label.h

很多二维 三维几何计算算法 C++ 类库

// Copyright (c) 2005  Stanford University (USA).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.3-branch/Kinetic_data_structures/include/CGAL/Tools/Label.h $
// $Id: Label.h 36638 2007-02-27 22:45:58Z drussel $
// 
//
// Author(s)     : Daniel Russel <[e-mail]>

#ifndef CGAL_LABEL_H_
#define CGAL_LABEL_H_
#include <CGAL/basic.h>
#include <iostream>
#include <sstream>

CGAL_BEGIN_NAMESPACE

//! A type which provides opaque, typed identifiers.
/*!
  Basically this is just an int with a type associated with it
  and one value (-1) picked out as the null value. It implements
  comparisons and things.
*/
template <class A_Type>
class Label
{
protected:
  typedef Label<A_Type> This;
  int id_;

public:
  //! Construct it from an int
  explicit Label(int i):id_(i){}
  //! Construct a default (null) label
  Label():id_(-1) {
    if(0) print();                        // make sure it is compiled
  }
  //! Make the next label
  This  next_label() {
    return Label(id_+1);
  }
  //! Return the null label
  bool is_valid() const {
    return id_ >=0;
  }
  unsigned int to_index() const {
    //CGAL_precondition(is_valid());
    assert(is_valid()); // change to remove PDB dependency on libCGAL
    return id_;
  }

  bool operator<(const This &o) const
  {
    return id_ < o.id_;
  }
  bool operator>=(const This &o) const
  {
    return id_ >= o.id_;
  }  
  bool operator<=(const This &o) const
  {
    return id_ <= o.id_;
  }
  bool operator>(const This &o) const
  {
    return id_ > o.id_;
  }
  bool operator==(const This &o) const
  {
    return id_ == o.id_;
  }
  bool operator!=(const This &o) const
  {
    return id_ != o.id_;
  }

  template <class OS>
  void write(OS &out) const
  {
    if (id_ == -1) out << "N";
    else out << id_;
  }
  void print() const
  {
    write(std::cout);
  }
  //! Convert to a string
  std::string string() const
  {
    std::ostringstream os;
    write(os);
    return os.str();
  }
};

template <class A_type>
std::ostream& operator<<(std::ostream &out, const Label<A_type> &label)
{
  out << "(";
  label.write(out);
  out << ")";
  return out;
}


CGAL_END_NAMESPACE
#endif