/// <summary>
/// Creates a new instance of <see cref="PageReplacementAlgorithm"/>.
/// </summary>
/// <param name="pool">The memory pool that blocks will be allocated from.</param>
public PageReplacementAlgorithm(MemoryPool pool)
{
if (pool.PageSize < 4096)
throw new ArgumentOutOfRangeException("PageSize Must be greater than 4096", "pool");
if (!BitMath.IsPowerOfTwo(pool.PageSize))
throw new ArgumentException("PageSize Must be a power of 2", "pool");
m_maxValidPosition = (int.MaxValue - 1) * (long)pool.PageSize; //Max position
m_syncRoot = new object();
m_memoryPageSizeMask = pool.PageSize - 1;
m_memoryPageSizeShiftBits = BitMath.CountBitsSet((uint)m_memoryPageSizeMask);
m_pageList = new PageList(pool);
m_arrayIndexLocks = new WeakList<PageLock>();
}
/// <summary>
/// Creates a <see cref="DiskMedium"/> from a <see cref="stream"/>.
/// This will read the existing header from the <see cref="stream"/>.
/// </summary>
/// <param name="stream">An open <see cref="FileStream"/> to use. The <see cref="DiskMedium"/>
/// will assume ownership of this <see cref="FileStream"/>.</param>
/// <param name="pool">The <see cref="MemoryPool"/> to allocate data from.</param>
/// <param name="fileStructureBlockSize">the block size of the file structure. Usually 4kb.</param>
/// <returns></returns>
public static DiskMedium OpenFile(CustomFileStream stream, MemoryPool pool, int fileStructureBlockSize)
{
byte[] buffer = new byte[fileStructureBlockSize];
stream.ReadRaw(0, buffer, fileStructureBlockSize);
FileHeaderBlock header = FileHeaderBlock.Open(buffer);
BufferedFile disk = new BufferedFile(stream, pool, header, isNewFile: false);
return new DiskMedium(disk, header);
}
/// <summary>
/// Creates a <see cref="DiskMedium"/> from a <see cref="stream"/>.
/// This will initialize the <see cref="stream"/> as an empty file structure.
/// </summary>
/// <param name="stream">An open <see cref="FileStream"/> to use. The <see cref="DiskMedium"/>
/// will assume ownership of this <see cref="FileStream"/>.</param>
/// <param name="pool">the <see cref="MemoryPool"/> to allocate data from</param>
/// <param name="fileStructureBlockSize">the block size of the file structure. Usually 4kb.</param>
/// <param name="flags">Flags to write to the file</param>
/// <returns></returns>
/// <remarks>
/// This will not check if the file is truely a new file. If calling this with an existing
/// archive file, it will overwrite the table of contents, corrupting the file.
/// </remarks>
public static DiskMedium CreateFile(CustomFileStream stream, MemoryPool pool, int fileStructureBlockSize, params Guid[] flags)
{
FileHeaderBlock header = FileHeaderBlock.CreateNew(fileStructureBlockSize, flags);
BufferedFile disk = new BufferedFile(stream, pool, header, isNewFile: true);
return new DiskMedium(disk, header);
}
/// <summary>
/// Creates a <see cref="DiskMedium"/> that is entirely based in memory.
/// </summary>
/// <param name="pool">the <see cref="MemoryPool"/> to allocate data from</param>
/// <param name="fileStructureBlockSize">the block size of the file structure. Usually 4kb.</param>
/// <param name="flags">Flags to write to the file</param>
/// <returns></returns>
public static DiskMedium CreateMemoryFile(MemoryPool pool, int fileStructureBlockSize, params Guid[] flags)
{
FileHeaderBlock header = FileHeaderBlock.CreateNew(fileStructureBlockSize, flags);
MemoryPoolFile disk = new MemoryPoolFile(pool);
return new DiskMedium(disk, header);
}
/// <summary>
/// Creates a new PageMetaDataList.
/// </summary>
/// <param name="memoryPool">The buffer pool to utilize if any unmanaged memory needs to be created.</param>
public PageList(MemoryPool memoryPool)
{
m_memoryPool = memoryPool;
m_listOfPages = new NullableLargeArray<InternalPageMetaData>();
m_pageIndexLookupByPositionIndex = new SortedList<int, int>();
}
/// <summary>
/// Creates a <see cref="BinaryStream"/> that is in memory only.
/// </summary>
public BinaryStream(MemoryPool pool)
: this(new MemoryPoolStream(pool), false)
{
if (!BitConverter.IsLittleEndian)
throw new Exception("Only designed to run on a little endian processor.");
}
/// <summary>
/// Create a new <see cref="MemoryPoolStream"/>
/// </summary>
public MemoryPoolStream(MemoryPool pool)
: base(pool)
{
m_blockSize = pool.PageSize;
}
static Globals()
{
MemoryPool = new MemoryPool(65536);
}
public static DiskIo OpenFile(string fileName, MemoryPool pool, bool isReadOnly)
{
int fileStructureBlockSize;
CustomFileStream fileStream = CustomFileStream.OpenFile(fileName, pool.PageSize, out fileStructureBlockSize, isReadOnly, true);
DiskMedium disk = DiskMedium.OpenFile(fileStream, pool, fileStructureBlockSize);
return new DiskIo(disk, isReadOnly);
}
public static DiskIo CreateFile(string fileName, MemoryPool pool, int fileStructureBlockSize, params Guid[] flags)
{
//Exclusive opening to prevent duplicate opening.
CustomFileStream fileStream = CustomFileStream.CreateFile(fileName, pool.PageSize, fileStructureBlockSize);
DiskMedium disk = DiskMedium.CreateFile(fileStream, pool, fileStructureBlockSize, flags);
return new DiskIo(disk, false);
}
public static DiskIo CreateMemoryFile(MemoryPool pool, int fileStructureBlockSize, params Guid[] flags)
{
DiskMedium disk = DiskMedium.CreateMemoryFile(pool, fileStructureBlockSize, flags);
return new DiskIo(disk, false);
}
/// <summary>
/// Create a new <see cref="MemoryPoolStream"/>
/// </summary>
public MemoryPoolStream(MemoryPool pool)
: base(pool)
{
m_blockSize = pool.PageSize;
}
/// <summary>
/// Releases the unmanaged resources used by the <see cref="MemoryFile"/> object and optionally releases the managed resources.
/// </summary>
/// <param name="disposing">true to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
private void Dispose(bool disposing)
{
if (!m_disposed)
{
try
{
if (!m_pool.IsDisposed)
{
m_pool.ReleasePages(m_settings.GetAllPageIndexes());
}
}
finally
{
m_pool = null;
m_settings = null;
m_disposed = true;
}
}
}
/// <summary>
/// Create a new <see cref="MemoryPoolStreamCore"/>
/// </summary>
public MemoryPoolStreamCore(MemoryPool pool)
{
m_pool = pool;
m_shiftLength = pool.PageShiftBits;
m_pageSize = pool.PageSize;
m_invertMask = ~(long)(pool.PageSize - 1);
m_settings = new Settings();
m_syncRoot = new object();
}
/// <summary>
/// Creates a file backed memory stream.
/// </summary>
/// <param name="stream">The <see cref="CustomFileStream"/> to buffer</param>
/// <param name="pool">The <see cref="MemoryPool"/> to allocate memory from</param>
/// <param name="header">The <see cref="FileHeaderBlock"/> to be managed when modifications occur</param>
/// <param name="isNewFile">Tells if this is a newly created file. This will make sure that the
/// first 10 pages have the header data copied to it.</param>
public BufferedFile(CustomFileStream stream, MemoryPool pool, FileHeaderBlock header, bool isNewFile)
{
m_fileStructureBlockSize = header.BlockSize;
m_diskBlockSize = pool.PageSize;
m_lengthOfHeader = header.BlockSize * header.HeaderBlockCount;
m_writeBuffer = new MemoryPoolStreamCore(pool);
m_pool = pool;
m_queue = stream;
m_syncRoot = new object();
m_pageReplacementAlgorithm = new PageReplacementAlgorithm(pool);
pool.RequestCollection += m_pool_RequestCollection;
if (isNewFile)
{
byte[] headerBytes = header.GetBytes();
for (int x = 0; x < header.HeaderBlockCount; x++)
{
m_queue.WriteRaw(0, headerBytes, headerBytes.Length);
}
}
m_lengthOfCommittedData = (header.LastAllocatedBlock + 1) * (long)header.BlockSize;
m_writeBuffer.ConfigureAlignment(m_lengthOfCommittedData, pool.PageSize);
}
/// <summary>
/// Create a new <see cref="MemoryPoolFile"/>
/// </summary>
public MemoryPoolFile(MemoryPool pool)
: base(pool)
{
m_ioSession = new IoSession(this);
m_isReadOnly = false;
}
