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ffmpeg/libavformat/sgi.c
Mike Melanson 44f110f509 patch courtesy of Todd Kirby: 
* Fixes a small memory leak in read_rle_sgi()
* Remove temp buffer in read_rle_sgi(). Write rle data directly to image
buffer.
* Adds sanity check to read_rle_sgi() to insure decoded rle data row
equals image width.

Originally committed as revision 2993 to svn://svn.ffmpeg.org/ffmpeg/trunk
2004-04-10 15:09:46 +00:00

456 lines
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/*
* SGI image format
* Todd Kirby <doubleshot@pacbell.net>
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "avformat.h"
#include "avio.h"
/* #define DEBUG */
/* sgi image file signature */
#define SGI_MAGIC 474
#define SGI_HEADER_SIZE 512
#define SGI_GRAYSCALE 1
#define SGI_RGB 3
#define SGI_RGBA 4
#define SGI_SINGLE_CHAN 2
#define SGI_MULTI_CHAN 3
typedef struct SGIInfo{
short magic;
char rle;
char bytes_per_channel;
unsigned short dimension;
unsigned short xsize;
unsigned short ysize;
unsigned short zsize;
} SGIInfo;
static int sgi_probe(AVProbeData *pd)
{
/* test for sgi magic */
if (pd->buf_size >= 2 && BE_16(&pd->buf[0]) == SGI_MAGIC) {
return AVPROBE_SCORE_MAX;
} else {
return 0;
}
}
/* read sgi header fields */
static void read_sgi_header(ByteIOContext *f, SGIInfo *info)
{
info->magic = (unsigned short) get_be16(f);
info->rle = get_byte(f);
info->bytes_per_channel = get_byte(f);
info->dimension = (unsigned short)get_be16(f);
info->xsize = (unsigned short) get_be16(f);
info->ysize = (unsigned short) get_be16(f);
info->zsize = (unsigned short) get_be16(f);
#ifdef DEBUG
printf("sgi header fields:\n");
printf(" magic: %d\n", info->magic);
printf(" rle: %d\n", info->rle);
printf(" bpc: %d\n", info->bytes_per_channel);
printf(" dim: %d\n", info->dimension);
printf(" xsize: %d\n", info->xsize);
printf(" ysize: %d\n", info->ysize);
printf(" zsize: %d\n", info->zsize);
#endif
return;
}
/* read an uncompressed sgi image */
static int read_uncompressed_sgi(const SGIInfo *si,
AVPicture *pict, ByteIOContext *f)
{
int x, y, z, chan_offset, ret = 0;
uint8_t *dest_row;
/* skip header */
url_fseek(f, SGI_HEADER_SIZE, SEEK_SET);
pict->linesize[0] = si->xsize;
for (z = 0; z < si->zsize; z++) {
#ifndef WORDS_BIGENDIAN
/* rgba -> bgra for rgba32 on little endian cpus */
if (si->zsize == 4 && z != 3)
chan_offset = 2 - z;
else
#endif
chan_offset = z;
for (y = si->ysize - 1; y >= 0; y--) {
dest_row = pict->data[0] + (y * si->xsize * si->zsize);
for (x = 0; x < si->xsize; x++) {
dest_row[chan_offset] = get_byte(f);
dest_row += si->zsize;
}
}
}
return ret;
}
/* expand an rle row into a channel */
static int expand_rle_row(ByteIOContext *f, unsigned char *optr,
int chan_offset, int pixelstride)
{
unsigned char pixel, count;
int length = 0;
#ifndef WORDS_BIGENDIAN
/* rgba -> bgra for rgba32 on little endian cpus */
if (pixelstride == 4 && chan_offset != 3) {
chan_offset = 2 - chan_offset;
}
#endif
optr += chan_offset;
while (1) {
pixel = get_byte(f);
if (!(count = (pixel & 0x7f))) {
return length;
}
if (pixel & 0x80) {
while (count--) {
*optr = get_byte(f);
length++;
optr += pixelstride;
}
} else {
pixel = get_byte(f);
while (count--) {
*optr = pixel;
length++;
optr += pixelstride;
}
}
}
}
/* read a run length encoded sgi image */
static int read_rle_sgi(const SGIInfo *sgi_info,
AVPicture *pict, ByteIOContext *f)
{
uint8_t *dest_row;
unsigned long *start_table;
int y, z, xsize, ysize, zsize, tablen;
long start_offset;
int ret = 0;
xsize = sgi_info->xsize;
ysize = sgi_info->ysize;
zsize = sgi_info->zsize;
/* skip header */
url_fseek(f, SGI_HEADER_SIZE, SEEK_SET);
/* size of rle offset and length tables */
tablen = ysize * zsize * sizeof(long);
start_table = (unsigned long *)av_malloc(tablen);
if (!get_buffer(f, (uint8_t *)start_table, tablen)) {
ret = AVERROR_IO;
goto fail;
}
/* skip run length table */
url_fseek(f, tablen, SEEK_CUR);
for (z = 0; z < zsize; z++) {
for (y = 0; y < ysize; y++) {
dest_row = pict->data[0] + (ysize - 1 - y) * (xsize * zsize);
start_offset = BE_32(&start_table[y + z * ysize]);
/* don't seek if already at the next rle start offset */
if (url_ftell(f) != start_offset) {
url_fseek(f, start_offset, SEEK_SET);
}
if (expand_rle_row(f, dest_row, z, zsize) != xsize) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
}
}
fail:
av_free(start_table);
return ret;
}
static int sgi_read(ByteIOContext *f,
int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
{
SGIInfo sgi_info, *s = &sgi_info;
AVImageInfo info1, *info = &info1;
int ret;
read_sgi_header(f, s);
if (s->bytes_per_channel != 1) {
return AVERROR_INVALIDDATA;
}
/* check for supported image dimensions */
if (s->dimension != 2 && s->dimension != 3) {
return AVERROR_INVALIDDATA;
}
if (s->zsize == SGI_GRAYSCALE) {
info->pix_fmt = PIX_FMT_GRAY8;
} else if (s->zsize == SGI_RGB) {
info->pix_fmt = PIX_FMT_RGB24;
} else if (s->zsize == SGI_RGBA) {
info->pix_fmt = PIX_FMT_RGBA32;
} else {
return AVERROR_INVALIDDATA;
}
info->width = s->xsize;
info->height = s->ysize;
ret = alloc_cb(opaque, info);
if (ret)
return ret;
if (s->rle) {
return read_rle_sgi(s, &info->pict, f);
} else {
return read_uncompressed_sgi(s, &info->pict, f);
}
return 0; /* not reached */
}
#ifdef CONFIG_ENCODERS
static void write_sgi_header(ByteIOContext *f, const SGIInfo *info)
{
int i;
put_be16(f, SGI_MAGIC);
put_byte(f, info->rle);
put_byte(f, info->bytes_per_channel);
put_be16(f, info->dimension);
put_be16(f, info->xsize);
put_be16(f, info->ysize);
put_be16(f, info->zsize);
/* The rest are constant in this implementation */
put_be32(f, 0L); /* pixmin */
put_be32(f, 255L); /* pixmax */
put_be32(f, 0L); /* dummy */
/* name */
for (i = 0; i < 80; i++) {
put_byte(f, 0);
}
put_be32(f, 0L); /* colormap */
/* The rest of the 512 byte header is unused. */
for (i = 0; i < 404; i++) {
put_byte(f, 0);
}
}
static int rle_row(ByteIOContext *f, char *row, int stride, int rowsize)
{
int length, count, i, x;
char *start, repeat = 0;
for (x = rowsize, length = 0; x > 0;) {
start = row;
row += (2 * stride);
x -= 2;
while (x > 0 && (row[-2 * stride] != row[-1 * stride] ||
row[-1 * stride] != row[0])) {
row += stride;
x--;
};
row -= (2 * stride);
x += 2;
count = (row - start) / stride;
while (count > 0) {
i = count > 126 ? 126 : count;
count -= i;
put_byte(f, 0x80 | i);
length++;
while (i > 0) {
put_byte(f, *start);
start += stride;
i--;
length++;
};
};
if (x <= 0) {
break;
}
start = row;
repeat = row[0];
row += stride;
x--;
while (x > 0 && *row == repeat) {
row += stride;
x--;
};
count = (row - start) / stride;
while (count > 0) {
i = count > 126 ? 126 : count;
count -= i;
put_byte(f, i);
length++;
put_byte(f, repeat);
length++;
};
};
length++;
put_byte(f, 0);
return (length);
}
static int sgi_write(ByteIOContext *pb, AVImageInfo *info)
{
SGIInfo sgi_info, *si = &sgi_info;
long *offsettab, *lengthtab;
int i, y, z;
int tablesize, chan_offset;
uint8_t *srcrow;
si->xsize = info->width;
si->ysize = info->height;
si->rle = 1;
si->bytes_per_channel = 1;
switch(info->pix_fmt) {
case PIX_FMT_GRAY8:
si->dimension = SGI_SINGLE_CHAN;
si->zsize = SGI_GRAYSCALE;
break;
case PIX_FMT_RGB24:
si->dimension = SGI_MULTI_CHAN;
si->zsize = SGI_RGB;
break;
case PIX_FMT_RGBA32:
si->dimension = SGI_MULTI_CHAN;
si->zsize = SGI_RGBA;
break;
default:
return AVERROR_INVALIDDATA;
}
write_sgi_header(pb, si);
tablesize = si->zsize * si->ysize * sizeof(long);
/* skip rle offset and length tables, write them at the end. */
url_fseek(pb, tablesize * 2, SEEK_CUR);
put_flush_packet(pb);
lengthtab = av_malloc(tablesize);
offsettab = av_malloc(tablesize);
for (z = 0; z < si->zsize; z++) {
#ifndef WORDS_BIGENDIAN
/* rgba -> bgra for rgba32 on little endian cpus */
if (si->zsize == 4 && z != 3)
chan_offset = 2 - z;
else
#endif
chan_offset = z;
srcrow = info->pict.data[0] + chan_offset;
for (y = si->ysize -1; y >= 0; y--) {
offsettab[(z * si->ysize) + y] = url_ftell(pb);
lengthtab[(z * si->ysize) + y] = rle_row(pb, srcrow,
si->zsize, si->xsize);
srcrow += info->pict.linesize[0];
}
}
url_fseek(pb, 512, SEEK_SET);
/* write offset table */
for (i = 0; i < (si->ysize * si->zsize); i++) {
put_be32(pb, offsettab[i]);
}
/* write length table */
for (i = 0; i < (si->ysize * si->zsize); i++) {
put_be32(pb, lengthtab[i]);
}
put_flush_packet(pb);
av_free(lengthtab);
av_free(offsettab);
return 0;
}
#endif // CONFIG_ENCODERS
AVImageFormat sgi_image_format = {
"sgi",
"sgi,rgb,rgba,bw",
sgi_probe,
sgi_read,
(1 << PIX_FMT_GRAY8) | (1 << PIX_FMT_RGB24) | (1 << PIX_FMT_RGBA32),
#ifdef CONFIG_ENCODERS
sgi_write,
#else
NULL,
#endif // CONFIG_ENCODERS
};
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