73 lines
1.8 KiB
C++
73 lines
1.8 KiB
C++
|
/* Copyright (C) Teemu Suutari */
|
||
|
|
|
||
|
|
#include "LZW4Decompressor.hpp"
|
||
|
|
#include "InputStream.hpp"
|
||
|
|
#include "OutputStream.hpp"
|
||
|
|
#include "common/Common.hpp"
|
||
|
|
|
||
|
|
|
||
|
|
namespace ancient::internal
|
||
|
|
{
|
||
|
|
|
||
|
|
bool LZW4Decompressor::detectHeaderXPK(uint32_t hdr) noexcept
|
||
|
|
{
|
||
|
|
return hdr==FourCC("LZW4");
|
||
|
|
}
|
||
|
|
|
||
|
|
std::shared_ptr<XPKDecompressor> LZW4Decompressor::create(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify)
|
||
|
|
{
|
||
|
|
return std::make_shared<LZW4Decompressor>(hdr,recursionLevel,packedData,state,verify);
|
||
|
|
}
|
||
|
|
|
||
|
|
LZW4Decompressor::LZW4Decompressor(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify) :
|
||
|
|
XPKDecompressor(recursionLevel),
|
||
|
|
_packedData(packedData)
|
||
|
|
{
|
||
|
|
if (!detectHeaderXPK(hdr)) throw Decompressor::InvalidFormatError();
|
||
|
|
}
|
||
|
|
|
||
|
|
LZW4Decompressor::~LZW4Decompressor()
|
||
|
|
{
|
||
|
|
// nothing needed
|
||
|
|
}
|
||
|
|
|
||
|
|
const std::string &LZW4Decompressor::getSubName() const noexcept
|
||
|
|
{
|
||
|
|
static std::string name="XPK-LZW4: LZW4 CyberYAFA compressor";
|
||
|
|
return name;
|
||
|
|
}
|
||
|
|
|
||
|
|
void LZW4Decompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
|
||
|
|
{
|
||
|
|
ForwardInputStream inputStream(_packedData,0,_packedData.size());
|
||
|
|
MSBBitReader<ForwardInputStream> bitReader(inputStream);
|
||
|
|
auto readBit=[&]()->uint32_t
|
||
|
|
{
|
||
|
|
return bitReader.readBitsBE32(1);
|
||
|
|
};
|
||
|
|
auto readByte=[&]()->uint8_t
|
||
|
|
{
|
||
|
|
return inputStream.readByte();
|
||
|
|
};
|
||
|
|
|
||
|
|
ForwardOutputStream outputStream(rawData,0,rawData.size());
|
||
|
|
|
||
|
|
while (!outputStream.eof())
|
||
|
|
{
|
||
|
|
if (!readBit())
|
||
|
|
{
|
||
|
|
outputStream.writeByte(readByte());
|
||
|
|
} else {
|
||
|
|
uint32_t distance=uint32_t(readByte())<<8;
|
||
|
|
distance|=uint32_t(readByte());
|
||
|
|
if (!distance) throw Decompressor::DecompressionError();
|
||
|
|
distance=65536-distance;
|
||
|
|
uint32_t count=uint32_t(readByte())+3;
|
||
|
|
|
||
|
|
outputStream.copy(distance,count);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|