hashers.h

Go to the documentation of this file.

#ifndef Hasher_h_included
#define Hasher_h_included

//
// Copyright 2002, Lowell Boggs Jr.
//
// This file or directory, containing source code for a computer program,
// is Copyrighted by Lowell Boggs, Jr.  987 Regency Drive, Lewisville
// TX (USA), 75067.  You may use, copy, modify, and distribute this
// source file without charge or obligation so long as you agree to
// the following:
//
//  1.  You must indemnify Lowell Boggs against any and all financial
//      obligations caused by its use, misuse, function, or malfunction.
//      Further, you acknowledge that there is no warranty of any kind,
//      whatsoever.
//
//  2.  You agree not to attempt to patent any portion of this original
//      work -- though you may attempt to patent your own extensions to
//      it if you so choose.
//
//  3.  You keep this copyright notice with the file and all copies
//      of the file and do not change it anyway except language translation.
//
// You are responsible for enforcing your own compliance with these
// conditions and may not use this source file if you cannot agree to the
// above terms and conditions.



#include <string>

namespace cxxtls
{


template<class T>
struct Hasher
  //
{
    unsigned int operator() (T const &t) { return (unsigned int)(t); }
};

template<>
struct Hasher<std::string>
{
    unsigned int operator() (std::string const &t)
    {
      unsigned int rv = t.size();

      std::string::const_iterator scan = t.begin(),
                                  end  = t.end();
                                
      while(scan != end)
      {
        rv <<= 1;
        
        rv |= *scan++;
      }

      return rv;
    }
};


template<>
struct Hasher<float>
{
    unsigned int operator() (float const &t)
    {
      unsigned int rv = 0;

      char const *scan = (char const*)(&t);
      char const *end  = scan + sizeof(t);
                                
      while(scan != end)
      {
        rv <<= 4;
        
        rv |= *scan++;
      }

      return rv;
    }
};

template<>
struct Hasher<double>
{
    unsigned int operator() (double const &t)
    {
      unsigned int rv = 0;

      char const *scan = (char const*)(&t);
      char const *end  = scan + sizeof(t);
                                
      while(scan != end)
      {
        rv <<= 4;
        
        rv |= *scan++;
      }

      return rv;
    }
};


} // namespace cxxtls

#endif