casacore
ObjectStack.h
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1 //# ObjectStack.h: A stack of re-usable objects
2 //# Copyright (C) 2007
3 //# Associated Universities, Inc. Washington DC, USA.
4 //#
5 //# This library is free software; you can redistribute it and/or modify it
6 //# under the terms of the GNU Library General Public License as published by
7 //# the Free Software Foundation; either version 2 of the License, or (at your
8 //# option) any later version.
9 //#
10 //# This library is distributed in the hope that it will be useful, but WITHOUT
11 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13 //# License for more details.
14 //#
15 //# You should have received a copy of the GNU Library General Public License
16 //# along with this library; if not, write to the Free Software Foundation,
17 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18 //#
19 //# Correspondence concerning AIPS++ should be addressed as follows:
20 //# Internet email: aips2-request@nrao.edu.
21 //# Postal address: AIPS++ Project Office
22 //# National Radio Astronomy Observatory
23 //# 520 Edgemont Road
24 //# Charlottesville, VA 22903-2475 USA
25 //#
26 //# $Id: ObjectStack.h,v 1.1 2007/11/16 04:08:17 wbrouw Exp $
27 
28 #ifndef CASA_OBJECTSTACK_H
29 #define CASA_OBJECTSTACK_H
30 
31 //# Includes
32 #include <casacore/casa/aips.h>
33 
34 #include <mutex>
35 #include <vector>
36 
37 namespace casacore { //# NAMESPACE CASACORE - BEGIN
38 
39  //# Forward declarations
40 
41  // <summary>
42  // A stack of re-usable objects
43  // </summary>
44  //
45  // <use visibility=export>
46  //
47  // <reviewed reviewer="Ger van Diepen" date="2001/07/03" tests="tObjectStack.cc" demos="">
48  // </reviewed>
49  //
50  // <prerequisite>
51  // <li>
52  // </prerequisite>
53  //
54  // <synopsis>
55  // An ObjectStack contains a set of pre-allocated Objects of the type
56  // <src>T</src>.
57  // The stack is a very simple stack, without the
58  // linking/unlinking of a normal Stack implementation.
59  // This lightweight implementation was especially designed for use
60  // with the <linkto class=AutoDiff>AutoDiff</linkto>
61  // classes, but can be used independently. The stack works best with small
62  // object sizes, or letter/envelope classes.
63  //
64  // The class is fully thread-safe, thus the same object can be used safely
65  // in multiple threads.
66  //
67  // </synopsis>
68  //
69  // <example>
70  // <srcblock>
71  // {
72  // // Get an element (and create stack!)
73  // SparseDiff<Double> elem;
74  // // Use it
75  // elem.value() = 27;
76  // // Release it (automatic by dtor on elem)
77  // }
78  // </srcblock>
79  // </example>
80  //
81  // <motivation>
82  // To improve the speed for the auto differentiating classes.
83  // </motivation>
84  //
85  // <templating arg=T>
86  // <li> the class T must have a <em>constructor(T::FULLREFRESH)</em>
87  // for creating new entries and destructor;
88  // and must possess a <em>clear()</em> method to enable element re-use.
89  // </templating>
90  //
91  // <todo asof="2007/11/27">
92  // </todo>
93 
94  template <class T> class ObjectStack {
95  public:
96 
97  //# Member functions
98  // Destructor
100 
101  // Create a singleton stack
103 
104  // Get a pointer to an object in the stack. The stack will be extended if
105  // no objects left.
106  T *get();
107 
108  // Return an object to the stack for re-use
109  void put(T *obj) { obj->clear(); stack_p.push_back(obj); };
110 
111  // Decimate the stack by getting rid of all unused elements in it
112  void clear();
113 
114  // Test if stack empty
115  Bool empty() { return stack_p.empty(); };
116 
117  // return the stack extend (for debugging use and checking mainly)
118  uInt nelements() const { return stack_p.size(); };
119 
120  private:
121  //# Data
122  // The Stack
123  std::vector<T*> stack_p;
124  std::mutex mutex_p;
125 
126  //# Constructors
127  // All ctor and assignment constructors and assignment (not implemented)
128  // <group>
132  // </group>
133 
134  //# Member functions
135  };
136 
137 
138 } //# NAMESPACE CASACORE - END
139 
140 #ifndef CASACORE_NO_AUTO_TEMPLATES
141 #include <casacore/casa/Containers/ObjectStack.tcc>
142 #endif //# CASACORE_NO_AUTO_TEMPLATES
143 #endif
static ObjectStack< T > & stack()
Create a singleton stack.
ObjectStack< T > & operator=(const ObjectStack< T > &other)
Bool empty()
Test if stack empty.
Definition: ObjectStack.h:115
uInt nelements() const
return the stack extend (for debugging use and checking mainly)
Definition: ObjectStack.h:118
std::vector< T * > stack_p
The Stack.
Definition: ObjectStack.h:118
void clear()
Decimate the stack by getting rid of all unused elements in it.
~ObjectStack()
Destructor.
ObjectStack(const ObjectStack< T > &other)
T * get()
Get a pointer to an object in the stack.
ObjectStack()
All ctor and assignment constructors and assignment (not implemented)
Definition: ObjectStack.h:129
void put(T *obj)
Return an object to the stack for re-use.
Definition: ObjectStack.h:109
this file contains all the compiler specific defines
Definition: mainpage.dox:28
unsigned int uInt
Definition: aipstype.h:51
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42