/// <summary>
/// Maps a file into a set of buffers </summary>
internal virtual ByteBuffer[] Map(MMapIndexInput input, FileStream fc, long offset, long length)
{
if (Number.URShift(length, chunkSizePower) >= int.MaxValue)
{
throw new ArgumentException("RandomAccessFile too big for chunk size: " + fc.ToString());
}
// LUCENENET specific: Return empty buffer if length is 0, rather than attempting to create a MemoryMappedFile.
// Part of a solution provided by Vincent Van Den Berghe: http://apache.markmail.org/message/hafnuhq2ydhfjmi2
if (length == 0)
{
return(new[] { ByteBuffer.Allocate(0).AsReadOnlyBuffer() });
}
long chunkSize = 1L << chunkSizePower;
// we always allocate one more buffer, the last one may be a 0 byte one
int nrBuffers = (int)((long)((ulong)length >> chunkSizePower)) + 1;
ByteBuffer[] buffers = new ByteBuffer[nrBuffers];
if (input.memoryMappedFile == null)
{
input.memoryMappedFile = MemoryMappedFile.CreateFromFile(
fileStream: fc,
mapName: null,
capacity: length,
access: MemoryMappedFileAccess.Read,
#if !NETSTANDARD
memoryMappedFileSecurity: null,
#endif
inheritability: HandleInheritability.Inheritable,
leaveOpen: true); // LUCENENET: We explicitly dispose the FileStream separately.
}
long bufferStart = 0L;
for (int bufNr = 0; bufNr < nrBuffers; bufNr++)
{
int bufSize = (int)((length > (bufferStart + chunkSize)) ? chunkSize : (length - bufferStart));
// LUCENENET: We get an UnauthorizedAccessException if we create a 0 byte file at the end of the range.
// See: https://stackoverflow.com/a/5501331
// We can fix this by moving back 1 byte on the offset if the bufSize is 0.
int adjust = 0;
if (bufSize == 0 && bufNr == (nrBuffers - 1) && (offset + bufferStart) > 0)
{
adjust = 1;
}
buffers[bufNr] = new MemoryMappedFileByteBuffer(
input.memoryMappedFile.CreateViewAccessor(
offset: (offset + bufferStart) - adjust,
size: bufSize,
access: MemoryMappedFileAccess.Read),
bufSize);
bufferStart += bufSize;
}
return(buffers);
}
// Closing a file closes its channel.
private static ByteBuffer MapFile(FileInfo path)
{
MemoryMappedFile file;
try
{
//file = new FileStream(path.FullName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
file = MemoryMappedFile.CreateFromFile(path.FullName);
var channel = file.CreateViewAccessor();
//FileChannel channel = file.getChannel();
ByteBuffer bytes = null;
try
{
//bytes = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
bytes = new MemoryMappedFileByteBuffer(channel, 0, 0);
}
finally
{
file.Dispose();
channel.Dispose();
}
return(bytes);
}
catch (FileNotFoundException ignored)
{
Console.Error.WriteLine(ignored);
}
catch (IOException ignored)
{
Console.Error.WriteLine(ignored);
}
return(null);
}
/// <summary>
/// Maps a file into a set of buffers </summary>
internal virtual ByteBuffer[] Map(MMapIndexInput input, FileStream fc, long offset, long length)
{
if (Number.URShift(length, chunkSizePower) >= int.MaxValue)
{
throw new ArgumentException("RandomAccessFile too big for chunk size: " + fc.ToString());
}
long chunkSize = 1L << chunkSizePower;
// we always allocate one more buffer, the last one may be a 0 byte one
int nrBuffers = (int)((long)((ulong)length >> chunkSizePower)) + 1;
ByteBuffer[] buffers = new ByteBuffer[nrBuffers];
/*
* public static MemoryMappedFile CreateFromFile(FileStream fileStream, String mapName, Int64 capacity,
* MemoryMappedFileAccess access, MemoryMappedFileSecurity memoryMappedFileSecurity,
* HandleInheritability inheritability, bool leaveOpen)
*/
long fileCapacity = length == 0 ? ushort.MaxValue : length;
if (input.memoryMappedFile == null)
{
#if NETSTANDARD
input.memoryMappedFile = MemoryMappedFile.CreateFromFile(fc, null, fileCapacity, MemoryMappedFileAccess.ReadWrite, HandleInheritability.Inheritable, false);
#else
input.memoryMappedFile = MemoryMappedFile.CreateFromFile(fc, null, fileCapacity, MemoryMappedFileAccess.ReadWrite, null, HandleInheritability.Inheritable, false);
#endif
}
long bufferStart = 0L;
for (int bufNr = 0; bufNr < nrBuffers; bufNr++)
{
int bufSize = (int)((length > (bufferStart + chunkSize)) ? chunkSize : (length - bufferStart));
// LUCENENET: We get a file access exception if we create a 0 byte file at the end of the range.
// We can fix this by moving back 1 byte if the bufSize is 0.
int adjust = 0;
if (bufSize == 0 && bufNr == (nrBuffers - 1) && (offset + bufferStart) > 0)
{
adjust = 1;
}
//buffers[bufNr] = new MemoryMappedFileByteBuffer(input.memoryMappedFile.CreateViewAccessor((offset + bufferStart) - adjust, bufSize, MemoryMappedFileAccess.Read), -1, 0, bufSize, bufSize);
buffers[bufNr] = new MemoryMappedFileByteBuffer(input.memoryMappedFile.CreateViewAccessor((offset + bufferStart) - adjust, bufSize, MemoryMappedFileAccess.Read), bufSize);
bufferStart += bufSize;
}
return(buffers);
}
/// <summary>
/// Maps a file into a set of buffers </summary>
internal virtual ByteBuffer[] Map(MMapIndexInput input, FileStream fc, long offset, long length)
{
if (Number.URShift(length, ChunkSizePower) >= int.MaxValue)
{
throw new ArgumentException("RandomAccessFile too big for chunk size: " + fc.ToString());
}
long chunkSize = 1L << ChunkSizePower;
// we always allocate one more buffer, the last one may be a 0 byte one
int nrBuffers = (int)((long)((ulong)length >> ChunkSizePower)) + 1;
ByteBuffer[] buffers = new ByteBuffer[nrBuffers];
/*
* public static MemoryMappedFile CreateFromFile(FileStream fileStream, String mapName, Int64 capacity,
* MemoryMappedFileAccess access, MemoryMappedFileSecurity memoryMappedFileSecurity,
* HandleInheritability inheritability, bool leaveOpen)
*/
if (input.memoryMappedFile == null)
{
input.memoryMappedFile = MemoryMappedFile.CreateFromFile(fc, null, length == 0 ? 100 : length, MemoryMappedFileAccess.Read, null, HandleInheritability.Inheritable, false);
}
long bufferStart = 0L;
for (int bufNr = 0; bufNr < nrBuffers; bufNr++)
{
int bufSize = (int)((length > (bufferStart + chunkSize)) ? chunkSize : (length - bufferStart));
//LUCENE TO-DO
buffers[bufNr] = new MemoryMappedFileByteBuffer(input.memoryMappedFile.CreateViewAccessor(offset + bufferStart, bufSize, MemoryMappedFileAccess.Read), -1, 0, bufSize, bufSize);
//buffers[bufNr] = fc.Map(FileStream.MapMode.READ_ONLY, offset + bufferStart, bufSize);
bufferStart += bufSize;
}
return(buffers);
}
