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SciJava Common is a shared library for SciJava software. It provides a plugin framework, with an extensible mechanism for service discovery, backed by its own annotation processor, so that plugins can be loaded dynamically. It is used by downstream projects in the SciJava ecosystem, such as ImageJ and SCIFIO.

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/*
 * #%L
 * SciJava Common shared library for SciJava software.
 * %%
 * Copyright (C) 2009 - 2017 Board of Regents of the University of
 * Wisconsin-Madison, Broad Institute of MIT and Harvard, Max Planck
 * Institute of Molecular Cell Biology and Genetics, University of
 * Konstanz, and KNIME GmbH.
 * %%
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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package org.scijava.io.handle;

import java.io.EOFException;
import java.io.IOException;

import org.scijava.io.ByteBank;
import org.scijava.io.location.BytesLocation;
import org.scijava.plugin.Plugin;

/**
 * {@link DataHandle} for a {@link BytesLocation}.
 *
 * @author Curtis Rueden
 * @author Melissa Linkert
 * @author Gabriel Einsdorf
 */
@Plugin(type = DataHandle.class)
public class BytesHandle extends AbstractDataHandle {

	private long offset = 0;

	// -- DataHandle methods --

	@Override
	public boolean isReadable() {
		return true;
	}

	@Override
	public boolean isWritable() {
		return !bytes().isReadOnly();
	}

	@Override
	public boolean exists() {
		return true;
	}

	@Override
	public long offset() {
		return offset;
	}

	@Override
	public long length() {
		return bytes().size();
	}

	@Override
	public void setLength(final long length) throws IOException {
		// check if new length is legal
		bytes().basicRangeCheck(0, length);
		// TODO update the maxLength?
	}

	@Override
	public int read(final byte[] b, final int off, int len) throws IOException {
		if (offset + len > length()) {
			len = (int) (length() - offset);
		}
		bytes().getBytes(offset, b, off, len);
		offset += len;
		return len;
	}

	@Override
	public void seek(final long pos) throws IOException {
		if (pos > length()) setLength(pos);
		offset = pos;
	}

	// -- DataInput methods --

	@Override
	public byte readByte() throws IOException {
		ensureReadable(1);
		try {
			// we need to convert the bytes into the range 0-255
			return bytes().getByte(offset++);
		}
		catch (final Exception e) {
			throw eofException(e);
		}
	}

	@Override
	public void readFully(final byte[] b, final int off, final int len)
		throws IOException
	{
		ensureReadable(len);
		try {
			bytes().getBytes(offset, b, off, len);
			offset += len;
		}
		catch (final Exception e) {
			throw eofException(e);
		}
	}

	// -- DataOutput methods --

	@Override
	public void write(final byte[] b, final int off, final int len)
		throws IOException
	{
		ensureWritable(len);
		bytes().setBytes(offset, b, off, len);
		offset += len;
	}

	@Override
	public void write(final int b) throws IOException {
		ensureWritable(1);
		bytes().setByte(offset, (byte) b);
		offset++;
	}

	// -- Closeable methods --

	@Override
	public void close() {
		// NB: No action needed.
	}

	// -- Typed methods --

	@Override
	public Class getType() {
		return BytesLocation.class;
	}

	// -- Helper methods --

	private ByteBank bytes() {
		return get().getByteBank();
	}

	private EOFException eofException(final Throwable cause) {
		final EOFException eof = new EOFException();
		eof.initCause(cause);
		return eof;
	}

}