multiplication_hash_function.cc

这是一个著名的应用层组播中间件的源码

//Copyright (c) 2004, Charles Killian, Adolfo Rodriguez, Dejan Kostic, Sooraj Bhat, and Amin Vahdat
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in
//     the documentation and/or other materials provided with the
//     distribution.
//   * Neither the names of Duke University nor The University of
//     California, San Diego, nor the names of its contributors
//     may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
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#include "multiplication_hash_function.h"
#include "math.h"
#include "stdio.h"

multiplication_hash_function::multiplication_hash_function(double factor1)
  :factor( factor1)
{
//   printf("factor %lf\n", factor);
}
multiplication_hash_function::~multiplication_hash_function()
{
}
// ---------------------------------------------- 
// hash
// ---------------------------------------------- 

int  multiplication_hash_function::hash (int item, int size)
{
  double intermediate = item*factor;
  intermediate -= floor( intermediate);
  return (int)floor( size*intermediate);
}