safe_conversion.hpp

/*
  Copyright 2023 SINTEF AS

  This file is part of the Open Porous Media project (OPM).

  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef OPM_CUISTL_SAFE_CONVERSION_HPP
#define OPM_CUISTL_SAFE_CONVERSION_HPP

#include <opm/common/ErrorMacros.hpp>

#include <cstddef>
#include <limits>
#include <type_traits>
#include <cuda_runtime.h>

#if CUDA_VERSION >= 12100
#include <fmt/format.h>
#else
#include <sstream>
#endif


namespace Opm::gpuistl::detail
{

inline int
to_int(std::size_t s)
{
    static_assert(
        std::is_signed_v<int>,
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");
    static_assert(
        !std::is_signed_v<std::size_t>,
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");

    static_assert(
        sizeof(int) <= sizeof(std::size_t),
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");


    if (s > std::size_t(std::numeric_limits<int>::max())) {
#if CUDA_VERSION >= 12100
        OPM_THROW(std::invalid_argument,
                  fmt::format(fmt::runtime("Trying to convert {} to int, but it is out of range. Maximum possible int: {}. "),
                              s,
                              std::numeric_limits<int>::max()));
#else
        std::stringstream str;
        str << "Trying to convert " << s << " to int, but it is out of range. Maximum possible int: "
            << std::numeric_limits<int>::max() << " .";
        OPM_THROW(std::invalid_argument, str.str());
#endif
    }

    // We know it will be in range here:
    return int(s);
}

__host__ __device__ inline std::size_t
to_size_t(int i)
{
    static_assert(
        std::is_signed_v<int>,
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");
    static_assert(
        !std::is_signed_v<std::size_t>,
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");

    static_assert(
        sizeof(int) <= sizeof(std::size_t),
        "Weird architecture or my understanding of the standard is flawed. Better have a look at this function.");

#if defined(__CUDA_ARCH__) || defined(__HIP_DEVICE_COMPILE__)
    assert(i >= int(0));
#else
    if (i < int(0)) {
#if CUDA_VERSION >= 12100
        OPM_THROW(std::invalid_argument, fmt::format(fmt::runtime("Trying to convert the negative number {} to size_t."), i));
#else
        std::stringstream str;
        str << "Trying to convert the negative number " << i << "  to size_t.";
        OPM_THROW(std::invalid_argument, str.str());
#endif
    }
#endif

    return std::size_t(i);
}
} // namespace Opm::gpuistl::detail

#endif