if (bytes_per_channel == 1)
ret = expand_rle_row8(logctx, dest_row, g, width);
else
ret = expand_rle_row16(logctx, (uint16_t *)dest_row, g, width);
if (ret != width)
return AVERROR_INVALIDDATA;
if (dest_row == out[z])
break;
dest_row -= stride[z];
}
}
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(uint8_t *const out[4], const ptrdiff_t stride[4],
GetByteContext *g, unsigned width, int height,
unsigned nb_components, unsigned bytes_per_channel)
{
unsigned rowsize = width * bytes_per_channel;
/* Test buffer size. */
if (rowsize * (int64_t)height * nb_components > bytestream2_get_bytes_left(g))
return AVERROR_INVALIDDATA;
for (unsigned z = 0; z < nb_components; z++) {
uint8_t *cur_row = out[z] + (height - 1) * stride[z];
while (1) {
bytestream2_get_bufferu(g, cur_row, rowsize);
if (cur_row == out[z])
break;
cur_row -= stride[z];
}
}
return 0;
}
static int decode_frame(AVCodecContext *avctx, AVFrame *p,
int *got_frame, AVPacket *avpkt)
{
GetByteContext g;
unsigned int bytes_per_channel, nb_components, dimension, rle, width;
uint8_t *out[4];
ptrdiff_t linesize[4];
int height;
int ret = 0;
bytestream2_init(&g, avpkt->data, avpkt->size);
if (bytestream2_get_bytes_left(&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(&g) != SGI_MAGIC) {
av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
return AVERROR_INVALIDDATA;
}
rle = bytestream2_get_byteu(&g);
bytes_per_channel = bytestream2_get_byteu(&g);
dimension = bytestream2_get_be16u(&g);
width = bytestream2_get_be16u(&g);
height = bytestream2_get_be16u(&g);
nb_components = bytestream2_get_be16u(&g);
if (bytes_per_channel != 1 && 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 (nb_components == SGI_GRAYSCALE) {
avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
} else if (nb_components == SGI_RGB) {
avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRP16BE : AV_PIX_FMT_GBRP;
} else if (nb_components == SGI_RGBA) {
avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRAP16BE : AV_PIX_FMT_GBRAP;
} else {
av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
return AVERROR_INVALIDDATA;
}
ret = ff_set_dimensions(avctx, width, height);
if (ret < 0)
return ret;
if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
return ret;
switch (nb_components) {
#define MAP(in_idx, out_idx) \
out[(in_idx)] = p->data[(out_idx)]; \
linesize[(in_idx)] = p->linesize[(out_idx)]
case SGI_GRAYSCALE:
MAP(0, 0);
break;
case SGI_RGBA:
MAP(3, 3);
/* fallthrough */
case SGI_RGB:
MAP(0, 2);
MAP(1, 0);
MAP(2, 1);
break;
}
p->pict_type = AV_PICTURE_TYPE_I;
p->flags |= AV_FRAME_FLAG_KEY;
/* Skip header. */
bytestream2_seek(&g, SGI_HEADER_SIZE, SEEK_SET);
if (rle) {
ret = read_rle_sgi(avctx, out, linesize, &g,
width, height, nb_components, bytes_per_channel);
} else {
ret = read_uncompressed_sgi(out, linesize, &g,
width, height, nb_components, bytes_per_channel);
}
if (ret)
return ret;
*got_frame = 1;
return avpkt->size;
}
const FFCodec ff_sgi_decoder = {
.p.name = "sgi",
CODEC_LONG_NAME("SGI image"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_SGI,
FF_CODEC_DECODE_CB(decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
};
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