mirror of
https://git.ffmpeg.org/ffmpeg.git
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566 lines
16 KiB
C
566 lines
16 KiB
C
/*
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* PNG image format
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* Copyright (c) 2003 Fabrice Bellard.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "avformat.h"
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#include <zlib.h>
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//#define DEBUG
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#define PNG_COLOR_MASK_PALETTE 1
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#define PNG_COLOR_MASK_COLOR 2
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#define PNG_COLOR_MASK_ALPHA 4
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#define PNG_COLOR_TYPE_GRAY 0
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#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
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#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
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#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
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#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
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#define PNG_FILTER_VALUE_NONE 0
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#define PNG_FILTER_VALUE_SUB 1
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#define PNG_FILTER_VALUE_UP 2
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#define PNG_FILTER_VALUE_AVG 3
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#define PNG_FILTER_VALUE_PAETH 4
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#define PNG_IHDR 0x0001
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#define PNG_IDAT 0x0002
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#define PNG_ALLIMAGE 0x0004
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#define PNG_PLTE 0x0008
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#define IOBUF_SIZE 4096
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typedef struct PNGDecodeState {
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int state;
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int width, height;
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int bit_depth;
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int color_type;
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int compression_type;
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int interlace_type;
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int filter_type;
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int channels;
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int bits_per_pixel;
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int bpp;
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uint8_t *image_buf;
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int image_linesize;
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uint32_t palette[256];
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uint8_t *crow_buf;
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uint8_t *empty_row;
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int crow_size; /* compressed row size (include filter type) */
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int row_size; /* decompressed row size */
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int y;
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z_stream zstream;
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} PNGDecodeState;
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static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
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static int png_probe(AVProbeData *pd)
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{
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if (pd->buf_size >= 8 &&
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memcmp(pd->buf, pngsig, 8) == 0)
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return AVPROBE_SCORE_MAX;
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else
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return 0;
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}
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static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
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{
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return av_malloc(items * size);
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}
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static void png_zfree(void *opaque, void *ptr)
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{
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av_free(ptr);
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}
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/* XXX: optimize */
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static void png_filter_row(uint8_t *dst, int filter_type,
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uint8_t *src, uint8_t *last, int size, int bpp)
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{
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int i, p;
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switch(filter_type) {
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case PNG_FILTER_VALUE_NONE:
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memcpy(dst, src, size);
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break;
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case PNG_FILTER_VALUE_SUB:
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for(i = 0; i < bpp; i++) {
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dst[i] = src[i];
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}
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for(i = bpp; i < size; i++) {
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p = dst[i - bpp];
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dst[i] = p + src[i];
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}
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break;
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case PNG_FILTER_VALUE_UP:
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for(i = 0; i < size; i++) {
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p = last[i];
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dst[i] = p + src[i];
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}
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break;
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case PNG_FILTER_VALUE_AVG:
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for(i = 0; i < bpp; i++) {
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p = (last[i] >> 1);
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dst[i] = p + src[i];
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}
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for(i = bpp; i < size; i++) {
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p = ((dst[i - bpp] + last[i]) >> 1);
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dst[i] = p + src[i];
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}
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break;
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case PNG_FILTER_VALUE_PAETH:
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for(i = 0; i < bpp; i++) {
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p = last[i];
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dst[i] = p + src[i];
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}
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for(i = bpp; i < size; i++) {
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int a, b, c, pa, pb, pc;
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a = dst[i - bpp];
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b = last[i];
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c = last[i - bpp];
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p = b - c;
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pc = a - c;
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pa = abs(p);
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pb = abs(pc);
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pc = abs(p + pc);
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if (pa <= pb && pa <= pc)
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p = a;
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else if (pb <= pc)
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p = b;
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else
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p = c;
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dst[i] = p + src[i];
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}
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break;
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}
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}
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static void png_handle_row(PNGDecodeState *s)
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{
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uint8_t *ptr, *last_row;
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ptr = s->image_buf + s->image_linesize * s->y;
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if (s->y == 0)
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last_row = s->empty_row;
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else
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last_row = ptr - s->image_linesize;
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png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
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last_row, s->row_size, s->bpp);
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}
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static int png_decode_idat(PNGDecodeState *s, ByteIOContext *f, int length)
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{
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uint8_t buf[IOBUF_SIZE];
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int buf_size;
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int ret;
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while (length > 0) {
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/* read the buffer */
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buf_size = IOBUF_SIZE;
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if (buf_size > length)
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buf_size = length;
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ret = get_buffer(f, buf, buf_size);
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if (ret != buf_size)
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return -1;
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s->zstream.avail_in = buf_size;
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s->zstream.next_in = buf;
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/* decode one line if possible */
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while (s->zstream.avail_in > 0) {
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ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END) {
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return -1;
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}
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if (s->zstream.avail_out == 0) {
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if (s->y < s->height) {
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png_handle_row(s);
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s->y++;
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if (s->y == s->height)
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s->state |= PNG_ALLIMAGE;
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}
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s->zstream.avail_out = s->crow_size;
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s->zstream.next_out = s->crow_buf;
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}
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}
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length -= buf_size;
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}
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return 0;
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}
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static int png_read(ByteIOContext *f,
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int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
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{
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AVImageInfo info1, *info = &info1;
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PNGDecodeState s1, *s = &s1;
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uint32_t tag, length;
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int ret, crc;
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uint8_t buf[8];
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/* check signature */
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ret = get_buffer(f, buf, 8);
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if (ret != 8)
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return -1;
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if (memcmp(buf, pngsig, 8) != 0)
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return -1;
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memset(s, 0, sizeof(PNGDecodeState));
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/* init the zlib */
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s->zstream.zalloc = png_zalloc;
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s->zstream.zfree = png_zfree;
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s->zstream.opaque = NULL;
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ret = inflateInit(&s->zstream);
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if (ret != Z_OK)
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return -1;
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for(;;) {
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if (url_feof(f))
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goto fail;
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length = get_be32(f);
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if (length > 0x7fffffff)
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goto fail;
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tag = get_le32(f);
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#ifdef DEBUG
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printf("png: tag=%c%c%c%c length=%u\n",
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(tag & 0xff),
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((tag >> 8) & 0xff),
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((tag >> 16) & 0xff),
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((tag >> 24) & 0xff), length);
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#endif
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switch(tag) {
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case MKTAG('I', 'H', 'D', 'R'):
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if (length != 13)
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goto fail;
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s->width = get_be32(f);
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s->height = get_be32(f);
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s->bit_depth = get_byte(f);
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s->color_type = get_byte(f);
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s->compression_type = get_byte(f);
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s->filter_type = get_byte(f);
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s->interlace_type = get_byte(f);
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crc = get_be32(f);
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s->state |= PNG_IHDR;
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#ifdef DEBUG
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printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
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s->width, s->height, s->bit_depth, s->color_type,
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s->compression_type, s->filter_type, s->interlace_type);
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#endif
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break;
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case MKTAG('I', 'D', 'A', 'T'):
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if (!(s->state & PNG_IHDR))
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goto fail;
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if (!(s->state & PNG_IDAT)) {
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/* init image info */
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info->width = s->width;
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info->height = s->height;
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s->channels = 1;
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if ((s->color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
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PNG_COLOR_MASK_COLOR)
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s->channels = 3;
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if (s->color_type & PNG_COLOR_MASK_ALPHA)
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s->channels++;
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s->bits_per_pixel = s->bit_depth * s->channels;
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s->bpp = (s->bits_per_pixel + 7) >> 3;
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if (s->bit_depth == 8 &&
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s->color_type == PNG_COLOR_TYPE_RGB) {
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info->pix_fmt = PIX_FMT_RGB24;
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s->row_size = s->width * 3;
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} else if (s->bit_depth == 8 &&
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s->color_type == PNG_COLOR_TYPE_GRAY) {
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info->pix_fmt = PIX_FMT_GRAY8;
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s->row_size = s->width;
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} else if (s->bit_depth == 1 &&
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s->color_type == PNG_COLOR_TYPE_GRAY) {
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info->pix_fmt = PIX_FMT_MONOBLACK;
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s->row_size = (s->width + 7) >> 3;
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} else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
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info->pix_fmt = PIX_FMT_PAL8;
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s->row_size = s->width;;
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} else {
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goto fail;
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}
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/* compute the compressed row size */
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if (!s->interlace_type) {
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s->crow_size = s->row_size + 1;
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} else {
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/* XXX: handle interlacing */
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goto fail;
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}
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ret = alloc_cb(opaque, info);
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if (ret)
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goto the_end;
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#ifdef DEBUG
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printf("row_size=%d crow_size =%d\n",
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s->row_size, s->crow_size);
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#endif
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s->image_buf = info->pict.data[0];
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s->image_linesize = info->pict.linesize[0];
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/* copy the palette if needed */
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if (s->color_type == PNG_COLOR_TYPE_PALETTE)
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memcpy(info->pict.data[1], s->palette, 256 * sizeof(uint32_t));
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/* empty row is used if differencing to the first row */
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s->empty_row = av_mallocz(s->row_size);
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if (!s->empty_row)
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goto fail;
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/* compressed row */
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s->crow_buf = av_malloc(s->crow_size);
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if (!s->crow_buf)
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goto fail;
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s->zstream.avail_out = s->crow_size;
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s->zstream.next_out = s->crow_buf;
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}
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s->state |= PNG_IDAT;
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if (png_decode_idat(s, f, length) < 0)
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goto fail;
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/* skip crc */
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crc = get_be32(f);
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break;
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case MKTAG('P', 'L', 'T', 'E'):
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{
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int n, i, r, g, b;
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if ((length % 3) != 0 || length > 256 * 3)
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goto skip_tag;
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/* read the palette */
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n = length / 3;
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for(i=0;i<n;i++) {
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r = get_byte(f);
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g = get_byte(f);
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b = get_byte(f);
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s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
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}
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for(;i<256;i++) {
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s->palette[i] = (0xff << 24);
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}
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s->state |= PNG_PLTE;
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crc = get_be32(f);
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}
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break;
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case MKTAG('t', 'R', 'N', 'S'):
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{
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int v, i;
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/* read the transparency. XXX: Only palette mode supported */
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if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
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length > 256 ||
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!(s->state & PNG_PLTE))
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goto skip_tag;
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for(i=0;i<length;i++) {
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v = get_byte(f);
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s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
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}
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crc = get_be32(f);
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}
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break;
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case MKTAG('I', 'E', 'N', 'D'):
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if (!(s->state & PNG_ALLIMAGE))
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goto fail;
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crc = get_be32(f);
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goto exit_loop;
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default:
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/* skip tag */
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skip_tag:
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url_fskip(f, length + 4);
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break;
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}
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}
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exit_loop:
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ret = 0;
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the_end:
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inflateEnd(&s->zstream);
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av_free(s->crow_buf);
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return ret;
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fail:
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ret = -1;
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goto the_end;
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}
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static void png_write_chunk(ByteIOContext *f, uint32_t tag,
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const uint8_t *buf, int length)
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{
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uint32_t crc;
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uint8_t tagbuf[4];
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put_be32(f, length);
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crc = crc32(0, Z_NULL, 0);
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tagbuf[0] = tag;
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tagbuf[1] = tag >> 8;
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tagbuf[2] = tag >> 16;
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tagbuf[3] = tag >> 24;
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crc = crc32(crc, tagbuf, 4);
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put_le32(f, tag);
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if (length > 0) {
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crc = crc32(crc, buf, length);
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put_buffer(f, buf, length);
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}
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put_be32(f, crc);
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}
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|
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/* XXX: use avcodec generic function ? */
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static void to_be32(uint8_t *p, uint32_t v)
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{
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p[0] = v >> 24;
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p[1] = v >> 16;
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p[2] = v >> 8;
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p[3] = v;
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}
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|
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static int png_write(ByteIOContext *f, AVImageInfo *info)
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{
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int bit_depth, color_type, y, len, row_size, ret;
|
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uint8_t *ptr;
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uint8_t buf[IOBUF_SIZE];
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uint8_t *crow_buf = NULL;
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z_stream zstream;
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|
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switch(info->pix_fmt) {
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case PIX_FMT_RGB24:
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bit_depth = 8;
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color_type = PNG_COLOR_TYPE_RGB;
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row_size = info->width * 3;
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break;
|
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case PIX_FMT_GRAY8:
|
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bit_depth = 8;
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color_type = PNG_COLOR_TYPE_GRAY;
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row_size = info->width;
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break;
|
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case PIX_FMT_MONOBLACK:
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bit_depth = 1;
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color_type = PNG_COLOR_TYPE_GRAY;
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row_size = (info->width + 7) >> 3;
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break;
|
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case PIX_FMT_PAL8:
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bit_depth = 8;
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color_type = PNG_COLOR_TYPE_PALETTE;
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row_size = info->width;
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break;
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default:
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return -1;
|
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}
|
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zstream.zalloc = png_zalloc;
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zstream.zfree = png_zfree;
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zstream.opaque = NULL;
|
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ret = deflateInit2(&zstream, Z_DEFAULT_COMPRESSION,
|
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Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
|
|
if (ret != Z_OK)
|
|
return -1;
|
|
crow_buf = av_malloc(row_size + 1);
|
|
if (!crow_buf)
|
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goto fail;
|
|
|
|
/* write png header */
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put_buffer(f, pngsig, 8);
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|
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to_be32(buf, info->width);
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to_be32(buf + 4, info->height);
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buf[8] = bit_depth;
|
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buf[9] = color_type;
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buf[10] = 0; /* compression type */
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buf[11] = 0; /* filter type */
|
|
buf[12] = 0; /* interlace type */
|
|
|
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png_write_chunk(f, MKTAG('I', 'H', 'D', 'R'), buf, 13);
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|
|
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/* put the palette if needed */
|
|
if (color_type == PNG_COLOR_TYPE_PALETTE) {
|
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int has_alpha, alpha, i;
|
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unsigned int v;
|
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uint32_t *palette;
|
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uint8_t *alpha_ptr;
|
|
|
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palette = (uint32_t *)info->pict.data[1];
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ptr = buf;
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alpha_ptr = buf + 256 * 3;
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has_alpha = 0;
|
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for(i = 0; i < 256; i++) {
|
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v = palette[i];
|
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alpha = v >> 24;
|
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if (alpha != 0xff)
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has_alpha = 1;
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*alpha_ptr++ = alpha;
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ptr[0] = v >> 16;
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ptr[1] = v >> 8;
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ptr[2] = v;
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ptr += 3;
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}
|
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png_write_chunk(f, MKTAG('P', 'L', 'T', 'E'), buf, 256 * 3);
|
|
if (has_alpha) {
|
|
png_write_chunk(f, MKTAG('t', 'R', 'N', 'S'), buf + 256 * 3, 256);
|
|
}
|
|
}
|
|
|
|
/* 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) | (1 << PIX_FMT_PAL8),
|
|
png_write,
|
|
};
|