SectorAccessibleDisk.cc

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#include "SectorAccessibleDisk.hh"
#include "EmptyDiskPatch.hh"
#include "IPSPatch.hh"
#include "DiskExceptions.hh"
#include "sha1.hh"
#include "xrange.hh"
#include <memory>

namespace openmsx {

#ifndef _MSC_VER
// This line is required according to the c++ standard, but because of a vc++
// extension, we get a link error in vc++ when we add this line. See also:
//   http://blogs.msdn.com/b/xiangfan/archive/2010/03/03/vc-s-evil-extension-implicit-definition-of-static-constant-member.aspx
const size_t SectorAccessibleDisk::SECTOR_SIZE;
#endif

SectorAccessibleDisk::SectorAccessibleDisk()
        : patch(std::make_unique<EmptyDiskPatch>(*this))
        , forcedWriteProtect(false)
        , peekMode(false)
{
}

SectorAccessibleDisk::~SectorAccessibleDisk() = default;

void SectorAccessibleDisk::readSector(size_t sector, SectorBuffer& buf)
{
        if (!isDummyDisk() && // in that case we want DriveEmptyException
            (sector > 1) && // allow reading sector 0 and 1 without calling
                            // getNbSectors() because this potentially calls
                            // detectGeometry() and that would cause an
                            // infinite loop
            (getNbSectors() <= sector)) {
                throw NoSuchSectorException("No such sector");
        }
        try {
                // in the end this calls readSectorImpl()
                patch->copyBlock(sector * sizeof(buf), buf.raw, sizeof(buf));
        } catch (MSXException& e) {
                throw DiskIOErrorException("Disk I/O error: ", e.getMessage());
        }
}

void SectorAccessibleDisk::writeSector(size_t sector, const SectorBuffer& buf)
{
        if (isWriteProtected()) {
                throw WriteProtectedException();
        }
        if (!isDummyDisk() && (getNbSectors() <= sector)) {
                throw NoSuchSectorException("No such sector");
        }
        try {
                writeSectorImpl(sector, buf);
        } catch (MSXException& e) {
                throw DiskIOErrorException("Disk I/O error: ", e.getMessage());
        }
        flushCaches();
}

size_t SectorAccessibleDisk::getNbSectors() const
{
        return getNbSectorsImpl();
}

void SectorAccessibleDisk::applyPatch(Filename patchFile)
{
        patch = std::make_unique<IPSPatch>(std::move(patchFile), std::move(patch));
}

std::vector<Filename> SectorAccessibleDisk::getPatches() const
{
        return patch->getFilenames();
}

bool SectorAccessibleDisk::hasPatches() const
{
        return !patch->isEmptyPatch();
}

Sha1Sum SectorAccessibleDisk::getSha1Sum(FilePool& filePool)
{
        checkCaches();
        if (sha1cache.empty()) {
                sha1cache = getSha1SumImpl(filePool);
        }
        return sha1cache;
}

Sha1Sum SectorAccessibleDisk::getSha1SumImpl(FilePool& /*filePool*/)
{
        try {
                setPeekMode(true);
                SHA1 sha1;
                for (auto i : xrange(getNbSectors())) {
                        SectorBuffer buf;
                        readSector(i, buf);
                        sha1.update(buf.raw, sizeof(buf));
                }
                setPeekMode(false);
                return sha1.digest();
        } catch (MSXException&) {
                setPeekMode(false);
                throw;
        }
}

int SectorAccessibleDisk::readSectors (
        SectorBuffer* buffers, size_t startSector, size_t nbSectors)
{
        try {
                for (auto i : xrange(nbSectors)) {
                        readSector(startSector + i, buffers[i]);
                }
                return 0;
        } catch (MSXException&) {
                return -1;
        }
}

int SectorAccessibleDisk::writeSectors(
        const SectorBuffer* buffers, size_t startSector, size_t nbSectors)
{
        try {
                for (auto i : xrange(nbSectors)) {
                        writeSector(startSector + i, buffers[i]);
                }
                return 0;
        } catch (MSXException&) {
                return -1;
        }
}

bool SectorAccessibleDisk::isWriteProtected() const
{
        return forcedWriteProtect || isWriteProtectedImpl();
}

void SectorAccessibleDisk::forceWriteProtect()
{
        // can't be undone
        forcedWriteProtect = true;
}

bool SectorAccessibleDisk::isDummyDisk() const
{
        return false;
}

void SectorAccessibleDisk::checkCaches()
{
        // nothing
}

void SectorAccessibleDisk::flushCaches()
{
        sha1cache.clear();
}

} // namespace openmsx