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◆ main openmsx / src / fdc / SectorAccessibleDisk.cc
4.0 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "SectorAccessibleDisk.hh"
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#include "DiskExceptions.hh"
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#include "DiskImageUtils.hh"
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#include "EmptyDiskPatch.hh"
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#include "IPSPatch.hh"
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#include "enumerate.hh"
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#include "sha1.hh"
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#include <array>
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#include <memory>
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namespace openmsx {
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SectorAccessibleDisk::SectorAccessibleDisk()
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	: patch(std::make_unique<EmptyDiskPatch>(*this))
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{
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}
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SectorAccessibleDisk::~SectorAccessibleDisk() = default;
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void SectorAccessibleDisk::readSector(size_t sector, SectorBuffer& buf)
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{
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	readSectors(std::span{&buf, 1}, sector);
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}
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void SectorAccessibleDisk::readSectors(
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	std::span<SectorBuffer> buffers, size_t startSector)
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{
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	auto last = startSector + buffers.size() - 1;
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	if (!isDummyDisk() && // in that case we want DriveEmptyException
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	    (last > 1) && // allow reading sector 0 and 1 without calling
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	                  // getNbSectors() because this potentially calls
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	                  // detectGeometry() and that would cause an
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	                  // infinite loop
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	    (getNbSectors() <= last)) {
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		throw NoSuchSectorException("No such sector");
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	}
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	try {
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		// in the end this calls readSectorsImpl()
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		patch->copyBlock(startSector * sizeof(SectorBuffer),
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		                 std::span{buffers[0].raw.data(),
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		                           buffers.size_bytes()});
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	} catch (MSXException& e) {
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		throw DiskIOErrorException("Disk I/O error: ", e.getMessage());
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	}
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}
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void SectorAccessibleDisk::readSectorsImpl(
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	std::span<SectorBuffer> buffers, size_t startSector)
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{
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	// Default implementation reads one sector at a time. But subclasses can
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	// override this method if they can do it more efficiently.
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	for (auto [i, buf] : enumerate(buffers)) {
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		readSectorImpl(startSector + i, buf);
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	}
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}
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void SectorAccessibleDisk::readSectorImpl(size_t /*sector*/, SectorBuffer& /*buf*/)
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{
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	// subclass should override exactly one of
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	//    readSectorImpl() or readSectorsImpl()
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	assert(false);
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}
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void SectorAccessibleDisk::writeSector(size_t sector, const SectorBuffer& buf)
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{
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	if (isWriteProtected()) {
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		throw WriteProtectedException();
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	}
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	if (!isDummyDisk() && (getNbSectors() <= sector)) {
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		throw NoSuchSectorException("No such sector");
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	}
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	try {
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		writeSectorImpl(sector, buf);
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	} catch (MSXException& e) {
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		throw DiskIOErrorException("Disk I/O error: ", e.getMessage());
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	}
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	flushCaches();
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}
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void SectorAccessibleDisk::writeSectors(
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	std::span<const SectorBuffer> buffers, size_t startSector)
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{
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	// Simply write one-at-a-time. There's no possibility (nor any need) yet
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	// to allow to optimize this
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	for (auto [i, buf] : enumerate(buffers)) {
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		writeSector(startSector + i, buf);
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	}
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}
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size_t SectorAccessibleDisk::getNbSectors()
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{
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	return getNbSectorsImpl();
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}
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void SectorAccessibleDisk::applyPatch(Filename patchFile)
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{
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	patch = std::make_unique<IPSPatch>(std::move(patchFile), std::move(patch));
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}
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std::vector<Filename> SectorAccessibleDisk::getPatches() const
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{
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	return patch->getFilenames();
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}
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bool SectorAccessibleDisk::hasPatches() const
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{
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	return !patch->isEmptyPatch();
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}
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Sha1Sum SectorAccessibleDisk::getSha1Sum(FilePool& filePool)
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{
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	checkCaches();
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	if (sha1cache.empty()) {
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		sha1cache = getSha1SumImpl(filePool);
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	}
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	return sha1cache;
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}
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Sha1Sum SectorAccessibleDisk::getSha1SumImpl(FilePool& /*filePool*/)
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{
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	try {
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		setPeekMode(true);
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		SHA1 sha1;
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		std::array<SectorBuffer, 32> buf;
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		size_t total = getNbSectors();
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		size_t sector = 0;
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		while (sector < total) {
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			auto chunk = std::min(buf.size(), total - sector);
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			auto sub = subspan(buf, 0, chunk);
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			readSectors(sub, sector);
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			sha1.update({sub[0].raw.data(), sub.size_bytes()});
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			sector += chunk;
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		}
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		setPeekMode(false);
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		return sha1.digest();
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	} catch (MSXException&) {
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		setPeekMode(false);
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		throw;
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	}
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}
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bool SectorAccessibleDisk::isWriteProtected() const
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{
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	return forcedWriteProtect || isWriteProtectedImpl();
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}
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void SectorAccessibleDisk::forceWriteProtect()
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{
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	// can't be undone
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	forcedWriteProtect = true;
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}
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bool SectorAccessibleDisk::isDummyDisk() const
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{
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	return false;
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}
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void SectorAccessibleDisk::checkCaches()
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{
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	// nothing
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}
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void SectorAccessibleDisk::flushCaches()
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{
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	sha1cache.clear();
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}
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} // namespace openmsx