memory.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 <cstring>
#include <type_traits>

namespace mrpt::system
{
/** \addtogroup mrpt_memory Memory utilities
 * Header: `#include <mrpt/system/memory.h>`.
 * Library: \ref mrpt_system_grp
 * \ingroup mrpt_system_grp
 *  @{ */

/** Returns the memory occupied by this process, in bytes */
unsigned long getMemoryUsage();

/** In platforms and compilers with support to "alloca", allocate a memory block
 * on the stack; if alloca is not supported, it is emulated as a normal "malloc"
 * - NOTICE: Since in some platforms alloca will be emulated with malloc,
 * alloca_free MUST BE ALWAYS CALLED to avoid memory leaks.
 *   This method MUST BE a macro rather than a function in order to operate on
 * the caller's stack.
 *  \sa mrpt_alloca_free
 */
#if defined(_MSC_VER) && (_MSC_VER >= 1400)
// Visual Studio 2005, 2008
#define mrpt_alloca(nBytes) _malloca(nBytes)
#elif defined(HAVE_ALLOCA)
// GCC
#define mrpt_alloca(nBytes) ::alloca(nBytes)
#else
// Default: Emulate with memory in the heap:
#define mrpt_alloca(nBytes) ::malloc(nBytes)
#endif

/** This method must be called to "free" each memory block allocated with
 * "system::alloca": If the block was really allocated in the stack, no
 * operation is actually performed, otherwise it will be freed from the heap.
 *   This method MUST BE a macro rather than a function in order to operate on
 * the caller's stack.
 * \sa mrpt_alloca
 */
#if defined(_MSC_VER) && (_MSC_VER >= 1400)
// Visual Studio 2005, 2008
#define mrpt_alloca_free(mem_block) _freea(mem_block)
#elif defined(HAVE_ALLOCA)
// GCC
#define mrpt_alloca_free(mem_block)
#else
// Default: Emulate with memory in the heap:
#define mrpt_alloca_free(mem_block) free(mem_block)
#endif

/** @} */

/** \addtogroup mrpt_memory Memory utilities
 *  @{ */
template <
    std::size_t alignment, typename T,
    typename = std::enable_if_t<std::is_pointer<T>::value>>
bool is_aligned(T ptr)
{
    return alignment == 0 ||
           reinterpret_cast<std::size_t>(ptr) % alignment == 0;
}
/** @} */

}  // namespace mrpt::system