org.jpedal.jbig2.io.StreamReader Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of OpenViewerFX Show documentation
An Open Source JavaFX PDF Viewer
The newest version!
/**
* ===========================================
* 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(final byte[] data) {
		this.data = data;
	}

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

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

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

		return bite;
	}

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

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

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

		bitPointer--;
		if (bitPointer == -1) {
			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) {
		bytePointer += ammount;
	}

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

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