74 lines
2.0 KiB
C++
Vendored
74 lines
2.0 KiB
C++
Vendored
/* Copyright (C) Teemu Suutari */
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#include "ILZRDecompressor.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 ILZRDecompressor::detectHeaderXPK(uint32_t hdr) noexcept
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{
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return hdr==FourCC("ILZR");
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}
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std::shared_ptr<XPKDecompressor> ILZRDecompressor::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<ILZRDecompressor>(hdr,recursionLevel,packedData,state,verify);
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}
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ILZRDecompressor::ILZRDecompressor(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) || packedData.size()<2)
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throw Decompressor::InvalidFormatError();
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_rawSize=_packedData.readBE16(0);
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if (!_rawSize) throw Decompressor::InvalidFormatError();
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}
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ILZRDecompressor::~ILZRDecompressor()
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{
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// nothing needed
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}
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const std::string &ILZRDecompressor::getSubName() const noexcept
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{
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static std::string name="XPK-ILZR: Incremental Lempel-Ziv-Renau compressor";
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return name;
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}
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void ILZRDecompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
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{
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if (rawData.size()!=_rawSize) throw Decompressor::DecompressionError();
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ForwardInputStream inputStream(_packedData,2,_packedData.size());
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MSBBitReader<ForwardInputStream> bitReader(inputStream);
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auto readBits=[&](uint32_t count)->uint32_t
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{
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return bitReader.readBits8(count);
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};
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ForwardOutputStream outputStream(rawData,0,rawData.size());
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uint32_t bits=8;
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while (!outputStream.eof())
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{
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if (readBits(1))
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{
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outputStream.writeByte(readBits(8));
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} else {
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while (outputStream.getOffset()>(1ULL<<bits)) bits++;
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uint32_t position=readBits(bits);
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uint32_t count=readBits(4)+3;
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if (position>=outputStream.getOffset()) throw Decompressor::DecompressionError();
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outputStream.copy(outputStream.getOffset()-position,count);
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}
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}
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}
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}
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