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An extension to the MongoDB Java Driver library that goes beyond what the GridFS feature supports. Compressed file storage, zip files, temporary files

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package me.lightspeed7.mongofs.util;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * 
 * @author David Buschman
 * 
 */
public class BytesCopier {

    private final InputStream in;
    private final OutputStream out;

    private final int blocksize;
    private boolean closeStreamOnPersist;

    public BytesCopier(final InputStream in, final OutputStream out) {

        this(8192, in, out, false);
    }

    public BytesCopier(final InputStream in, final OutputStream out, final boolean closeStreamOnPersist) {

        this(8192, in, out, closeStreamOnPersist);
    }

    public BytesCopier(final int blocksize, final InputStream in, final OutputStream out) {

        this(blocksize, in, out, false);
    }

    public BytesCopier(final int blocksize, final InputStream in, final OutputStream out, final boolean closeStreamOnPersist) {

        this.closeStreamOnPersist = closeStreamOnPersist;
        this.blocksize = blocksize;
        this.in = in;
        this.out = out;
    }

    public BytesCopier closeOutput() {
        this.closeStreamOnPersist = true;
        return this;
    }

    public void transfer(final boolean flush) throws IOException {

        int nread;
        byte[] buf = new byte[blocksize];
        while ((nread = in.read(buf)) != -1) {
            out.write(buf, 0, nread);
        }
        if (flush) {
            out.flush();
        }
        if (closeStreamOnPersist) {
            in.close();
        }
    }

    public void transfer(final long bytesToRead, final boolean flush) throws IOException {

        long bytesLeft = bytesToRead;
        while (bytesLeft > 0) {
            long buffSize = bytesToRead < blocksize ? bytesToRead : blocksize;
            bytesLeft -= blocksize;

            byte[] buf = new byte[(int) buffSize];
            int nread = in.read(buf);

            // write any bytes
            if (nread != -1) {
                out.write(buf, 0, nread);
            }

            if (nread != buffSize) { // hit EOF
                if (flush) {
                    out.flush();
                }
                if (closeStreamOnPersist) {
                    in.close();
                }
                bytesLeft = 0;
            }
        }
        if (flush) {
            out.flush();
        }

    }

}