1 // Copyright 2012 Google Inc. All Rights Reserved.
3 // Use of this source code is governed by a BSD-style license
4 // that can be found in the COPYING file in the root of the source
5 // tree. An additional intellectual property rights grant can be found
6 // in the file PATENTS. All contributing project authors may
7 // be found in the AUTHORS file in the root of the source tree.
8 // -----------------------------------------------------------------------------
10 // Lossless decoder: internal header.
12 // Author: Skal (pascal.massimino@gmail.com)
13 // Vikas Arora(vikaas.arora@gmail.com)
15 #ifndef WEBP_DEC_VP8LI_H_
16 #define WEBP_DEC_VP8LI_H_
18 #include <string.h> // for memcpy()
20 #include "../utils/bit_reader.h"
21 #include "../utils/color_cache.h"
22 #include "../utils/huffman.h"
23 #include "../webp/format_constants.h"
25 #if defined(__cplusplus) || defined(c_plusplus)
35 typedef struct VP8LTransform VP8LTransform;
36 struct VP8LTransform {
37 VP8LImageTransformType type_; // transform type.
38 int bits_; // subsampling bits defining transform window.
39 int xsize_; // transform window X index.
40 int ysize_; // transform window Y index.
41 uint32_t *data_; // transform data.
45 HuffmanTree htrees_[HUFFMAN_CODES_PER_META_CODE];
49 int color_cache_size_;
50 VP8LColorCache color_cache_;
53 int huffman_subsample_bits_;
55 uint32_t *huffman_image_;
56 int num_htree_groups_;
57 HTreeGroup *htree_groups_;
61 VP8StatusCode status_;
62 VP8LDecodeState action_;
63 VP8LDecodeState state_;
66 const WebPDecBuffer *output_; // shortcut to io->opaque->output
68 uint32_t *pixels_; // Internal data: either uint8_t* for alpha
69 // or uint32_t* for BGRA.
70 uint32_t *argb_cache_; // Scratch buffer for temporary BGRA storage.
76 int last_row_; // last input row decoded so far.
77 int last_out_row_; // last row output so far.
82 VP8LTransform transforms_[NUM_TRANSFORMS];
83 // or'd bitset storing the transforms types.
84 uint32_t transforms_seen_;
86 uint8_t *rescaler_memory; // Working memory for rescaling work.
87 WebPRescaler *rescaler; // Common rescaler for all channels.
90 //------------------------------------------------------------------------------
91 // internal functions. Not public.
95 // Decodes a raw image stream (without header) and store the alpha data
96 // into *output, which must be of size width x height. Returns false in case
98 int VP8LDecodeAlphaImageStream(int width, int height, const uint8_t* const data,
99 size_t data_size, uint8_t* const output);
101 // Allocates and initialize a new lossless decoder instance.
102 VP8LDecoder* VP8LNew(void);
104 // Decodes the image header. Returns false in case of error.
105 int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io);
107 // Decodes an image. It's required to decode the lossless header before calling
108 // this function. Returns false in case of error, with updated dec->status_.
109 int VP8LDecodeImage(VP8LDecoder* const dec);
111 // Resets the decoder in its initial state, reclaiming memory.
112 // Preserves the dec->status_ value.
113 void VP8LClear(VP8LDecoder* const dec);
115 // Clears and deallocate a lossless decoder instance.
116 void VP8LDelete(VP8LDecoder* const dec);
118 //------------------------------------------------------------------------------
120 #if defined(__cplusplus) || defined(c_plusplus)
124 #endif /* WEBP_DEC_VP8LI_H_ */