itkStructHashFunction.h

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/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkStructHashFunction.h,v $
  Language:  C++
  Date:      $Date: 2006/02/05 20:57:46 $
  Version:   $Revision: 1.3 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef itkStructHashFunction_h
#define itkStructHashFunction_h

namespace itk
{

template< class TInput >
class StructHashFunction
{
public:

  typedef StructHashFunction Self;

  typedef TInput InputType;

  unsigned int operator()( const InputType& key ) const;

};

template< class TInput >
inline unsigned int
StructHashFunction< TInput >
::operator()( const InputType& key ) const
{
  int len = sizeof( InputType );
  const char* p = reinterpret_cast< const char* >( &key );
  int hash = 0;
  while( len-- )
    {
    hash = hash * 65 + *p++;
    }
  hash += (hash >> 5);
  return hash;
}

}

#endif  // ndef itkStructHashFunction_h

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