//
// Copyright 2011 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//

#pragma once

#include <uhd/config.hpp>
#include <cstddef>

namespace uhd {

/*!
 * Reference vector:
 *  - Provides a std::vector-like interface for an array.
 *  - Statically sized, and does not manage the memory.
 */
template <typename T>
class UHD_API ref_vector
{
public:
    /*!
     * Create a reference vector of size 1 from a pointer.
     * Therefore: rv[0] == ptr and rv.size() == 1
     * \param ptr a pointer to a chunk of memory
     */
    template <typename Ptr>
    ref_vector(Ptr* ptr) : _ptr(T(ptr)), _mem(_mem_t(&_ptr)), _size(1)
    {
        /* NOP */
    }

    /*!
     * Create a reference vector from a std::vector container.
     * Therefore: rv[n] == vec[n] and rv.size() == vec.size()
     * \param vec a const reference to an std::vector
     */
    template <typename Vector>
    ref_vector(const Vector& vec)
        : _ptr(T()), _mem(_mem_t(&vec.front())), _size(vec.size())
    {
        /* NOP */
    }

    /*!
     * Create a reference vector from a pointer and a length
     * Therefore: rv[n] == mem[n] and rv.size() == len
     * \param mem a pointer to an array of pointers
     * \param len the length of the array of pointers
     */
    ref_vector(const T* mem, size_t len) : _ptr(T()), _mem(_mem_t(mem)), _size(len)
    {
        /* NOP */
    }

    //! Index operator gets the value of rv[index]
    const T& operator[](size_t index) const
    {
        return _mem[index];
    }

    //! The number of elements in this container
    size_t size(void) const
    {
        return _size;
    }

private:
    const T _ptr;
    typedef T* _mem_t;
    const _mem_t _mem;
    const size_t _size;
};

} // namespace uhd
