284 lines
6.5 KiB
C++
284 lines
6.5 KiB
C++
// Copyright (c) 2006 Tel-Aviv University (Israel).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org).
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Minkowski_sum_2/include/CGAL/Minkowski_sum_2/Labels.h $
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// $Id: Labels.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Ron Wein <wein_r@yahoo.com>
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#ifndef CGAL_MINKOWSKI_SUM_LABELS_H
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#define CGAL_MINKOWSKI_SUM_LABELS_H
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#include <CGAL/license/Minkowski_sum_2.h>
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namespace CGAL {
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/*! \class
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* A label for endpoints of Minkowski-sum curves.
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*/
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class Point_label
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{
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private:
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unsigned int _component; // The index of the component this point
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// belongs to.
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unsigned int _index; // Index of the point in the component.
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public:
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/*! Default constructor. */
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Point_label () :
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_component (0),
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_index (0)
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{}
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/*!
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* Constructor.
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* \param component The index of the component.
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* \param index Index of the point within the component.
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*/
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Point_label (unsigned int component,
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unsigned int index) :
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_component (component),
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_index (index)
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{
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CGAL_precondition (component != 0);
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}
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/*! Check whether the label is valid. */
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bool is_valid () const
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{
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return (_component != 0);
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}
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/*! Check two labels for equality. */
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bool operator== (const Point_label& label) const
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{
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if (_component == 0 || label._component == 0)
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return (false);
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return (_component == label._component &&
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_index == label._index);
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}
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/*! Get the component. */
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unsigned int component () const
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{
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return (_component);
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}
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/*! Get the index within the component. */
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unsigned int index () const
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{
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return (_index);
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}
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/*! Set the component. */
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void set_component (unsigned int component)
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{
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CGAL_precondition (component != 0);
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_component = component;
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return;
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}
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/*! Set the index. */
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void set_index (unsigned int index)
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{
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_index = index;
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return;
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}
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};
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/*! \class
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* A label for Minkowski-sum x-monotone curves.
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*/
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class X_curve_label
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{
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private:
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unsigned int _component; // The index of the component the x-monotone
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// curve belongs to.
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unsigned int _index; // Index of the curve in the component.
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bool _is_last; // Is the curve the last one in its component.
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int _right; // The number of curves directed from left to
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// right that are associated with the curve.
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int _left; // The number of curves directed from right to
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// left that are associated with the curve.
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public:
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/*! Default constructor. */
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X_curve_label () :
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_component (0),
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_index (0),
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_is_last (false),
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_right (0),
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_left (0)
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{}
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/*!
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* Constructor.
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* \param is_directed_right Is the curve directed from left to right.
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* \param component The index of the component.
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* \param index Index of the curve in the component.
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* \param is_last Is this the last curve of the component.
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*/
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X_curve_label (bool is_directed_right,
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unsigned int component,
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unsigned int index,
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bool is_last = false) :
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_component (component),
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_index (index),
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_is_last (is_last),
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_right (is_directed_right ? 1 : 0),
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_left (is_directed_right ? 0 : 1)
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{
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CGAL_precondition (component != 0);
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}
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/*!
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* Construct a merged curve label.
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* \param label1 The first label.
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* \param label2 The second label.
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*/
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X_curve_label (const X_curve_label& label1,
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const X_curve_label& label2) :
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_component (0),
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_index (0),
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_is_last (false),
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_right (label1._right + label2._right),
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_left (label1._left + label2._left)
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{}
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/*! Check whether the label is valid. */
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bool is_valid () const
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{
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return (_component != 0);
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}
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/*! Check two labels for equality. */
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bool operator== (const X_curve_label& label) const
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{
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if (_component == 0)
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return (false);
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return (_component == label._component &&
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_index == label._index);
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}
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/*! Check whether the given label is the predecessor of this label. */
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bool is_prev (const X_curve_label& label) const
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{
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if (_component == 0)
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return (false);
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return (_component == label._component &&
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(label._index + 1 == _index ||
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(label._is_last && _index == 0)));
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}
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/*! Check whether the given label is the succcessor of this label. */
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bool is_next (const X_curve_label& label) const
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{
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if (_component == 0)
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return (false);
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return (_component == label._component &&
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(_index + 1 == label._index ||
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(_is_last && label._index == 0)));
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}
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/*!
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* Check if the given label is the successor of this label
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* (or vice-versa).
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*/
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bool is_adjacent (const X_curve_label& label) const
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{
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if (_component == 0)
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return (false);
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// Two curves can be adjacent only if they belong to the same component.
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if (_component != label._component)
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return (false);
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// Check if one label is adjacent to the next.
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return ((_index + 1 == label._index) ||
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(label._index + 1 == _index) ||
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(_is_last && label._index == 0) ||
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(label._is_last && _index == 0));
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}
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/*! Get the number of curves directed from left to right. */
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int right_count () const
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{
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return (_right);
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}
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/*! Get the number of curves directed from right to left. */
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int left_count () const
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{
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return (_left);
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}
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/*! Get the component. */
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unsigned int component () const
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{
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return (_component);
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}
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/*! Get the index within the component. */
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unsigned int index () const
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{
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return (_index);
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}
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/*! Check whether this is the last curve in the component. */
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bool is_last () const
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{
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return (_is_last);
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}
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/*! Set the component. */
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void set_component (unsigned int component)
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{
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CGAL_precondition (component != 0);
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_component = component;
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return;
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}
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/*!
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* Set the curve index within the component.
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* \param index The index in the component.
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* \param is_last Is this the last curve of the component.
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*/
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void set_index (unsigned int index, bool is_last = false)
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{
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_index = index;
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_is_last = is_last;
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return;
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}
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/*! Get the flag value. */
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bool get_flag () const
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{
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return (_is_last);
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}
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/*! Set the flag value. */
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void set_flag (bool flag)
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{
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_is_last = flag;
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return;
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}
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};
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} //namespace CGAL
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#endif
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