org.jpedal.io.RandomAccessDataBuffer Maven / Gradle / Ivy

/*
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.idrsolutions.com
 * Help section for developers at http://www.idrsolutions.com/support/
 *
 * (C) Copyright 1997-2017 IDRsolutions and Contributors.
 *
 * This file is part of JPedal/JPDF2HTML5
 *
     This library 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 2.1 of the License, or (at your option) any later version.

    This library is 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, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


 *
 * ---------------
 * RandomAccessDataBuffer.java
 * ---------------
 */

package org.jpedal.io;

import java.io.IOException;

public class RandomAccessDataBuffer implements RandomAccessBuffer {

    private byte[] data;
    private long pointer;

    public RandomAccessDataBuffer(final byte[] data) {
        this.data = data;
        this.pointer = -1;
    }

    @Override
    public long getFilePointer() throws IOException {
        return pointer;
    }

    @Override
    public void seek(final long pos) throws IOException {
        if (checkPos(pos)) {
            this.pointer = pos;
        } else {
            throw new IOException("Position out of bounds");
        }
    }

    @Override
    public void close() throws IOException {
        this.data = null;
        this.pointer = -1;
    }

    @Override
    public long length() throws IOException {

        if (data != null) {
            return data.length;
        } else {
            throw new IOException("Data buffer not initialized.");
        }
    }

    @Override
    public int read() throws IOException {
        if (checkPos(this.pointer)) {
            return b2i(this.data[(int) pointer++]);
        } else {
            return -1;
        }
    }

    private int peek() throws IOException {
        if (checkPos(this.pointer)) {
            return b2i(this.data[(int) pointer]);
        } else {
            return -1;
        }
    }

    /**
     * return next line (returns null if no line)
     */
    @Override
    public String readLine() throws IOException {

        if (this.pointer >= this.data.length - 1) {
            return null;
        } else {

            final StringBuilder buf = new StringBuilder();
            int c;
            while ((c = read()) >= 0) {
                if ((c == 10) || (c == 13)) {
                    if (((peek() == 10) || (peek() == 13)) && (peek() != c)) {
                        read();
                    }
                    break;
                }
                buf.append((char) c);
            }
            return buf.toString();
        }
    }

    @Override
    public int read(final byte[] b) throws IOException {
        if (data == null) {
            throw new IOException("Data buffer not initialized.");
        }
        if (pointer < 0 || pointer >= data.length) {
            return -1;
        }
        final int length = Math.min(b.length, data.length - (int) pointer);
        for (int i = 0; i < length; i++) {
            b[i] = data[(int) pointer++];
        }
        return length;
    }

    private static int b2i(final byte b) {
        if (b >= 0) {
            return b;
        }
        return 256 + b;
    }

    private boolean checkPos(final long pos) throws IOException {
        return ((pos >= 0) && (pos < length()));
    }

    /* returns the byte data*/
    @Override
    public byte[] getPdfBuffer() {
        return data;
    }
}