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PlantUML is a component that allows to quickly write diagrams from text.
There is a newer version: 1.2024.8
// THIS FILE HAS BEEN GENERATED BY A PREPROCESSOR.
/* +=======================================================================
 * |
 * |      PlantUML : a free UML diagram generator
 * |
 * +=======================================================================
 *
 * (C) Copyright 2009-2024, Arnaud Roques
 *
 * Project Info:  https://plantuml.com
 *
 * If you like this project or if you find it useful, you can support us at:
 *
 * https://plantuml.com/patreon (only 1$ per month!)
 * https://plantuml.com/liberapay (only 1€ per month!)
 * https://plantuml.com/paypal
 *
 *
 * PlantUML is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PlantUML distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see .
 *
 * PlantUML can occasionally display sponsored or advertising messages. Those
 * messages are usually generated on welcome or error images and never on
 * functional diagrams.
 * See https://plantuml.com/professional if you want to remove them
 *
 * Images (whatever their format : PNG, SVG, EPS...) generated by running PlantUML
 * are owned by the author of their corresponding sources code (that is, their
 * textual description in PlantUML language). Those images are not covered by
 * this LGPL license.
 *
 * The generated images can then be used without any reference to the LGPL license.
 * It is not even necessary to stipulate that they have been generated with PlantUML,
 * although this will be appreciated by the PlantUML team.
 *
 * There is an exception : if the textual description in PlantUML language is also covered
 * by any license, then the generated images are logically covered
 * by the very same license.
 *
 * This is the IGY distribution (Install GraphViz by Yourself).
 * You have to install GraphViz and to setup the GRAPHVIZ_DOT environment variable
 * (see https://plantuml.com/graphviz-dot )
 *
 * Icons provided by OpenIconic :  https://useiconic.com/open
 * Archimate sprites provided by Archi :  http://www.archimatetool.com
 * Stdlib AWS provided by https://github.com/milo-minderbinder/AWS-PlantUML
 * Stdlib Icons provided https://github.com/tupadr3/plantuml-icon-font-sprites
 * ASCIIMathML (c) Peter Jipsen http://www.chapman.edu/~jipsen
 * ASCIIMathML (c) David Lippman http://www.pierce.ctc.edu/dlippman
 * CafeUndZopfli ported by Eugene Klyuchnikov https://github.com/eustas/CafeUndZopfli
 * Brotli (c) by the Brotli Authors https://github.com/google/brotli
 * Themes (c) by Brett Schwarz https://github.com/bschwarz/puml-themes
 * Twemoji (c) by Twitter at https://twemoji.twitter.com/
 *
 */

package net.sourceforge.plantuml.brotli;

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

/**
 * A set of utility methods.
 */
final class Utils {

	private static final byte[] BYTE_ZEROES = new byte[1024];

	private static final int[] INT_ZEROES = new int[1024];

	/**
	 * Fills byte array with zeroes.
	 *
	 * 
	 * Current implementation uses {@link System#arraycopy}, so it should be used
	 * for length not less than 16.
	 *
	 * @param dest  array to fill with zeroes
	 * @param start the first byte to fill
	 * @param end   the last byte to fill
	 */
	static void fillBytesWithZeroes(byte[] dest, int start, int end) {
		int cursor = start;
		while (cursor < end) {
			int step = Math.min(cursor + 1024, end) - cursor;
			System.arraycopy(BYTE_ZEROES, 0, dest, cursor, step);
			cursor += step;
		}
	}

	/**
	 * Fills int array with zeroes.
	 *
	 * 
	 * Current implementation uses {@link System#arraycopy}, so it should be used
	 * for length not less than 16.
	 *
	 * @param dest  array to fill with zeroes
	 * @param start the first item to fill
	 * @param end   the last item to fill
	 */
	static void fillIntsWithZeroes(int[] dest, int start, int end) {
		int cursor = start;
		while (cursor < end) {
			int step = Math.min(cursor + 1024, end) - cursor;
			System.arraycopy(INT_ZEROES, 0, dest, cursor, step);
			cursor += step;
		}
	}

	static void copyBytesWithin(byte[] bytes, int target, int start, int end) {
		System.arraycopy(bytes, start, bytes, target, end - start);
	}

	static int readInput(InputStream src, byte[] dst, int offset, int length) {
		try {
			return src.read(dst, offset, length);
		} catch (IOException e) {
			throw new BrotliRuntimeException("Failed to read input", e);
		}
	}

	static void closeInput(InputStream src) throws IOException {
		src.close();
	}
}