iText layout.jar Source Code

layout.jar is a component in iText Java library to provide layout functionalities. iText Java library allows you to generate and manage PDF documents.

The Source Code files are provided together with the JAR file in the binary packge like iText7-Core-7.1.4.zip. You can download it at iText 7 Core Download site.

You can compile it to generate your JAR file, using layout.pom as the build configuration file.

The source code of layout-7.1.4.jar is provided below:

✍: FYIcenter.com

com/itextpdf/layout/hyphenation/HyphenationTree.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.itextpdf.layout.hyphenation;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * <p>
 * This tree structure stores the hyphenation patterns in an efficient
 * way for fast lookup. It provides the provides the method to
 * hyphenate a word.
 *
 * <p>
 * This work was authored by Carlos Villegas (cav@uniscope.co.jp).
 */
public class HyphenationTree extends TernaryTree implements IPatternConsumer {

    private static final long serialVersionUID = -7842107987915665573L;

    /**
     * value space: stores the interletter values
     */
    protected ByteVector vspace;

    /**
     * This map stores hyphenation exceptions
     */
    protected Map<String, List> stoplist;

    /**
     * This map stores the character classes
     */
    protected TernaryTree classmap;

    /**
     * Temporary map to store interletter values on pattern loading.
     */
    private transient TernaryTree ivalues;

    /** Default constructor. */
    public HyphenationTree() {
        stoplist = new HashMap<>(23);
        classmap = new TernaryTree();
        vspace = new ByteVector();
        vspace.alloc(1);    // this reserves index 0, which we don't use
    }

    private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
        ois.defaultReadObject();
    }

    /**
     * Packs the values by storing them in 4 bits, two values into a byte
     * Values range is from 0 to 9. We use zero as terminator,
     * so we'll add 1 to the value.
     * @param values a string of digits from '0' to '9' representing the
     * interletter values.
     * @return the index into the vspace array where the packed values
     * are stored.
     */
    protected int packValues(String values) {
        int i;
        int n = values.length();
        int m = (n & 1) == 1 ? (n >> 1) + 2 : (n >> 1) + 1;
        int offset = vspace.alloc(m);
        byte[] va = vspace.getArray();
        for (i = 0; i < n; i++) {
            int j = i >> 1;
            byte v = (byte)((values.charAt(i) - '0' + 1) & 0x0f);
            if ((i & 1) == 1) {
                va[j + offset] = (byte)(va[j + offset] | v);
            } else {
                va[j + offset] = (byte)(v << 4);    // big endian
            }
        }
        va[m - 1 + offset] = 0;    // terminator
        return offset;
    }

    /**
     * Unpack values.
     * @param k an integer
     * @return a string
     */
    protected String unpackValues(int k) {
        StringBuffer buf = new StringBuffer();
        byte v = vspace.get(k++);
        while (v != 0) {
            char c = (char)((v >>> 4) - 1 + '0');
            buf.append(c);
            c = (char)(v & 0x0f);
            if (c == 0) {
                break;
            }
            c = (char)(c - 1 + '0');
            buf.append(c);
            v = vspace.get(k++);
        }
        return buf.toString();
    }

    /**
     * Read hyphenation patterns from an XML file.
     * @param filename the filename
     * @throws HyphenationException In case the parsing fails
     */
    public void loadPatterns(String filename) throws HyphenationException, FileNotFoundException {
        loadPatterns(new FileInputStream(filename), filename);
    }

    /**
     * Read hyphenation patterns from an XML file.
     * @param stream the InputSource for the file
     * @param name unique key representing country-language combination
     * @throws HyphenationException In case the parsing fails
     */
    public void loadPatterns(InputStream stream, String name) throws HyphenationException {
        PatternParser pp = new PatternParser(this);
        ivalues = new TernaryTree();

        pp.parse(stream, name);

        // patterns/values should be now in the tree
        // let's optimize a bit
        trimToSize();
        vspace.trimToSize();
        classmap.trimToSize();

        // get rid of the auxiliary map
        ivalues = null;
    }

    /**
     * Find pattern.
     * @param pat a pattern
     * @return a string
     */
    public String findPattern(String pat) {
        int k = super.find(pat);
        if (k >= 0) {
            return unpackValues(k);
        }
        return "";
    }

    /**
     * String compare, returns 0 if equal or
     * t is a substring of s.
     * @param s first character array
     * @param si starting index into first array
     * @param t second character array
     * @param ti starting index into second array
     * @return an integer
     */
    protected int hstrcmp(char[] s, int si, char[] t, int ti) {
        for (; s[si] == t[ti]; si++, ti++) {
            if (s[si] == 0) {
                return 0;
            }
        }
        if (t[ti] == 0) {
            return 0;
        }
        return s[si] - t[ti];
    }

    /**
     * Get values.
     * @param k an integer
     * @return a byte array
     */
    protected byte[] getValues(int k) {
        StringBuffer buf = new StringBuffer();
        byte v = vspace.get(k++);
        while (v != 0) {
            char c = (char)((v >>> 4) - 1);
            buf.append(c);
            c = (char)(v & 0x0f);
            if (c == 0) {
                break;
            }
            c = (char)(c - 1);
            buf.append(c);
            v = vspace.get(k++);
        }
        byte[] res = new byte[buf.length()];
        for (int i = 0; i < res.length; i++) {
            res[i] = (byte)buf.charAt(i);
        }
        return res;
    }

    /**
     * <p>Search for all possible partial matches of word starting
     * at index an update interletter values. In other words, it
     * does something like:</p>
     * <code>
     * for(i=0; i&lt;patterns.length; i++) {
     * if ( word.substring(index).startsWidth(patterns[i]) )
     * update_interletter_values(patterns[i]);
     * }
     * </code>
     * <p>But it is done in an efficient way since the patterns are
     * stored in a ternary tree. In fact, this is the whole purpose
     * of having the tree: doing this search without having to test
     * every single pattern. The number of patterns for languages
     * such as English range from 4000 to 10000. Thus, doing thousands
     * of string comparisons for each word to hyphenate would be
     * really slow without the tree. The tradeoff is memory, but
     * using a ternary tree instead of a trie, almost halves the
     * the memory used by Lout or TeX. It's also faster than using
     * a hash table</p>
     * @param word null terminated word to match
     * @param index start index from word
     * @param il interletter values array to update
     */
    protected void searchPatterns(char[] word, int index, byte[] il) {
        byte[] values;
        int i = index;
        char p;
        char q;
        char sp = word[i];
        p = root;

        while (p > 0 && p < sc.length) {
            if (sc[p] == 0xFFFF) {
                if (hstrcmp(word, i, kv.getArray(), lo[p]) == 0) {
                    values = getValues(eq[p]);    // data pointer is in eq[]
                    int j = index;
                    for (int k = 0; k < values.length; k++) {
                        if (j < il.length && values[k] > il[j]) {
                            il[j] = values[k];
                        }
                        j++;
                    }
                }
                return;
            }
            int d = sp - sc[p];
            if (d == 0) {
                if (sp == 0) {
                    break;
                }
                sp = word[++i];
                p = eq[p];
                q = p;

                // look for a pattern ending at this position by searching for
                // the null char ( splitchar == 0 )
                while (q > 0 && q < sc.length) {
                    if (sc[q] == 0xFFFF) {        // stop at compressed branch
                        break;
                    }
                    if (sc[q] == 0) {
                        values = getValues(eq[q]);
                        int j = index;
                        for (int k = 0; k < values.length; k++) {
                            if (j < il.length && values[k] > il[j]) {
                                il[j] = values[k];
                            }
                            j++;
                        }
                        break;
                    } else {
                        q = lo[q];

                        /**
                         * actually the code should be:
                         * q = sc[q] < 0 ? hi[q] : lo[q];
                         * but java chars are unsigned
                         */
                    }
                }
            } else {
                p = d < 0 ? lo[p] : hi[p];
            }
        }
    }

    /**
     * Hyphenate word and return a Hyphenation object.
     * @param word the word to be hyphenated
     * @param remainCharCount Minimum number of characters allowed
     * before the hyphenation point.
     * @param pushCharCount Minimum number of characters allowed after
     * the hyphenation point.
     * @return a {@link Hyphenation Hyphenation} object representing
     * the hyphenated word or null if word is not hyphenated.
     */
    public Hyphenation hyphenate(String word, int remainCharCount,
                                 int pushCharCount) {
        char[] w = word.toCharArray();
        if (isMultiPartWord(w, w.length)) {
            List<char[]> words = splitOnNonCharacters(w);
            return new Hyphenation(new String(w),
                    getHyphPointsForWords(words, remainCharCount, pushCharCount));
        } else {
            return hyphenate(w, 0, w.length, remainCharCount, pushCharCount);
        }
    }

    private boolean isMultiPartWord(char[] w, int len) {
        int wordParts = 0;
        for (int i = 0; i < len; i++) {
            char[] c = new char[2];
            c[0] = w[i];
            int nc = classmap.find(c, 0);
            if (nc > 0) {
                if (wordParts > 1) {
                    return true;
                }
                wordParts = 1;
            } else {
                if (wordParts == 1) {
                    wordParts++;
                }
            }
        }
        return false;
    }

    private List<char[]> splitOnNonCharacters(char[] word) {
        List<Integer> breakPoints = getNonLetterBreaks(word);
        if (breakPoints.size() == 0) {
            return Collections.<char[]>emptyList();
        }
        List<char[]> words = new ArrayList<char[]>();
        for (int ibreak = 0; ibreak < breakPoints.size(); ibreak++) {
            char[] newWord = getWordFromCharArray(word, ((ibreak == 0)
                    ? 0 : breakPoints.get(ibreak - 1)), breakPoints.get(ibreak));
            words.add(newWord);
        }
        if (word.length - breakPoints.get(breakPoints.size() - 1) - 1 > 1) {
            char[] newWord = getWordFromCharArray(word, breakPoints.get(breakPoints.size() - 1),
                    word.length);
            words.add(newWord);
        }
        return words;
    }

    private List<Integer> getNonLetterBreaks(char[] word) {
        char[] c = new char[2];
        List<Integer> breakPoints = new ArrayList<Integer>();
        boolean foundLetter = false;
        for (int i = 0; i < word.length; i++) {
            c[0] = word[i];
            if (classmap.find(c, 0) < 0) {
                if (foundLetter) {
                    breakPoints.add(i);
                }
            } else {
                foundLetter = true;
            }
        }
        return breakPoints;
    }

    private char[] getWordFromCharArray(char[] word, int startIndex, int endIndex) {
        char[] newWord = new char[endIndex - ((startIndex == 0) ? startIndex : startIndex + 1)];
        int iChar = 0;
        for (int i = (startIndex == 0) ? 0 : startIndex + 1; i < endIndex; i++) {
            newWord[iChar++] = word[i];
        }
        return newWord;
    }

    private int[] getHyphPointsForWords(List<char[]> nonLetterWords, int remainCharCount,
            int pushCharCount) {
        int[] breaks = new int[0];
        for (int iNonLetterWord = 0; iNonLetterWord < nonLetterWords.size(); iNonLetterWord++) {
            char[] nonLetterWord = nonLetterWords.get(iNonLetterWord);
            Hyphenation curHyph = hyphenate(nonLetterWord, 0, nonLetterWord.length,
                    (iNonLetterWord == 0) ? remainCharCount : 1,
                    (iNonLetterWord == nonLetterWords.size() - 1) ? pushCharCount : 1);
            if (curHyph == null) {
                continue;
            }
            int[] combined = new int[breaks.length + curHyph.getHyphenationPoints().length];
            int[] hyphPoints = curHyph.getHyphenationPoints();
            int foreWordsSize = calcForeWordsSize(nonLetterWords, iNonLetterWord);
            for (int i = 0; i < hyphPoints.length; i++) {
                hyphPoints[i] += foreWordsSize;
            }
            System.arraycopy(breaks, 0, combined, 0, breaks.length);
            System.arraycopy(hyphPoints, 0, combined, breaks.length, hyphPoints.length);
            breaks = combined;
        }
        return breaks;
    }

    private int calcForeWordsSize(List<char[]> nonLetterWords, int iNonLetterWord) {
        int result = 0;
        for (int i = 0; i < iNonLetterWord; i++) {
            result += nonLetterWords.get(i).length + 1;
        }
        return result;
    }

    /**
     * w = "****nnllllllnnn*****",
     * where n is a non-letter, l is a letter,
     * all n may be absent, the first n is at offset,
     * the first l is at offset + iIgnoreAtBeginning;
     * word = ".llllll.'\0'***",
     * where all l in w are copied into word.
     * In the first part of the routine len = w.length,
     * in the second part of the routine len = word.length.
     * Three indices are used:
     * index(w), the index in w,
     * index(word), the index in word,
     * letterindex(word), the index in the letter part of word.
     * The following relations exist:
     * index(w) = offset + i - 1
     * index(word) = i - iIgnoreAtBeginning
     * letterindex(word) = index(word) - 1
     * (see first loop).
     * It follows that:
     * index(w) - index(word) = offset - 1 + iIgnoreAtBeginning
     * index(w) = letterindex(word) + offset + iIgnoreAtBeginning
     */

    /**
     * Hyphenate word and return an array of hyphenation points.
     * @param w char array that contains the word
     * @param offset Offset to first character in word
     * @param len Length of word
     * @param remainCharCount Minimum number of characters allowed
     * before the hyphenation point.
     * @param pushCharCount Minimum number of characters allowed after
     * the hyphenation point.
     * @return a {@link Hyphenation Hyphenation} object representing
     * the hyphenated word or null if word is not hyphenated.
     */
    public Hyphenation hyphenate(char[] w, int offset, int len,
                                 int remainCharCount, int pushCharCount) {
        int i;
        char[] word = new char[len + 3];

        // normalize word
        char[] c = new char[2];
        int iIgnoreAtBeginning = 0;
        int iLength = len;
        boolean bEndOfLetters = false;
        for (i = 1; i <= len; i++) {
            c[0] = w[offset + i - 1];
            int nc = classmap.find(c, 0);
            if (nc < 0) {    // found a non-letter character ...
                if (i == (1 + iIgnoreAtBeginning)) {
                    // ... before any letter character
                    iIgnoreAtBeginning++;
                } else {
                    // ... after a letter character
                    bEndOfLetters = true;
                }
                iLength--;
            } else {
                if (!bEndOfLetters) {
                    word[i - iIgnoreAtBeginning] = (char)nc;
                } else {
                    return null;
                }
            }
        }

        len = iLength;
        if (len < (remainCharCount + pushCharCount)) {
            // word is too short to be hyphenated
            return null;
        }
        int[] result = new int[len + 1];
        int k = 0;

        // check exception list first
        String sw = new String(word, 1, len);
        if (stoplist.containsKey(sw)) {
            // assume only simple hyphens (Hyphen.pre="-", Hyphen.post = Hyphen.no = null)
            ArrayList hw = (ArrayList)stoplist.get(sw);
            int j = 0;
            for (i = 0; i < hw.size(); i++) {
                Object o = hw.get(i);
                // j = index(sw) = letterindex(word)?
                // result[k] = corresponding index(w)
                if (o instanceof String) {
                    j += ((String)o).length();
                    if (j >= remainCharCount && j < (len - pushCharCount)) {
                        result[k++] = j + iIgnoreAtBeginning;
                    }
                }
            }
        } else {
            // use algorithm to get hyphenation points
            word[0] = '.';                    // word start marker
            word[len + 1] = '.';              // word end marker
            word[len + 2] = 0;                // null terminated
            byte[] il = new byte[len + 3];    // initialized to zero
            for (i = 0; i < len + 1; i++) {
                searchPatterns(word, i, il);
            }

            // hyphenation points are located where interletter value is odd
            // i is letterindex(word),
            // i + 1 is index(word),
            // result[k] = corresponding index(w)
            for (i = 0; i < len; i++) {
                if (((il[i + 1] & 1) == 1) && i >= remainCharCount
                        && i <= (len - pushCharCount)) {
                    result[k++] = i;
                }
            }
        }


        if (k > 0) {
            // trim result array
            int[] res = new int[k];
            System.arraycopy(result, 0, res, 0, k);
            return new Hyphenation(new String(w, iIgnoreAtBeginning, len), res);
        } else {
            return null;
        }
    }

    /**
     * Add a character class to the tree. It is used by
     * {@link PatternParser PatternParser} as callback to
     * add character classes. Character classes define the
     * valid word characters for hyphenation. If a word contains
     * a character not defined in any of the classes, it is not hyphenated.
     * It also defines a way to normalize the characters in order
     * to compare them with the stored patterns. Usually pattern
     * files use only lower case characters, in this case a class
     * for letter 'a', for example, should be defined as "aA", the first
     * character being the normalization char.
     * @param chargroup a character class (group)
     */
    public void addClass(String chargroup) {
        if (chargroup.length() > 0) {
            char equivChar = chargroup.charAt(0);
            char[] key = new char[2];
            key[1] = 0;
            for (int i = 0; i < chargroup.length(); i++) {
                key[0] = chargroup.charAt(i);
                classmap.insert(key, 0, equivChar);
            }
        }
    }

    /**
     * Add an exception to the tree. It is used by
     * {@link PatternParser PatternParser} class as callback to
     * store the hyphenation exceptions.
     * @param word normalized word
     * @param hyphenatedword a vector of alternating strings and
     * {@link Hyphen hyphen} objects.
     */
    public void addException(String word, List hyphenatedword) {
        stoplist.put(word, hyphenatedword);
    }

    /**
     * Add a pattern to the tree. Mainly, to be used by
     * {@link PatternParser PatternParser} class as callback to
     * add a pattern to the tree.
     * @param pattern the hyphenation pattern
     * @param ivalue interletter weight values indicating the
     * desirability and priority of hyphenating at a given point
     * within the pattern. It should contain only digit characters.
     * (i.e. '0' to '9').
     */
    public void addPattern(String pattern, String ivalue) {
        int k = ivalues.find(ivalue);
        if (k <= 0) {
            k = packValues(ivalue);
            ivalues.insert(ivalue, (char)k);
        }
        insert(pattern, (char)k);
    }

}

com/itextpdf/layout/hyphenation/HyphenationTree.java

 

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2021-07-03, 9154👍, 0💬