hash_fun.h

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/*****************************************************************************/
/*!
 *\file hash_fun.h
 *\brief hash functions
 *
 * Author: Alexander Fuchs
 *
 * Created: Fri Oct 20 11:04:00 2006
 *
 * <hr>
 *
 * License to use, copy, modify, sell and/or distribute this software
 * and its documentation for any purpose is hereby granted without
 * royalty, subject to the terms and conditions defined in the \ref
 * LICENSE file provided with this distribution.
 * 
 * <hr>
 */
/*****************************************************************************/

/*
 * Copyright (c) 1996-1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 */

// this is basically (modulo renaming and namespace) the SGI implementation:
// http://www.sgi.com/tech/stl/stl_hash_fun.h

#ifndef _cvc3__hash__hash_fun_h_
#define _cvc3__hash__hash_fun_h_

// to get size_t
#include <cstddef>


namespace Hash {
  using std::size_t;

  template <class _Key> struct hash { };
  
  inline size_t __stl_hash_string(const char* __s)
  {
    unsigned long __h = 0; 
    for ( ; *__s; ++__s)
      __h = 5*__h + *__s;
    
    return size_t(__h);
  }
  
  template<> struct hash<char*> {
    size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
  };

  template<> struct hash<const char*>
  {
    size_t operator()(const char* __s) const { return __stl_hash_string(__s); }
  };
  
  template<> struct hash<char> {
    size_t operator()(char __x) const { return __x; }
  };

  template<> struct hash<unsigned char> {
    size_t operator()(unsigned char __x) const { return __x; }
  };
  
  template<> struct hash<signed char> {
    size_t operator()(unsigned char __x) const { return __x; }
  };
  
  template<> struct hash<short> {
    size_t operator()(short __x) const { return __x; }
  };

  template<> struct hash<unsigned short> {
    size_t operator()(unsigned short __x) const { return __x; }
  };

  template<> struct hash<int> {
    size_t operator()(int __x) const { return __x; }
  };

  template<> struct hash<unsigned int> {
    size_t operator()(unsigned int __x) const { return __x; }
  };

  template<> struct hash<long> {
    size_t operator()(long __x) const { return __x; }
  };

  template<> struct hash<unsigned long> {
    size_t operator()(unsigned long __x) const { return __x; }
  };

}

#endif