79 lines
2.0 KiB
C++
79 lines
2.0 KiB
C++
/* Copyright (C) Teemu Suutari */
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#include "SMPLDecompressor.hpp"
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#include "InputStream.hpp"
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#include "OutputStream.hpp"
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#include "HuffmanDecoder.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 SMPLDecompressor::detectHeaderXPK(uint32_t hdr) noexcept
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{
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return hdr==FourCC("SMPL");
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}
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std::shared_ptr<XPKDecompressor> SMPLDecompressor::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<SMPLDecompressor>(hdr,recursionLevel,packedData,state,verify);
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}
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SMPLDecompressor::SMPLDecompressor(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) throw Decompressor::InvalidFormatError();
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if (packedData.readBE16(0)!=1) throw Decompressor::InvalidFormatError();
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}
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SMPLDecompressor::~SMPLDecompressor()
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{
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// nothing needed
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}
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const std::string &SMPLDecompressor::getSubName() const noexcept
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{
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static std::string name="XPK-SMPL: Huffman compressor with delta encoding";
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return name;
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}
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void SMPLDecompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
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{
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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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auto readBit=[&]()->uint32_t
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{
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return bitReader.readBits8(1);
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};
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ForwardOutputStream outputStream(rawData,0,rawData.size());
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HuffmanDecoder<uint32_t> decoder;
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for (uint32_t i=0;i<256;i++)
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{
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uint32_t codeLength=readBits(4);
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if (!codeLength) continue;
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if (codeLength==15) codeLength=readBits(4)+15;
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uint32_t code=readBits(codeLength);
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decoder.insert(HuffmanCode<uint32_t>{codeLength,code,i});
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}
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uint8_t accum=0;
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while (!outputStream.eof())
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{
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uint32_t code=decoder.decode(readBit);
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accum+=code;
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outputStream.writeByte(accum);
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}
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}
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}
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