text: /* ========================================================================= *
   *                                                                           *
   *                               OpenMesh                                    *
   *           Copyright (c) 2001-2015, RWTH-Aachen University                 *
   *           Department of Computer Graphics and Multimedia                  *
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   *                            www.openmesh.org                               *
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   * This file is part of OpenMesh.                                            *
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   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS       *
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   * ========================================================================= */
  
  /*===========================================================================*\
   *                                                                           *             
   *   $Revision: 1258 $                                                         *
   *   $Date: 2015-04-28 15:07:46 +0200 (Di, 28 Apr 2015) $                   *
   *                                                                           *
  \*===========================================================================*/
  
  #ifndef OPENMESH_BASEPROPERTY_HH
  #define OPENMESH_BASEPROPERTY_HH
  
  #include <string>
  #include <OpenMesh/Core/IO/StoreRestore.hh>
  #include <OpenMesh/Core/System/omstream.hh>
  
  namespace OpenMesh {
  
  //== CLASS DEFINITION =========================================================
  
  /** \class BaseProperty Property.hh <OpenMesh/Core/Utils/PropertyT.hh>
  
      Abstract class defining the basic interface of a dynamic property.
  **/
  
  class OPENMESHDLLEXPORT BaseProperty
  {
  public:
  
    /// Indicates an error when a size is returned by a member.
    static const size_t UnknownSize = size_t(-1);
  
  public:
  
    /// \brief Default constructor.
    ///
    /// In %OpenMesh all mesh data is stored in so-called properties.
    /// We distinuish between standard properties, which can be defined at
    /// compile time using the Attributes in the traits definition and
    /// at runtime using the request property functions defined in one of
    /// the kernels.
    ///
    /// If the property should be stored along with the default properties
    /// in the OM-format one must name the property and enable the persistant
    /// flag with set_persistent().
    ///
    /// \param _name Optional textual name for the property.
    ///
    BaseProperty(const std::string& _name = "<unknown>")
    : name_(_name), persistent_(false)
    {}
  
    /// \brief Copy constructor
    BaseProperty(const BaseProperty & _rhs)
        : name_( _rhs.name_ ), persistent_( _rhs.persistent_ ) {}
  
    /// Destructor.
    virtual ~BaseProperty() {}
  
  public: // synchronized array interface
  
    /// Reserve memory for n elements.
    virtual void reserve(size_t _n) = 0;
  
    /// Resize storage to hold n elements.
    virtual void resize(size_t _n) = 0;
  
    /// Clear all elements and free memory.
    virtual void clear() = 0;
  
    /// Extend the number of elements by one.
    virtual void push_back() = 0;
  
    /// Let two elements swap their storage place.
    virtual void swap(size_t _i0, size_t _i1) = 0;
  
    /// Copy one element to another
    virtual void copy(size_t _io, size_t _i1) = 0;
    
    /// Return a deep copy of self.
    virtual BaseProperty* clone () const = 0;
  
  public: // named property interface
  
    /// Return the name of the property
    const std::string& name() const { return name_; }
  
    virtual void stats(std::ostream& _ostr) const;
  
  public: // I/O support
  
    /// Returns true if the persistent flag is enabled else false.
    bool persistent(void) const { return persistent_; }
  
    /// Enable or disable persistency. Self must be a named property to enable
    /// persistency.
    virtual void set_persistent( bool _yn ) = 0;
  
    /// Number of elements in property
    virtual size_t       n_elements() const = 0;
  
    /// Size of one element in bytes or UnknownSize if not known.
    virtual size_t       element_size() const = 0;
  
    /// Return size of property in bytes
    virtual size_t       size_of() const
    {
      return size_of( n_elements() );
    }
  
    /// Estimated size of property if it has _n_elem elements.
    /// The member returns UnknownSize if the size cannot be estimated.
    virtual size_t       size_of(size_t _n_elem) const
    {
      return (element_size()!=UnknownSize)
        ? (_n_elem*element_size())
        : UnknownSize;
    }
  
    /// Store self as one binary block
    virtual size_t store( std::ostream& _ostr, bool _swap ) const = 0;
  
    /** Restore self from a binary block. Uses reserve() to set the
        size of self before restoring.
    **/
    virtual size_t restore( std::istream& _istr, bool _swap ) = 0;
  
  protected:
  
    // To be used in a derived class, when overloading set_persistent()
    template < typename T >
    void check_and_set_persistent( bool _yn )
    {
      if ( _yn && !IO::is_streamable<T>() )
        omerr() << "Warning! Type of property value is not binary storable!\n";
      persistent_ = IO::is_streamable<T>() && _yn;
    }
  
  private:
  
    std::string name_;
    bool        persistent_;
  };
  
  }//namespace OpenMesh
  
  #endif //OPENMESH_BASEPROPERTY_HH
  
  
  