ContainerReadOnlyProxyAccessor.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/core/exceptions.h>
#include <cstdlib>  // size_t

namespace mrpt::containers
{
/** \addtogroup stlext_grp
 * @{ */

/** A generic proxy accessor template that only allows read-only access to the
 * original binded STL container object. */
template <typename STLCONTAINER>
struct ContainerReadOnlyProxyAccessor
{
    /** ctor: binds to source object */
    ContainerReadOnlyProxyAccessor(STLCONTAINER& source) : m_source(source) {}
    /** (Deleted ctor) ignore copies (keep reference to original object) */
    ContainerReadOnlyProxyAccessor(
        const ContainerReadOnlyProxyAccessor<STLCONTAINER>&) = delete;
    /** Don't copy the reference to the source object, but copy the contained
     * data. This is only allowed if the size of the buffers coincide. */
    ContainerReadOnlyProxyAccessor<STLCONTAINER>& operator=(
        const ContainerReadOnlyProxyAccessor<STLCONTAINER>& o)
    {
        ASSERT_EQUAL_(m_source.size(), o.m_source.size());
        m_source = o.m_source;
        return *this;
    }
    /** Transparent conversion to const ref to original source object. */
    operator const STLCONTAINER&() const { return m_source; }
    size_t size() const { return m_source.size(); }
    const typename STLCONTAINER::value_type& operator[](const int i) const
    {
        return m_source[i];
    }

    typename STLCONTAINER::const_iterator begin() const
    {
        return m_source.begin();
    }
    typename STLCONTAINER::const_iterator end() const { return m_source.end(); }
    typename STLCONTAINER::const_reverse_iterator rbegin() const
    {
        return m_source.rbegin();
    }
    typename STLCONTAINER::const_reverse_iterator rend() const
    {
        return m_source.rend();
    }

   private:
    STLCONTAINER& m_source;
};

/** @} */  // end of grouping
}  // namespace mrpt::containers