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https://github.com/webmproject/libwebp.git
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9b3d1f3a1b
replaces mixed use of int/uint32_t for buffer sizes further changes the API/ABI. Change-Id: I91d70fd82ee3e1ac34b884b8ead9a114a9b1015a
132 lines
4.1 KiB
C
132 lines
4.1 KiB
C
// Copyright 2012 Google Inc. All Rights Reserved.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Lossless decoder: internal header.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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// Vikas Arora(vikaas.arora@gmail.com)
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#ifndef WEBP_DEC_VP8LI_H_
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#define WEBP_DEC_VP8LI_H_
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#include <string.h> // for memcpy()
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#include "./webpi.h"
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#include "../utils/bit_reader.h"
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#include "../utils/color_cache.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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#define NUM_TRANSFORMS 8
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#define HUFFMAN_CODES_PER_META_CODE 5
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#define ARGB_BLACK 0xff000000
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#define NUM_LITERAL_CODES 256
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#define NUM_ARGB_CACHE_ROWS 16
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#define LOSSLESS_MAGIC_BYTE 0x64
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#define LOSSLESS_MAGIC_BYTE_RSVD 0x65
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struct HuffmanTree;
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typedef enum {
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READ_DATA = 0,
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READ_HDR = 1,
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READ_DIM = 2
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} VP8LDecodeState;
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typedef enum {
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PREDICTOR_TRANSFORM = 0,
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CROSS_COLOR_TRANSFORM = 1,
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SUBTRACT_GREEN = 2,
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COLOR_INDEXING_TRANSFORM = 3
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} VP8LImageTransformType;
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typedef struct VP8LTransform VP8LTransform;
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struct VP8LTransform {
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VP8LImageTransformType type_; // transform type.
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int bits_; // subsampling bits defining transform window.
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size_t xsize_; // transform window X index.
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size_t ysize_; // transform window Y index.
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uint32_t *data_; // transform data.
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};
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typedef struct {
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int color_cache_size_;
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VP8LColorCache *color_cache_;
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int num_huffman_trees_;
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int huffman_mask_;
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int huffman_subsample_bits_;
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int huffman_xsize_;
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uint32_t *meta_codes_;
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uint32_t *huffman_image_;
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struct HuffmanTree *htrees_;
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struct HuffmanTree *meta_htrees_[HUFFMAN_CODES_PER_META_CODE];
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} VP8LMetadata;
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typedef struct {
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VP8StatusCode status_;
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VP8LDecodeState action_;
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VP8LDecodeState state_;
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VP8Io *io_;
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uint32_t *argb_; // Internal data: always in BGRA color mode.
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uint32_t *argb_cache_; // Scratch buffer for temporary BGRA storage.
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VP8LBitReader br_;
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int width_;
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int height_;
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int last_row_; // last input row decoded so far.
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int last_out_row_; // last row output so far.
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VP8LMetadata hdr_;
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int next_transform_;
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VP8LTransform transforms_[NUM_TRANSFORMS];
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uint8_t *rescaler_memory; // Working memory for rescaling work.
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WebPRescaler *rescaler; // Common rescaler for all channels.
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} VP8LDecoder;
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//------------------------------------------------------------------------------
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// internal functions. Not public.
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// in vp8l.c
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// Validates the VP8L data-header and retrieves basic header information viz
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// width and height. Returns 0 in case of formatting error. width/height
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// can be passed NULL.
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int VP8LGetInfo(const uint8_t* data,
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size_t data_size, // data available so far
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int *width, int *height);
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// Allocates and initialize a new lossless decoder instance.
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VP8LDecoder* VP8LNew(void);
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// Decodes the image header. Returns false in case of error.
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int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);
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// Decodes an image. It's required to decode the lossless header before calling
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// this function. Returns false in case of error, with updated dec->status_.
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int VP8LDecodeImage(VP8LDecoder* const dec);
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// Resets the decoder in its initial state, reclaiming memory.
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// Preserves the dec->status_ value.
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void VP8LClear(VP8LDecoder* const dec);
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// Clears and deallocate a lossless decoder instance.
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void VP8LDelete(VP8LDecoder* const dec);
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//------------------------------------------------------------------------------
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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#endif /* WEBP_DEC_VP8LI_H_ */
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