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/*
*******************************************************************************
* Copyright (C) 2011-2012, International Business Machines
* Corporation and others. All Rights Reserved.
*******************************************************************************
* created on: 2011jan07
* created by: Markus W. Scherer
* ported from ICU4C ucharstriebuilder/.cpp
*/
package com.ibm.icu.util;
import java.nio.CharBuffer;
/**
* Builder class for CharsTrie.
*
* This class is not intended for public subclassing.
*
* @stable ICU 4.8
* @author Markus W. Scherer
*/
public final class CharsTrieBuilder extends StringTrieBuilder {
/**
* Constructs an empty builder.
* @stable ICU 4.8
*/
public CharsTrieBuilder() {}
/**
* Adds a (string, value) pair.
* The string must be unique.
* The string contents will be copied; the builder does not keep
* a reference to the input CharSequence.
* @param s The input string.
* @param value The value associated with this char sequence.
* @return this
* @stable ICU 4.8
*/
public CharsTrieBuilder add(CharSequence s, int value) {
addImpl(s, value);
return this;
}
/**
* Builds a CharsTrie for the add()ed data.
* Once built, no further data can be add()ed until clear() is called.
*
*
Multiple calls to build() or buildCharSequence() return tries or sequences
* which share the builder's char array, without rebuilding.
* After clear() has been called, a new array will be used.
* @param buildOption Build option, see StringTrieBuilder.Option.
* @return A new CharsTrie for the add()ed data.
* @stable ICU 4.8
*/
public CharsTrie build(StringTrieBuilder.Option buildOption) {
return new CharsTrie(buildCharSequence(buildOption), 0);
}
/**
* Builds a CharsTrie for the add()ed data and char-serializes it.
* Once built, no further data can be add()ed until clear() is called.
*
*
Multiple calls to build() or buildCharSequence() return tries or sequences
* which share the builder's char array, without rebuilding.
* After clear() has been called, a new array will be used.
* @param buildOption Build option, see StringTrieBuilder.Option.
* @return A CharSequence with the char-serialized CharsTrie for the add()ed data.
* @stable ICU 4.8
*/
public CharSequence buildCharSequence(StringTrieBuilder.Option buildOption) {
buildChars(buildOption);
return CharBuffer.wrap(chars, chars.length-charsLength, charsLength);
}
private void buildChars(StringTrieBuilder.Option buildOption) {
// Create and char-serialize the trie for the elements.
if(chars==null) {
chars=new char[1024];
}
buildImpl(buildOption);
}
/**
* Removes all (string, value) pairs.
* New data can then be add()ed and a new trie can be built.
* @return this
* @stable ICU 4.8
*/
public CharsTrieBuilder clear() {
clearImpl();
chars=null;
charsLength=0;
return this;
}
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected boolean matchNodesCanHaveValues() /*const*/ { return true; }
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int getMaxBranchLinearSubNodeLength() /*const*/ { return CharsTrie.kMaxBranchLinearSubNodeLength; }
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int getMinLinearMatch() /*const*/ { return CharsTrie.kMinLinearMatch; }
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int getMaxLinearMatchLength() /*const*/ { return CharsTrie.kMaxLinearMatchLength; }
private void ensureCapacity(int length) {
if(length>chars.length) {
int newCapacity=chars.length;
do {
newCapacity*=2;
} while(newCapacity<=length);
char[] newChars=new char[newCapacity];
System.arraycopy(chars, chars.length-charsLength,
newChars, newChars.length-charsLength, charsLength);
chars=newChars;
}
}
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int write(int unit) {
int newLength=charsLength+1;
ensureCapacity(newLength);
charsLength=newLength;
chars[chars.length-charsLength]=(char)unit;
return charsLength;
}
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int write(int offset, int length) {
int newLength=charsLength+length;
ensureCapacity(newLength);
charsLength=newLength;
int charsOffset=chars.length-charsLength;
while(length>0) {
chars[charsOffset++]=strings.charAt(offset++);
--length;
}
return charsLength;
}
private int write(char[] s, int length) {
int newLength=charsLength+length;
ensureCapacity(newLength);
charsLength=newLength;
System.arraycopy(s, 0, chars, chars.length-charsLength, length);
return charsLength;
}
// For writeValueAndFinal(), writeValueAndType() and writeDeltaTo().
private final char[] intUnits=new char[3];
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int writeValueAndFinal(int i, boolean isFinal) {
if(0<=i && i<=CharsTrie.kMaxOneUnitValue) {
return write(i|(isFinal ? CharsTrie.kValueIsFinal : 0));
}
int length;
if(i<0 || i>CharsTrie.kMaxTwoUnitValue) {
intUnits[0]=(char)(CharsTrie.kThreeUnitValueLead);
intUnits[1]=(char)(i>>16);
intUnits[2]=(char)i;
length=3;
// } else if(i<=CharsTrie.kMaxOneUnitValue) {
// intUnits[0]=(char)(i);
// length=1;
} else {
intUnits[0]=(char)(CharsTrie.kMinTwoUnitValueLead+(i>>16));
intUnits[1]=(char)i;
length=2;
}
intUnits[0]=(char)(intUnits[0]|(isFinal ? CharsTrie.kValueIsFinal : 0));
return write(intUnits, length);
}
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int writeValueAndType(boolean hasValue, int value, int node) {
if(!hasValue) {
return write(node);
}
int length;
if(value<0 || value>CharsTrie.kMaxTwoUnitNodeValue) {
intUnits[0]=(char)(CharsTrie.kThreeUnitNodeValueLead);
intUnits[1]=(char)(value>>16);
intUnits[2]=(char)value;
length=3;
} else if(value<=CharsTrie.kMaxOneUnitNodeValue) {
intUnits[0]=(char)((value+1)<<6);
length=1;
} else {
intUnits[0]=(char)(CharsTrie.kMinTwoUnitNodeValueLead+((value>>10)&0x7fc0));
intUnits[1]=(char)value;
length=2;
}
intUnits[0]|=(char)node;
return write(intUnits, length);
}
/**
* {@inheritDoc}
* @internal
* @deprecated This API is ICU internal only.
*/
@Override
protected int writeDeltaTo(int jumpTarget) {
int i=charsLength-jumpTarget;
assert(i>=0);
if(i<=CharsTrie.kMaxOneUnitDelta) {
return write(i);
}
int length;
if(i<=CharsTrie.kMaxTwoUnitDelta) {
intUnits[0]=(char)(CharsTrie.kMinTwoUnitDeltaLead+(i>>16));
length=1;
} else {
intUnits[0]=(char)(CharsTrie.kThreeUnitDeltaLead);
intUnits[1]=(char)(i>>16);
length=2;
}
intUnits[length++]=(char)i;
return write(intUnits, length);
}
// char serialization of the trie.
// Grows from the back: charsLength measures from the end of the buffer!
private char[] chars;
private int charsLength;
}