public bool NextBreak(out LineBreak lineBreak)
        {
            // get the first char if we're at the beginning of the string
            if (_first)
            {
                _first = false;
                var firstClass = nextCharClass();
                _curClass  = mapFirst(firstClass);
                _nextClass = firstClass;
                _LB8a      = (firstClass == LineBreakClass.ZWJ);
                _LB30a     = 0;
            }

            while (_pos < _codePoints.Length)
            {
                _lastPos = _pos;
                var lastClass = _nextClass;
                _nextClass = nextCharClass();

                // explicit newline
                if ((_curClass == LineBreakClass.BK) || ((_curClass == LineBreakClass.CR) && (_nextClass != LineBreakClass.LF)))
                {
                    _curClass = mapFirst(mapClass(_nextClass));
                    lineBreak = new LineBreak(findPriorNonWhitespace(_lastPos), _lastPos, true);
                    return(true);
                }

                bool?shouldBreak = getSimpleBreak();

                if (!shouldBreak.HasValue)
                {
                    shouldBreak = getPairTableBreak(lastClass);
                }

                // Rule LB8a
                _LB8a = (_nextClass == LineBreakClass.ZWJ);

                if (shouldBreak.Value)
                {
                    lineBreak = new LineBreak(findPriorNonWhitespace(_lastPos), _lastPos, false);
                    return(true);
                }
            }

            if (_lastPos < _codePoints.Length)
            {
                _lastPos = _codePoints.Length;
                var required = (_curClass == LineBreakClass.BK) || ((_curClass == LineBreakClass.CR) && (_nextClass != LineBreakClass.LF));
                lineBreak = new LineBreak(findPriorNonWhitespace(_codePoints.Length), _lastPos, required);
                return(true);
            }
            else
            {
                lineBreak = new LineBreak(0, 0, false);
                return(false);
            }
        }
        /// <summary>
        /// Get the next line break info
        /// </summary>
        /// <param name="lineBreak">A LineBreak structure returned by this method</param>
        /// <returns>True if there was another line break</returns>
        public bool NextBreak(out LineBreak lineBreak)
        {
            // get the first char if we're at the beginning of the string
            if (!_curClass.HasValue)
            {
                if (this.peekCharClass() == LineBreakClass.SP)
                {
                    this._curClass = LineBreakClass.WJ;
                }
                else
                {
                    this._curClass = mapFirst(this.readCharClass());
                }
            }

            while (_pos < _codePoints.Length)
            {
                _lastPos = _pos;
                var lastClass = _nextClass;
                _nextClass = this.readCharClass();

                // explicit newline
                if (_curClass.HasValue && ((_curClass == LineBreakClass.BK) || ((_curClass == LineBreakClass.CR) && (this._nextClass != LineBreakClass.LF))))
                {
                    _curClass = mapFirst(mapClass(_nextClass.Value));
                    lineBreak = new LineBreak(findPriorNonWhitespace(_lastPos), _lastPos, true);
                    return(true);
                }

                // handle classes not handled by the pair table
                LineBreakClass?cur = null;
                switch (_nextClass.Value)
                {
                case LineBreakClass.SP:
                    cur = _curClass;
                    break;

                case LineBreakClass.BK:
                case LineBreakClass.LF:
                case LineBreakClass.NL:
                    cur = LineBreakClass.BK;
                    break;

                case LineBreakClass.CR:
                    cur = LineBreakClass.CR;
                    break;

                case LineBreakClass.CB:
                    cur = LineBreakClass.BA;
                    break;
                }

                if (cur != null)
                {
                    _curClass = cur;
                    if (_nextClass.HasValue && _nextClass.Value == LineBreakClass.CB)
                    {
                        lineBreak = new LineBreak(findPriorNonWhitespace(_lastPos), _lastPos);
                        return(true);
                    }
                    continue;
                }

                // if not handled already, use the pair table
                var shouldBreak = false;
                switch (LineBreakPairTable.table[(int)this._curClass.Value][(int)this._nextClass.Value])
                {
                case LineBreakPairTable.DI_BRK:     // Direct break
                    shouldBreak = true;
                    break;

                case LineBreakPairTable.IN_BRK:     // possible indirect break
                    shouldBreak = lastClass.HasValue && lastClass.Value == LineBreakClass.SP;
                    break;

                case LineBreakPairTable.CI_BRK:
                    shouldBreak = lastClass.HasValue && lastClass.Value == LineBreakClass.SP;
                    if (!shouldBreak)
                    {
                        continue;
                    }
                    break;

                case LineBreakPairTable.CP_BRK:     // prohibited for combining marks
                    if (!lastClass.HasValue || lastClass.Value != LineBreakClass.SP)
                    {
                        continue;
                    }
                    break;
                }

                _curClass = _nextClass;
                if (shouldBreak)
                {
                    lineBreak = new LineBreak(findPriorNonWhitespace(_lastPos), _lastPos);
                    return(true);
                }
            }

            if (_pos >= _codePoints.Length)
            {
                if (_lastPos < _codePoints.Length)
                {
                    _lastPos = _codePoints.Length;
                    var  cls      = UnicodeClasses.LineBreakClass(_codePoints[_codePoints.Length - 1]);
                    bool required = cls == LineBreakClass.BK || cls == LineBreakClass.LF || cls == LineBreakClass.CR;
                    lineBreak = new LineBreak(findPriorNonWhitespace(_codePoints.Length), _codePoints.Length, required);
                    return(true);
                }
            }

            lineBreak = new LineBreak(0, 0, false);
            return(false);
        }