vp8li_dec.h | Explore in Territory

// Copyright 2012 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Lossless decoder: internal header.
//
// Author: Skal ([email protected])
//         Vikas Arora([email protected])

#ifndef WEBP_DEC_VP8LI_DEC_H_
#define WEBP_DEC_VP8LI_DEC_H_

#include <string.h>     // for memcpy()
#include "src/dec/webpi_dec.h"
#include "src/utils/bit_reader_utils.h"
#include "src/utils/color_cache_utils.h"
#include "src/utils/huffman_utils.h"
#include "src/webp/types.h"

#ifdef __cplusplus
extern "C" {
#endif

VP8LDecodeState;

VP8LTransform;
struct VP8LTransform { … };

VP8LMetadata;

VP8LDecoder;
struct VP8LDecoder { … };

//------------------------------------------------------------------------------
// internal functions. Not public.

struct ALPHDecoder;  // Defined in dec/alphai.h.

// in vp8l.c

// Decodes image header for alpha data stored using lossless compression.
// Returns false in case of error.
WEBP_NODISCARD int VP8LDecodeAlphaHeader(struct ALPHDecoder* const alph_dec,
                                         const uint8_t* const data,
                                         size_t data_size);

// Decodes *at least* 'last_row' rows of alpha. If some of the initial rows are
// already decoded in previous call(s), it will resume decoding from where it
// was paused.
// Returns false in case of bitstream error.
WEBP_NODISCARD int VP8LDecodeAlphaImageStream(
    struct ALPHDecoder* const alph_dec, int last_row);

// Allocates and initialize a new lossless decoder instance.
WEBP_NODISCARD VP8LDecoder* VP8LNew(void);

// Decodes the image header. Returns false in case of error.
WEBP_NODISCARD int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);

// Decodes an image. It's required to decode the lossless header before calling
// this function. Returns false in case of error, with updated dec->status_.
WEBP_NODISCARD int VP8LDecodeImage(VP8LDecoder* const dec);

// Resets the decoder in its initial state, reclaiming memory.
// Preserves the dec->status_ value.
void VP8LClear(VP8LDecoder* const dec);

// Clears and deallocate a lossless decoder instance.
void VP8LDelete(VP8LDecoder* const dec);

// Helper function for reading the different Huffman codes and storing them in
// 'huffman_tables' and 'htree_groups'.
// If mapping is NULL 'num_htree_groups_max' must equal 'num_htree_groups'.
// If it is not NULL, it maps 'num_htree_groups_max' indices to the
// 'num_htree_groups' groups. If 'num_htree_groups_max' > 'num_htree_groups',
// some of those indices map to -1. This is used for non-balanced codes to
// limit memory usage.
WEBP_NODISCARD int ReadHuffmanCodesHelper(
    int color_cache_bits, int num_htree_groups, int num_htree_groups_max,
    const int* const mapping, VP8LDecoder* const dec,
    HuffmanTables* const huffman_tables, HTreeGroup** const htree_groups);

//------------------------------------------------------------------------------

#ifdef __cplusplus
}    // extern "C"
#endif

#endif  // WEBP_DEC_VP8LI_DEC_H_
godot/thirdparty/libwebp/src/dec/vp8li_dec.h
