/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
// using ByteBuffer = java.nio.ByteBuffer; // {{Aroush-1.9}}
// using FileChannel = java.nio.channels.FileChannel; // {{Aroush-1.9}}
// using MapMode = java.nio.channels.FileChannel.MapMode; // {{Aroush-1.9}}
namespace Lucene.Net.Store{
/// <summary>File-based {@link Directory} implementation that uses mmap for input.
///
/// <p>To use this, invoke Java with the System property
/// Lucene.Net.FSDirectory.class set to
/// Lucene.Net.store.MMapDirectory. This will cause {@link
/// FSDirectory#GetDirectory(File,boolean)} to return instances of this class.
/// </summary>
public class MMapDirectory : FSDirectory
{
private class MMapIndexInput : IndexInput, System.ICloneable
{
private System.IO.FileStream buffer; // private ByteBuffer buffer; // {{Aroush-1.9}}
private long length;
internal MMapIndexInput(System.IO.FileStream raf)
{
this.length = raf.Length;
// this.buffer = raf.getChannel().map(MapMode.READ_ONLY, 0, length); // {{Aroush-1.9}}
}
public override byte ReadByte()
{
return 0; // return buffer.get_Renamed(); // {{Aroush-1.9}}
}
public override void ReadBytes(byte[] b, int offset, int len)
{
// buffer.get_Renamed(b, offset, len); // {{Aroush-1.9}}
}
public override long GetFilePointer()
{
return buffer.Position;
}
public override void Seek(long pos)
{
buffer.Seek(pos, System.IO.SeekOrigin.Begin);
}
public override long Length()
{
return length;
}
public override System.Object Clone()
{
MMapIndexInput clone = (MMapIndexInput) base.Clone();
// clone.buffer = buffer.duplicate(); // {{Aroush-1.9}}
return clone;
}
public override void Close()
{
}
}
/* Added class MultiMMapIndexInput, Paul Elschot.
* Slightly adapted constructor of MMapIndexInput.
* Licensed under the Apache License, Version 2.0.
*/
private class MultiMMapIndexInput:IndexInput, System.ICloneable
{
private System.IO.FileStream[] buffers; // private ByteBuffer[] buffers; // {{Aroush-1.9}}
private int[] bufSizes; // keep here, ByteBuffer.size() method is optional
private long length;
private int curBufIndex;
private int maxBufSize;
private System.IO.FileStream curBuf; // private ByteBuffer curBuf; // {{Aroush-1.9}} // redundant for speed: buffers[curBufIndex]
private int curAvail; // redundant for speed: (bufSizes[curBufIndex] - curBuf.position())
public MultiMMapIndexInput(System.IO.FileStream raf, int maxBufSize)
{
this.length = raf.Length;
this.maxBufSize = maxBufSize;
if (maxBufSize <= 0)
throw new System.ArgumentException("Non positive maxBufSize: " + maxBufSize);
if ((length / maxBufSize) > System.Int32.MaxValue)
{
throw new System.ArgumentException("RandomAccessFile too big for maximum buffer size: " + raf.ToString());
}
int nrBuffers = (int) (length / maxBufSize);
if ((nrBuffers * maxBufSize) < length)
nrBuffers++;
this.buffers = new System.IO.FileStream[nrBuffers]; // this.buffers = new ByteBuffer[nrBuffers]; // {{Aroush-1.9}}
this.bufSizes = new int[nrBuffers];
long bufferStart = 0;
System.IO.FileStream rafc = null; // FileChannel rafc = raf.getChannel(); // {{Aroush-1.9}}
for (int bufNr = 0; bufNr < nrBuffers; bufNr++)
{
int bufSize = (length > (bufferStart + maxBufSize))?maxBufSize:(int) (length - bufferStart);
// this.buffers[bufNr] = rafc.map(MapMode.READ_ONLY, bufferStart, bufSize); // {{Aroush-1.9}}
this.bufSizes[bufNr] = bufSize;
bufferStart += bufSize;
}
Seek(0L);
}
public override byte ReadByte()
{
// Performance might be improved by reading ahead into an array of
// eg. 128 bytes and readByte() from there.
if (curAvail == 0)
{
curBufIndex++;
curBuf = buffers[curBufIndex]; // index out of bounds when too many bytes requested
curBuf.Seek(0, System.IO.SeekOrigin.Begin);
curAvail = bufSizes[curBufIndex];
}
curAvail--;
return 0; // return curBuf.get_Renamed(); // {{Aroush-1.9}}
}
public override void ReadBytes(byte[] b, int offset, int len)
{
while (len > curAvail)
{
// curBuf.get_Renamed(b, offset, curAvail); // {{Aroush-1.9}}
len -= curAvail;
offset += curAvail;
curBufIndex++;
curBuf = buffers[curBufIndex]; // index out of bounds when too many bytes requested
curBuf.Seek(0, System.IO.SeekOrigin.Begin);
curAvail = bufSizes[curBufIndex];
}
// curBuf.get_Renamed(b, offset, len); // {{Aroush-1.9}}
curAvail -= len;
}
public override long GetFilePointer()
{
return (curBufIndex * (long) maxBufSize) + curBuf.Position;
}
public override void Seek(long pos)
{
curBufIndex = (int) (pos / maxBufSize);
curBuf = buffers[curBufIndex];
int bufOffset = (int) (pos - (curBufIndex * maxBufSize));
curBuf.Seek(bufOffset, System.IO.SeekOrigin.Begin);
curAvail = bufSizes[curBufIndex] - bufOffset;
}
public override long Length()
{
return length;
}
public override System.Object Clone()
{
MultiMMapIndexInput clone = (MultiMMapIndexInput) base.Clone();
// clone.buffers = new ByteBuffer[buffers.length]; // {{Aroush-1.9}}
// No need to clone bufSizes.
// Since most clones will use only one buffer, duplicate() could also be
// done lazy in clones, eg. when adapting curBuf.
for (int bufNr = 0; bufNr < buffers.Length; bufNr++)
{
// clone.buffers[bufNr] = buffers[bufNr].duplicate(); // {{Aroush-1.9}}
}
try
{
clone.Seek(GetFilePointer());
}
catch (System.IO.IOException ioe)
{
throw new System.Exception(ioe.ToString()); // {{Aroush-1.9}} should be re-thrown as RuntimeException
}
return clone;
}
public override void Close()
{
}
}
private int MAX_BBUF = System.Int32.MaxValue;
public override IndexInput OpenInput(System.String name)
{
System.IO.FileInfo f = new System.IO.FileInfo(GetFile().FullName + "\\" + name);
System.IO.FileStream raf = new System.IO.FileStream(f.FullName, System.IO.FileMode.Open, System.IO.FileAccess.Read);
try
{
return (raf.Length <= MAX_BBUF) ? (IndexInput) new MMapIndexInput(raf) : (IndexInput) new MultiMMapIndexInput(raf, MAX_BBUF);
}
finally
{
raf.Close();
}
}
}
}
|