ITK  4.2.0
Insight Segmentation and Registration Toolkit
itkStructHashFunction.h
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1 /*=========================================================================
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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.
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14  * See the License for the specific language governing permissions and
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17  *=========================================================================*/
18 #ifndef __itkStructHashFunction_h
19 #define __itkStructHashFunction_h
20 
21 #include "itkIntTypes.h"
22 #include "itkMacro.h"
23 
24 namespace itk
25 {
39 template< class TInput >
40 class ITK_EXPORT StructHashFunction
41 {
42 public:
43 
46 
48  typedef TInput InputType;
49 
50  IdentifierType operator()(const InputType & key) const;
51 };
52 
53 template< class TInput >
54 inline IdentifierType
56 ::operator()(const InputType & key) const
57 {
58  IdentifierType len = static_cast< IdentifierType >( sizeof( InputType ) );
59  const char * p = reinterpret_cast< const char * >( &key );
60  IdentifierType hash = 0;
61  while ( len-- )
62  {
63  hash = hash * 65 + *p++;
64  }
65  hash += ( hash >> 5 );
66  return hash;
67 }
68 }
69 
70 #endif // ndef itkStructHashFunction_h
71