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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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;
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.MemoryStream buffer;
private long length;
internal MMapIndexInput(System.IO.FileStream raf)
{
byte[] data = new byte[raf.Length];
raf.Read(data, 0, (int) raf.Length);
this.length = raf.Length;
this.buffer = new System.IO.MemoryStream(data); // this.buffer = raf.getChannel().map(MapMode.READ_ONLY, 0, length); // {{Aroush-1.9}}
}
public override byte ReadByte()
{
return (byte) buffer.ReadByte();
}
public override void ReadBytes(byte[] b, int offset, int len)
{
buffer.Read(b, offset, len);
}
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()
{
}
}
private class MultiMMapIndexInput : IndexInput, System.ICloneable
{
private System.IO.MemoryStream[] buffers;
private int[] bufSizes; // keep here, ByteBuffer.size() method is optional
private long length;
private int curBufIndex;
private int maxBufSize;
private System.IO.MemoryStream curBuf; // 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.MemoryStream[nrBuffers]; // {{Aroush-1.9}}
this.bufSizes = new int[nrBuffers];
long bufferStart = 0;
System.IO.FileStream rafc = raf;
for (int bufNr = 0; bufNr < nrBuffers; bufNr++)
{
byte[] data = new byte[rafc.Length];
raf.Read(data, 0, (int) rafc.Length);
int bufSize = (length > (bufferStart + maxBufSize)) ? maxBufSize : (int) (length - bufferStart);
this.buffers[bufNr] = new System.IO.MemoryStream(data); // 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 (byte) curBuf.ReadByte();
}
public override void ReadBytes(byte[] b, int offset, int len)
{
while (len > curAvail)
{
curBuf.Read(b, offset, curAvail);
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.Read(b, offset, len);
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 System.IO.MemoryStream[buffers.Length];
// 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]; // clone.buffers[bufNr] = buffers[bufNr].duplicate(); // {{Aroush-1.9}} how do we clone?!
}
try
{
clone.Seek(GetFilePointer());
}
catch (System.IO.IOException ioe)
{
System.Exception newException = new System.Exception("", ioe); // {{Aroush-2.0}} This should be SystemException
throw newException;
}
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(System.IO.Path.Combine(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();
}
}
public override IndexInput OpenInput(System.String name, int bufferSize)
{
return OpenInput(name);
}
}
}
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