1 // Copyright 2017 PDFium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com 6 7 #ifndef CORE_FXCODEC_GIF_CFX_LZWDECOMPRESSOR_H_ 8 #define CORE_FXCODEC_GIF_CFX_LZWDECOMPRESSOR_H_ 9 10 #include <memory> 11 #include <vector> 12 13 #include "core/fxcodec/gif/cfx_gif.h" 14 15 class CFX_LZWDecompressor { 16 public: 17 typedef struct { 18 uint16_t prefix; 19 uint8_t suffix; 20 } CodeEntry; 21 22 // Returns nullptr on error 23 static std::unique_ptr<CFX_LZWDecompressor> Create(uint8_t color_exp, 24 uint8_t code_exp); 25 ~CFX_LZWDecompressor(); 26 27 CFX_GifDecodeStatus Decode(uint8_t* src_buf, 28 uint32_t src_size, 29 uint8_t* des_buf, 30 uint32_t* des_size); 31 32 // Used by unittests, should not be called in production code. 33 uint32_t ExtractDataForTest(uint8_t* des_buf, uint32_t des_size) { 34 return ExtractData(des_buf, des_size); 35 } 36 37 std::vector<uint8_t>* DecompressedForTest() { return &decompressed_; } 38 39 size_t* DecompressedNextForTest() { return &decompressed_next_; } 40 41 private: 42 CFX_LZWDecompressor(uint8_t color_exp, uint8_t code_exp); 43 void ClearTable(); 44 void AddCode(uint16_t prefix_code, uint8_t append_char); 45 bool DecodeString(uint16_t code); 46 uint32_t ExtractData(uint8_t* des_buf, uint32_t des_size); 47 48 uint8_t code_size_; 49 uint8_t code_size_cur_; 50 uint16_t code_color_end_; 51 uint16_t code_clear_; 52 uint16_t code_end_; 53 uint16_t code_next_; 54 uint8_t code_first_; 55 std::vector<uint8_t> decompressed_; 56 size_t decompressed_next_; 57 CodeEntry code_table_[GIF_MAX_LZW_CODE]; 58 uint16_t code_old_; 59 uint8_t* next_in_; 60 uint32_t avail_in_; 61 uint8_t bits_left_; 62 uint32_t code_store_; 63 }; 64 65 #endif // CORE_FXCODEC_GIF_CFX_LZWDECOMPRESSOR_H_ 66
