/*
*******************************************************************************
* Copyright (C) 2000-2007, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*/
package com.ibm.icu.dev.tool.ime.indic;
import java.awt.im.spi.InputMethodContext;
import java.awt.event.KeyEvent;
import java.awt.event.InputMethodEvent;
import java.awt.font.TextAttribute;
import java.awt.font.TextHitInfo;
import java.text.AttributedCharacterIterator;
import java.util.Hashtable;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
class IndicInputMethodImpl {
protected char[] KBD_MAP;
private static final char SUBSTITUTION_BASE = '\uff00';
// Indexed by map value - SUBSTITUTION_BASE
protected char[][] SUBSTITUTION_TABLE;
// Invalid character.
private static final char INVALID_CHAR = '\uffff';
// Unmapped versions of some interesting characters.
private static final char KEY_SIGN_VIRAMA = '\u0064'; // or just 'd'??
private static final char KEY_SIGN_NUKTA = '\u005d'; // or just ']'??
// Two succeeding viramas are replaced by one virama and one ZWNJ.
// Viram followed by Nukta is replaced by one VIRAMA and one ZWJ
private static final char ZWJ = '\u200d';
private static final char ZWNJ = '\u200c';
// Backspace
private static final char BACKSPACE = '\u0008';
// Sorted list of characters which can be followed by Nukta
protected char[] JOIN_WITH_NUKTA;
// Nukta form of the above characters
protected char[] NUKTA_FORM;
//private int log2;
private int power;
private int extra;
// cached TextHitInfo. Only one type of TextHitInfo is required.
private static final TextHitInfo ZERO_TRAILING_HIT_INFO = TextHitInfo.trailing(0);
/**
* Returns the index of the given character in the JOIN_WITH_NUKTA array.
* If character is not found, -1 is returned.
*/
private int nuktaIndex(char ch) {
if (JOIN_WITH_NUKTA == null) {
return -1;
}
int probe = power;
int index = 0;
if (JOIN_WITH_NUKTA[extra] <= ch) {
index = extra;
}
while (probe > (1 << 0)) {
probe >>= 1;
if (JOIN_WITH_NUKTA[index + probe] <= ch) {
index += probe;
}
}
if (JOIN_WITH_NUKTA[index] != ch) {
index = -1;
}
return index;
}
/**
* Returns the equivalent character for hindi locale.
* @param originalChar The original character.
*/
private char getMappedChar(char originalChar) {
if (originalChar <= KBD_MAP.length) {
return KBD_MAP[originalChar];
}
return originalChar;
}
// Array used to hold the text to be sent.
// If the last character was not committed it is stored in text[0].
// The variable totalChars give an indication of whether the last
// character was committed or not. If at any time ( but not within a
// a call to dispatchEvent ) totalChars is not equal to 0 ( it can
// only be 1 otherwise ) the last character was not committed.
private char [] text = new char[4];
// this is always 0 before and after call to dispatchEvent. This character assumes
// significance only within a call to dispatchEvent.
private int committedChars = 0;// number of committed characters
// the total valid characters in variable text currently.
private int totalChars = 0;//number of total characters ( committed + composed )
private boolean lastCharWasVirama = false;
private InputMethodContext context;
//
// Finds the high bit by binary searching
// through the bits in n.
//
private static byte highBit(int n) {
if (n <= 0) {
return -32;
}
byte bit = 0;
if (n >= 1 << 16) {
n >>= 16;
bit += 16;
}
if (n >= 1 << 8) {
n >>= 8;
bit += 8;
}
if (n >= 1 << 4) {
n >>= 4;
bit += 4;
}
if (n >= 1 << 2) {
n >>= 2;
bit += 2;
}
if (n >= 1 << 1) {
n >>= 1;
bit += 1;
}
return bit;
}
IndicInputMethodImpl(char[] keyboardMap, char[] joinWithNukta, char[] nuktaForm,
char[][] substitutionTable) {
KBD_MAP = keyboardMap;
JOIN_WITH_NUKTA = joinWithNukta;
NUKTA_FORM = nuktaForm;
SUBSTITUTION_TABLE = substitutionTable;
if (JOIN_WITH_NUKTA != null) {
int log2 = highBit(JOIN_WITH_NUKTA.length);
power = 1 << log2;
extra = JOIN_WITH_NUKTA.length - power;
} else {
power = extra = 0;
}
}
void setInputMethodContext(InputMethodContext context) {
this.context = context;
}
void handleKeyTyped(KeyEvent kevent) {
char keyChar = kevent.getKeyChar();
char currentChar = getMappedChar(keyChar);
// The Explicit and Soft Halanta case.
if ( lastCharWasVirama ) {
switch (keyChar) {
case KEY_SIGN_NUKTA:
currentChar = ZWJ;
break;
case KEY_SIGN_VIRAMA:
currentChar = ZWNJ;
break;
default:
}//endSwitch
}//endif
if (currentChar == INVALID_CHAR) {
kevent.consume();
return;
}
if (currentChar == BACKSPACE) {
lastCharWasVirama = false;
if (totalChars > 0) {
totalChars = committedChars = 0;
} else {
return;
}
}
else if (keyChar == KEY_SIGN_NUKTA) {
int nuktaIndex = nuktaIndex(text[0]);
if (nuktaIndex != -1) {
text[0] = NUKTA_FORM[nuktaIndex];
} else {
// the last character was committed, commit just Nukta.
// Note : the lastChar must have been committed if it is not one of
// the characters which combine with nukta.
// the state must be totalChars = committedChars = 0;
text[totalChars++] = currentChar;
}
committedChars += 1;
}
else {
int nuktaIndex = nuktaIndex(currentChar);
if (nuktaIndex != -1) {
// Commit everything but currentChar
text[totalChars++] = currentChar;
committedChars = totalChars-1;
} else {
if (currentChar >= SUBSTITUTION_BASE) {
char[] sub = SUBSTITUTION_TABLE[currentChar - SUBSTITUTION_BASE];
System.arraycopy(sub, 0, text, totalChars, sub.length);
totalChars += sub.length;
} else {
text[totalChars++] = currentChar;
}
committedChars = totalChars;
}
}
ACIText aText = new ACIText( text, 0, totalChars, committedChars );
int composedCharLength = totalChars - committedChars;
TextHitInfo caret=null,visiblePosition=null;
switch( composedCharLength ) {
case 0:
break;
case 1:
visiblePosition = caret = ZERO_TRAILING_HIT_INFO;
break;
default:
// The code should not reach here. There is no case where there can be
// more than one character pending.
}
context.dispatchInputMethodEvent(InputMethodEvent.INPUT_METHOD_TEXT_CHANGED,
aText,
committedChars,
caret,
visiblePosition);
if (totalChars == 0) {
text[0] = INVALID_CHAR;
} else {
text[0] = text[totalChars - 1];// make text[0] hold the last character
}
lastCharWasVirama = keyChar == KEY_SIGN_VIRAMA && !lastCharWasVirama;
totalChars -= committedChars;
committedChars = 0;
// state now text[0] = last character
// totalChars = ( last character committed )? 0 : 1;
// committedChars = 0;
kevent.consume();// prevent client from getting this event.
}
void endComposition() {
if( totalChars != 0 ) {// if some character is not committed.
ACIText aText = new ACIText( text, 0, totalChars, totalChars );
context.dispatchInputMethodEvent( InputMethodEvent.INPUT_METHOD_TEXT_CHANGED,
aText, totalChars, null, null );
totalChars = committedChars = 0;
text[0] = INVALID_CHAR;
lastCharWasVirama = false;
}
}
// custom AttributedCharacterIterator -- much lightweight since currently there is no
// attribute defined on the text being generated by the input method.
private class ACIText implements AttributedCharacterIterator {
private char [] text = null;
private int committed = 0;
private int index = 0;
ACIText( char [] chArray, int offset, int length, int committed ) {
this.text = new char[length];
this.committed = committed;
System.arraycopy( chArray, offset, text, 0, length );
}
// CharacterIterator methods.
public char first() {
return _setIndex( 0 );
}
public char last() {
if( text.length == 0 ) {
return _setIndex( text.length );
}
return _setIndex( text.length - 1 );
}
public char current() {
if( index == text.length )
return DONE;
return text[index];
}
public char next() {
if( index == text.length ) {
return DONE;
}
return _setIndex( index + 1 );
}
public char previous() {
if( index == 0 )
return DONE;
return _setIndex( index - 1 );
}
public char setIndex(int position) {
if( position < 0 || position > text.length ) {
throw new IllegalArgumentException();
}
return _setIndex( position );
}
public int getBeginIndex() {
return 0;
}
public int getEndIndex() {
return text.length;
}
public int getIndex() {
return index;
}
public Object clone() {
try {
ACIText clone = (ACIText) super.clone();
return clone;
} catch (CloneNotSupportedException e) {
throw new IllegalStateException();
}
}
// AttributedCharacterIterator methods.
public int getRunStart() {
return index >= committed ? committed : 0;
}
public int getRunStart(AttributedCharacterIterator.Attribute attribute) {
return (index >= committed &&
attribute == TextAttribute.INPUT_METHOD_UNDERLINE) ? committed : 0;
}
public int getRunStart(Set attributes) {
return (index >= committed &&
attributes.contains(TextAttribute.INPUT_METHOD_UNDERLINE)) ? committed : 0;
}
public int getRunLimit() {
return index < committed ? committed : text.length;
}
public int getRunLimit(AttributedCharacterIterator.Attribute attribute) {
return (index < committed &&
attribute == TextAttribute.INPUT_METHOD_UNDERLINE) ? committed : text.length;
}
public int getRunLimit(Set attributes) {
return (index < committed &&
attributes.contains(TextAttribute.INPUT_METHOD_UNDERLINE)) ? committed : text.length;
}
public Map getAttributes() {
Hashtable result = new Hashtable();
if (index >= committed && committed < text.length) {
result.put(TextAttribute.INPUT_METHOD_UNDERLINE,
TextAttribute.UNDERLINE_LOW_ONE_PIXEL);
}
return result;
}
public Object getAttribute(AttributedCharacterIterator.Attribute attribute) {
if (index >= committed &&
committed < text.length &&
attribute == TextAttribute.INPUT_METHOD_UNDERLINE) {
return TextAttribute.UNDERLINE_LOW_ONE_PIXEL;
}
return null;
}
public Set getAllAttributeKeys() {
HashSet result = new HashSet();
if (committed < text.length) {
result.add(TextAttribute.INPUT_METHOD_UNDERLINE);
}
return result;
}
// private methods
/**
* This is always called with valid i ( 0 < i <= text.length )
*/
private char _setIndex( int i ) {
index = i;
if( i == text.length ) {
return DONE;
}
return text[i];
}
}
}