RAMOutputStream.cs
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上传日期:2013-09-30
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文件大小:3k
- /*
- * 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;
- namespace Lucene.Net.Store
- {
-
- /// <summary> A memory-resident {@link IndexOutput} implementation.
- ///
- /// </summary>
- /// <version> $Id: RAMOutputStream.java 150537 2004-09-28 20:45:26Z cutting $
- /// </version>
-
- public class RAMOutputStream : BufferedIndexOutput
- {
- private RAMFile file;
- private int pointer = 0;
-
- /// <summary>Construct an empty output buffer. </summary>
- public RAMOutputStream() : this(new RAMFile())
- {
- }
-
- internal RAMOutputStream(RAMFile f)
- {
- file = f;
- }
-
- /// <summary>Copy the current contents of this buffer to the named output. </summary>
- public virtual void WriteTo(IndexOutput out_Renamed)
- {
- Flush();
- long end = file.length;
- long pos = 0;
- int buffer = 0;
- while (pos < end)
- {
- int length = BUFFER_SIZE;
- long nextPos = pos + length;
- if (nextPos > end)
- {
- // at the last buffer
- length = (int) (end - pos);
- }
- out_Renamed.WriteBytes((byte[]) file.buffers[buffer++], length);
- pos = nextPos;
- }
- }
-
- /// <summary>Resets this to an empty buffer. </summary>
- public virtual void Reset()
- {
- try
- {
- Seek(0);
- }
- catch (System.IO.IOException e)
- {
- // should never happen
- throw new System.SystemException(e.ToString());
- }
-
- file.length = 0;
- }
-
- public override void FlushBuffer(byte[] src, int len)
- {
- int bufferNumber = pointer / BUFFER_SIZE;
- int bufferOffset = pointer % BUFFER_SIZE;
- int bytesInBuffer = BUFFER_SIZE - bufferOffset;
- int bytesToCopy = bytesInBuffer >= len?len:bytesInBuffer;
-
- if (bufferNumber == file.buffers.Count)
- file.buffers.Add(new byte[BUFFER_SIZE]);
-
- byte[] buffer = (byte[]) file.buffers[bufferNumber];
- Array.Copy(src, 0, buffer, bufferOffset, bytesToCopy);
-
- if (bytesToCopy < len)
- {
- // not all in one buffer
- int srcOffset = bytesToCopy;
- bytesToCopy = len - bytesToCopy; // remaining bytes
- bufferNumber++;
- if (bufferNumber == file.buffers.Count)
- file.buffers.Add(new byte[BUFFER_SIZE]);
- buffer = (byte[]) file.buffers[bufferNumber];
- Array.Copy(src, srcOffset, buffer, 0, bytesToCopy);
- }
- pointer += len;
- if (pointer > file.length)
- file.length = pointer;
-
- file.lastModified = System.DateTime.Now.Ticks;
- }
-
- public override void Close()
- {
- base.Close();
- }
-
- public override void Seek(long pos)
- {
- base.Seek(pos);
- pointer = (int) pos;
- }
- public override long Length()
- {
- return file.length;
- }
- }
- }