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Diffstat (limited to 'media/libwebp/dec/vp8li_dec.h')
| -rw-r--r-- | media/libwebp/dec/vp8li_dec.h | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/media/libwebp/dec/vp8li_dec.h b/media/libwebp/dec/vp8li_dec.h new file mode 100644 index 000000000..097a9d058 --- /dev/null +++ b/media/libwebp/dec/vp8li_dec.h @@ -0,0 +1,135 @@ +// 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 (pascal.massimino@gmail.com) +// Vikas Arora(vikaas.arora@gmail.com) + +#ifndef WEBP_DEC_VP8LI_H_ +#define WEBP_DEC_VP8LI_H_ + +#include <string.h> // for memcpy() +#include "./webpi_dec.h" +#include "../utils/bit_reader_utils.h" +#include "../utils/color_cache_utils.h" +#include "../utils/huffman_utils.h" + +#ifdef __cplusplus +extern "C" { +#endif + +typedef enum { + READ_DATA = 0, + READ_HDR = 1, + READ_DIM = 2 +} VP8LDecodeState; + +typedef struct VP8LTransform VP8LTransform; +struct VP8LTransform { + VP8LImageTransformType type_; // transform type. + int bits_; // subsampling bits defining transform window. + int xsize_; // transform window X index. + int ysize_; // transform window Y index. + uint32_t *data_; // transform data. +}; + +typedef struct { + int color_cache_size_; + VP8LColorCache color_cache_; + VP8LColorCache saved_color_cache_; // for incremental + + int huffman_mask_; + int huffman_subsample_bits_; + int huffman_xsize_; + uint32_t *huffman_image_; + int num_htree_groups_; + HTreeGroup *htree_groups_; + HuffmanCode *huffman_tables_; +} VP8LMetadata; + +typedef struct VP8LDecoder VP8LDecoder; +struct VP8LDecoder { + VP8StatusCode status_; + VP8LDecodeState state_; + VP8Io *io_; + + const WebPDecBuffer *output_; // shortcut to io->opaque->output + + uint32_t *pixels_; // Internal data: either uint8_t* for alpha + // or uint32_t* for BGRA. + uint32_t *argb_cache_; // Scratch buffer for temporary BGRA storage. + + VP8LBitReader br_; + int incremental_; // if true, incremental decoding is expected + VP8LBitReader saved_br_; // note: could be local variables too + int saved_last_pixel_; + + int width_; + int height_; + int last_row_; // last input row decoded so far. + int last_pixel_; // last pixel decoded so far. However, it may + // not be transformed, scaled and + // color-converted yet. + int last_out_row_; // last row output so far. + + VP8LMetadata hdr_; + + int next_transform_; + VP8LTransform transforms_[NUM_TRANSFORMS]; + // or'd bitset storing the transforms types. + uint32_t transforms_seen_; + + uint8_t *rescaler_memory; // Working memory for rescaling work. + WebPRescaler *rescaler; // Common rescaler for all channels. +}; + +//------------------------------------------------------------------------------ +// 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. +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. +int VP8LDecodeAlphaImageStream(struct ALPHDecoder* const alph_dec, + int last_row); + +// Allocates and initialize a new lossless decoder instance. +VP8LDecoder* VP8LNew(void); + +// Decodes the image header. Returns false in case of error. +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_. +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); + +//------------------------------------------------------------------------------ + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif /* WEBP_DEC_VP8LI_H_ */ |