102 lines
2.3 KiB
C++
102 lines
2.3 KiB
C++
/* Copyright (C) Teemu Suutari */
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#include "RDCNDecompressor.hpp"
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#include "InputStream.hpp"
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#include "OutputStream.hpp"
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#include "common/Common.hpp"
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namespace ancient::internal
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{
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bool RDCNDecompressor::detectHeaderXPK(uint32_t hdr) noexcept
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{
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return hdr==FourCC("RDCN");
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}
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std::shared_ptr<XPKDecompressor> RDCNDecompressor::create(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify)
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{
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return std::make_shared<RDCNDecompressor>(hdr,recursionLevel,packedData,state,verify);
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}
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RDCNDecompressor::RDCNDecompressor(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify) :
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XPKDecompressor(recursionLevel),
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_packedData(packedData)
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{
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if (!detectHeaderXPK(hdr)) throw Decompressor::InvalidFormatError();
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}
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RDCNDecompressor::~RDCNDecompressor()
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{
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// nothing needed
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}
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const std::string &RDCNDecompressor::getSubName() const noexcept
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{
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static std::string name="XPK-RDCN: Ross data compression";
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return name;
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}
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void RDCNDecompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
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{
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ForwardInputStream inputStream(_packedData,0,_packedData.size());
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MSBBitReader<ForwardInputStream> bitReader(inputStream);
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auto readBit=[&]()->uint32_t
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{
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return bitReader.readBitsBE16(1);
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};
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auto readByte=[&]()->uint8_t
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{
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return inputStream.readByte();
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};
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ForwardOutputStream outputStream(rawData,0,rawData.size());
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while (!outputStream.eof())
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{
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if (!readBit())
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{
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outputStream.writeByte(readByte());
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} else {
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uint8_t tmp=readByte();
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uint32_t count=tmp&0xf;
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uint32_t code=tmp>>4;
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uint32_t distance=0;
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uint8_t repeatChar=0;
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bool doRLE=false;
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switch (code)
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{
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case 0:
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repeatChar=readByte();
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count+=3;
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doRLE=true;
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break;
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case 1:
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count=(count|(uint32_t(readByte())<<4))+19;
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repeatChar=readByte();
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doRLE=true;
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break;
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case 2:
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distance=(count|(uint32_t(readByte())<<4))+3;
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count=uint32_t(readByte())+16;
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break;
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default: /* 3 to 15 */
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distance=(count|(uint32_t(readByte())<<4))+3;
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count=code;
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break;
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}
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if (doRLE)
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{
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for (uint32_t i=0;i<count;i++) outputStream.writeByte(repeatChar);
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} else {
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outputStream.copy(distance,count);
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}
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}
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}
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}
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}
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