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With inspiration from other libraries
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html#License
/*
******************************************************************************
* Copyright (C) 1996-2011, International Business Machines Corporation and *
* others. All Rights Reserved. *
******************************************************************************
*/
package com.ibm.icu.lang;
import com.ibm.icu.impl.UCharacterName;
import com.ibm.icu.impl.UCharacterNameChoice;
import com.ibm.icu.util.ValueIterator;
/**
* Class enabling iteration of the codepoints and their names.
* Result of each iteration contains a valid codepoint that has valid
* name.
* See UCharacter.getNameIterator() for an example of use.
* @author synwee
* @since release 2.1, March 5 2002
*/
class UCharacterNameIterator implements ValueIterator
{
// public methods ----------------------------------------------------
/**
* Gets the next result for this iteration and returns
* true if we are not at the end of the iteration, false otherwise.
* If the return boolean is a false, the contents of elements will not
* be updated.
* @param element for storing the result codepoint and name
* @return true if we are not at the end of the iteration, false otherwise.
* @see com.ibm.icu.util.ValueIterator.Element
*/
@Override
public boolean next(ValueIterator.Element element)
{
if (m_current_ >= m_limit_) {
return false;
}
if (m_choice_ == UCharacterNameChoice.UNICODE_CHAR_NAME ||
m_choice_ == UCharacterNameChoice.EXTENDED_CHAR_NAME
) {
int length = m_name_.getAlgorithmLength();
if (m_algorithmIndex_ < length) {
while (m_algorithmIndex_ < length) {
// find the algorithm range that could contain m_current_
if (m_algorithmIndex_ < 0 ||
m_name_.getAlgorithmEnd(m_algorithmIndex_) <
m_current_) {
m_algorithmIndex_ ++;
}
else {
break;
}
}
if (m_algorithmIndex_ < length) {
// interleave the data-driven ones with the algorithmic ones
// iterate over all algorithmic ranges; assume that they are
// in ascending order
int start = m_name_.getAlgorithmStart(m_algorithmIndex_);
if (m_current_ < start) {
// this should get rid of those codepoints that are not
// in the algorithmic range
int end = start;
if (m_limit_ <= start) {
end = m_limit_;
}
if (!iterateGroup(element, end)) {
m_current_ ++;
return true;
}
}
/*
// "if (m_current_ >= m_limit_)" would not return true
// because it can never be reached due to:
// 1) It has already been checked earlier
// 2) When m_current_ is updated earlier, it returns true
// 3) No updates on m_limit_*/
if (m_current_ >= m_limit_) {
// after iterateGroup fails, current codepoint may be
// greater than limit
return false;
}
element.integer = m_current_;
element.value = m_name_.getAlgorithmName(m_algorithmIndex_,
m_current_);
// reset the group index if we are in the algorithmic names
m_groupIndex_ = -1;
m_current_ ++;
return true;
}
}
}
// enumerate the character names after the last algorithmic range
if (!iterateGroup(element, m_limit_)) {
m_current_ ++;
return true;
}
else if (m_choice_ == UCharacterNameChoice.EXTENDED_CHAR_NAME) {
if (!iterateExtended(element, m_limit_)) {
m_current_ ++;
return true;
}
}
return false;
}
/**
* Resets the iterator to start iterating from the integer index
* UCharacter.MIN_VALUE or X if a setRange(X, Y) has been called previously.
*
*/
@Override
public void reset()
{
m_current_ = m_start_;
m_groupIndex_ = -1;
m_algorithmIndex_ = -1;
}
/**
* Restricts the range of integers to iterate and resets the iteration
* to begin at the index argument start.
* If setRange(start, end) is not performed before next(element) is
* called, the iteration will start from the integer index
* UCharacter.MIN_VALUE and end at UCharacter.MAX_VALUE.
*
* If this range is set outside the range of UCharacter.MIN_VALUE and
* UCharacter.MAX_VALUE, next(element) will always return false.
*
* @param start first integer in range to iterate
* @param limit 1 integer after the last integer in range
* @exception IllegalArgumentException thrown when attempting to set an
* illegal range. E.g limit <= start
*/
@Override
public void setRange(int start, int limit)
{
if (start >= limit) {
throw new IllegalArgumentException(
"start or limit has to be valid Unicode codepoints and start < limit");
}
if (start < UCharacter.MIN_VALUE) {
m_start_ = UCharacter.MIN_VALUE;
}
else {
m_start_ = start;
}
if (limit > UCharacter.MAX_VALUE + 1) {
m_limit_ = UCharacter.MAX_VALUE + 1;
}
else {
m_limit_ = limit;
}
m_current_ = m_start_;
}
// protected constructor ---------------------------------------------
/**
* Constructor
* @param name name data
* @param choice name choice from the class
* com.ibm.icu.lang.UCharacterNameChoice
*/
protected UCharacterNameIterator(UCharacterName name, int choice)
{
if(name==null){
throw new IllegalArgumentException("UCharacterName name argument cannot be null. Missing unames.icu?");
}
m_name_ = name;
// no explicit choice in UCharacter so no checks on choice
m_choice_ = choice;
m_start_ = UCharacter.MIN_VALUE;
m_limit_ = UCharacter.MAX_VALUE + 1;
m_current_ = m_start_;
}
// private data members ---------------------------------------------
/**
* Name data
*/
private UCharacterName m_name_;
/**
* Name choice
*/
private int m_choice_;
/**
* Start iteration range
*/
private int m_start_;
/**
* End + 1 iteration range
*/
private int m_limit_;
/**
* Current codepoint
*/
private int m_current_;
/**
* Group index
*/
private int m_groupIndex_ = -1;
/**
* Algorithm index
*/
private int m_algorithmIndex_ = -1;
/**
* Group use
*/
private static char GROUP_OFFSETS_[] =
new char[UCharacterName.LINES_PER_GROUP_ + 1];
private static char GROUP_LENGTHS_[] =
new char[UCharacterName.LINES_PER_GROUP_ + 1];
// private methods --------------------------------------------------
/**
* Group name iteration, iterate all the names in the current 32-group and
* returns the first codepoint that has a valid name.
* @param result stores the result codepoint and name
* @param limit last codepoint + 1 in range to search
* @return false if a codepoint with a name is found in group and we can
* bail from further iteration, true to continue on with the
* iteration
*/
private boolean iterateSingleGroup(ValueIterator.Element result, int limit)
{
synchronized(GROUP_OFFSETS_) {
synchronized(GROUP_LENGTHS_) {
int index = m_name_.getGroupLengths(m_groupIndex_, GROUP_OFFSETS_,
GROUP_LENGTHS_);
while (m_current_ < limit) {
int offset = UCharacterName.getGroupOffset(m_current_);
String name = m_name_.getGroupName(
index + GROUP_OFFSETS_[offset],
GROUP_LENGTHS_[offset], m_choice_);
if ((name == null || name.length() == 0) &&
m_choice_ == UCharacterNameChoice.EXTENDED_CHAR_NAME) {
name = m_name_.getExtendedName(m_current_);
}
if (name != null && name.length() > 0) {
result.integer = m_current_;
result.value = name;
return false;
}
++ m_current_;
}
}
}
return true;
}
/**
* Group name iteration, iterate all the names in the current 32-group and
* returns the first codepoint that has a valid name.
* @param result stores the result codepoint and name
* @param limit last codepoint + 1 in range to search
* @return false if a codepoint with a name is found in group and we can
* bail from further iteration, true to continue on with the
* iteration
*/
private boolean iterateGroup(ValueIterator.Element result, int limit)
{
if (m_groupIndex_ < 0) {
m_groupIndex_ = m_name_.getGroup(m_current_);
}
while (m_groupIndex_ < m_name_.m_groupcount_ &&
m_current_ < limit) {
// iterate till the last group or the last codepoint
int startMSB = UCharacterName.getCodepointMSB(m_current_);
int gMSB = m_name_.getGroupMSB(m_groupIndex_); // can be -1
if (startMSB == gMSB) {
if (startMSB == UCharacterName.getCodepointMSB(limit - 1)) {
// if start and limit - 1 are in the same group, then enumerate
// only in that one
return iterateSingleGroup(result, limit);
}
// enumerate characters in the partial start group
// if (m_name_.getGroupOffset(m_current_) != 0) {
if (!iterateSingleGroup(result,
UCharacterName.getGroupLimit(gMSB))) {
return false;
}
++ m_groupIndex_; // continue with the next group
}
else if (startMSB > gMSB) {
// make sure that we start enumerating with the first group
// after start
m_groupIndex_ ++;
}
else {
int gMIN = UCharacterName.getGroupMin(gMSB);
if (gMIN > limit) {
gMIN = limit;
}
if (m_choice_ == UCharacterNameChoice.EXTENDED_CHAR_NAME) {
if (!iterateExtended(result, gMIN)) {
return false;
}
}
m_current_ = gMIN;
}
}
return true;
}
/**
* Iterate extended names.
* @param result stores the result codepoint and name
* @param limit last codepoint + 1 in range to search
* @return false if a codepoint with a name is found and we can
* bail from further iteration, true to continue on with the
* iteration (this will always be false for valid codepoints)
*/
private boolean iterateExtended(ValueIterator.Element result,
int limit)
{
while (m_current_ < limit) {
String name = m_name_.getExtendedOr10Name(m_current_);
if (name != null && name.length() > 0) {
result.integer = m_current_;
result.value = name;
return false;
}
++ m_current_;
}
return true;
}
}