Internals.hpp

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    1 /**
    2  * MOAB, a Mesh-Oriented datABase, is a software component for creating,
    3  * storing and accessing finite element mesh data.
    4  *
    5  * Copyright 2004 Sandia Corporation.  Under the terms of Contract
    6  * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
    7  * retains certain rights in this software.
    8  *
    9  * This library is free software; you can redistribute it and/or
   10  * modify it under the terms of the GNU Lesser General Public
   11  * License as published by the Free Software Foundation; either
   12  * version 2.1 of the License, or (at your option) any later version.
   13  *
   14  */
   15  
   16 #ifndef MB_INTERNALS_HPP
   17 #define MB_INTERNALS_HPP
   18  
   19 #ifdef WIN32
   20 #pragma warning( disable : 4786 )
   21 #endif
   22  
   23 #ifndef IS_BUILDING_MB
   24 #error "Internals.hpp isn't supposed to be included into an application"
   25 #endif
   26  
   27 #include "moab/Types.hpp"
   28 #include <cassert>
   29  
   30 namespace moab
   31 {
   32  
   33 /*! Define EntityHandle for both 32 bit and 64 bit systems.
   34  *  The decision to use 64 bit handles must be made at compile time.
   35  *  \bug we should probably have an Int64 typedef
   36  *
   37  *  EntityHandle format:
   38  *  0xXYYYYYYY  (assuming a 32-bit handle.  Top 4 bits reserved on a 64 bit system)
   39  *  X - reserved for entity type.  This system can only handle 15 different types
   40  *  Y - Entity id space.  Max id is over 200M
   41  *
   42  *  Note that for specialized databases (such as all hex) 16 bits are not
   43  *  required for the entity type and the id space can be increased to over 2B.
   44  */
   45 #define MB_TYPE_WIDTH 4
   46 #define MB_ID_WIDTH   ( 8 * sizeof( EntityHandle ) - MB_TYPE_WIDTH )
   47 #define MB_TYPE_MASK  ( (EntityHandle)0xF << MB_ID_WIDTH )
   48 //             2^MB_TYPE_WIDTH-1 ------^
   49  
   50 #define MB_START_ID ( (EntityID)1 )           //!< All entity id's currently start at 1
   51 #define MB_END_ID   ( (EntityID)MB_ID_MASK )  //!< Last id is the complement of the MASK
   52 #define MB_ID_MASK  ( ~MB_TYPE_MASK )
   53  
   54 //! Given a type and an id create a handle.
   55 inline EntityHandle CREATE_HANDLE( const unsigned type, const EntityID id, int& err )
   56 {
   57     err = 0;  //< Assume that there is a real error value defined somewhere
   58  
   59     if( id > MB_END_ID || type > MBMAXTYPE )
   60     {
   61         err = 1;   //< Assume that there is a real error value defined somewhere
   62         return 1;  //<You've got to return something.  What do you return?
   63     }
   64  
   65     return ( ( (EntityHandle)type ) << MB_ID_WIDTH ) | id;
   66 }
   67  
   68 inline EntityHandle CREATE_HANDLE( const unsigned type, const EntityID id )
   69 {
   70     assert( id <= MB_END_ID && type <= MBMAXTYPE );
   71     return ( ( (EntityHandle)type ) << MB_ID_WIDTH ) | id;
   72 }
   73  
   74 inline EntityHandle FIRST_HANDLE( unsigned type )
   75 {
   76     return ( ( (EntityHandle)type ) << MB_ID_WIDTH ) | MB_START_ID;
   77 }
   78  
   79 inline EntityHandle LAST_HANDLE( unsigned type )
   80 {
   81     return ( (EntityHandle)( type + 1 ) << MB_ID_WIDTH ) - 1;
   82 }
   83  
   84 //! Get the entity id out of the handle.
   85 inline EntityID ID_FROM_HANDLE( EntityHandle handle )
   86 {
   87     return ( handle & MB_ID_MASK );
   88 }
   89  
   90 //! Get the type out of the handle.  Can do a simple shift because
   91 //! handles are unsigned (therefore shifting fills with zero's)
   92 inline EntityType TYPE_FROM_HANDLE( EntityHandle handle )
   93 {
   94     return static_cast< EntityType >( handle >> MB_ID_WIDTH );
   95 }
   96  
   97 }  // namespace moab
   98  
   99 #endif