Mesh Oriented datABase  (version 5.5.0)
An array-based unstructured mesh library
Internals.hpp
Go to the documentation of this file.
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