/*
* 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 IndexInputLucene.Net.Store.IndexInput;
using BitVectorLucene.Net.Util.BitVector;
namespace Lucene.Net.Index{
class SegmentTermDocs : TermDocs
{
protected internal SegmentReader parent;
protected internal IndexInput freqStream;
protected internal int count;
protected internal int df;
protected internal BitVector deletedDocs;
internal int doc = 0;
internal int freq;
private int skipInterval;
private int numSkips;
private int skipCount;
private IndexInput skipStream;
private int skipDoc;
private long freqPointer;
private long proxPointer;
private long skipPointer;
private bool haveSkipped;
protected internal SegmentTermDocs(SegmentReader parent)
{
this.parent = parent;
this.freqStream = (IndexInput) parent.freqStream.Clone();
this.deletedDocs = parent.deletedDocs;
this.skipInterval = parent.tis.GetSkipInterval();
}
public virtual void Seek(Term term)
{
TermInfo ti = parent.tis.Get(term);
Seek(ti);
}
public virtual void Seek(TermEnum termEnum)
{
TermInfo ti;
// use comparison of fieldinfos to verify that termEnum belongs to the same segment as this SegmentTermDocs
if (termEnum is SegmentTermEnum && ((SegmentTermEnum) termEnum).fieldInfos == parent.fieldInfos)
// optimized case
ti = ((SegmentTermEnum) termEnum).TermInfo();
// punt case
else
ti = parent.tis.Get(termEnum.Term());
Seek(ti);
}
internal virtual void Seek(TermInfo ti)
{
count = 0;
if (ti == null)
{
df = 0;
}
else
{
df = ti.docFreq;
doc = 0;
skipDoc = 0;
skipCount = 0;
numSkips = df / skipInterval;
freqPointer = ti.freqPointer;
proxPointer = ti.proxPointer;
skipPointer = freqPointer + ti.skipOffset;
freqStream.Seek(freqPointer);
haveSkipped = false;
}
}
public virtual void Close()
{
freqStream.Close();
if (skipStream != null)
skipStream.Close();
}
public int Doc()
{
return doc;
}
public int Freq()
{
return freq;
}
protected internal virtual void SkippingDoc()
{
}
public virtual bool Next()
{
while (true)
{
if (count == df)
return false;
int docCode = freqStream.ReadVInt();
doc += (int) (((uint) docCode) >> 1); // shift off low bit
if ((docCode & 1) != 0)
// if low bit is set
freq = 1;
// freq is one
else
freq = freqStream.ReadVInt(); // else read freq
count++;
if (deletedDocs == null || !deletedDocs.Get(doc))
break;
SkippingDoc();
}
return true;
}
/// <summary>Optimized implementation. </summary>
public virtual int Read(int[] docs, int[] freqs)
{
int length = docs.Length;
int i = 0;
while (i < length && count < df)
{
// manually inlined call to next() for speed
int docCode = freqStream.ReadVInt();
doc += (int) (((uint) docCode) >> 1); // shift off low bit
if ((docCode & 1) != 0)
// if low bit is set
freq = 1;
// freq is one
else
freq = freqStream.ReadVInt(); // else read freq
count++;
if (deletedDocs == null || !deletedDocs.Get(doc))
{
docs[i] = doc;
freqs[i] = freq;
++i;
}
}
return i;
}
/// <summary>Overridden by SegmentTermPositions to skip in prox stream. </summary>
protected internal virtual void SkipProx(long proxPointer)
{
}
/// <summary>Optimized implementation. </summary>
public virtual bool SkipTo(int target)
{
if (df >= skipInterval)
{
// optimized case
if (skipStream == null)
skipStream = (IndexInput) freqStream.Clone(); // lazily clone
if (!haveSkipped)
{
// lazily seek skip stream
skipStream.Seek(skipPointer);
haveSkipped = true;
}
// scan skip data
int lastSkipDoc = skipDoc;
long lastFreqPointer = freqStream.GetFilePointer();
long lastProxPointer = - 1;
int numSkipped = - 1 - (count % skipInterval);
while (target > skipDoc)
{
lastSkipDoc = skipDoc;
lastFreqPointer = freqPointer;
lastProxPointer = proxPointer;
if (skipDoc != 0 && skipDoc >= doc)
numSkipped += skipInterval;
if (skipCount >= numSkips)
break;
skipDoc += skipStream.ReadVInt();
freqPointer += skipStream.ReadVInt();
proxPointer += skipStream.ReadVInt();
skipCount++;
}
// if we found something to skip, then skip it
if (lastFreqPointer > freqStream.GetFilePointer())
{
freqStream.Seek(lastFreqPointer);
SkipProx(lastProxPointer);
doc = lastSkipDoc;
count += numSkipped;
}
}
// done skipping, now just scan
do
{
if (!Next())
return false;
}
while (target > doc);
return true;
}
}
}
|