63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
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/* Copyright (C) Teemu Suutari */
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#include "DLTADecode.hpp"
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#include "common/OverflowCheck.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 DLTADecode::detectHeaderXPK(uint32_t hdr) noexcept
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{
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return hdr==FourCC("DLTA");
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}
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std::shared_ptr<XPKDecompressor> DLTADecode::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<DLTADecode>(hdr,recursionLevel,packedData,state,verify);
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}
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DLTADecode::DLTADecode(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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DLTADecode::~DLTADecode()
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{
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// nothing needed
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}
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const std::string &DLTADecode::getSubName() const noexcept
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{
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static std::string name="XPK-DLTA: Delta encoding";
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return name;
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}
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void DLTADecode::decode(Buffer &bufferDest,const Buffer &bufferSrc,size_t offset,size_t size)
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{
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if (OverflowCheck::sum(offset,size)>bufferSrc.size()) throw Buffer::OutOfBoundsError();
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if (OverflowCheck::sum(offset,size)>bufferDest.size()) throw Buffer::OutOfBoundsError();
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const uint8_t *src=bufferSrc.data()+offset;
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uint8_t *dest=bufferDest.data()+offset;
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uint8_t ctr=0;
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for (size_t i=0;i<size;i++)
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{
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ctr+=src[i];
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dest[i]=ctr;
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}
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}
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void DLTADecode::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
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{
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if (rawData.size()<_packedData.size()) throw Decompressor::DecompressionError();
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decode(rawData,_packedData,0,_packedData.size());
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}
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}
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