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An Open Source JavaFX PDF Viewer
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/*
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.idrsolutions.com
 * Help section for developers at http://www.idrsolutions.com/support/
 *
 * (C) Copyright 1997-2015 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


 *
 * ---------------
 * ASCIIHex.java
 * ---------------
 */
package org.jpedal.io.filter;

import org.jpedal.objects.raw.PdfObject;
import org.jpedal.utils.LogWriter;
import org.jpedal.utils.repositories.FastByteArrayOutputStream;

import java.io.*;
import java.util.Map;

/**
 *
 */
public class ASCIIHex extends BaseFilter implements PdfFilter {
    public ASCIIHex(final PdfObject decodeParms) {
        super(decodeParms);
    }

    /**
     * asciihexdecode using our own implementation
     */
    @Override
    public byte[] decode(final byte[] data) throws IOException {

        String line;
        StringBuilder value = new StringBuilder();
        final StringBuilder valuesRead = new StringBuilder();
        BufferedReader mappingStream = null;
        ByteArrayInputStream bis = null;

        // read in ASCII mode to handle line returns
        try {
            bis = new ByteArrayInputStream(data);
            mappingStream = new BufferedReader(new InputStreamReader(bis));

            // read values into lookup table
            if (mappingStream != null) {

                while (true) {
                    line = mappingStream.readLine();

                    if (line == null) {
                        break;
                    }

                    // append to data
                    valuesRead.append(line);

                }
            }

        } catch (final Exception e) {
        	LogWriter.writeLog("Exception " + e + " reading ASCII stream ");
        }

        if (mappingStream != null) {
            try {
                mappingStream.close();
                bis.close();
            } catch (final IOException e) {
                LogWriter.writeLog("Exception: "+e.getMessage());
            }
        }

        final int data_size = valuesRead.length();
        int i = 0, count = 0;
        char current;

        final FastByteArrayOutputStream bos = new FastByteArrayOutputStream(data.length);

        /** loop to read and process */
        while (true) {

            current = valuesRead.charAt(i);

            if ((current >= '0' && current <= '9')
                    || (current >= 'a' && current <= 'f')
                    || (current >= 'A' && current <= 'F')) {
                value.append(current);
                if (count == 1) {
                    bos.write(Integer.valueOf(value.toString(), 16));
                    count = 0;
                    value = new StringBuilder();
                } else {
                    count++;
                }

            }

            if (current == '>') {
                break;
            }

            i++;

            if (i == data_size) {
                break;
            }
        }

        // write any last char
        if (count == 1) {
            value.append('0');
            bos.write(Integer.valueOf(value.toString(), 16));
        }

        return bos.toByteArray();
    }

    /**
     * asciihexdecode using our own implementation
     */
    @Override
    public void decode(final BufferedInputStream bis, final BufferedOutputStream streamCache, final String cacheName, final Map cachedObjects) {

        this.bis=bis;
        this.streamCache=streamCache;
        this.cachedObjects=cachedObjects;

        try{
            StringBuffer value = new StringBuffer();
            char current;

            /** loop to read and process */
            int count = bis.available();
            for (int i = 0; i < count; i++) {

                current = (char) bis.read();
                while (current == '\n') {
                    current = (char) bis.read();
                }

                if ((current >= '0' && current <= '9')
                        || (current >= 'a' && current <= 'f')
                        || (current >= 'A' && current <= 'F')) {
                    value.append(current);
                    if (count == 1) {
                        streamCache.write(Integer.valueOf(value.toString(), 16));
                        count = 0;
                        value = new StringBuffer();
                    } else {
                        count++;
                    }

                }

                if (current == '>') {
                    break;
                }
            }

            // write any last char
            if (count == 1) {
                value.append('0');
                streamCache.write(Integer.valueOf(value.toString(), 16));
            }

        } catch (final IOException e1) {
        	LogWriter.writeLog("IO exception in RunLength "+e1);
        }
    }
}