include/opencascade/MeshVS_Buffer.hxx

0001 // Created on: 2007-03-07
0002 // Created by: msv@EUCLIDEX
0003 // Copyright (c) 2007-2014 OPEN CASCADE SAS
0004 //
0005 // This file is part of Open CASCADE Technology software library.
0006 //
0007 // This library is free software; you can redistribute it and/or modify it under
0008 // the terms of the GNU Lesser General Public License version 2.1 as published
0009 // by the Free Software Foundation, with special exception defined in the file
0010 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
0011 // distribution for complete text of the license and disclaimer of any warranty.
0012 //
0013 // Alternatively, this file may be used under the terms of Open CASCADE
0014 // commercial license or contractual agreement.
0015
0016 #ifndef MeshVS_Buffer_HeaderFile
0017 #define MeshVS_Buffer_HeaderFile
0018
0019 #include <Standard.hxx>
0020 #include <gp_Pnt.hxx>
0021
0022 /**
0023  * General purpose buffer that is allocated on the stack with a
0024  * constant size MeshVS_BufSize, or is allocated dynamically if the requested
0025  * size exceeds the standard one.
0026  * It is useful when an allocation of an array of unknown size is needed,
0027  * and most often the array is small enough to allocate as automatic C array.
0028  */
0029
0030 //! define the constant to the size of 10 points
0031 #define MeshVS_BufSize 10 * 3 * sizeof(double)
0032
0033 class MeshVS_Buffer
0034 {
0035 public:
0036   //! Constructor of the buffer of the requested size
0037   MeshVS_Buffer(const size_t theSize)
0038       : myDynData(nullptr)
0039   {
0040     if (theSize > MeshVS_BufSize)
0041       myDynData = Standard::Allocate(theSize);
0042   }
0043
0044   //! Destructor
0045   ~MeshVS_Buffer()
0046   {
0047     Standard::Free(myDynData);
0048     myDynData = nullptr;
0049   }
0050
0051   //! Cast the buffer to the void pointer
0052   operator void*() { return myDynData ? myDynData : (void*)myAutoData; }
0053
0054   //! Interpret the buffer as a reference to double
0055   operator double&() { return *(myDynData ? (double*)myDynData : (double*)myAutoData); }
0056
0057   //! Interpret the buffer as a reference to int
0058   operator int&() { return *(myDynData ? (int*)myDynData : (int*)myAutoData); }
0059
0060   //! Interpret the buffer as a reference to gp_Pnt
0061   operator gp_Pnt&() { return *(myDynData ? (gp_Pnt*)myDynData : (gp_Pnt*)myAutoData); }
0062
0063 private:
0064   //! Deprecate copy constructor
0065   MeshVS_Buffer(const MeshVS_Buffer&) {}
0066
0067   //! Deprecate copy operation
0068   MeshVS_Buffer& operator=(const MeshVS_Buffer&) { return *this; }
0069
0070   char  myAutoData[MeshVS_BufSize];
0071   void* myDynData;
0072 };
0073
0074 #endif