Files
winamp/Src/external_dependencies/openmpt-trunk/include/ancient/src/LIN1Decompressor.cpp
2024-09-24 14:54:57 +02:00

124 lines
2.9 KiB
C++
Vendored

/* Copyright (C) Teemu Suutari */
#include "LIN1Decompressor.hpp"
#include "InputStream.hpp"
#include "OutputStream.hpp"
#include "common/Common.hpp"
namespace ancient::internal
{
bool LIN1Decompressor::detectHeaderXPK(uint32_t hdr) noexcept
{
return hdr==FourCC("LIN1") || hdr==FourCC("LIN3");
}
std::shared_ptr<XPKDecompressor> LIN1Decompressor::create(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify)
{
return std::make_shared<LIN1Decompressor>(hdr,recursionLevel,packedData,state,verify);
}
LIN1Decompressor::LIN1Decompressor(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();
_ver=(hdr==FourCC("LIN1"))?1:3;
if (packedData.size()<5) throw Decompressor::InvalidFormatError();
uint32_t tmp=packedData.readBE32(0);
if (tmp) throw Decompressor::InvalidFormatError(); // password set
}
LIN1Decompressor::~LIN1Decompressor()
{
// nothing needed
}
const std::string &LIN1Decompressor::getSubName() const noexcept
{
static std::string name1="XPK-LIN1: LIN1 LINO packer";
static std::string name3="XPK-LIN3: LIN3 LINO packer";
return (_ver==1)?name1:name3;
}
void LIN1Decompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
{
ForwardInputStream inputStream(_packedData,5,_packedData.size());
MSBBitReader<ForwardInputStream> bitReader(inputStream);
auto readBits=[&](uint32_t count)->uint32_t
{
return bitReader.readBits8(count);
};
auto readByte=[&]()->uint8_t
{
return inputStream.readByte();
};
size_t rawSize=rawData.size();
ForwardOutputStream outputStream(rawData,0,rawSize);
while (!outputStream.eof())
{
if (!readBits(1))
{
outputStream.writeByte(readByte()^0x55);
} else {
uint32_t count=3;
if (readBits(1))
{
count=readBits(2);
if (count==3)
{
count=readBits(3);
if (count==7)
{
count=readBits(4);
if (count==15)
{
count=readByte();
if (count==0xff) throw Decompressor::DecompressionError();
count+=3;
} else count+=14;
} else count+=7;
} else count+=4;
}
uint32_t distance = 0;
switch (readBits(2))
{
case 0:
distance=readByte()+1;
break;
case 1:
distance=uint32_t(readBits(2))<<8;
distance|=readByte();
distance+=0x101;
break;
case 2:
distance=uint32_t(readBits(4))<<8;
distance|=readByte();
distance+=0x501;
break;
case 3:
distance=uint32_t(readBits(6))<<8;
distance|=readByte();
distance+=0x1501;
break;
}
// buggy compressors
count=std::min(count,uint32_t(rawSize-outputStream.getOffset()));
if (!count) throw Decompressor::DecompressionError();
outputStream.copy(distance,count);
}
}
}
}