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// 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_CFX_LZWDECOMPRESSOR_H_
#define CORE_FXCODEC_GIF_CFX_LZWDECOMPRESSOR_H_
#include <memory>
#include <vector>
#include "core/fxcodec/gif/cfx_gif.h"
class CFX_LZWDecompressor {
public:
typedef struct {
uint16_t prefix;
uint8_t suffix;
} CodeEntry;
// Returns nullptr on error
static std::unique_ptr<CFX_LZWDecompressor> Create(uint8_t color_exp,
uint8_t code_exp);
~CFX_LZWDecompressor();
CFX_GifDecodeStatus 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>* DecompressedForTest() { return &decompressed_; }
size_t* DecompressedNextForTest() { return &decompressed_next_; }
private:
CFX_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);
uint8_t code_size_;
uint8_t code_size_cur_;
uint16_t code_color_end_;
uint16_t code_clear_;
uint16_t code_end_;
uint16_t code_next_;
uint8_t code_first_;
std::vector<uint8_t> decompressed_;
size_t decompressed_next_;
uint16_t code_old_;
const uint8_t* next_in_;
uint32_t avail_in_;
uint8_t bits_left_;
uint32_t code_store_;
CodeEntry code_table_[GIF_MAX_LZW_CODE];
};
#endif // CORE_FXCODEC_GIF_CFX_LZWDECOMPRESSOR_H_
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