separate en/decoder specific parts from png.c

Originally committed as revision 9686 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 111 insertions, 0 deletions

diff --git a/libavcodec/png.h b/libavcodec/png.h
new file mode 100644
index 0000000000..fb5ec06122
--- /dev/null
+++ b/libavcodec/png.h
@@ -0,0 +1,111 @@
+/*
+ * PNG image format
+ * Copyright (c) 2003 Fabrice Bellard.
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_PNG_H
+#define AVCODEC_PNG_H
+
+#include <stdint.h>
+#include <zlib.h>
+
+#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 PNG_PLTE      0x0008
+
+#define NB_PASSES 7
+
+#define IOBUF_SIZE 4096
+
+typedef struct PNGContext {
+    uint8_t *bytestream;
+    uint8_t *bytestream_start;
+    uint8_t *bytestream_end;
+    AVFrame picture;
+
+    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;
+    uint32_t palette[256];
+    uint8_t *crow_buf;
+    uint8_t *last_row;
+    uint8_t *tmp_row;
+    int pass;
+    int crow_size; /* compressed row size (include filter type) */
+    int row_size; /* decompressed row size */
+    int pass_row_size; /* decompress row size of the current pass */
+    int y;
+    z_stream zstream;
+    uint8_t buf[IOBUF_SIZE];
+} PNGContext;
+
+extern const uint8_t ff_pngsig[8];
+
+/* Mask to determine which y pixels are valid in a pass */
+extern const uint8_t ff_png_pass_ymask[NB_PASSES];
+
+/* minimum x value */
+extern const uint8_t ff_png_pass_xmin[NB_PASSES];
+
+/* x shift to get row width */
+extern const uint8_t ff_png_pass_xshift[NB_PASSES];
+
+/* Mask to determine which pixels are valid in a pass */
+extern const uint8_t ff_png_pass_mask[NB_PASSES];
+
+extern void *ff_png_zalloc(void *opaque, unsigned int items,
+                           unsigned int size);
+
+extern void ff_png_zfree(void *opaque, void *ptr);
+
+extern int ff_png_get_nb_channels(int color_type);
+
+/* compute the row size of an interleaved pass */
+extern int ff_png_pass_row_size(int pass, int bits_per_pixel, int width);
+
+extern int ff_png_common_init(AVCodecContext *avctx);
+
+#endif