internal static MemoryMapping Grow(long bytesToGrow, MemoryMapping mapping)
{
if (bytesToGrow <= 0 || bytesToGrow % Constants.AllocationGranularity != 0)
{
throw new ArgumentException("The growth must be a multiple of 64Kb and greater than zero");
}
long offset = mapping.fileStream.Length;
mapping.fileStream.SetLength(mapping.fileStream.Length + bytesToGrow);
var mmf = MemoryMappedFile.CreateFromFile(mapping.fileStream, null, mapping.fileStream.Length, MemoryMappedFileAccess.ReadWrite, HandleInheritability.None, true);
uint *offsetPointer = (uint *)&offset;
var lastArea = mapping.areas[mapping.areas.Count - 1];
byte *desiredAddress = lastArea.Address + lastArea.Size;
ulong bytesToMap = (ulong)bytesToGrow;
var address = Win32FileMapping.MapViewOfFileEx(mmf.SafeMemoryMappedFileHandle.DangerousGetHandle(),
Win32FileMapping.FileMapAccess.Read | Win32FileMapping.FileMapAccess.Write,
offsetPointer[1], offsetPointer[0], new UIntPtr(bytesToMap), desiredAddress);
if (address == null)
{
bytesToMap = (ulong)mapping.fileStream.Length;
address = Win32FileMapping.MapViewOfFileEx(mmf.SafeMemoryMappedFileHandle.DangerousGetHandle(),
Win32FileMapping.FileMapAccess.Read | Win32FileMapping.FileMapAccess.Write,
0, 0, new UIntPtr(bytesToMap), null);
if (address == null)
{
throw new Win32Exception();
}
mapping = new MemoryMapping()
{
baseAddress = address,
fileStream = mapping.fileStream,
refCount = 1
};
}
var area = new MemoryMappedArea
{
Address = address,
Mmf = mmf,
Size = (long)bytesToMap
};
mapping.areas.Add(area);
return(mapping);
}
internal static MemoryMapping Create(FileStream fs, long bytesToMap = 0)
{
var mmf = MemoryMappedFile.CreateFromFile(fs, null, fs.Length, MemoryMappedFileAccess.ReadWrite, HandleInheritability.None, true);
var address = Win32FileMapping.MapViewOfFileEx(mmf.SafeMemoryMappedFileHandle.DangerousGetHandle(),
Win32FileMapping.FileMapAccess.Read | Win32FileMapping.FileMapAccess.Write,
0, 0, new UIntPtr((ulong)bytesToMap), null);
if (address == null)
{
throw new Win32Exception();
}
var mapping = new MemoryMapping()
{
refCount = 1,
fileStream = fs,
baseAddress = address
};
mapping.areas.Add(new MemoryMappedArea(mmf, address, fs.Length));
return(mapping);
}
