1 /*=========================================================================
2  *
3  *  Copyright Insight Software Consortium
4  *
5  *  Licensed under the Apache License, Version 2.0 (the "License");
6  *  you may not use this file except in compliance with the License.
7  *  You may obtain a copy of the License at
8  *
9  *         http://www.apache.org/licenses/LICENSE-2.0.txt
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  *=========================================================================*/
18 #ifndef itkImageContainerInterface_h
19 #define itkImageContainerInterface_h
20 
21 #include "itkObject.h"
22 
23 namespace itk
24 {
25 /** \class ImageContainerInterface
26  *  \brief Used for reference when writing containers conforming to
27  *         this interface.
28  *
29  * This should only be used for reference when writing containers
30  * conforming to this interface.  ITK uses generic programming to
31  * allow container type substitution, so polymorphism is not needed to
32  * use containers through this interface.  This means that a container
33  * conforming to this interface need not be derived from it, and that
34  * their methods should not be virtual.  However, the container must
35  * derive from Object in order to support the reference counting,
36  * modification time, and debug information required by this
37  * interface.
38  *
39  * Note that many comments refer to a "default element" or "default element
40  * value".  This value is equal to the default constructor of the
41  * Element type.  Also note that all non-const methods assume that the
42  * container was modified, and update the modification time.
43  *
44  * \tparam TElementIdentifier A type that shall be used to index the
45  * container. It must have a < operator defined for ordering.
46  *
47  * \tparam TElement The element type stored in the container.
48  *
49  * \ingroup ImageObjects
50  * \ingroup ITKCommon
51  */
52 template< typename TElementIdentifier, typename TElement >
53 class ImageContainerInterface:public Object
54 {
55 public:
56   /** Standard class type aliases. */
57   using Self = ImageContainerInterface;
58   using Superclass = Object;
59   using Pointer = SmartPointer< Self >;
60   using ConstPointer = SmartPointer< const Self >;
61 
62   /** Standard part of every itk Object. */
63   itkTypeMacro(ImageContainerInterface, Object);
64 
65   /** Save the template parameters. */
66   using ElementIdentifier = TElementIdentifier;
67   using Element = TElement;
68 
69   /** Index operator. This version can be an lvalue. */
70   virtual TElement & operator[](const ElementIdentifier) = 0;
71 
72   /** Index operator. This version can only be an rvalue */
73   virtual const TElement & operator[](const ElementIdentifier) const = 0;
74 
75   /** Return a pointer to the beginning of the buffer.  This is used by
76    * the image iterator class. */
77   virtual TElement * GetBufferPointer() = 0;
78 
79   /** Get the number of elements currently stored in the container. */
80   virtual ElementIdentifier Size() const = 0;
81 
82   /** Tell the container to allocate enough memory to allow at least
83    * as many elements as the size given to be stored.  This is NOT
84    * guaranteed to actually allocate any memory, but is useful if the
85    * implementation of the container allocates contiguous storage. */
86   virtual void Reserve(ElementIdentifier) = 0;
87 
88   /** Tell the container to try to minimize its memory usage for storage of
89    * the current number of elements.  This is NOT guaranteed to decrease
90    * memory usage. */
91   virtual void Squeeze() = 0;
92 };
93 } // end namespace itk
94 
95 #endif
96