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/**
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.jpedal.org
 * (C) Copyright 1997-2008, IDRsolutions and Contributors.
 * Main Developer: Simon Barnett
 *
 * 	This file is part of JPedal
 *
 * Copyright (c) 2008, IDRsolutions
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the IDRsolutions nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY IDRsolutions ``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 IDRsolutions BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Other JBIG2 image decoding implementations include
 * jbig2dec (http://jbig2dec.sourceforge.net/)
 * xpdf (http://www.foolabs.com/xpdf/)
 * 
 * The final draft JBIG2 specification can be found at http://www.jpeg.org/public/fcd14492.pdf
 * 
 * All three of the above resources were used in the writing of this software, with methodologies,
 * processes and inspiration taken from all three.
 *
 * ---------------
 * StreamReader.java
 * ---------------
 */
package org.jpedal.jbig2.io;

import java.io.IOException;

import org.jpedal.jbig2.examples.pdf.PDFSegment;

public class StreamReader {
	private byte[] data;

	private int bitPointer = 7;

	private int bytePointer = 0;

	public StreamReader(byte[] data) {
		this.data = data;
	}

	public short readByte(PDFSegment pdfSeg) {
		short bite = (short) (this.data[this.bytePointer++] & 255);

		if (pdfSeg != null) pdfSeg.writeToHeader(bite);

		return bite;
	}

	public void readByte(short[] buf, PDFSegment pdfSeg) throws IOException {
		for (int i = 0; i < buf.length; i++) {
			buf[i] = (short) (this.data[this.bytePointer++] & 255);
		}

		if (pdfSeg != null) pdfSeg.writeToHeader(buf);
	}

	public short readByte() {
		short bite = (short) (this.data[this.bytePointer++] & 255);

		return bite;
	}

	public void readByte(short[] buf) {
		for (int i = 0; i < buf.length; i++) {
			buf[i] = (short) (this.data[this.bytePointer++] & 255);
		}
	}

	public int readBit() {
		short buf = readByte();
		short mask = (short) (1 << this.bitPointer);

		int bit = (buf & mask) >> this.bitPointer;

		this.bitPointer--;
		if (this.bitPointer == -1) {
			this.bitPointer = 7;
		}
		else {
			movePointer(-1);
		}

		return bit;
	}

	public int readBits(int num) {
		int result = 0;

		for (int i = 0; i < num; i++) {
			result = (result << 1) | readBit();
		}

		return result;
	}

	public void movePointer(int ammount) {
		this.bytePointer += ammount;
	}

	public void consumeRemainingBits() {
		if (this.bitPointer != 7) readBits(this.bitPointer + 1);
	}

	public boolean isFinished() {
		return this.bytePointer == this.data.length;
	}
}