svn-gvsig-desktop / trunk / org.gvsig.desktop / org.gvsig.desktop.library / org.gvsig.utils / src / main / java / org / gvsig / utils / bigfile / BigByteBuffer.java @ 40561
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/**
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* gvSIG. Desktop Geographic Information System.
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*
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* Copyright (C) 2007-2013 gvSIG Association.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 3
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*
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* For any additional information, do not hesitate to contact us
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* at info AT gvsig.com, or visit our website www.gvsig.com.
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*/
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package org.gvsig.utils.bigfile; |
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import java.io.IOException; |
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import java.nio.Buffer; |
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import java.nio.ByteBuffer; |
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import java.nio.ByteOrder; |
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import java.nio.CharBuffer; |
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import java.nio.DoubleBuffer; |
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import java.nio.FloatBuffer; |
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import java.nio.IntBuffer; |
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import java.nio.LongBuffer; |
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import java.nio.MappedByteBuffer; |
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import java.nio.ShortBuffer; |
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import java.nio.channels.FileChannel; |
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/**
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* @author Fjp
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*
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* Clase para trabajar con ficheros grandes. Mapea solo un trozo
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* de fichero en memoria, y cuando intentas acceder fuera de esa
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* zona, se ocupa de leer autom?ticamente el trozo que le falta.
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*/
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public class BigByteBuffer { |
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private static long DEFAULT_SIZE = 50*1024*1024; // 50 Megas m?ximo |
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MappedByteBuffer bb;
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FileChannel fc;
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long minAbs, maxAbs, posAbs;
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int minRel, maxRel, posRel;
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long sizeChunk, amountMem;
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long fileSize;
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FileChannel.MapMode mode;
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/**
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* Revisa la posici?n absoluta, y si hace falta, carga el buffer
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* con la parte de fichero que toca.
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* @throws IOException
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*/
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private void prepareBuffer(long posActual, int numBytesToRead) |
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{ |
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long desiredPos = posActual + numBytesToRead;
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if ((desiredPos > maxAbs) || (posActual < minAbs))
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{ |
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// Quiero leer fuera:
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sizeChunk = Math.min(fileSize-posActual, amountMem);
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try {
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ByteOrder lastOrder = bb.order();
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bb = fc.map(mode, posActual, sizeChunk); |
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minAbs = posActual; |
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maxAbs = sizeChunk + posActual; |
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bb.order(lastOrder); |
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// System.out.println("BigByteBuffer: min=" + minAbs
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// + " maxAbs=" + maxAbs + " posAbs = " + posAbs);
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} catch (IOException e) { |
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// TODO Auto-generated catch block
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e.printStackTrace(); |
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} |
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} |
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// Dejamos posAbs apuntando a donde va a quedar
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// "a priori", antes de leer de verdad, que se hace
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// al salir de esta funci?n.
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posAbs = desiredPos; |
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} |
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public BigByteBuffer(FileChannel fc, FileChannel.MapMode mode, long amountMem) throws IOException |
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{ |
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this.amountMem = amountMem;
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this.fc = fc;
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this.fileSize = fc.size();
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this.mode = mode;
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sizeChunk = Math.min(fc.size(), amountMem);
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bb = fc.map(mode, 0L, sizeChunk);
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minAbs = 0;
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maxAbs = sizeChunk; |
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} |
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public BigByteBuffer(FileChannel fc, FileChannel.MapMode mode) throws IOException |
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{ |
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this.amountMem = DEFAULT_SIZE;
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this.fc = fc;
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this.fileSize = fc.size();
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this.mode = mode;
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sizeChunk = Math.min(fc.size(), amountMem);
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bb = fc.map(mode, 0L, sizeChunk);
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minAbs = 0;
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maxAbs = sizeChunk; |
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} |
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public synchronized byte get() { |
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prepareBuffer(posAbs,1);
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return bb.get();
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} |
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public synchronized ByteBuffer get(byte[] dst) |
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{ |
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prepareBuffer(posAbs, dst.length); |
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return bb.get(dst);
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} |
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public synchronized char getChar() { |
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prepareBuffer(posAbs,2);
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return bb.getChar();
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} |
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public synchronized double getDouble() { |
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prepareBuffer(posAbs,8);
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return bb.getDouble();
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} |
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public synchronized float getFloat() { |
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prepareBuffer(posAbs,4);
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return bb.getFloat();
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} |
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public synchronized int getInt() { |
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prepareBuffer(posAbs,4);
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return bb.getInt();
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} |
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public synchronized long getLong() { |
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prepareBuffer(posAbs,8);
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return bb.getLong();
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} |
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public synchronized short getShort() { |
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prepareBuffer(posAbs,2);
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return bb.getShort();
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} |
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public boolean isDirect() { |
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return bb.isDirect();
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} |
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public synchronized byte get(int index) { |
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prepareBuffer(index,1);
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return bb.get(index - (int) minAbs); |
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} |
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public synchronized char getChar(int index) { |
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prepareBuffer(index,2);
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return bb.getChar(index - (int) minAbs); |
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} |
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public synchronized double getDouble(int index) { |
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prepareBuffer(index,8);
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return bb.getDouble(index - (int) minAbs); |
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} |
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public synchronized float getFloat(int index) { |
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prepareBuffer(index,4);
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return bb.getFloat(index - (int) minAbs); |
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} |
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public synchronized int getInt(int index) { |
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prepareBuffer(index,4);
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return bb.getInt(index - (int) minAbs); |
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} |
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public synchronized long getLong(int index) { |
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prepareBuffer(index,8);
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return bb.getLong(index - (int) minAbs); |
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} |
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public synchronized short getShort(int index) { |
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prepareBuffer(index,2);
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return bb.getShort(index - (int) minAbs); |
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} |
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public ByteBuffer asReadOnlyBuffer() { |
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return bb.asReadOnlyBuffer();
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} |
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public ByteBuffer compact() { |
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return bb.compact();
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} |
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public ByteBuffer duplicate() { |
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return bb.duplicate();
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} |
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public ByteBuffer slice() { |
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return bb.slice();
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} |
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public synchronized ByteBuffer put(byte b) { |
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prepareBuffer(posAbs,1);
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return bb.put(b);
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} |
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public synchronized ByteBuffer putChar(char value) { |
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prepareBuffer(posAbs,2);
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return bb.putChar(value);
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} |
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public synchronized ByteBuffer putDouble(double value) { |
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prepareBuffer(posAbs,8);
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return bb.putDouble(value);
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} |
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public synchronized ByteBuffer putFloat(float value) { |
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prepareBuffer(posAbs,4);
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return bb.putFloat(value);
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} |
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public synchronized ByteBuffer putInt(int value) { |
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prepareBuffer(posAbs,4);
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return bb.putInt(value);
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} |
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public synchronized ByteBuffer put(int index, byte b) { |
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prepareBuffer(index,1);
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return bb.put(index- (int) minAbs, b); |
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} |
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public synchronized ByteBuffer putChar(int index, char value) { |
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prepareBuffer(index,2);
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return bb.putChar(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putDouble(int index, double value) { |
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prepareBuffer(index,8);
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return bb.putDouble(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putFloat(int index, float value) { |
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prepareBuffer(index,4);
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return bb.putFloat(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putInt(int index, int value) { |
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prepareBuffer(index,4);
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return bb.putInt(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putLong(int index, long value) { |
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prepareBuffer(index,8);
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return bb.putLong(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putShort(int index, short value) { |
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prepareBuffer(index,2);
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return bb.putShort(index- (int) minAbs, value); |
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} |
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public synchronized ByteBuffer putLong(long value) { |
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prepareBuffer(posAbs,8);
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return bb.putLong(value);
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} |
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public synchronized ByteBuffer putShort(short value) { |
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prepareBuffer(posAbs,2);
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return bb.putShort(value);
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} |
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public CharBuffer asCharBuffer() { |
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return bb.asCharBuffer();
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} |
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public DoubleBuffer asDoubleBuffer() { |
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return bb.asDoubleBuffer();
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} |
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public FloatBuffer asFloatBuffer() { |
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return bb.asFloatBuffer();
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} |
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public IntBuffer asIntBuffer() { |
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return bb.asIntBuffer();
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} |
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public LongBuffer asLongBuffer() { |
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return bb.asLongBuffer();
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} |
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public ShortBuffer asShortBuffer() { |
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return bb.asShortBuffer();
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} |
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public boolean isReadOnly() { |
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return bb.isReadOnly();
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} |
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public final ByteOrder order() |
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{ |
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return bb.order();
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} |
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public final ByteBuffer order(ByteOrder bo) |
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{ |
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return bb.order(bo);
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} |
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public final long position() |
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{ |
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return posAbs;
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} |
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public synchronized final Buffer position(long newPosition) |
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{ |
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prepareBuffer(newPosition,0);
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int relPos = (int) (newPosition - minAbs); |
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// System.out.println("Position=" + newPosition);
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return bb.position(relPos);
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} |
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} |