/usr/include/ITK-4.5/itkStructHashFunction.h is in libinsighttoolkit4-dev 4.5.0-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef __itkStructHashFunction_h
#define __itkStructHashFunction_h
#include "itkIntTypes.h"
#include "itkMacro.h"
namespace itk
{
/** \class StructHashFunction
*
* \brief Generic hash function for an arbitrary struct (or class).
*
* This regards the input key as a string of bytes, and applies a
* hash function similar to one that has been used in perl. If the
* data in the input key has pointers to other classes, then the
* function will be hashing on the value of the pointer itself, not
* on the data it points to. It is imagined that this function will
* be used more for structs (with fully exposed data) than for
* general classes.
* \ingroup ITKCommon
*/
template< typename TInput >
class StructHashFunction
{
public:
/** Standard class typedefs. */
typedef StructHashFunction Self;
/** Input type */
typedef TInput InputType;
IdentifierType operator()(const InputType & key) const;
};
template< typename TInput >
inline IdentifierType
StructHashFunction< TInput >
::operator()(const InputType & key) const
{
IdentifierType len = static_cast< IdentifierType >( sizeof( InputType ) );
const char * p = reinterpret_cast< const char * >( &key );
IdentifierType hash = 0UL;
while ( len-- )
{
hash = hash * 65UL + static_cast<IdentifierType>(*p++);
}
hash += ( hash >> 5 );
return hash;
}
}
#endif // ndef itkStructHashFunction_h
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