1 | // Copyright 2012 Google Inc. All Rights Reserved. |
2 | // |
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 | // ----------------------------------------------------------------------------- |
9 | // |
10 | // Lossless decoder: internal header. |
11 | // |
12 | // Author: Skal (pascal.massimino@gmail.com) |
13 | // Vikas Arora(vikaas.arora@gmail.com) |
14 | |
15 | #ifndef WEBP_DEC_VP8LI_DEC_H_ |
16 | #define WEBP_DEC_VP8LI_DEC_H_ |
17 | |
18 | #include <string.h> // for memcpy() |
19 | #include "src/dec/webpi_dec.h" |
20 | #include "src/utils/bit_reader_utils.h" |
21 | #include "src/utils/color_cache_utils.h" |
22 | #include "src/utils/huffman_utils.h" |
23 | |
24 | #ifdef __cplusplus |
25 | extern "C" { |
26 | #endif |
27 | |
28 | typedef enum { |
29 | READ_DATA = 0, |
30 | READ_HDR = 1, |
31 | READ_DIM = 2 |
32 | } VP8LDecodeState; |
33 | |
34 | typedef struct VP8LTransform VP8LTransform; |
35 | struct VP8LTransform { |
36 | VP8LImageTransformType type_; // transform type. |
37 | int bits_; // subsampling bits defining transform window. |
38 | int xsize_; // transform window X index. |
39 | int ysize_; // transform window Y index. |
40 | uint32_t* data_; // transform data. |
41 | }; |
42 | |
43 | typedef struct { |
44 | int color_cache_size_; |
45 | VP8LColorCache color_cache_; |
46 | VP8LColorCache saved_color_cache_; // for incremental |
47 | |
48 | int huffman_mask_; |
49 | int huffman_subsample_bits_; |
50 | int huffman_xsize_; |
51 | uint32_t* huffman_image_; |
52 | int num_htree_groups_; |
53 | HTreeGroup* htree_groups_; |
54 | HuffmanCode* huffman_tables_; |
55 | } VP8LMetadata; |
56 | |
57 | typedef struct VP8LDecoder VP8LDecoder; |
58 | struct VP8LDecoder { |
59 | VP8StatusCode status_; |
60 | VP8LDecodeState state_; |
61 | VP8Io* io_; |
62 | |
63 | const WebPDecBuffer* output_; // shortcut to io->opaque->output |
64 | |
65 | uint32_t* pixels_; // Internal data: either uint8_t* for alpha |
66 | // or uint32_t* for BGRA. |
67 | uint32_t* argb_cache_; // Scratch buffer for temporary BGRA storage. |
68 | |
69 | VP8LBitReader br_; |
70 | int incremental_; // if true, incremental decoding is expected |
71 | VP8LBitReader saved_br_; // note: could be local variables too |
72 | int saved_last_pixel_; |
73 | |
74 | int width_; |
75 | int height_; |
76 | int last_row_; // last input row decoded so far. |
77 | int last_pixel_; // last pixel decoded so far. However, it may |
78 | // not be transformed, scaled and |
79 | // color-converted yet. |
80 | int last_out_row_; // last row output so far. |
81 | |
82 | VP8LMetadata hdr_; |
83 | |
84 | int next_transform_; |
85 | VP8LTransform transforms_[NUM_TRANSFORMS]; |
86 | // or'd bitset storing the transforms types. |
87 | uint32_t transforms_seen_; |
88 | |
89 | uint8_t* rescaler_memory; // Working memory for rescaling work. |
90 | WebPRescaler* rescaler; // Common rescaler for all channels. |
91 | }; |
92 | |
93 | //------------------------------------------------------------------------------ |
94 | // internal functions. Not public. |
95 | |
96 | struct ALPHDecoder; // Defined in dec/alphai.h. |
97 | |
98 | // in vp8l.c |
99 | |
100 | // Decodes image header for alpha data stored using lossless compression. |
101 | // Returns false in case of error. |
102 | int (struct ALPHDecoder* const alph_dec, |
103 | const uint8_t* const data, size_t data_size); |
104 | |
105 | // Decodes *at least* 'last_row' rows of alpha. If some of the initial rows are |
106 | // already decoded in previous call(s), it will resume decoding from where it |
107 | // was paused. |
108 | // Returns false in case of bitstream error. |
109 | int VP8LDecodeAlphaImageStream(struct ALPHDecoder* const alph_dec, |
110 | int last_row); |
111 | |
112 | // Allocates and initialize a new lossless decoder instance. |
113 | VP8LDecoder* VP8LNew(void); |
114 | |
115 | // Decodes the image header. Returns false in case of error. |
116 | int (VP8LDecoder* const dec, VP8Io* const io); |
117 | |
118 | // Decodes an image. It's required to decode the lossless header before calling |
119 | // this function. Returns false in case of error, with updated dec->status_. |
120 | int VP8LDecodeImage(VP8LDecoder* const dec); |
121 | |
122 | // Resets the decoder in its initial state, reclaiming memory. |
123 | // Preserves the dec->status_ value. |
124 | void VP8LClear(VP8LDecoder* const dec); |
125 | |
126 | // Clears and deallocate a lossless decoder instance. |
127 | void VP8LDelete(VP8LDecoder* const dec); |
128 | |
129 | //------------------------------------------------------------------------------ |
130 | |
131 | #ifdef __cplusplus |
132 | } // extern "C" |
133 | #endif |
134 | |
135 | #endif // WEBP_DEC_VP8LI_DEC_H_ |
136 | |