/*
*******************************************************************************
* Copyright (C) 1996-2007, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*/
package com.ibm.icu.text;
import java.io.IOException;
import com.ibm.icu.impl.UCaseProps;
import com.ibm.icu.util.ULocale;
import com.ibm.icu.text.ReplaceableContextIterator;
/**
* A transliterator that performs locale-sensitive toLower()
* case mapping.
*/
class LowercaseTransliterator extends Transliterator{
/**
* Package accessible ID.
*/
static final String _ID = "Any-Lower";
// TODO: Add variants for tr, az, lt, default = default locale
/**
* System registration hook.
*/
static void register() {
Transliterator.registerFactory(_ID, new Transliterator.Factory() {
public Transliterator getInstance(String ID) {
return new LowercaseTransliterator(ULocale.US);
}
});
Transliterator.registerSpecialInverse("Lower", "Upper", true);
}
private ULocale locale;
private UCaseProps csp;
private ReplaceableContextIterator iter;
private StringBuffer result;
private int[] locCache;
/**
* Constructs a transliterator.
*/
public LowercaseTransliterator(ULocale loc) {
super(_ID, null);
locale = loc;
try {
csp=UCaseProps.getSingleton();
} catch (IOException e) {
csp=null;
}
iter=new ReplaceableContextIterator();
result = new StringBuffer();
locCache = new int[1];
locCache[0]=0;
}
/**
* Implements {@link Transliterator#handleTransliterate}.
*/
protected void handleTransliterate(Replaceable text,
Position offsets, boolean isIncremental) {
if(csp==null) {
return;
}
if(offsets.start >= offsets.limit) {
return;
}
iter.setText(text);
result.setLength(0);
int c, delta;
// Walk through original string
// If there is a case change, modify corresponding position in replaceable
iter.setIndex(offsets.start);
iter.setLimit(offsets.limit);
iter.setContextLimits(offsets.contextStart, offsets.contextLimit);
while((c=iter.nextCaseMapCP())>=0) {
c=csp.toFullLower(c, iter, result, locale, locCache);
if(iter.didReachLimit() && isIncremental) {
// the case mapping function tried to look beyond the context limit
// wait for more input
offsets.start=iter.getCaseMapCPStart();
return;
}
/* decode the result */
if(c<0) {
/* c mapped to itself, no change */
continue;
} else if(c<=UCaseProps.MAX_STRING_LENGTH) {
/* replace by the mapping string */
delta=iter.replace(result.toString());
result.setLength(0);
} else {
/* replace by single-code point mapping */
delta=iter.replace(UTF16.valueOf(c));
}
if(delta!=0) {
offsets.limit += delta;
offsets.contextLimit += delta;
}
}
offsets.start = offsets.limit;
}
}