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/*
* ContainerPP20.cpp
* -----------------
* Purpose: Handling of PowerPack PP20 compressed modules
* Notes : (currently none)
* Authors: Olivier Lapicque
* OpenMPT Devs
* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
*/
#include "stdafx.h"
#include "../common/FileReader.h"
#include "Container.h"
#include "Sndfile.h"
#include <stdexcept>
OPENMPT_NAMESPACE_BEGIN
#if !defined(MPT_WITH_ANCIENT)
struct PPBITBUFFER
{
uint32 bitcount = 0;
uint32 bitbuffer = 0;
const uint8 *pStart = nullptr;
const uint8 *pSrc = nullptr;
uint32 GetBits(uint32 n);
};
uint32 PPBITBUFFER::GetBits(uint32 n)
{
uint32 result = 0;
for(uint32 i = 0; i < n; i++)
{
if(!bitcount)
{
bitcount = 8;
if(pSrc != pStart)
pSrc--;
bitbuffer = *pSrc;
}
result = (result << 1) | (bitbuffer & 1);
bitbuffer >>= 1;
bitcount--;
}
return result;
}
static bool PP20_DoUnpack(mpt::span<const uint8> src, uint8 *pDst, uint32 dstLen)
{
const std::array<uint8, 4> modeTable{src[0], src[1], src[2], src[3]};
PPBITBUFFER BitBuffer;
BitBuffer.pStart = src.data();
BitBuffer.pSrc = src.data() + src.size() - 4;
BitBuffer.GetBits(src.data()[src.size() - 1]);
uint32 bytesLeft = dstLen;
while(bytesLeft > 0)
{
if(!BitBuffer.GetBits(1))
{
uint32 count = 1, countAdd;
do
{
countAdd = BitBuffer.GetBits(2);
count += countAdd;
} while(countAdd == 3);
LimitMax(count, bytesLeft);
for(uint32 i = 0; i < count; i++)
{
pDst[--bytesLeft] = (uint8)BitBuffer.GetBits(8);
}
if(!bytesLeft)
break;
}
{
uint32 modeIndex = BitBuffer.GetBits(2);
MPT_CHECKER_ASSUME(modeIndex < 4);
uint32 count = modeIndex + 2, offset;
if(modeIndex == 3)
{
offset = BitBuffer.GetBits((BitBuffer.GetBits(1)) ? modeTable[modeIndex] : 7);
uint32 countAdd = 7;
do
{
countAdd = BitBuffer.GetBits(3);
count += countAdd;
} while(countAdd == 7);
} else
{
offset = BitBuffer.GetBits(modeTable[modeIndex]);
}
LimitMax(count, bytesLeft);
for(uint32 i = 0; i < count; i++)
{
pDst[bytesLeft - 1] = (bytesLeft + offset < dstLen) ? pDst[bytesLeft + offset] : 0;
--bytesLeft;
}
}
}
return true;
}
struct PP20header
{
char magic[4]; // "PP20"
uint8 efficiency[4];
};
MPT_BINARY_STRUCT(PP20header, 8)
static bool ValidateHeader(const PP20header &hdr)
{
if(std::memcmp(hdr.magic, "PP20", 4) != 0)
{
return false;
}
if(hdr.efficiency[0] < 9 || hdr.efficiency[0] > 15
|| hdr.efficiency[1] < 9 || hdr.efficiency[1] > 15
|| hdr.efficiency[2] < 9 || hdr.efficiency[2] > 15
|| hdr.efficiency[3] < 9 || hdr.efficiency[3] > 15)
{
return false;
}
return true;
}
CSoundFile::ProbeResult CSoundFile::ProbeFileHeaderPP20(MemoryFileReader file, const uint64 *pfilesize)
{
PP20header hdr;
if(!file.ReadStruct(hdr))
{
return ProbeWantMoreData;
}
if(!ValidateHeader(hdr))
{
return ProbeFailure;
}
MPT_UNREFERENCED_PARAMETER(pfilesize);
return ProbeSuccess;
}
bool UnpackPP20(std::vector<ContainerItem> &containerItems, FileReader &file, ContainerLoadingFlags loadFlags)
{
file.Rewind();
containerItems.clear();
PP20header hdr;
if(!file.ReadStruct(hdr))
{
return false;
}
if(!ValidateHeader(hdr))
{
return false;
}
if(loadFlags == ContainerOnlyVerifyHeader)
{
return true;
}
if(!file.CanRead(4))
{
return false;
}
containerItems.emplace_back();
containerItems.back().data_cache = std::make_unique<std::vector<char> >();
std::vector<char> & unpackedData = *(containerItems.back().data_cache);
FileReader::pos_type length = file.GetLength();
if(!mpt::in_range<uint32>(length)) return false;
// Length word must be aligned
if((length % 2u) != 0)
return false;
file.Seek(length - 4);
uint32 dstLen = file.ReadUint24BE();
if(dstLen == 0)
return false;
try
{
unpackedData.resize(dstLen);
} catch(mpt::out_of_memory e)
{
mpt::delete_out_of_memory(e);
return false;
}
file.Seek(4);
FileReader::PinnedView compressedData = file.GetPinnedView(mpt::saturate_cast<uint32>(length - 4));
bool result = PP20_DoUnpack(mpt::byte_cast<mpt::span<const uint8>>(compressedData.span()), mpt::byte_cast<uint8 *>(unpackedData.data()), dstLen);
if(result)
{
containerItems.back().file = FileReader(mpt::byte_cast<mpt::const_byte_span>(mpt::as_span(unpackedData)));
}
return result;
}
#endif // !MPT_WITH_ANCIENT
OPENMPT_NAMESPACE_END
|
