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package org.netbeans.lib.profiler.heap;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;


/**
 *
 * @author Tomas Hurka
 */
class HprofMappedByteBuffer extends HprofByteBuffer {
    //~ Instance fields ----------------------------------------------------------------------------------------------------------

    private MappedByteBuffer dumpBuffer;

    //~ Constructors -------------------------------------------------------------------------------------------------------------

    HprofMappedByteBuffer(File dumpFile) throws IOException {
        FileInputStream fis = new FileInputStream(dumpFile);
        FileChannel channel = fis.getChannel();
        length = channel.size();
        dumpBuffer = channel.map(FileChannel.MapMode.READ_ONLY, 0, length);
        channel.close();
        readHeader();
    }

    //~ Methods ------------------------------------------------------------------------------------------------------------------

    char getChar(long index) {
        return dumpBuffer.getChar((int) index);
    }

    double getDouble(long index) {
        return dumpBuffer.getDouble((int) index);
    }

    float getFloat(long index) {
        return dumpBuffer.getFloat((int) index);
    }

    int getInt(long index) {
        return dumpBuffer.getInt((int) index);
    }

    long getLong(long index) {
        return dumpBuffer.getLong((int) index);
    }

    short getShort(long index) {
        return dumpBuffer.getShort((int) index);
    }

    // delegate to MappedByteBuffer
    byte get(long index) {
        return dumpBuffer.get((int) index);
    }

    synchronized void get(long position, byte[] chars) {
        dumpBuffer.position((int) position);
        dumpBuffer.get(chars);
    }
    
    public String toString() {
        return "Memory mapped file strategy";
    }
}