com.lowagie.text.pdf.hyphenation.HyphenationTree Maven / Gradle / Ivy
/*
* $Id: HyphenationTree.java,v 1.32 2004/12/27 07:10:04 blowagie Exp $
* Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
* For license details please refer to http://xml.apache.org/fop
*/
package com.lowagie.text.pdf.hyphenation;
import java.io.*;
import java.util.ArrayList;
import java.util.Hashtable;
/**
* This tree structure stores the hyphenation patterns in an efficient
* way for fast lookup. It provides the provides the method to
* hyphenate a word.
*
* @author Carlos Villegas
*/
public class HyphenationTree extends TernaryTree implements PatternConsumer,
Serializable {
/**
* value space: stores the inteletter values
*/
protected ByteVector vspace;
/**
* This map stores hyphenation exceptions
*/
protected Hashtable stoplist;
/**
* This map stores the character classes
*/
protected TernaryTree classmap;
/**
* Temporary map to store interletter values on pattern loading.
*/
private transient TernaryTree ivalues;
public HyphenationTree() {
stoplist = new Hashtable(23); // usually a small table
classmap = new TernaryTree();
vspace = new ByteVector();
vspace.alloc(1); // this reserves index 0, which we don't use
}
/**
* 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, 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;
}
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.
*/
/* public void loadPatterns(String filename) throws HyphenationException {
PatternParser pp = new PatternParser(this);
ivalues = new TernaryTree();
pp.parse(filename);
// 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;
}*/
/**
* Read hyphenation patterns from an internal format file.
*/
public void loadInternalPatterns(String filename) throws HyphenationException {
PatternInternalParser pp = new PatternInternalParser(this);
ivalues = new TernaryTree();
pp.parse(filename);
// 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;
}
/**
* Read hyphenation patterns from an internal format file.
*/
public void loadInternalPatterns(InputStream is) throws HyphenationException {
PatternInternalParser pp = new PatternInternalParser(this);
ivalues = new TernaryTree();
pp.parse(is);
// 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;
}
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
*/
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];
}
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
* 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, 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();
return hyphenate(w, 0, w.length, remainCharCount, pushCharCount);
}
/**
* 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];
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, abort
return null;
}
word[i] = (char)nc;
}
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);
if (o instanceof String) {
j += ((String)o).length();
if (j >= remainCharCount && j < (len - pushCharCount))
result[k++] = j;
}
}
} 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
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, offset, len), res);
} else {
return null;
}
}
/**
* Add a character class to the tree. It is used by
* 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.
*/
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
* 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, ArrayList hyphenatedword) {
stoplist.put(word, hyphenatedword);
}
/**
* Add a pattern to the tree. Mainly, to be used by
* 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);
}
public void printStats() {
System.out.println("Value space size = "
+ Integer.toString(vspace.length()));
super.printStats();
}
/*
public static void main(String[] argv) throws Exception {
HyphenationTree ht = null;
int minCharCount = 2;
BufferedReader in =
new BufferedReader(new InputStreamReader(System.in));
for (; ; ) {
System.out.print("l:\tload patterns from XML\nL:\tload patterns from serialized object\ns:\tset minimun character count\nw:\twrite hyphenation tree to object file\nh:\thyphenate\nf:\tfind pattern\nb:\tbenchmark\nq:\tquit\n\nCommand:");
String token = in.readLine().trim();
if (token.equals("f")) {
System.out.print("Pattern: ");
token = in.readLine().trim();
System.out.println("Values: " + ht.findPattern(token));
} else if (token.equals("s")) {
System.out.print("Minimun value: ");
token = in.readLine().trim();
minCharCount = Integer.parseInt(token);
} else if (token.equals("l")) {
ht = new HyphenationTree();
System.out.print("XML file name: ");
token = in.readLine().trim();
ht.loadPatterns(token);
} else if (token.equals("L")) {
ObjectInputStream ois = null;
System.out.print("Object file name: ");
token = in.readLine().trim();
try {
ois = new ObjectInputStream(new FileInputStream(token));
ht = (HyphenationTree)ois.readObject();
} catch (Exception e) {
e.printStackTrace();
}
finally {
if (ois != null) {
try {
ois.close();
} catch (IOException e) {}
}
}
} else if (token.equals("w")) {
System.out.print("Object file name: ");
token = in.readLine().trim();
ObjectOutputStream oos = null;
try {
oos = new ObjectOutputStream(new FileOutputStream(token));
oos.writeObject(ht);
} catch (Exception e) {
e.printStackTrace();
}
finally {
if (oos != null) {
try {
oos.flush();
} catch (IOException e) {}
try {
oos.close();
} catch (IOException e) {}
}
}
} else if (token.equals("h")) {
System.out.print("Word: ");
token = in.readLine().trim();
System.out.print("Hyphenation points: ");
System.out.println(ht.hyphenate(token, minCharCount,
minCharCount));
} else if (token.equals("b")) {
if (ht == null) {
System.out.println("No patterns has been loaded.");
break;
}
System.out.print("Word list filename: ");
token = in.readLine().trim();
long starttime = 0;
int counter = 0;
;
try {
BufferedReader reader =
new BufferedReader(new FileReader(token));
String line;
starttime = System.currentTimeMillis();
while ((line = reader.readLine()) != null) {
// System.out.print("\nline: ");
Hyphenation hyp = ht.hyphenate(line, minCharCount,
minCharCount);
if (hyp != null) {
String hword = hyp.toString();
// System.out.println(line);
// System.out.println(hword);
} else {
// System.out.println("No hyphenation");
}
counter++;
}
} catch (Exception ioe) {
System.out.println("Exception " + ioe);
ioe.printStackTrace();
}
long endtime = System.currentTimeMillis();
long result = endtime - starttime;
System.out.println(counter + " words in " + result
+ " Millisekunden hyphenated");
} else if (token.equals("q"))
break;
}
}*/
}