tbb_allocator.h

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/*
    Copyright (c) 2005-2020 Intel Corporation

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#ifndef __TBB_tbb_allocator_H
#define __TBB_tbb_allocator_H

#include "tbb_stddef.h"
#include <new>
#if __TBB_ALLOCATOR_CONSTRUCT_VARIADIC
 #include <utility> // std::forward
#endif
#include <cstring>

namespace tbb {

namespace internal {


    void __TBB_EXPORTED_FUNC deallocate_via_handler_v3( void *p );


    void* __TBB_EXPORTED_FUNC allocate_via_handler_v3( size_t n );

    bool __TBB_EXPORTED_FUNC is_malloc_used_v3();
}

#if _MSC_VER && !defined(__INTEL_COMPILER)
    // Workaround for erroneous "unreferenced parameter" warning in method destroy.
    #pragma warning (push)
    #pragma warning (disable: 4100)
#endif


template<typename T>
class tbb_allocator {
public:
    typedef typename internal::allocator_type<T>::value_type value_type;
    typedef value_type* pointer;
    typedef const value_type* const_pointer;
    typedef value_type& reference;
    typedef const value_type& const_reference;
    typedef size_t size_type;
    typedef ptrdiff_t difference_type;
    template<typename U> struct rebind {
        typedef tbb_allocator<U> other;
    };

    enum malloc_type {
        scalable,
        standard
    };

    tbb_allocator() throw() {}
    tbb_allocator( const tbb_allocator& ) throw() {}
    template<typename U> tbb_allocator(const tbb_allocator<U>&) throw() {}

    pointer address(reference x) const {return &x;}
    const_pointer address(const_reference x) const {return &x;}

    pointer allocate( size_type n, const void* /*hint*/ = 0) {
        return pointer(internal::allocate_via_handler_v3( n * sizeof(value_type) ));
    }

    void deallocate( pointer p, size_type ) {
        internal::deallocate_via_handler_v3(p);
    }

    size_type max_size() const throw() {
        size_type max = static_cast<size_type>(-1) / sizeof (value_type);
        return (max > 0 ? max : 1);
    }

#if __TBB_ALLOCATOR_CONSTRUCT_VARIADIC
    template<typename U, typename... Args>
    void construct(U *p, Args&&... args)
        { ::new((void *)p) U(std::forward<Args>(args)...); }
#else // __TBB_ALLOCATOR_CONSTRUCT_VARIADIC
#if __TBB_CPP11_RVALUE_REF_PRESENT
    void construct( pointer p, value_type&& value ) {::new((void*)(p)) value_type(std::move(value));}
#endif
    void construct( pointer p, const value_type& value ) {::new((void*)(p)) value_type(value);}
#endif // __TBB_ALLOCATOR_CONSTRUCT_VARIADIC

    void destroy( pointer p ) {p->~value_type();}

    static malloc_type allocator_type() {
        return internal::is_malloc_used_v3() ? standard : scalable;
    }
};

#if _MSC_VER && !defined(__INTEL_COMPILER)
    #pragma warning (pop)
#endif // warning 4100 is back


template<>
class tbb_allocator<void> {
public:
    typedef void* pointer;
    typedef const void* const_pointer;
    typedef void value_type;
    template<typename U> struct rebind {
        typedef tbb_allocator<U> other;
    };
};

template<typename T, typename U>
inline bool operator==( const tbb_allocator<T>&, const tbb_allocator<U>& ) {return true;}

template<typename T, typename U>
inline bool operator!=( const tbb_allocator<T>&, const tbb_allocator<U>& ) {return false;}


template <typename T, template<typename X> class Allocator = tbb_allocator>
class zero_allocator : public Allocator<T>
{
public:
    typedef Allocator<T> base_allocator_type;
    typedef typename base_allocator_type::value_type value_type;
    typedef typename base_allocator_type::pointer pointer;
    typedef typename base_allocator_type::const_pointer const_pointer;
    typedef typename base_allocator_type::reference reference;
    typedef typename base_allocator_type::const_reference const_reference;
    typedef typename base_allocator_type::size_type size_type;
    typedef typename base_allocator_type::difference_type difference_type;
    template<typename U> struct rebind {
        typedef zero_allocator<U, Allocator> other;
    };

    zero_allocator() throw() { }
    zero_allocator(const zero_allocator &a) throw() : base_allocator_type( a ) { }
    template<typename U>
    zero_allocator(const zero_allocator<U> &a) throw() : base_allocator_type( Allocator<U>( a ) ) { }

    pointer allocate(const size_type n, const void *hint = 0 ) {
        pointer ptr = base_allocator_type::allocate( n, hint );
        std::memset( static_cast<void*>(ptr), 0, n * sizeof(value_type) );
        return ptr;
    }
};


template<template<typename T> class Allocator>
class zero_allocator<void, Allocator> : public Allocator<void> {
public:
    typedef Allocator<void> base_allocator_type;
    typedef typename base_allocator_type::value_type value_type;
    typedef typename base_allocator_type::pointer pointer;
    typedef typename base_allocator_type::const_pointer const_pointer;
    template<typename U> struct rebind {
        typedef zero_allocator<U, Allocator> other;
    };
};

template<typename T1, template<typename X1> class B1, typename T2, template<typename X2> class B2>
inline bool operator==( const zero_allocator<T1,B1> &a, const zero_allocator<T2,B2> &b) {
    return static_cast< B1<T1> >(a) == static_cast< B2<T2> >(b);
}
template<typename T1, template<typename X1> class B1, typename T2, template<typename X2> class B2>
inline bool operator!=( const zero_allocator<T1,B1> &a, const zero_allocator<T2,B2> &b) {
    return static_cast< B1<T1> >(a) != static_cast< B2<T2> >(b);
}

} // namespace tbb

#endif /* __TBB_tbb_allocator_H */