hashMap.h

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// -*- Mode: C++; tab-width: 2; -*-
// vi: set ts=2:
//

#ifndef BALL_DATATYPE_HASHMAP_H
#define BALL_DATATYPE_HASHMAP_H

#ifndef BALL_COMMON_H
# include <BALL/common.h>
#endif

#ifndef BALL_COMMON_HASH_H
# include <BALL/COMMON/hash.h>
#endif

#ifndef BALL_DATATYPE_TRIPLE_H
# include <BALL/DATATYPE/triple.h>
#endif

#ifndef BALL_DATATYPE_QUADRUPLE_H
# include <BALL/DATATYPE/quadruple.h>
#endif

#include <utility>
#include <algorithm>

#ifdef BALL_HAS_UNORDERED_MAP

#if defined(BALL_HAS_STD_UNORDERED_MAP)
# include <unordered_map>
#elif defined(BALL_HAS_TR1_UNORDERED_MAP)
# include <tr1/unordered_map>
#elif defined(BALL_HAS_BOOST_UNORDERED_MAP)
# include <boost/unordered_map.hpp>
#endif

#elif defined(BALL_HAS_HASH_MAP)
#if defined(BALL_EXT_INCLUDE_PREFIX)
# include <ext/hash_map>
# include <ext/hash_fun.h>
#else
# include <hash_map>
# include <hash_fun.h>
#endif
#else
# include <map>
#endif

#if defined(BALL_HAS_UNORDERED_MAP) && !defined(BALL_HAS_BOOST_UNORDERED_MAP)

#ifdef BALL_EXTEND_HASH_IN_STD_NS
namespace std
{
#endif // BALL_EXTEND_HASH_IN_STD_NS

#ifdef BALL_HAS_TR1_UNORDERED_MAP
  namespace tr1
  {
#endif // BALL_HAS_TR1_UNORDERED_MAP
    
    // borrowed from boost
    template<typename T> 
    void hash_combine_ala_boost(size_t & seed, T const & v)
    {
      hash<T> h;
      seed ^= h(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }

    template<class A, class B>
    struct hash<pair<A, B> > : public std::unary_function<pair<A,B>, size_t>
    {
      inline size_t
      operator()(pair<A, B> p) const
      {
        size_t seed = 0;
        hash_combine_ala_boost(seed, p.first);
        hash_combine_ala_boost(seed, p.second);

        return seed;
      }
    };

    template <class A, class B, class C>
    struct hash< ::BALL::Triple<A, B, C> > : public std::unary_function< ::BALL::Triple<A, B, C>, size_t>
    {
      inline size_t
      operator()(::BALL::Triple<A, B, C> t) const
      {
        size_t seed = 0;
        hash_combine_ala_boost(seed, t.first);
        hash_combine_ala_boost(seed, t.second);
        hash_combine_ala_boost(seed, t.third);

        return seed;
      }
    };

    template <class A, class B, class C, class D>
    struct hash< ::BALL::Quadruple<A, B, C, D> > : public std::unary_function< const ::BALL::Quadruple<A, B, C, D>, size_t> 
    {
      inline size_t
      operator()( ::BALL::Quadruple<A, B, C, D> q) const
      {
        size_t seed = 0;
        hash_combine_ala_boost(seed, q.first);
        hash_combine_ala_boost(seed, q.second);
        hash_combine_ala_boost(seed, q.third);
        hash_combine_ala_boost(seed, q.fourth);

        return seed;
      }
    };

#ifndef BALL_COMPILER_MSVC
    template<>
    struct hash<const ::BALL::String&> : public std::unary_function<const ::BALL::String &, size_t>
    {
      inline size_t
      operator()(const ::BALL::String& s) const
      {
        hash<const string&> h;
        return h(s);
      }
    };
#endif

    template<>
    struct hash< ::BALL::String > : public std::unary_function< ::BALL::String, size_t >
    {
      inline size_t
      operator()( ::BALL::String s) const
      {
        hash<string> h;
        return h(s);
      }
    };
#ifdef BALL_HAS_TR1_UNORDERED_MAP
  }
#endif // BALL_HAS_TR1_UNORDERED_MAP

#ifdef BALL_EXTEND_HASH_IN_STD_NS
}
#endif // BALL_EXTEND_HASH_IN_STD_NS

#endif // if defined(BALL_HAS_UNORDERED_MAP) && !defined(BALL_HAS_BOOST_UNORDERED_MAP)

#ifdef BALL_HAS_HASH_MAP
namespace BALL_MAP_NAMESPACE
{
  template<class T>
  struct hash<T*>
  {
    size_t operator()(const T* x) const { return (size_t)x; }
  };

  template<>
  struct hash<BALL::String>
  {
    size_t operator () (const BALL::String& s) const {return __stl_hash_string(s.c_str());}
  };

#ifdef BALL_NEEDS_LONGSIZE_HASH
  template<>
  struct hash<BALL::LongSize>
  {
    size_t operator()(BALL::LongSize x) const { return (size_t)x; }
  };
#endif
}
#endif // BALL_HAS_HASH_MAP

namespace BALL
{
  template <class Key, class T>
  class HashMap
    : public BALL_MAP_NAME
  {
    public:

      class IllegalKey
        : public Exception::GeneralException
      {
        public:
        IllegalKey(const char* file, int line)
          : Exception::GeneralException(file, line)
        {
        }
      };
      

      typedef BALL_MAP_NAME Base;
      typedef typename Base::value_type ValueType;
      typedef Key KeyType;
      typedef typename Base::value_type* PointerType;
      typedef typename Base::iterator Iterator;
      typedef typename Base::const_iterator ConstIterator;

      inline bool has(const Key& key) const
      {
        return Base::find(key)!=Base::end();
      }

      const T& operator [] (const Key& key) const;

      T& operator [] (const Key& key);
      
      bool operator == (const HashMap<Key, T>& rhs) const;
      
      Size size() const { return BALL_MAP_NAME::size(); }
  };
  
  //******************************************************************************************
  // Implementations of template methods
  //******************************************************************************************
  
  template <class Key, class T>
  const T& HashMap<Key, T>::operator [] (const Key& key) const
  {
    ConstIterator it = this->find(key);
    if (it == Base::end())
    {
      throw IllegalKey(__FILE__, __LINE__);
    }
    else
    {
      return it->second;
    }
  }


  template <class Key, class T>
  bool HashMap<Key, T>::operator == (const HashMap<Key, T>& rhs) const
  {
    // No equality if sizes differ.
    if (size() != rhs.size()) 
    {
      return false; 
    }

    // Equality if bothe have the same size and every element of lhs is 
    // is contained in lhs. Testing the other way round is obviously
    // unnecessary.
    ConstIterator it(BALL_MAP_NAME::begin());
    for (; it != BALL_MAP_NAME::end(); ++it)
    {
      if (!rhs.has(it->first)) return false;
    }
    return true;
  }

  template <class Key, class T>
  T& HashMap<Key, T>::operator [] (const Key& key)
  {
    return BALL_MAP_NAME::operator[] (key);
  }

} // namespace BALL

#endif // BALL_DATATYPE_HASHMAP_H