| // Copyright 2017 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #ifndef CORE_FXCODEC_GIF_LZW_DECOMPRESSOR_H_ |
| #define CORE_FXCODEC_GIF_LZW_DECOMPRESSOR_H_ |
| |
| #include <memory> |
| #include <vector> |
| |
| #include "core/fxcodec/gif/cfx_gif.h" |
| #include "core/fxcrt/fx_memory_wrappers.h" |
| |
| namespace fxcodec { |
| |
| class LZWDecompressor { |
| public: |
| enum class Status { |
| kError, |
| kSuccess, |
| kUnfinished, |
| kInsufficientDestSize, |
| }; |
| |
| struct CodeEntry { |
| uint16_t prefix; |
| uint8_t suffix; |
| }; |
| |
| // Returns nullptr on error |
| static std::unique_ptr<LZWDecompressor> Create(uint8_t color_exp, |
| uint8_t code_exp); |
| ~LZWDecompressor(); |
| |
| Status Decode(const uint8_t* src_buf, |
| uint32_t src_size, |
| uint8_t* dest_buf, |
| uint32_t* dest_size); |
| |
| // Used by unittests, should not be called in production code. |
| uint32_t ExtractDataForTest(uint8_t* dest_buf, uint32_t dest_size) { |
| return ExtractData(dest_buf, dest_size); |
| } |
| |
| std::vector<uint8_t, FxAllocAllocator<uint8_t>>* DecompressedForTest() { |
| return &decompressed_; |
| } |
| size_t* DecompressedNextForTest() { return &decompressed_next_; } |
| |
| private: |
| // Use Create() instead. |
| LZWDecompressor(uint8_t color_exp, uint8_t code_exp); |
| |
| void ClearTable(); |
| void AddCode(uint16_t prefix_code, uint8_t append_char); |
| bool DecodeString(uint16_t code); |
| uint32_t ExtractData(uint8_t* dest_buf, uint32_t dest_size); |
| |
| const uint8_t code_size_; |
| uint8_t code_size_cur_ = 0; |
| const uint16_t code_color_end_; |
| const uint16_t code_clear_; |
| const uint16_t code_end_; |
| uint16_t code_next_ = 0; |
| uint8_t code_first_ = 0; |
| std::vector<uint8_t, FxAllocAllocator<uint8_t>> decompressed_; |
| size_t decompressed_next_ = 0; |
| uint16_t code_old_ = 0; |
| const uint8_t* next_in_ = nullptr; |
| uint32_t avail_in_ = 0; |
| uint8_t bits_left_ = 0; |
| uint32_t code_store_ = 0; |
| CodeEntry code_table_[GIF_MAX_LZW_CODE]; |
| }; |
| |
| } // namespace fxcodec |
| |
| using LZWDecompressor = fxcodec::LZWDecompressor; |
| |
| #endif // CORE_FXCODEC_GIF_LZW_DECOMPRESSOR_H_ |