//*****************************************************************************
// Copyright 2017-2020 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.
//*****************************************************************************

#pragma once

#include <cstddef>

#include "ngraph/util.hpp"

namespace ngraph
{
    namespace runtime
    {
        class AlignedBuffer;
    }
}

/// \brief Allocates a block of memory on the specified alignment. The actual size of the
/// allocated memory is larger than the requested size by the alignment, so allocating 1 byte
/// on 64 byte alignment will allocate 65 bytes.
class NGRAPH_API ngraph::runtime::AlignedBuffer
{
public:
    // Allocator objects and the allocation interfaces are owned by the
    // creators of AlignedBuffers. They need to ensure that the lifetime of
    // allocator exceeds the lifetime of this AlignedBuffer.
    AlignedBuffer(size_t byte_size, size_t alignment = 64);

    AlignedBuffer();
    ~AlignedBuffer();

    AlignedBuffer(AlignedBuffer&& other);
    AlignedBuffer& operator=(AlignedBuffer&& other);

    size_t size() const { return m_byte_size; }
    void* get_ptr(size_t offset) const { return m_aligned_buffer + offset; }
    void* get_ptr() { return m_aligned_buffer; }
    const void* get_ptr() const { return m_aligned_buffer; }
    template <typename T>
    T* get_ptr()
    {
        return reinterpret_cast<T*>(m_aligned_buffer);
    }
    template <typename T>
    const T* get_ptr() const
    {
        return reinterpret_cast<const T*>(m_aligned_buffer);
    }

    template <typename T>
    explicit operator T*()
    {
        return get_ptr<T>();
    }

private:
    AlignedBuffer(const AlignedBuffer&) = delete;
    AlignedBuffer& operator=(const AlignedBuffer&) = delete;

    char* m_allocated_buffer;
    char* m_aligned_buffer;
    size_t m_byte_size;
};

namespace ngraph
{
    template <>
    class NGRAPH_API AttributeAdapter<std::shared_ptr<runtime::AlignedBuffer>>
        : public ValueAccessor<void*>
    {
    public:
        AttributeAdapter(std::shared_ptr<runtime::AlignedBuffer>& value);
        void* get_ptr() override;
        size_t size() override;

        static constexpr DiscreteTypeInfo type_info{
            "AttributeAdapter<std::shared_ptr<runtime::AlignedBuffer>>", 0};
        const DiscreteTypeInfo& get_type_info() const override { return type_info; }
    protected:
        std::shared_ptr<runtime::AlignedBuffer>& m_ref;
    };
}
