boost/functional/hash/hash.hpp
// Copyright 2005-2009 Daniel James.
// Distributed under 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/hash_fwd.hpp>
#include <functional>
#include <boost/functional/hash/detail/hash_float.hpp>
#include <string>
#include <boost/limits.hpp>
#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
#include <boost/type_traits/is_pointer.hpp>
#endif
#if !defined(BOOST_NO_CXX11_HDR_TYPEINDEX)
#include <typeindex>
#endif
#if BOOST_WORKAROUND(__GNUC__, < 3) \
&& !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION)
#define BOOST_HASH_CHAR_TRAITS string_char_traits
#else
#define BOOST_HASH_CHAR_TRAITS char_traits
#endif
namespace boost
{
namespace hash_detail
{
struct enable_hash_value { typedef std::size_t type; };
template <typename T> struct basic_numbers {};
template <typename T> struct long_numbers {};
template <typename T> struct ulong_numbers {};
template <typename T> struct float_numbers {};
template <> struct basic_numbers<bool> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<char> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<unsigned char> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<signed char> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<short> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<unsigned short> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<int> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<unsigned int> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<long> :
boost::hash_detail::enable_hash_value {};
template <> struct basic_numbers<unsigned long> :
boost::hash_detail::enable_hash_value {};
#if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
template <> struct basic_numbers<wchar_t> :
boost::hash_detail::enable_hash_value {};
#endif
#if !defined(BOOST_NO_LONG_LONG)
template <> struct long_numbers<boost::long_long_type> :
boost::hash_detail::enable_hash_value {};
template <> struct ulong_numbers<boost::ulong_long_type> :
boost::hash_detail::enable_hash_value {};
#endif
template <> struct float_numbers<float> :
boost::hash_detail::enable_hash_value {};
template <> struct float_numbers<double> :
boost::hash_detail::enable_hash_value {};
template <> struct float_numbers<long double> :
boost::hash_detail::enable_hash_value {};
}
template <typename T>
typename boost::hash_detail::basic_numbers<T>::type hash_value(T);
template <typename T>
typename boost::hash_detail::long_numbers<T>::type hash_value(T);
template <typename T>
typename boost::hash_detail::ulong_numbers<T>::type hash_value(T);
#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 (&x)[N]);
template< class T, unsigned N >
std::size_t hash_value(T (&x)[N]);
#endif
template <class Ch, class A>
std::size_t hash_value(
std::basic_string<Ch, std::BOOST_HASH_CHAR_TRAITS<Ch>, A> const&);
template <typename T>
typename boost::hash_detail::float_numbers<T>::type hash_value(T);
#if !defined(BOOST_NO_CXX11_HDR_TYPEINDEX)
std::size_t hash_value(std::type_index);
#endif
// Implementation
namespace hash_detail
{
template <class T>
inline std::size_t hash_value_signed(T val)
{
const int size_t_bits = std::numeric_limits<std::size_t>::digits;
// ceiling(std::numeric_limits<T>::digits / size_t_bits) - 1
const int length = (std::numeric_limits<T>::digits - 1)
/ size_t_bits;
std::size_t seed = 0;
T positive = val < 0 ? -1 - val : val;
// Hopefully, this loop can be unrolled.
for(unsigned int i = length * size_t_bits; i > 0; i -= size_t_bits)
{
seed ^= (std::size_t) (positive >> i) + (seed<<6) + (seed>>2);
}
seed ^= (std::size_t) val + (seed<<6) + (seed>>2);
return seed;
}
template <class T>
inline std::size_t hash_value_unsigned(T val)
{
const int size_t_bits = std::numeric_limits<std::size_t>::digits;
// ceiling(std::numeric_limits<T>::digits / size_t_bits) - 1
const int length = (std::numeric_limits<T>::digits - 1)
/ size_t_bits;
std::size_t seed = 0;
// Hopefully, this loop can be unrolled.
for(unsigned int i = length * size_t_bits; i > 0; i -= size_t_bits)
{
seed ^= (std::size_t) (val >> i) + (seed<<6) + (seed>>2);
}
seed ^= (std::size_t) val + (seed<<6) + (seed>>2);
return seed;
}
}
template <typename T>
typename boost::hash_detail::basic_numbers<T>::type hash_value(T v)
{
return static_cast<std::size_t>(v);
}
template <typename T>
typename boost::hash_detail::long_numbers<T>::type hash_value(T v)
{
return hash_detail::hash_value_signed(v);
}
template <typename T>
typename boost::hash_detail::ulong_numbers<T>::type hash_value(T v)
{
return hash_detail::hash_value_unsigned(v);
}
// 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
{
#if defined(__VMS) && __INITIAL_POINTER_SIZE == 64
// for some reason ptrdiff_t on OpenVMS compiler with
// 64 bit is not 64 bit !!!
std::size_t x = static_cast<std::size_t>(
reinterpret_cast<long long int>(v));
#else
std::size_t x = static_cast<std::size_t>(
reinterpret_cast<std::ptrdiff_t>(v));
#endif
return x + (x >> 3);
}
#if defined(BOOST_MSVC)
#pragma warning(push)
#if BOOST_MSVC <= 1400
#pragma warning(disable:4267) // 'argument' : conversion from 'size_t' to
// 'unsigned int', possible loss of data
// A misguided attempt to detect 64-bit
// incompatability.
#endif
#endif
#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);
}
#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif
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 (&x)[N])
{
return hash_range(x, x + N);
}
template< class T, unsigned N >
inline std::size_t hash_value(T (&x)[N])
{
return hash_range(x, x + 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());
}
template <typename T>
typename boost::hash_detail::float_numbers<T>::type hash_value(T v)
{
return boost::hash_detail::float_hash_value(v);
}
#if !defined(BOOST_NO_CXX11_HDR_TYPEINDEX)
inline std::size_t hash_value(std::type_index v)
{
return v.hash_code();
}
#endif
//
// boost::hash
//
// Define the specializations required by the standard. The general purpose
// boost::hash is defined later in extensions.hpp if
// BOOST_HASH_NO_EXTENSIONS is not defined.
// BOOST_HASH_SPECIALIZE - define a specialization for a type which is
// passed by copy.
//
// BOOST_HASH_SPECIALIZE_REF - define a specialization for a type which is
// passed by copy.
//
// These are undefined later.
#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
#if !defined(BOOST_NO_LONG_LONG)
BOOST_HASH_SPECIALIZE(boost::long_long_type)
BOOST_HASH_SPECIALIZE(boost::ulong_long_type)
#endif
#if !defined(BOOST_NO_CXX11_HDR_TYPEINDEX)
BOOST_HASH_SPECIALIZE(std::type_index)
#endif
#undef BOOST_HASH_SPECIALIZE
#undef BOOST_HASH_SPECIALIZE_REF
// Specializing boost::hash for pointers.
#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
{
#if !BOOST_WORKAROUND(__SUNPRO_CC, <= 0x590)
return boost::hash_value(v);
#else
std::size_t x = static_cast<std::size_t>(
reinterpret_cast<std::ptrdiff_t>(v));
return x + (x >> 3);
#endif
}
};
#else
// For compilers without partial specialization, we define a
// boost::hash for all remaining types. But hash_impl is only defined
// for pointers in 'extensions.hpp' - so when BOOST_HASH_NO_EXTENSIONS
// is defined there will still be a compile error for types not supported
// in the standard.
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
{
#if !BOOST_WORKAROUND(__SUNPRO_CC, <= 590)
return boost::hash_value(val);
#else
std::size_t x = static_cast<std::size_t>(
reinterpret_cast<std::ptrdiff_t>(val));
return x + (x >> 3);
#endif
}
};
};
}
template <class T> struct hash
: public boost::hash_detail::hash_impl<boost::is_pointer<T>::value>
::BOOST_NESTED_TEMPLATE inner<T>
{
};
#endif
}
#undef BOOST_HASH_CHAR_TRAITS
#endif // BOOST_FUNCTIONAL_HASH_HASH_HPP
// Include this outside of the include guards in case the file is included
// twice - once with BOOST_HASH_NO_EXTENSIONS defined, and then with it
// undefined.
#if !defined(BOOST_HASH_NO_EXTENSIONS) \
&& !defined(BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP)
#include <boost/functional/hash/extensions.hpp>
#endif