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| 1 // Copyright 2012 Google Inc. All Rights Reserved. |
| 2 // |
| 3 // This code is licensed under the same terms as WebM: |
| 4 // Software License Agreement: http://www.webmproject.org/license/software/ |
| 5 // Additional IP Rights Grant: http://www.webmproject.org/license/additional/ |
| 6 // ----------------------------------------------------------------------------- |
| 7 // |
| 8 // Lossless decoder: internal header. |
| 9 // |
| 10 // Author: Skal (pascal.massimino@gmail.com) |
| 11 // Vikas Arora(vikaas.arora@gmail.com) |
| 12 |
| 13 #ifndef WEBP_DEC_VP8LI_H_ |
| 14 #define WEBP_DEC_VP8LI_H_ |
| 15 |
| 16 #include <string.h> // for memcpy() |
| 17 #include "./webpi.h" |
| 18 #include "../utils/bit_reader.h" |
| 19 #include "../utils/color_cache.h" |
| 20 #include "../utils/huffman.h" |
| 21 #include "../webp/format_constants.h" |
| 22 |
| 23 #if defined(__cplusplus) || defined(c_plusplus) |
| 24 extern "C" { |
| 25 #endif |
| 26 |
| 27 typedef enum { |
| 28 READ_DATA = 0, |
| 29 READ_HDR = 1, |
| 30 READ_DIM = 2 |
| 31 } VP8LDecodeState; |
| 32 |
| 33 typedef struct VP8LTransform VP8LTransform; |
| 34 struct VP8LTransform { |
| 35 VP8LImageTransformType type_; // transform type. |
| 36 int bits_; // subsampling bits defining transform window. |
| 37 int xsize_; // transform window X index. |
| 38 int ysize_; // transform window Y index. |
| 39 uint32_t *data_; // transform data. |
| 40 }; |
| 41 |
| 42 typedef struct { |
| 43 HuffmanTree htrees_[HUFFMAN_CODES_PER_META_CODE]; |
| 44 } HTreeGroup; |
| 45 |
| 46 typedef struct { |
| 47 int color_cache_size_; |
| 48 VP8LColorCache color_cache_; |
| 49 |
| 50 int huffman_mask_; |
| 51 int huffman_subsample_bits_; |
| 52 int huffman_xsize_; |
| 53 uint32_t *huffman_image_; |
| 54 int num_htree_groups_; |
| 55 HTreeGroup *htree_groups_; |
| 56 } VP8LMetadata; |
| 57 |
| 58 typedef struct { |
| 59 VP8StatusCode status_; |
| 60 VP8LDecodeState action_; |
| 61 VP8LDecodeState state_; |
| 62 VP8Io *io_; |
| 63 |
| 64 const WebPDecBuffer *output_; // shortcut to io->opaque->output |
| 65 |
| 66 uint32_t *argb_; // Internal data: always in BGRA color mode. |
| 67 uint32_t *argb_cache_; // Scratch buffer for temporary BGRA storage. |
| 68 |
| 69 VP8LBitReader br_; |
| 70 |
| 71 int width_; |
| 72 int height_; |
| 73 int last_row_; // last input row decoded so far. |
| 74 int last_out_row_; // last row output so far. |
| 75 |
| 76 VP8LMetadata hdr_; |
| 77 |
| 78 int next_transform_; |
| 79 VP8LTransform transforms_[NUM_TRANSFORMS]; |
| 80 // or'd bitset storing the transforms types. |
| 81 uint32_t transforms_seen_; |
| 82 |
| 83 uint8_t *rescaler_memory; // Working memory for rescaling work. |
| 84 WebPRescaler *rescaler; // Common rescaler for all channels. |
| 85 } VP8LDecoder; |
| 86 |
| 87 //------------------------------------------------------------------------------ |
| 88 // internal functions. Not public. |
| 89 |
| 90 // in vp8l.c |
| 91 |
| 92 // Decodes a raw image stream (without header) and store the alpha data |
| 93 // into *output, which must be of size width x height. Returns false in case |
| 94 // of error. |
| 95 int VP8LDecodeAlphaImageStream(int width, int height, const uint8_t* const data, |
| 96 size_t data_size, uint8_t* const output); |
| 97 |
| 98 // Allocates and initialize a new lossless decoder instance. |
| 99 VP8LDecoder* VP8LNew(void); |
| 100 |
| 101 // Decodes the image header. Returns false in case of error. |
| 102 int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io); |
| 103 |
| 104 // Decodes an image. It's required to decode the lossless header before calling |
| 105 // this function. Returns false in case of error, with updated dec->status_. |
| 106 int VP8LDecodeImage(VP8LDecoder* const dec); |
| 107 |
| 108 // Resets the decoder in its initial state, reclaiming memory. |
| 109 // Preserves the dec->status_ value. |
| 110 void VP8LClear(VP8LDecoder* const dec); |
| 111 |
| 112 // Clears and deallocate a lossless decoder instance. |
| 113 void VP8LDelete(VP8LDecoder* const dec); |
| 114 |
| 115 //------------------------------------------------------------------------------ |
| 116 |
| 117 #if defined(__cplusplus) || defined(c_plusplus) |
| 118 } // extern "C" |
| 119 #endif |
| 120 |
| 121 #endif /* WEBP_DEC_VP8LI_H_ */ |
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