Boost C++ Libraries

boost/functional/hash/hash.hpp

//  Copyright Daniel James 2005-2006. Use, modification, and distribution are
//  subject to the Boost Software License, Version 1.0. (See accompanying
//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

//  Based on Peter Dimov's proposal
//  http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1756.pdf
//  issue 6.18. 

#if !defined(BOOST_FUNCTIONAL_HASH_HASH_HPP)
#define BOOST_FUNCTIONAL_HASH_HASH_HPP

#include <boost/functional/hash_fwd.hpp>
#include <functional>
#include <boost/functional/detail/hash_float.hpp>
#include <boost/functional/detail/container_fwd.hpp>
#include <string>

#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
#include <boost/type_traits/is_pointer.hpp>
#endif

#if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
#include <boost/type_traits/is_array.hpp>
#endif

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
#include <boost/type_traits/is_const.hpp>
#endif

namespace boost
{
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
    // Borland complains about an ambiguous function overload
    // when compiling boost::hash<bool>.
    std::size_t hash_value(bool);
#endif
    
    std::size_t hash_value(int);
    std::size_t hash_value(unsigned int);
    std::size_t hash_value(long);
    std::size_t hash_value(unsigned long);

#if defined(BOOST_MSVC) && defined(_WIN64)
    // On 64-bit windows std::size_t is a typedef for unsigned long long, which
    // isn't due to be supported until Boost 1.35. So add support here.
    // (Technically, Boost.Hash isn't actually documented as supporting
    // std::size_t. But it would be pretty silly not to).
    std::size_t hash_value(std::size_t);
#endif

#if !BOOST_WORKAROUND(__DMC__, <= 0x848)
    template <class T> std::size_t hash_value(T* const&);
#else
    template <class T> std::size_t hash_value(T*);
#endif

#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
    template< class T, unsigned N >
    std::size_t hash_value(const T (&array)[N]);

    template< class T, unsigned N >
    std::size_t hash_value(T (&array)[N]);
#endif

    std::size_t hash_value(float v);
    std::size_t hash_value(double v);
    std::size_t hash_value(long double v);

    template <class Ch, class A>
    std::size_t hash_value(std::basic_string<Ch, std::BOOST_HASH_CHAR_TRAITS<Ch>, A> const&);

    template <class A, class B>
    std::size_t hash_value(std::pair<A, B> const&);
    template <class T, class A>
    std::size_t hash_value(std::vector<T, A> const&);
    template <class T, class A>
    std::size_t hash_value(std::list<T, A> const& v);
    template <class T, class A>
    std::size_t hash_value(std::deque<T, A> const& v);
    template <class K, class C, class A>
    std::size_t hash_value(std::set<K, C, A> const& v);
    template <class K, class C, class A>
    std::size_t hash_value(std::multiset<K, C, A> const& v);
    template <class K, class T, class C, class A>
    std::size_t hash_value(std::map<K, T, C, A> const& v);
    template <class K, class T, class C, class A>
    std::size_t hash_value(std::multimap<K, T, C, A> const& v);

    // Implementation

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
    inline std::size_t hash_value(bool v)
    {
        return static_cast<std::size_t>(v);
    }
#endif

    inline std::size_t hash_value(int v)
    {
        return static_cast<std::size_t>(v);
    }

    inline std::size_t hash_value(unsigned int v)
    {
        return static_cast<std::size_t>(v);
    }

    inline std::size_t hash_value(long v)
    {
        return static_cast<std::size_t>(v);
    }

    inline std::size_t hash_value(unsigned long v)
    {
        return static_cast<std::size_t>(v);
    }

#if defined(_M_X64) && defined(_WIN64)
    inline std::size_t hash_value(long long v)
    {
        return v;
    }

    inline std::size_t hash_value(unsigned long long v)
    {
        return v;
    }
#endif

    // Implementation by Alberto Barbati and Dave Harris.
#if !BOOST_WORKAROUND(__DMC__, <= 0x848)
    template <class T> std::size_t hash_value(T* const& v)
#else
    template <class T> std::size_t hash_value(T* v)
#endif
    {
        std::size_t x = static_cast<std::size_t>(
           reinterpret_cast<std::ptrdiff_t>(v));
        return x + (x >> 3);
    }

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
    template <class T>
    inline void hash_combine(std::size_t& seed, T& v)
#else
    template <class T>
    inline void hash_combine(std::size_t& seed, T const& v)
#endif
    {
        boost::hash<T> hasher;
        seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }

    template <class It>
    inline std::size_t hash_range(It first, It last)
    {
        std::size_t seed = 0;

        for(; first != last; ++first)
        {
            hash_combine(seed, *first);
        }

        return seed;
    }

    template <class It>
    inline void hash_range(std::size_t& seed, It first, It last)
    {
        for(; first != last; ++first)
        {
            hash_combine(seed, *first);
        }
    }

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
    template <class T>
    inline std::size_t hash_range(T* first, T* last)
    {
        std::size_t seed = 0;

        for(; first != last; ++first)
        {
            boost::hash<T> hasher;
            seed ^= hasher(*first) + 0x9e3779b9 + (seed<<6) + (seed>>2);
        }

        return seed;
    }

    template <class T>
    inline void hash_range(std::size_t& seed, T* first, T* last)
    {
        for(; first != last; ++first)
        {
            boost::hash<T> hasher;
            seed ^= hasher(*first) + 0x9e3779b9 + (seed<<6) + (seed>>2);
        }
    }
#endif

#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
    template< class T, unsigned N >
    inline std::size_t hash_value(const T (&array)[N])
    {
        return hash_range(array, array + N);
    }

    template< class T, unsigned N >
    inline std::size_t hash_value(T (&array)[N])
    {
        return hash_range(array, array + N);
    }
#endif

    template <class Ch, class A>
    inline std::size_t hash_value(std::basic_string<Ch, std::BOOST_HASH_CHAR_TRAITS<Ch>, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    inline std::size_t hash_value(float v)
    {
        return boost::hash_detail::float_hash_value(v);
    }

    inline std::size_t hash_value(double v)
    {
        return boost::hash_detail::float_hash_value(v);
    }

    inline std::size_t hash_value(long double v)
    {
        return boost::hash_detail::float_hash_value(v);
    }

    template <class A, class B>
    std::size_t hash_value(std::pair<A, B> const& v)
    {
        std::size_t seed = 0;
        hash_combine(seed, v.first);
        hash_combine(seed, v.second);
        return seed;
    }

    template <class T, class A>
    std::size_t hash_value(std::vector<T, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class T, class A>
    std::size_t hash_value(std::list<T, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class T, class A>
    std::size_t hash_value(std::deque<T, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class K, class C, class A>
    std::size_t hash_value(std::set<K, C, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class K, class C, class A>
    std::size_t hash_value(std::multiset<K, C, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class K, class T, class C, class A>
    std::size_t hash_value(std::map<K, T, C, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    template <class K, class T, class C, class A>
    std::size_t hash_value(std::multimap<K, T, C, A> const& v)
    {
        return hash_range(v.begin(), v.end());
    }

    //
    // boost::hash
    //

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
#define BOOST_HASH_SPECIALIZE(type) \
    template <> struct hash<type> \
         : public std::unary_function<type, std::size_t> \
    { \
        std::size_t operator()(type v) const \
        { \
            return boost::hash_value(v); \
        } \
    };

#define BOOST_HASH_SPECIALIZE_REF(type) \
    template <> struct hash<type> \
         : public std::unary_function<type, std::size_t> \
    { \
        std::size_t operator()(type const& v) const \
        { \
            return boost::hash_value(v); \
        } \
    };
#else
#define BOOST_HASH_SPECIALIZE(type) \
    template <> struct hash<type> \
         : public std::unary_function<type, std::size_t> \
    { \
        std::size_t operator()(type v) const \
        { \
            return boost::hash_value(v); \
        } \
    }; \
    \
    template <> struct hash<const type> \
         : public std::unary_function<const type, std::size_t> \
    { \
        std::size_t operator()(const type v) const \
        { \
            return boost::hash_value(v); \
        } \
    };

#define BOOST_HASH_SPECIALIZE_REF(type) \
    template <> struct hash<type> \
         : public std::unary_function<type, std::size_t> \
    { \
        std::size_t operator()(type const& v) const \
        { \
            return boost::hash_value(v); \
        } \
    }; \
    \
    template <> struct hash<const type> \
         : public std::unary_function<const type, std::size_t> \
    { \
        std::size_t operator()(type const& v) const \
        { \
            return boost::hash_value(v); \
        } \
    };
#endif

    BOOST_HASH_SPECIALIZE(bool)
    BOOST_HASH_SPECIALIZE(char)
    BOOST_HASH_SPECIALIZE(signed char)
    BOOST_HASH_SPECIALIZE(unsigned char)
#if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
    BOOST_HASH_SPECIALIZE(wchar_t)
#endif
    BOOST_HASH_SPECIALIZE(short)
    BOOST_HASH_SPECIALIZE(unsigned short)
    BOOST_HASH_SPECIALIZE(int)
    BOOST_HASH_SPECIALIZE(unsigned int)
    BOOST_HASH_SPECIALIZE(long)
    BOOST_HASH_SPECIALIZE(unsigned long)

    BOOST_HASH_SPECIALIZE(float)
    BOOST_HASH_SPECIALIZE(double)
    BOOST_HASH_SPECIALIZE(long double)

    BOOST_HASH_SPECIALIZE_REF(std::string)
#if !defined(BOOST_NO_STD_WSTRING)
    BOOST_HASH_SPECIALIZE_REF(std::wstring)
#endif

#undef BOOST_HASH_SPECIALIZE
#undef BOOST_HASH_SPECIALIZE_REF

#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
    template <class T>
    struct hash<T*>
        : public std::unary_function<T*, std::size_t>
    {
        std::size_t operator()(T* v) const \
        { \
            return boost::hash_value(v); \
        } \
    };
#else
    namespace hash_detail
    {
        template <bool IsPointer>
        struct hash_impl;

        template <>
        struct hash_impl<true>
        {
            template <class T>
            struct inner
                : public std::unary_function<T, std::size_t>
            {
                std::size_t operator()(T val) const
                {
                    return boost::hash_value(val);
                }
            };
        };
    }

    template <class T> struct hash
        : public boost::hash_detail::hash_impl<boost::is_pointer<T>::value>
            ::BOOST_NESTED_TEMPLATE inner<T>
    {
    };
#endif
}

#endif // BOOST_FUNCTIONAL_HASH_HASH_HPP

////////////////////////////////////////////////////////////////////////////////

#if !defined(BOOST_HASH_NO_EXTENSIONS) \
    && !defined(BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP)
#define BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP

namespace boost
{

#if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
    namespace hash_detail
    {
        template <bool IsArray>
        struct call_hash_impl
        {
            template <class T>
            struct inner
            {
                static std::size_t call(T const& v)
                {
                    using namespace boost;
                    return hash_value(v);
                }
            };
        };

        template <>
        struct call_hash_impl<true>
        {
            template <class Array>
            struct inner
            {
#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
                static std::size_t call(Array const& v)
#else
                static std::size_t call(Array& v)
#endif
                {
                    const int size = sizeof(v) / sizeof(*v);
                    return boost::hash_range(v, v + size);
                }
            };
        };

        template <class T>
        struct call_hash
            : public call_hash_impl<boost::is_array<T>::value>
                ::BOOST_NESTED_TEMPLATE inner<T>
        {
        };
    }
#endif // BOOST_NO_FUNCTION_TEMPLATE_ORDERING

#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)

    template <class T> struct hash
        : std::unary_function<T, std::size_t>
    {
#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
        std::size_t operator()(T const& val) const
        {
            return hash_value(val);
        }
#else
        std::size_t operator()(T const& val) const
        {
            return hash_detail::call_hash<T>::call(val);
        }
#endif
    };

#if BOOST_WORKAROUND(__DMC__, <= 0x848)
    template <class T, unsigned int n> struct hash<T[n]>
        : std::unary_function<T[n], std::size_t>
    {
        std::size_t operator()(const T* val) const
        {
            return boost::hash_range(val, val+n);
        }
    };
#endif

#else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION

    // On compilers without partial specialization, boost::hash<T>
    // has already been declared to deal with pointers, so just
    // need to supply the non-pointer version.

    namespace hash_detail
    {
        template <bool IsPointer>
        struct hash_impl;

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)

        template <>
        struct hash_impl<false>
        {
            template <class T>
            struct inner
                : std::unary_function<T, std::size_t>
            {
#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
                std::size_t operator()(T const& val) const
                {
                    return hash_value(val);
                }
#else
                std::size_t operator()(T const& val) const
                {
                    return hash_detail::call_hash<T>::call(val);
                }
#endif
            };
        };

#else // Visual C++ 6.5

    // There's probably a more elegant way to Visual C++ 6.5 to work
    // but I don't know what it is.

        template <bool IsConst>
        struct hash_impl_msvc
        {
            template <class T>
            struct inner
                : public std::unary_function<T, std::size_t>
            {
                std::size_t operator()(T const& val) const
                {
                    return hash_detail::call_hash<T const>::call(val);
                }

                std::size_t operator()(T& val) const
                {
                    return hash_detail::call_hash<T>::call(val);
                }
            };
        };

        template <>
        struct hash_impl_msvc<true>
        {
            template <class T>
            struct inner
                : public std::unary_function<T, std::size_t>
            {
                std::size_t operator()(T& val) const
                {
                    return hash_detail::call_hash<T>::call(val);
                }
            };
        };
        
        template <class T>
        struct hash_impl_msvc2
            : public hash_impl_msvc<boost::is_const<T>::value>
                    ::BOOST_NESTED_TEMPLATE inner<T> {};
        
        template <>
        struct hash_impl<false>
        {
            template <class T>
            struct inner : public hash_impl_msvc2<T> {};
        };

#endif // Visual C++ 6.5
    }
#endif  // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
}

#endif