org.jpedal.io.PageLabels 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
 *
 @LICENSE@
 *
 * ---------------
 * PageLabels.java
 * ---------------
 */
package org.jpedal.io;

import java.util.HashMap;

import org.jpedal.objects.raw.PageLabelObject;
import org.jpedal.objects.raw.PdfArrayIterator;
import org.jpedal.objects.raw.PdfDictionary;
import org.jpedal.objects.raw.PdfObject;

/**
 * convert names to refs
 */
public class PageLabels extends HashMap {

    private final PdfFileReader objectReader;

    private final int pageCount;

    private static final String symbolLowerCase[] = {"m", "cm", "d", "cd", "c", "xc", "l", "xl", "x", "ix", "v", "iv", "i"};
    private static final String symbolUpperCase[] = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
    private static final String lettersLowerCase[] = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n",
            "o", "p", "q", "r", "s", "t", "u", "v", "x", "w", "y", "z"};
    private static final String lettersUpperCase[] = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N",
            "O", "P", "Q", "R", "S", "T", "U", "V", "X", "W", "Y", "Z"};
    private static final int[] power = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};

    PageLabels(final PdfFileReader objectReader, final int pageCount) {
        this.objectReader = objectReader;
        this.pageCount = pageCount;
    }

    void readLabels(final PdfObject pageObj) {

        final PdfArrayIterator numList = pageObj.getMixedArray(PdfDictionary.Nums);

        if (numList != null && objectReader != null && numList.hasMoreTokens()) {

            int endPage, numbType, St, pageNum;
            String convertedPage, pageLabel;
            PageLabelObject labelObj;
            boolean isFirstToken = true;

            //read first page values
            int startPage = numList.getNextValueAsInteger(true) + 1;

            while (numList.hasMoreTokens()) {

                //read LabelObject
                labelObj = getObject(numList.getNextValueAsByte(true));

                numbType = labelObj.getNameAsConstant(PdfDictionary.S);
                pageLabel = labelObj.getTextStreamValue(PdfDictionary.P);

                St = labelObj.getInt(PdfDictionary.St);
                if (St > 0) {
                    pageNum = St;
                } else {
                    pageNum = 1;
                }

                // Do not store PageLabels if the only token is /S /D (default behavior). E.g. sample_pdfs_html/12jul/1997.pdf
                // Do store in any other case (even if P matches page number). E.g. sample_pdfs_html/12jul/1130MA0711w.pdf
                // This is the same behavior as Adobe Reader.
                if (isFirstToken && numbType == PdfDictionary.D &&
                        pageLabel == null && St <= 0 && !numList.hasMoreTokens()) {
                    break;
                }
                isFirstToken = false;

                if (numList.hasMoreTokens()) {
                    endPage = numList.getNextValueAsInteger(true) + 1;
                } else {
                    endPage = pageCount + 1;
                }

                //now decode type of naming and fill range
                for (int page = startPage; page < endPage; page++) {

                    if (pageLabel != null) {
                        convertedPage = pageLabel + getNumberValue(numbType, pageNum);
                    } else {
                        convertedPage = getNumberValue(numbType, pageNum);
                    }

                    this.put(page, convertedPage);

                    pageNum++;
                }

                startPage = endPage;
            }
        }
    }

    private PageLabelObject getObject(final byte[] data) {

        final PageLabelObject labelObj = new PageLabelObject(new String(data));

        if (data[0] == '<') {
            labelObj.setStatus(PdfObject.UNDECODED_DIRECT);
        } else {
            labelObj.setStatus(PdfObject.UNDECODED_REF);
        }
        labelObj.setUnresolvedData(data, PdfDictionary.PageLabels);

        final ObjectDecoder objectDecoder = new ObjectDecoder(this.objectReader);
        objectDecoder.checkResolved(labelObj);

        return labelObj;
    }

    private static String getNumberValue(final int numbType, final int page) {

        final String convertedPage;

        switch (numbType) {
            case PdfDictionary.a:
                convertedPage = convertLetterToNumber(page, lettersLowerCase);
                break;

            case PdfDictionary.A:
                convertedPage = convertLetterToNumber(page, lettersUpperCase);
                break;

            case PdfDictionary.D:
                convertedPage = String.valueOf(page);
                break;

            case PdfDictionary.R:
                convertedPage = convertToRoman(page, symbolUpperCase);
                break;

            case PdfDictionary.r:
                convertedPage = convertToRoman(page, symbolLowerCase);
                break;

            default:
                convertedPage = "";
        }
        return convertedPage;
    }

    private static String convertToRoman(int arabicNumber, final String[] symbols) {

        final StringBuilder romanNumeral = new StringBuilder();
        int repeat;

        for (int x = 0; arabicNumber > 0; x++) {
            repeat = arabicNumber / power[x];

            for (int chars = 1; chars <= repeat; chars++) {
                romanNumeral.append(symbols[x]);
            }
            arabicNumber %= power[x];
        }

        return romanNumeral.toString();
    }

    private static String convertLetterToNumber(final int page, final String[] letters) {

        final StringBuilder finalLetters = new StringBuilder();
        final int repeat = page / 26;
        final int remainder = page % 26;

        if (repeat > 0) {
            for (int x = 0; x < repeat; x++) {
                finalLetters.append(letters[25]);
            }
        }
        if (remainder != 0) {
            finalLetters.append(letters[remainder - 1]);
        }
        return finalLetters.toString();
    }
}