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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!)
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 *
 * PlantUML is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License V2.
 *
 * THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE PUBLIC
 * LICENSE ("AGREEMENT"). [GNU General Public License V2]
 *
 * ANY USE, REPRODUCTION OR DISTRIBUTION OF THE PROGRAM CONSTITUTES
 * RECIPIENT'S ACCEPTANCE OF THIS AGREEMENT.
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 * You may obtain a copy of the License at
 *
 * https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * 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
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 * 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 GPL v2 license.
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 * The generated images can then be used without any reference to the GPL v2 license.
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 * although this will be appreciated by the PlantUML team.
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 * 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
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 * 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
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 *
 */
package net.sourceforge.plantuml.code.deflate;

/* 
 * Simple DEFLATE decompressor
 * Copyright (c) Project Nayuki
 * 
 * https://www.nayuki.io/page/simple-deflate-decompressor
 * https://github.com/nayuki/Simple-DEFLATE-decompressor
 */

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Objects;

/**
 * A stream of bits that can be read. Because they come from an underlying byte
 * stream, the total number of bits is always a multiple of 8. The bits are read
 * in little endian. Mutable and not thread-safe.
 */
public final class ByteBitInputStream implements BitInputStream {

	/*---- Fields ----*/

	// The underlying byte stream to read from (not null).
	private InputStream input;

	// Either in the range [0x00, 0xFF] if bits are available, or -1 if end of
	// stream is reached.
	private int currentByte;

	// Number of remaining bits in the current byte, always between 0 and 7
	// (inclusive).
	private int numBitsRemaining;

	/*---- Constructor ----*/

	/**
	 * Constructs a bit input stream based on the specified byte input stream.
	 * 
	 * @param in the byte input stream (not {@code null})
	 * @throws NullPointerException if the input stream is {@code null}
	 */
	public ByteBitInputStream(InputStream in) {
		input = Objects.requireNonNull(in);
		currentByte = 0;
		numBitsRemaining = 0;
	}

	/*---- Methods ----*/

	public int getBitPosition() {
		if (numBitsRemaining < 0 || numBitsRemaining > 7)
			throw new IllegalStateException();
		return (8 - numBitsRemaining) % 8;
	}

	public int readByte() throws IOException {
		currentByte = 0;
		numBitsRemaining = 0;
		return input.read();
	}

	public int read() throws IOException {
		if (currentByte == -1)
			return -1;
		if (numBitsRemaining == 0) {
			currentByte = input.read();
			if (currentByte == -1)
				return -1;
			numBitsRemaining = 8;
		}
		if (numBitsRemaining <= 0)
			throw new IllegalStateException();
		numBitsRemaining--;
		return (currentByte >>> (7 - numBitsRemaining)) & 1;
	}

	public int readNoEof() throws IOException {
		int result = read();
		if (result == -1)
			throw new EOFException();
		return result;
	}

	public void close() throws IOException {
		input.close();
		currentByte = -1;
		numBitsRemaining = 0;
	}

}