// 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. // ----------------------------------------------------------------------------- // // main entry for the decoder // // Authors: Vikas Arora ([email protected]) // Jyrki Alakuijala ([email protected]) #include <assert.h> #include <stdlib.h> #include "src/dec/alphai_dec.h" #include "src/dec/vp8li_dec.h" #include "src/dsp/dsp.h" #include "src/dsp/lossless.h" #include "src/dsp/lossless_common.h" #include "src/dsp/yuv.h" #include "src/utils/endian_inl_utils.h" #include "src/utils/huffman_utils.h" #include "src/utils/utils.h" #define NUM_ARGB_CACHE_ROWS … static const int kCodeLengthLiterals = …; static const int kCodeLengthRepeatCode = …; static const uint8_t kCodeLengthExtraBits[3] = …; static const uint8_t kCodeLengthRepeatOffsets[3] = …; // ----------------------------------------------------------------------------- // Five Huffman codes are used at each meta code: // 1. green + length prefix codes + color cache codes, // 2. alpha, // 3. red, // 4. blue, and, // 5. distance prefix codes. HuffIndex; static const uint16_t kAlphabetSize[HUFFMAN_CODES_PER_META_CODE] = …; static const uint8_t kLiteralMap[HUFFMAN_CODES_PER_META_CODE] = …; #define NUM_CODE_LENGTH_CODES … static const uint8_t kCodeLengthCodeOrder[NUM_CODE_LENGTH_CODES] = …; #define CODE_TO_PLANE_CODES … static const uint8_t kCodeToPlane[CODE_TO_PLANE_CODES] = …; // Memory needed for lookup tables of one Huffman tree group. Red, blue, alpha // and distance alphabets are constant (256 for red, blue and alpha, 40 for // distance) and lookup table sizes for them in worst case are 630 and 410 // respectively. Size of green alphabet depends on color cache size and is equal // to 256 (green component values) + 24 (length prefix values) // + color_cache_size (between 0 and 2048). // All values computed for 8-bit first level lookup with Mark Adler's tool: // https://github.com/madler/zlib/blob/v1.2.5/examples/enough.c #define FIXED_TABLE_SIZE … static const uint16_t kTableSize[12] = …; static int VP8LSetError(VP8LDecoder* const dec, VP8StatusCode error) { … } static int DecodeImageStream(int xsize, int ysize, int is_level0, VP8LDecoder* const dec, uint32_t** const decoded_data); //------------------------------------------------------------------------------ int VP8LCheckSignature(const uint8_t* const data, size_t size) { … } static int ReadImageInfo(VP8LBitReader* const br, int* const width, int* const height, int* const has_alpha) { … } int VP8LGetInfo(const uint8_t* data, size_t data_size, int* const width, int* const height, int* const has_alpha) { … } //------------------------------------------------------------------------------ static WEBP_INLINE int GetCopyDistance(int distance_symbol, VP8LBitReader* const br) { … } static WEBP_INLINE int GetCopyLength(int length_symbol, VP8LBitReader* const br) { … } static WEBP_INLINE int PlaneCodeToDistance(int xsize, int plane_code) { … } //------------------------------------------------------------------------------ // Decodes the next Huffman code from bit-stream. // VP8LFillBitWindow(br) needs to be called at minimum every second call // to ReadSymbol, in order to pre-fetch enough bits. static WEBP_INLINE int ReadSymbol(const HuffmanCode* table, VP8LBitReader* const br) { … } // Reads packed symbol depending on GREEN channel #define BITS_SPECIAL_MARKER … #define PACKED_NON_LITERAL_CODE … static WEBP_INLINE int ReadPackedSymbols(const HTreeGroup* group, VP8LBitReader* const br, uint32_t* const dst) { … } static int AccumulateHCode(HuffmanCode hcode, int shift, HuffmanCode32* const huff) { … } static void BuildPackedTable(HTreeGroup* const htree_group) { … } static int ReadHuffmanCodeLengths( VP8LDecoder* const dec, const int* const code_length_code_lengths, int num_symbols, int* const code_lengths) { … } // 'code_lengths' is pre-allocated temporary buffer, used for creating Huffman // tree. static int ReadHuffmanCode(int alphabet_size, VP8LDecoder* const dec, int* const code_lengths, HuffmanTables* const table) { … } static int ReadHuffmanCodes(VP8LDecoder* const dec, int xsize, int ysize, int color_cache_bits, int allow_recursion) { … } 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) { … } //------------------------------------------------------------------------------ // Scaling. #if !defined(WEBP_REDUCE_SIZE) static int AllocateAndInitRescaler(VP8LDecoder* const dec, VP8Io* const io) { … } #endif // WEBP_REDUCE_SIZE //------------------------------------------------------------------------------ // Export to ARGB #if !defined(WEBP_REDUCE_SIZE) // We have special "export" function since we need to convert from BGRA static int Export(WebPRescaler* const rescaler, WEBP_CSP_MODE colorspace, int rgba_stride, uint8_t* const rgba) { … } // Emit scaled rows. static int EmitRescaledRowsRGBA(const VP8LDecoder* const dec, uint8_t* in, int in_stride, int mb_h, uint8_t* const out, int out_stride) { … } #endif // WEBP_REDUCE_SIZE // Emit rows without any scaling. static int EmitRows(WEBP_CSP_MODE colorspace, const uint8_t* row_in, int in_stride, int mb_w, int mb_h, uint8_t* const out, int out_stride) { … } //------------------------------------------------------------------------------ // Export to YUVA static void ConvertToYUVA(const uint32_t* const src, int width, int y_pos, const WebPDecBuffer* const output) { … } static int ExportYUVA(const VP8LDecoder* const dec, int y_pos) { … } static int EmitRescaledRowsYUVA(const VP8LDecoder* const dec, uint8_t* in, int in_stride, int mb_h) { … } static int EmitRowsYUVA(const VP8LDecoder* const dec, const uint8_t* in, int in_stride, int mb_w, int num_rows) { … } //------------------------------------------------------------------------------ // Cropping. // Sets io->mb_y, io->mb_h & io->mb_w according to start row, end row and // crop options. Also updates the input data pointer, so that it points to the // start of the cropped window. Note that pixels are in ARGB format even if // 'in_data' is uint8_t*. // Returns true if the crop window is not empty. static int SetCropWindow(VP8Io* const io, int y_start, int y_end, uint8_t** const in_data, int pixel_stride) { … } //------------------------------------------------------------------------------ static WEBP_INLINE int GetMetaIndex( const uint32_t* const image, int xsize, int bits, int x, int y) { … } static WEBP_INLINE HTreeGroup* GetHtreeGroupForPos(VP8LMetadata* const hdr, int x, int y) { … } //------------------------------------------------------------------------------ // Main loop, with custom row-processing function ProcessRowsFunc; static void ApplyInverseTransforms(VP8LDecoder* const dec, int start_row, int num_rows, const uint32_t* const rows) { … } // Processes (transforms, scales & color-converts) the rows decoded after the // last call. static void ProcessRows(VP8LDecoder* const dec, int row) { … } // Row-processing for the special case when alpha data contains only one // transform (color indexing), and trivial non-green literals. static int Is8bOptimizable(const VP8LMetadata* const hdr) { … } static void AlphaApplyFilter(ALPHDecoder* const alph_dec, int first_row, int last_row, uint8_t* out, int stride) { … } static void ExtractPalettedAlphaRows(VP8LDecoder* const dec, int last_row) { … } //------------------------------------------------------------------------------ // Helper functions for fast pattern copy (8b and 32b) // cyclic rotation of pattern word static WEBP_INLINE uint32_t Rotate8b(uint32_t V) { … } // copy 1, 2 or 4-bytes pattern static WEBP_INLINE void CopySmallPattern8b(const uint8_t* src, uint8_t* dst, int length, uint32_t pattern) { … } static WEBP_INLINE void CopyBlock8b(uint8_t* const dst, int dist, int length) { … } // copy pattern of 1 or 2 uint32_t's static WEBP_INLINE void CopySmallPattern32b(const uint32_t* src, uint32_t* dst, int length, uint64_t pattern) { … } static WEBP_INLINE void CopyBlock32b(uint32_t* const dst, int dist, int length) { … } //------------------------------------------------------------------------------ static int DecodeAlphaData(VP8LDecoder* const dec, uint8_t* const data, int width, int height, int last_row) { … } static void SaveState(VP8LDecoder* const dec, int last_pixel) { … } static void RestoreState(VP8LDecoder* const dec) { … } #define SYNC_EVERY_N_ROWS … static int DecodeImageData(VP8LDecoder* const dec, uint32_t* const data, int width, int height, int last_row, ProcessRowsFunc process_func) { … } // ----------------------------------------------------------------------------- // VP8LTransform static void ClearTransform(VP8LTransform* const transform) { … } // For security reason, we need to remap the color map to span // the total possible bundled values, and not just the num_colors. static int ExpandColorMap(int num_colors, VP8LTransform* const transform) { … } static int ReadTransform(int* const xsize, int const* ysize, VP8LDecoder* const dec) { … } // ----------------------------------------------------------------------------- // VP8LMetadata static void InitMetadata(VP8LMetadata* const hdr) { … } static void ClearMetadata(VP8LMetadata* const hdr) { … } // ----------------------------------------------------------------------------- // VP8LDecoder VP8LDecoder* VP8LNew(void) { … } void VP8LClear(VP8LDecoder* const dec) { … } void VP8LDelete(VP8LDecoder* const dec) { … } static void UpdateDecoder(VP8LDecoder* const dec, int width, int height) { … } static int DecodeImageStream(int xsize, int ysize, int is_level0, VP8LDecoder* const dec, uint32_t** const decoded_data) { … } //------------------------------------------------------------------------------ // Allocate internal buffers dec->pixels_ and dec->argb_cache_. static int AllocateInternalBuffers32b(VP8LDecoder* const dec, int final_width) { … } static int AllocateInternalBuffers8b(VP8LDecoder* const dec) { … } //------------------------------------------------------------------------------ // Special row-processing that only stores the alpha data. static void ExtractAlphaRows(VP8LDecoder* const dec, int last_row) { … } int VP8LDecodeAlphaHeader(ALPHDecoder* const alph_dec, const uint8_t* const data, size_t data_size) { … } int VP8LDecodeAlphaImageStream(ALPHDecoder* const alph_dec, int last_row) { … } //------------------------------------------------------------------------------ int VP8LDecodeHeader(VP8LDecoder* const dec, VP8Io* const io) { … } int VP8LDecodeImage(VP8LDecoder* const dec) { … } //------------------------------------------------------------------------------
Codebase Browser
godot