/*
    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_DETAILS_ALLOCATOR_H
#define CDSLIB_DETAILS_ALLOCATOR_H

#include <type_traits>
#include <memory>
#include <cds/details/defs.h>
#include <cds/user_setup/allocator.h>

namespace cds {
    namespace details {

        /// Extends \p std::allocator interface to provide semantics like operator \p new and \p delete
        /**
            The class is the wrapper around underlying \p Alloc class.
            \p Alloc provides the \p std::allocator interface.
        */
        template <typename T, class Alloc = CDS_DEFAULT_ALLOCATOR >
        class Allocator
            : public std::conditional<
                        std::is_same< T, typename Alloc::value_type>::value
                        , Alloc
                        , typename Alloc::template rebind<T>::other
                     >::type
        {
        public:
            /// Underlying allocator type
            typedef typename std::conditional<
                std::is_same< T, typename Alloc::value_type>::value
                , Alloc
                , typename Alloc::template rebind<T>::other
            >::type allocator_type;

            /// \p true if underlined allocator is \p std::allocator, \p false otherwise
            static CDS_CONSTEXPR bool const c_bStdAllocator = std::is_same< allocator_type, std::allocator<T>>::value;

            /// Element type
            typedef T   value_type;

            /// Analogue of operator new T(\p src... )
            template <typename... S>
            value_type *  New( S const&... src )
            {
                return Construct( allocator_type::allocate( 1, nullptr ), src... );
            }

            /// Analogue of <tt>operator new T( std::forward<Args>(args)... )</tt> (move semantics)
            template <typename... Args>
            value_type * MoveNew( Args&&... args )
            {
                return MoveConstruct( allocator_type::allocate( 1, nullptr ), std::forward<Args>(args)... );
            }

            /// Analogue of operator new T[\p nCount ]
            value_type * NewArray( size_t nCount )
            {
                value_type * p = allocator_type::allocate( nCount, nullptr );
                for ( size_t i = 0; i < nCount; ++i )
                    Construct( p + i );
                return p;
            }

            /// Analogue of operator new T[\p nCount ].
            /**
                Each item of array of type T is initialized by parameter \p src: T( src )
            */
            template <typename S>
            value_type * NewArray( size_t nCount, S const& src )
            {
                value_type * p = allocator_type::allocate( nCount, nullptr );
                for ( size_t i = 0; i < nCount; ++i )
                    Construct( p + i, src );
                return p;
            }

#       if CDS_COMPILER == CDS_COMPILER_INTEL
            //@cond
            value_type * NewBlock( size_t nSize )
            {
                return Construct( heap_alloc( nSize ));
            }
            //@endcond
#       endif
            /// Allocates block of memory of size at least \p nSize bytes.
            /**
                Internally, the block is allocated as an array of \p void* pointers,
                then \p Construct() method is called to initialize \p T.

                Precondition: <tt> nSize >= sizeof(T) </tt>
            */
            template <typename... S>
            value_type *  NewBlock( size_t nSize, S const&... src )
            {
                return Construct( heap_alloc( nSize ), src... );
            }

            /// Analogue of operator delete
            void Delete( value_type * p )
            {
                allocator_type::destroy( p );
                allocator_type::deallocate( p, 1 );
            }

            /// Analogue of operator delete []
            void Delete( value_type * p, size_t nCount )
            {
                 for ( size_t i = 0; i < nCount; ++i )
                     allocator_type::destroy( p + i );
                allocator_type::deallocate( p, nCount );
            }

#       if CDS_COMPILER == CDS_COMPILER_INTEL
            //@cond
            value_type * Construct( void * p )
            {
                return new( p ) value_type;
            }
            //@endcond
#       endif
            /// Analogue of placement operator new( \p p ) T( src... )
            template <typename... S>
            value_type * Construct( void * p, S const&... src )
            {
                value_type * pv = new( p ) value_type( src... );
                return pv;
            }

            /// Analogue of placement <tt>operator new( p ) T( std::forward<Args>(args)... )</tt>
            template <typename... Args>
            value_type * MoveConstruct( void * p, Args&&... args )
            {
                value_type * pv = new( p ) value_type( std::forward<Args>(args)... );
                return pv;
            }

            /// Rebinds allocator to other type \p Q instead of \p T
            template <typename Q>
            struct rebind {
                typedef Allocator< Q, typename Alloc::template rebind<Q>::other >    other ; ///< Rebinding result
            };

        private:
            //@cond
            void * heap_alloc( size_t nByteSize )
            {
                assert( nByteSize >= sizeof(value_type));

                size_t const nPtrSize = ( nByteSize + sizeof(void *) - 1 ) / sizeof(void *);
                typedef typename allocator_type::template rebind< void * >::other void_allocator;
                return void_allocator().allocate( nPtrSize );
            }
            //@endcond
        };

        /// Deferral removing of the object of type \p T. Helper class
        template <typename T, typename Alloc = CDS_DEFAULT_ALLOCATOR>
        struct deferral_deleter {
            typedef T           type            ; ///< Type
            typedef Alloc       allocator_type  ; ///< Allocator for removing

            /// Frees the object \p p
            /**
                Caveats: this function uses temporary object of type \ref cds::details::Allocator to free the node \p p.
                So, the node allocator should be stateless. It is standard requirement for \p std::allocator class objects.

                Do not use this function directly.
            */
            static void free( T * p )
            {
                Allocator<type, allocator_type> a;
                a.Delete( p );
            }
        };

    }    // namespace details
}    // namespace cds

#endif    // #ifndef CDSLIB_DETAILS_ALLOCATOR_H
