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FFmpeg/libavformat/png.c

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/*
* PNG image format
* Copyright (c) 2003 Fabrice Bellard.
*
* 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 <zlib.h>
//#define DEBUG
#define PNG_COLOR_MASK_PALETTE 1
#define PNG_COLOR_MASK_COLOR 2
#define PNG_COLOR_MASK_ALPHA 4
#define PNG_COLOR_TYPE_GRAY 0
#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
#define PNG_FILTER_VALUE_NONE 0
#define PNG_FILTER_VALUE_SUB 1
#define PNG_FILTER_VALUE_UP 2
#define PNG_FILTER_VALUE_AVG 3
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_IHDR 0x0001
#define PNG_IDAT 0x0002
#define PNG_ALLIMAGE 0x0004
#define IOBUF_SIZE 4096
typedef struct PNGDecodeState {
int state;
int width, height;
int bit_depth;
int color_type;
int compression_type;
int interlace_type;
int filter_type;
int channels;
int bits_per_pixel;
int bpp;
uint8_t *image_buf;
int image_linesize;
uint8_t *crow_buf;
uint8_t *empty_row;
int crow_size; /* compressed row size (include filter type) */
int row_size; /* decompressed row size */
int y;
z_stream zstream;
} PNGDecodeState;
const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
static int png_probe(AVProbeData *pd)
{
if (pd->buf_size >= 8 &&
memcmp(pd->buf, pngsig, 8) == 0)
return AVPROBE_SCORE_MAX;
else
return 0;
}
void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
{
return av_malloc(items * size);
}
void png_zfree(void *opaque, void *ptr)
{
av_free(ptr);
}
/* XXX: optimize */
static void png_filter_row(uint8_t *dst, int filter_type,
uint8_t *src, uint8_t *last, int size, int bpp)
{
int i, p;
switch(filter_type) {
case PNG_FILTER_VALUE_NONE:
memcpy(dst, src, size);
break;
case PNG_FILTER_VALUE_SUB:
for(i = 0; i < bpp; i++) {
dst[i] = src[i];
}
for(i = bpp; i < size; i++) {
p = dst[i - bpp];
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_UP:
for(i = 0; i < size; i++) {
p = last[i];
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_AVG:
for(i = 0; i < bpp; i++) {
p = (last[i] >> 1);
dst[i] = p + src[i];
}
for(i = bpp; i < size; i++) {
p = ((dst[i - bpp] + last[i]) >> 1);
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_PAETH:
for(i = 0; i < bpp; i++) {
p = last[i];
dst[i] = p + src[i];
}
for(i = bpp; i < size; i++) {
int a, b, c, pa, pb, pc;
a = dst[i - bpp];
b = last[i];
c = last[i - bpp];
p = b - c;
pc = a - c;
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
if (pa <= pb && pa <= pc)
p = a;
else if (pb <= pc)
p = b;
else
p = c;
dst[i] = p + src[i];
}
break;
}
}
static void png_handle_row(PNGDecodeState *s)
{
uint8_t *ptr, *last_row;
ptr = s->image_buf + s->image_linesize * s->y;
if (s->y == 0)
last_row = s->empty_row;
else
last_row = ptr - s->image_linesize;
png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
last_row, s->row_size, s->bpp);
}
static int png_decode_idat(PNGDecodeState *s, ByteIOContext *f, int length)
{
uint8_t buf[IOBUF_SIZE];
int buf_size;
int ret;
while (length > 0) {
/* read the buffer */
buf_size = IOBUF_SIZE;
if (buf_size > length)
buf_size = length;
ret = get_buffer(f, buf, buf_size);
if (ret != buf_size)
return -1;
s->zstream.avail_in = buf_size;
s->zstream.next_in = buf;
/* decode one line if possible */
while (s->zstream.avail_in > 0) {
ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END) {
return -1;
}
if (s->zstream.avail_out == 0) {
if (s->y < s->height) {
png_handle_row(s);
s->y++;
if (s->y == s->height)
s->state |= PNG_ALLIMAGE;
}
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
}
}
length -= buf_size;
}
return 0;
}
static int png_read(ByteIOContext *f,
int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
{
AVImageInfo info1, *info = &info1;
PNGDecodeState s1, *s = &s1;
uint32_t tag, length;
int ret, crc;
uint8_t buf[8];
/* check signature */
ret = get_buffer(f, buf, 8);
if (ret != 8)
return -1;
if (memcmp(buf, pngsig, 8) != 0)
return -1;
memset(s, 0, sizeof(PNGDecodeState));
/* init the zlib */
s->zstream.zalloc = png_zalloc;
s->zstream.zfree = png_zfree;
s->zstream.opaque = NULL;
ret = inflateInit(&s->zstream);
if (ret != Z_OK)
return -1;
for(;;) {
if (url_feof(f))
goto fail;
length = get_be32(f);
if (length > 0x7fffffff)
goto fail;
tag = get_le32(f);
#ifdef DEBUG
printf("png: tag=%c%c%c%c length=%u\n",
(tag & 0xff),
((tag >> 8) & 0xff),
((tag >> 16) & 0xff),
((tag >> 24) & 0xff), length);
#endif
switch(tag) {
case MKTAG('I', 'H', 'D', 'R'):
if (length != 13)
goto fail;
s->width = get_be32(f);
s->height = get_be32(f);
s->bit_depth = get_byte(f);
s->color_type = get_byte(f);
s->compression_type = get_byte(f);
s->filter_type = get_byte(f);
s->interlace_type = get_byte(f);
crc = get_be32(f);
s->state |= PNG_IHDR;
#ifdef DEBUG
printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
s->width, s->height, s->bit_depth, s->color_type,
s->compression_type, s->filter_type, s->interlace_type);
#endif
break;
case MKTAG('I', 'D', 'A', 'T'):
if (!(s->state & PNG_IHDR))
goto fail;
if (!(s->state & PNG_IDAT)) {
/* init image info */
info->width = s->width;
info->height = s->height;
s->channels = 1;
if ((s->color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
PNG_COLOR_MASK_COLOR)
s->channels = 3;
if (s->color_type & PNG_COLOR_MASK_ALPHA)
s->channels++;
s->bits_per_pixel = s->bit_depth * s->channels;
s->bpp = (s->bits_per_pixel + 7) >> 3;
if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_RGB) {
info->pix_fmt = PIX_FMT_RGB24;
s->row_size = s->width * 3;
} else if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
info->pix_fmt = PIX_FMT_GRAY8;
s->row_size = s->width;
} else if (s->bit_depth == 1 &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
info->pix_fmt = PIX_FMT_MONOBLACK;
s->row_size = (s->width + 7) >> 3;
} else {
goto fail;
}
/* compute the compressed row size */
if (!s->interlace_type) {
s->crow_size = s->row_size + 1;
} else {
/* XXX: handle interlacing */
goto fail;
}
ret = alloc_cb(opaque, info);
if (ret)
goto the_end;
#ifdef DEBUG
printf("row_size=%d crow_size =%d\n",
s->row_size, s->crow_size);
#endif
s->image_buf = info->pict.data[0];
s->image_linesize = info->pict.linesize[0];
/* empty row is used if differencing to the first row */
s->empty_row = av_mallocz(s->row_size);
if (!s->empty_row)
goto fail;
/* compressed row */
s->crow_buf = av_malloc(s->crow_size);
if (!s->crow_buf)
goto fail;
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
}
s->state |= PNG_IDAT;
if (png_decode_idat(s, f, length) < 0)
goto fail;
/* skip crc */
crc = get_be32(f);
break;
case MKTAG('I', 'E', 'N', 'D'):
if (!(s->state & PNG_ALLIMAGE))
goto fail;
crc = get_be32(f);
goto exit_loop;
default:
/* skip tag */
url_fskip(f, length + 4);
break;
}
}
exit_loop:
ret = 0;
the_end:
inflateEnd(&s->zstream);
av_free(s->crow_buf);
return ret;
fail:
ret = -1;
goto the_end;
}
static void png_write_chunk(ByteIOContext *f, uint32_t tag,
const uint8_t *buf, int length)
{
uint32_t crc;
uint8_t tagbuf[4];
put_be32(f, length);
crc = crc32(0, Z_NULL, 0);
tagbuf[0] = tag;
tagbuf[1] = tag >> 8;
tagbuf[2] = tag >> 16;
tagbuf[3] = tag >> 24;
crc = crc32(crc, tagbuf, 4);
put_le32(f, tag);
if (length > 0) {
crc = crc32(crc, buf, length);
put_buffer(f, buf, length);
}
put_be32(f, crc);
}
/* XXX: use avcodec generic function ? */
static void to_be32(uint8_t *p, uint32_t v)
{
p[0] = v >> 24;
p[1] = v >> 16;
p[2] = v >> 8;
p[3] = v;
}
static int png_write(ByteIOContext *f, AVImageInfo *info)
{
int bit_depth, color_type, y, len, row_size, ret;
uint8_t *ptr;
uint8_t buf[IOBUF_SIZE];
uint8_t *crow_buf = NULL;
z_stream zstream;
switch(info->pix_fmt) {
case PIX_FMT_RGB24:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB;
row_size = info->width * 3;
break;
case PIX_FMT_GRAY8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY;
row_size = info->width;
break;
case PIX_FMT_MONOBLACK:
bit_depth = 1;
color_type = PNG_COLOR_TYPE_GRAY;
row_size = (info->width + 7) >> 3;
break;
default:
return -1;
}
zstream.zalloc = png_zalloc;
zstream.zfree = png_zfree;
zstream.opaque = NULL;
ret = deflateInit2(&zstream, Z_DEFAULT_COMPRESSION,
Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
return -1;
crow_buf = av_malloc(row_size + 1);
if (!crow_buf)
goto fail;
/* write png header */
put_buffer(f, pngsig, 8);
to_be32(buf, info->width);
to_be32(buf + 4, info->height);
buf[8] = bit_depth;
buf[9] = color_type;
buf[10] = 0; /* compression type */
buf[11] = 0; /* filter type */
buf[12] = 0; /* interlace type */
png_write_chunk(f, MKTAG('I', 'H', 'D', 'R'), buf, 13);
/* now put each row */
zstream.avail_out = IOBUF_SIZE;
zstream.next_out = buf;
for(y = 0;y < info->height; y++) {
/* XXX: do filtering */
ptr = info->pict.data[0] + y * info->pict.linesize[0];
memcpy(crow_buf + 1, ptr, row_size);
crow_buf[0] = PNG_FILTER_VALUE_NONE;
zstream.avail_in = row_size + 1;
zstream.next_in = crow_buf;
while (zstream.avail_in > 0) {
ret = deflate(&zstream, Z_NO_FLUSH);
if (ret != Z_OK)
goto fail;
if (zstream.avail_out == 0) {
png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), buf, IOBUF_SIZE);
zstream.avail_out = IOBUF_SIZE;
zstream.next_out = buf;
}
}
}
/* compress last bytes */
for(;;) {
ret = deflate(&zstream, Z_FINISH);
if (ret == Z_OK || ret == Z_STREAM_END) {
len = IOBUF_SIZE - zstream.avail_out;
if (len > 0) {
png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), buf, len);
}
zstream.avail_out = IOBUF_SIZE;
zstream.next_out = buf;
if (ret == Z_STREAM_END)
break;
} else {
goto fail;
}
}
png_write_chunk(f, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
put_flush_packet(f);
ret = 0;
the_end:
av_free(crow_buf);
deflateEnd(&zstream);
return ret;
fail:
ret = -1;
goto the_end;
}
AVImageFormat png_image_format = {
"png",
"png",
png_probe,
png_read,
(1 << PIX_FMT_RGB24) | (1 << PIX_FMT_GRAY8) | (1 << PIX_FMT_MONOBLACK),
png_write,
};