+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef CDSLIB_OPT_HASH_H
+#define CDSLIB_OPT_HASH_H
+
+#include <tuple>
+#include <functional>
+#include <cds/opt/options.h>
+
+namespace cds { namespace opt {
+
+ /// [type-option] Option setter for a hash function
+ /**
+ This option setter specifies hash functor used in unordered containers.
+
+ The default value of template argument \p Functor is \p cds::opt::v::hash
+ that is synonym for <tt>std::hash</tt> implementation of standard library.
+ */
+ template <typename Functor>
+ struct hash {
+ //@cond
+ template <typename Base> struct pack: public Base
+ {
+ typedef Functor hash;
+ };
+ //@endcond
+ };
+
+ namespace v {
+ //@cond
+ using std::hash;
+
+ /// Metafunction selecting default hash implementation
+ /**
+ The metafunction selects appropriate hash functor implementation.
+ If \p Hash is not equal to opt::none, then result of metafunction is \p Hash.
+ Otherwise, the result is <tt> std::hash<Q> </tt>.
+
+ Note that default hash function like <tt> std::hash<Q> </tt>
+ is generally not suitable for complex type \p Q and its derivatives.
+ You should manually provide particular hash functor for such types.
+ */
+ template <typename Hash>
+ struct hash_selector
+ {
+ typedef Hash type; ///< resulting implementation of hash functor
+ };
+
+ template <>
+ struct hash_selector<opt::none>
+ {
+ struct type {
+ template <typename Q>
+ size_t operator()( Q const& key ) const
+ {
+ return std::hash<Q>()( key );
+ }
+ };
+ };
+ //@endcond
+ } // namespace v
+
+ //@cond
+ namespace details {
+ template <class> struct hash_list;
+ template <typename... Functors>
+ struct hash_list< std::tuple<Functors...> >
+ {
+ static size_t const size = sizeof...(Functors);
+ typedef size_t values[size];
+ typedef std::tuple<Functors...> hash_tuple_type;
+
+ hash_tuple_type hash_tuple;
+
+ hash_list()
+ {}
+
+ hash_list( hash_tuple_type const& t)
+ : hash_tuple( t )
+ {}
+ hash_list( hash_tuple_type&& t)
+ : hash_tuple( std::forward<hash_tuple_type>(t))
+ {}
+
+ template <size_t I, typename T>
+ typename std::enable_if< (I == sizeof...(Functors)) >::type apply( size_t * /*dest*/, T const& /*v*/ ) const
+ {}
+
+ template <size_t I, typename T>
+ typename std::enable_if< (I < sizeof...(Functors)) >::type apply( size_t * dest, T const& v ) const
+ {
+ dest[I] = std::get<I>( hash_tuple )( v );
+ apply<I+1>( dest, v );
+ }
+
+ template <typename T>
+ void operator()( size_t * dest, T const& v ) const
+ {
+ apply<0>( dest, v );
+ }
+ };
+ } // namespace details
+ //@endcond
+
+ /// Declare tuple for hash functors \p Functors
+ template <typename... Functors>
+ using hash_tuple = details::hash_list< std::tuple< Functors... >>;
+
+ //@cond
+ // At least, two functors must be provided. Single functor is not supported
+ template <typename Functor> struct hash< std::tuple<Functor> >;
+ //@endcond
+
+ /// Multi-functor hash option setter - specialization for \p std::tuple
+ template <typename... Functors>
+ struct hash< std::tuple<Functors...> >
+ {
+ //@cond
+ template <typename Base> struct pack: public Base
+ {
+ typedef details::hash_list< std::tuple<Functors...> > hash;
+ };
+ //@endcond
+ };
+
+
+ //@cond
+ namespace details {
+
+ template <class HashList, typename WrappedType, typename Wrapper>
+ struct hash_list_wrapper {
+ typedef HashList hash_list;
+ typedef WrappedType wrapped_type;
+ typedef Wrapper wrapper_type;
+
+ typedef typename hash_list::hash_tuple_type hash_tuple_type;
+ static size_t const size = hash_list::size;
+
+ hash_list m_wrappedList;
+
+ hash_list_wrapper()
+ {}
+ hash_list_wrapper( hash_tuple_type const& t)
+ : m_wrappedList( t )
+ {}
+ hash_list_wrapper( hash_tuple_type&& t)
+ : m_wrappedList( std::forward<hash_tuple_type>(t))
+ {}
+
+ void operator()( size_t * dest, wrapped_type const& what ) const
+ {
+ m_wrappedList( dest, wrapper_type()( what ));
+ }
+
+ template <typename Q>
+ void operator()( size_t * dest, Q const& what) const
+ {
+ m_wrappedList( dest, what );
+ }
+ };
+
+ } // namespace details
+ //@endcond
+
+}} // namespace cds::opt
+
+#endif // #ifndef CDSLIB_OPT_HASH_H