Play-/Source/OpticalMedia.cpp
2018-10-19 12:53:50 -04:00

126 lines
3.9 KiB
C++

#include <cassert>
#include <cstring>
#include "OpticalMedia.h"
#define DVD_LAYER_MAX_BLOCKS 2295104
COpticalMedia* COpticalMedia::CreateAuto(StreamPtr& stream)
{
auto result = new COpticalMedia();
//Simulate a disk with only one data track
try
{
auto blockProvider = std::make_shared<ISO9660::CBlockProvider2048>(stream);
result->m_fileSystem = std::make_unique<CISO9660>(blockProvider);
result->m_track0DataType = TRACK_DATA_TYPE_MODE1_2048;
}
catch(...)
{
//Failed with block size 2048, try with CD-ROM XA
auto blockProvider = std::make_shared<ISO9660::CBlockProviderCDROMXA>(stream);
result->m_fileSystem = std::make_unique<CISO9660>(blockProvider);
result->m_track0DataType = TRACK_DATA_TYPE_MODE2_2352;
}
if(result->m_track0DataType == TRACK_DATA_TYPE_MODE1_2048)
{
result->CheckDualLayerDvd(stream);
result->SetupSecondLayer(stream);
}
return result;
}
COpticalMedia* COpticalMedia::CreateDvd(StreamPtr& stream, bool isDualLayer, uint32 secondLayerStart)
{
auto result = new COpticalMedia();
auto blockProvider = std::make_shared<ISO9660::CBlockProvider2048>(stream);
result->m_fileSystem = std::make_unique<CISO9660>(blockProvider);
result->m_track0DataType = TRACK_DATA_TYPE_MODE1_2048;
result->m_dvdIsDualLayer = isDualLayer;
result->m_dvdSecondLayerStart = secondLayerStart;
result->SetupSecondLayer(stream);
return result;
}
COpticalMedia::TRACK_DATA_TYPE COpticalMedia::GetTrackDataType(uint32 trackIndex) const
{
assert(trackIndex == 0);
return m_track0DataType;
}
CISO9660* COpticalMedia::GetFileSystem()
{
return m_fileSystem.get();
}
CISO9660* COpticalMedia::GetFileSystemL1()
{
return m_fileSystemL1.get();
}
bool COpticalMedia::GetDvdIsDualLayer() const
{
return m_dvdIsDualLayer;
}
uint32 COpticalMedia::GetDvdSecondLayerStart() const
{
//The PS2 seems to report a second layer LBN that is 0x10
//sectors less than what the actual layer break position is
return m_dvdSecondLayerStart - 0x10;
}
void COpticalMedia::CheckDualLayerDvd(const StreamPtr& stream)
{
//Heuristic to detect dual layer DVD disc images
static const uint32 blockSize = 2048;
auto imageSize = stream->GetLength();
uint32 imageBlockCount = static_cast<uint32>(imageSize / blockSize);
//DL discs may be smaller than the capacity of a SL DVD, but we assume
//that games that use DL discs use more than the SL DVD capacity
if(imageBlockCount < DVD_LAYER_MAX_BLOCKS) return;
//Bigger than the capacity of a SL DVD, certainly a dual layer disc
m_dvdIsDualLayer = true;
//We need to look for the start of the second layer
//The second layer is at most as big as the first one, so
//we can start looking from half of the disk image
//NOTE: Wild Arms: Alter Code F seems to have a second layer that's a bit
//larger than the first one? That's why we start looking at 15 / 32 of the image's size
auto searchBlockAddress = imageBlockCount * 15 / 32;
stream->Seek(static_cast<uint64>(searchBlockAddress) * blockSize, Framework::STREAM_SEEK_SET);
//Scan all blocks from the search point, looking for a valid ISO9660 descriptor
for(auto lba = searchBlockAddress; lba < imageBlockCount; lba++)
{
static const uint32 blockHeaderSize = 6;
static_assert(blockSize >= blockHeaderSize, "Block header size is too large");
char blockHeader[blockHeaderSize];
stream->Read(blockHeader, blockHeaderSize);
if(
(blockHeader[0] == 0x01) &&
(!strncmp(blockHeader + 1, "CD001", 5)))
{
//We've found a valid ISO9660 descriptor
m_dvdSecondLayerStart = lba;
break;
}
stream->Seek(blockSize - blockHeaderSize, Framework::STREAM_SEEK_CUR);
}
//If we haven't found it, something's wrong
assert(m_dvdSecondLayerStart != 0);
}
void COpticalMedia::SetupSecondLayer(const StreamPtr& stream)
{
if(!m_dvdIsDualLayer) return;
auto blockProvider = std::make_shared<ISO9660::CBlockProvider2048>(stream, GetDvdSecondLayerStart());
m_fileSystemL1 = std::make_unique<CISO9660>(blockProvider);
}