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/*
 * 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.
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package com.itextpdf.layout.hyphenation;

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

/**
 * This tree structure stores the hyphenation patterns in an efficient
 * way for fast lookup. It provides the provides the method to
 * hyphenate a word.
 * 

* This work was authored by Carlos Villegas ([email protected]). */ public class HyphenationTree extends TernaryTree implements IPatternConsumer { /** * value space: stores the interletter values */ protected ByteVector vspace; /** * This map stores hyphenation exceptions */ protected Map stoplist; /** * This map stores the character classes */ protected TernaryTree classmap; /** * Temporary map to store interletter values on pattern loading. */ private TernaryTree ivalues; /** Default constructor. */ public HyphenationTree() { stoplist = new HashMap<>(23); classmap = new TernaryTree(); vspace = new ByteVector(); // this reserves index 0, which we don't use vspace.alloc(1); } /** * 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 { // big endian va[j + offset] = (byte)(v << 4); } } // terminator va[m - 1 + offset] = 0; 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 * @throws FileNotFoundException When the specified file is not found */ 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; } /** * Search for all possible partial matches of word starting * at index an update interletter values. In other words, it * does something like: *

* * for(i=0; i<patterns.length; i++) { * if ( word.substring(index).startsWidth(patterns[i]) ) * update_interletter_values(patterns[i]); * } * *

* 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 * @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) { // data pointer is in eq[] values = getValues(eq[p]); 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) { // stop at compressed branch if (sc[q] == 0xFFFF) { 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 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 splitOnNonCharacters(char[] word) { List breakPoints = getNonLetterBreaks(word); if (breakPoints.size() == 0) { return Collections.emptyList(); } List words = new ArrayList(); 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 getNonLetterBreaks(char[] word) { char[] c = new char[2]; List breakPoints = new ArrayList(); 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 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 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); // found a non-letter character ... if (nc < 0) { 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 start marker word[0] = '.'; // word end marker word[len + 1] = '.'; // null terminated word[len + 2] = 0; // initialized to zero byte[] il = new byte[len + 3]; 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); } }





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