// Copyright (c) 2001

// Kevin Atkinson

//

// 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. Kevin Atkinson makes no

// representations about the suitability of this software for any

// purpose.  It is provided "as is" without express or implied

// warranty.

#ifndef acommon_hash_fun__hpp

#define acommon_hash_fun__hpp

namespace acommon {

  template <typename K> struct hash {};

  template <> struct hash<char>  {unsigned long operator()(char  v) const {return v;}};

  template <> struct hash<short> {unsigned long operator()(short v) const {return v;}};

  template <> struct hash<int>   {unsigned long operator()(int   v) const {return v;}};

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

  template <> struct hash<unsigned char>  {unsigned long operator()(unsigned char  v) const {return v;}};

  template <> struct hash<unsigned short> {unsigned long operator()(unsigned short v) const {return v;}};

  template <> struct hash<unsigned int>   {unsigned long operator()(unsigned int   v) const {return v;}};

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

  template <> struct hash<const char *> {

    inline unsigned long operator() (const char * s) const {

      unsigned long h = 0;

      for (; *s; ++s)

  h=5*h + *s;

      return h;

    }

  };

  template<class Str>

  struct HashString {

    inline unsigned long operator() (const Str &str) const {

      unsigned long h = 0;

      typename Str::const_iterator end = str.end();

      for (typename Str::const_iterator s = str.begin(); 

     s != end; 

     ++s)

  h=5*h + *s;

      return h;

    }

  };

}

#endif