/*
*******************************************************************************
* Copyright (C) 1996-2007, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*/
package com.ibm.icu.text;
import java.io.InputStream;
import java.io.DataInputStream;
import java.io.FileNotFoundException;
import java.io.UnsupportedEncodingException;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.FileOutputStream;
import com.ibm.icu.util.CompactByteArray;
/**
* This is the class that represents the list of known words used by
* DictionaryBasedBreakIterator. The conceptual data structure used
* here is a trie: there is a node hanging off the root node for every
* letter that can start a word. Each of these nodes has a node hanging
* off of it for every letter that can be the second letter of a word
* if this node is the first letter, and so on. The trie is represented
* as a two-dimensional array that can be treated as a table of state
* transitions. Indexes are used to compress this array, taking
* advantage of the fact that this array will always be very sparse.
* @internal
* @deprecated This API is ICU internal only.
*/
public class BreakDictionary {
//=================================================================================
// testing and debugging
//=================================================================================
/**
* @internal
* @deprecated This API is ICU internal only.
*/
public static void main(String args[])
throws FileNotFoundException, UnsupportedEncodingException, IOException {
String filename = args[0];
BreakDictionary dictionary = new BreakDictionary(new FileInputStream(filename));
PrintWriter out = null;
if(args.length >= 2) {
out = new PrintWriter(new OutputStreamWriter(new FileOutputStream(args[1]), "UnicodeLittle"));
}
dictionary.printWordList("", 0, out);
if (out != null) {
out.close();
}
}
/**
* @internal
* @deprecated This API is ICU internal only.
*/
public void printWordList(String partialWord, int state, PrintWriter out)
throws IOException {
if (state == 0xFFFF) {
System.out.println(partialWord);
if (out != null) {
out.println(partialWord);
}
}
else {
for (int i = 0; i < numCols; i++) {
int newState = (at(state, i)) & 0xFFFF;
if (newState != 0) {
char newChar = reverseColumnMap[i];
String newPartialWord = partialWord;
if (newChar != 0) {
newPartialWord += newChar;
}
printWordList(newPartialWord, newState, out);
}
}
}
}
/**
* A map used to go from column numbers to characters. Used only
* for debugging right now.
*/
private char[] reverseColumnMap = null;
//=================================================================================
// data members
//=================================================================================
/**
* Maps from characters to column numbers. The main use of this is to
* avoid making room in the array for empty columns.
*/
private CompactByteArray columnMap = null;
/**
* The number of actual columns in the table
*/
private int numCols;
/*
* Columns are organized into groups of 32. This says how many
* column groups. (We could calculate this, but we store the
* value to avoid having to repeatedly calculate it.)
*/
//private int numColGroups;
/**
* The actual compressed state table. Each conceptual row represents
* a state, and the cells in it contain the row numbers of the states
* to transition to for each possible letter. 0 is used to indicate
* an illegal combination of letters (i.e., the error state). The
* table is compressed by eliminating all the unpopulated (i.e., zero)
* cells. Multiple conceptual rows can then be doubled up in a single
* physical row by sliding them up and possibly shifting them to one
* side or the other so the populated cells don't collide. Indexes
* are used to identify unpopulated cells and to locate populated cells.
*/
private short[] table = null;
/**
* This index maps logical row numbers to physical row numbers
*/
private short[] rowIndex = null;
/**
* A bitmap is used to tell which cells in the comceptual table are
* populated. This array contains all the unique bit combinations
* in that bitmap. If the table is more than 32 columns wide,
* successive entries in this array are used for a single row.
*/
private int[] rowIndexFlags = null;
/**
* This index maps from a logical row number into the bitmap table above.
* (This keeps us from storing duplicate bitmap combinations.) Since there
* are a lot of rows with only one populated cell, instead of wasting space
* in the bitmap table, we just store a negative number in this index for
* rows with one populated cell. The absolute value of that number is
* the column number of the populated cell.
*/
private short[] rowIndexFlagsIndex = null;
/**
* For each logical row, this index contains a constant that is added to
* the logical column number to get the physical column number
*/
private byte[] rowIndexShifts = null;
//=================================================================================
// deserialization
//=================================================================================
/**
* @internal
* @deprecated This API is ICU internal only.
*/
public BreakDictionary(InputStream dictionaryStream) throws IOException {
readDictionaryFile(new DataInputStream(dictionaryStream));
}
/**
* @internal
* @deprecated This API is ICU internal only.
*/
public void readDictionaryFile(DataInputStream in) throws IOException {
int l;
// read in the version number (right now we just ignore it)
in.readInt();
// read in the column map (this is serialized in its internal form:
// an index array followed by a data array)
l = in.readInt();
char[] temp = new char[l];
for (int i = 0; i < temp.length; i++)
temp[i] = (char)in.readShort();
l = in.readInt();
byte[] temp2 = new byte[l];
for (int i = 0; i < temp2.length; i++)
temp2[i] = in.readByte();
columnMap = new CompactByteArray(temp, temp2);
// read in numCols and numColGroups
numCols = in.readInt();
/*numColGroups = */in.readInt();
// read in the row-number index
l = in.readInt();
rowIndex = new short[l];
for (int i = 0; i < rowIndex.length; i++)
rowIndex[i] = in.readShort();
// load in the populated-cells bitmap: index first, then bitmap list
l = in.readInt();
rowIndexFlagsIndex = new short[l];
for (int i = 0; i < rowIndexFlagsIndex.length; i++)
rowIndexFlagsIndex[i] = in.readShort();
l = in.readInt();
rowIndexFlags = new int[l];
for (int i = 0; i < rowIndexFlags.length; i++)
rowIndexFlags[i] = in.readInt();
// load in the row-shift index
l = in.readInt();
rowIndexShifts = new byte[l];
for (int i = 0; i < rowIndexShifts.length; i++)
rowIndexShifts[i] = in.readByte();
// finally, load in the actual state table
l = in.readInt();
table = new short[l];
for (int i = 0; i < table.length; i++)
table[i] = in.readShort();
// this data structure is only necessary for testing and debugging purposes
reverseColumnMap = new char[numCols];
for (char c = 0; c < 0xffff; c++) {
int col = columnMap.elementAt(c);
if (col != 0) {
reverseColumnMap[col] = c;
}
}
// close the stream
in.close();
}
//=================================================================================
// access to the words
//=================================================================================
/**
* Uses the column map to map the character to a column number, then
* passes the row and column number to the other version of at()
* @param row The current state
* @param ch The character whose column we're interested in
* @return The new state to transition to
* @internal
* @deprecated This API is ICU internal only.
*/
public final short at(int row, char ch) {
int col = columnMap.elementAt(ch);
return at(row, col);
}
/**
* Returns the value in the cell with the specified (logical) row and
* column numbers. In DictionaryBasedBreakIterator, the row number is
* a state number, the column number is an input, and the return value
* is the row number of the new state to transition to. (0 is the
* "error" state, and -1 is the "end of word" state in a dictionary)
* @param row The row number of the current state
* @param col The column number of the input character (0 means "not a
* dictionary character")
* @return The row number of the new state to transition to
* @internal
* @deprecated This API is ICU internal only.
*/
public final short at(int row, int col) {
if (cellIsPopulated(row, col)) {
// we map from logical to physical row number by looking up the
// mapping in rowIndex; we map from logical column number to
// physical column number by looking up a shift value for this
// logical row and offsetting the logical column number by
// the shift amount. Then we can use internalAt() to actually
// get the value out of the table.
return internalAt(rowIndex[row], col + rowIndexShifts[row]);
}
else {
return 0;
}
}
/**
* Given (logical) row and column numbers, returns true if the
* cell in that position is populated
*/
private final boolean cellIsPopulated(int row, int col) {
// look up the entry in the bitmap index for the specified row.
// If it's a negative number, it's the column number of the only
// populated cell in the row
if (rowIndexFlagsIndex[row] < 0) {
return col == -rowIndexFlagsIndex[row];
}
// if it's a positive number, it's the offset of an entry in the bitmap
// list. If the table is more than 32 columns wide, the bitmap is stored
// successive entries in the bitmap list, so we have to divide the column
// number by 32 and offset the number we got out of the index by the result.
// Once we have the appropriate piece of the bitmap, test the appropriate
// bit and return the result.
else {
int flags = rowIndexFlags[rowIndexFlagsIndex[row] + (col >> 5)];
return (flags & (1 << (col & 0x1f))) != 0;
}
}
/**
* Implementation of at() when we know the specified cell is populated.
* @param row The PHYSICAL row number of the cell
* @param col The PHYSICAL column number of the cell
* @return The value stored in the cell
*/
private final short internalAt(int row, int col) {
// the table is a one-dimensional array, so this just does the math necessary
// to treat it as a two-dimensional array (we don't just use a two-dimensional
// array because two-dimensional arrays are inefficient in Java)
return table[row * numCols + col];
}
}