winamp/Src/external_dependencies/openmpt-trunk/include/ancient/src/CBR0Decompressor.cpp

65 lines
1.8 KiB
C++

/* Copyright (C) Teemu Suutari */
#include "CBR0Decompressor.hpp"
#include "InputStream.hpp"
#include "OutputStream.hpp"
#include "common/Common.hpp"
namespace ancient::internal
{
bool CBR0Decompressor::detectHeaderXPK(uint32_t hdr) noexcept
{
// CBR1 is practical joke: it is the same as CBR0 but with ID changed
return hdr==FourCC("CBR0") || hdr==FourCC("CBR1");
}
std::shared_ptr<XPKDecompressor> CBR0Decompressor::create(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify)
{
return std::make_shared<CBR0Decompressor>(hdr,recursionLevel,packedData,state,verify);
}
CBR0Decompressor::CBR0Decompressor(uint32_t hdr,uint32_t recursionLevel,const Buffer &packedData,std::shared_ptr<XPKDecompressor::State> &state,bool verify) :
XPKDecompressor(recursionLevel),
_packedData(packedData),
_isCBR0(hdr==FourCC("CBR0"))
{
if (!detectHeaderXPK(hdr)) throw Decompressor::InvalidFormatError();
}
CBR0Decompressor::~CBR0Decompressor()
{
// nothing needed
}
const std::string &CBR0Decompressor::getSubName() const noexcept
{
static std::string nameCBR0="XPK-CBR0: RLE-compressor";
static std::string nameCBR1="XPK-CBR1: RLE-compressor";
return (_isCBR0)?nameCBR0:nameCBR1;
}
void CBR0Decompressor::decompressImpl(Buffer &rawData,const Buffer &previousData,bool verify)
{
ForwardInputStream inputStream(_packedData,0,_packedData.size());
ForwardOutputStream outputStream(rawData,0,rawData.size());
// barely different than RLEN, however the count is well defined here.
while (!outputStream.eof())
{
uint32_t count=inputStream.readByte();
if (count<128)
{
count++;
for (uint32_t i=0;i<count;i++) outputStream.writeByte(inputStream.readByte());
} else {
count=257-count;
uint8_t ch=inputStream.readByte();
for (uint32_t i=0;i<count;i++) outputStream.writeByte(ch);
}
}
}
}