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package org.monte.media.binary;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Arrays;
import java.util.WeakHashMap;


public class FileBasedBinaryModel implements BinaryModel {

    private int segsize = 1024;
    private long offset;
    private long length;
    private RandomAccessFile racf;
    private WeakHashMap cache = new WeakHashMap();
    private File file;

    public FileBasedBinaryModel(File file) throws IOException {
        this(file, 0, file.length());
    }

    public FileBasedBinaryModel(File file, long offset, long length) throws IOException {
        racf = new RandomAccessFile(file, "r");
        this.offset = offset;
        this.length = length;
        this.file = file;
    }

    @Override
    public String toString() {
        return "FileBasedBinaryModel " + file.getName() + " " + offset + " " + length;
    }

    @Override
    public long getLength() {
        return length;
    }

    @Override
    public int getBytes(long off, int len, byte[] target) {
        byte[] cdat = cache.get(off);

        if (off + len > length) {
            len = (int) (length - off);
        }

        if (cdat != null) {
            if (cdat.length >= len) {
                System.arraycopy(cdat, 0, target, 0, len);
                return len;
            }
        }

        try {


            racf.seek(off + offset);
            racf.readFully(target, 0, len);
            byte[] cached = target.clone();
            cache.put(off, cached);

        } catch (IOException ex) {
            Arrays.fill(target, 0, len, (byte) 0);
            ex.printStackTrace();
        }
        return len;
    }

    @Override
    public void close() {
        if (racf != null) {
            try {
                racf.close();
                racf = null;
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }

    @Override
    public void finalize() {
        close();
    }
}