ceph/src/jaegertracing/opentelemetry-cpp/third_party/ms-gsl/include/gsl/gsl_narrow

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 // Copyright (c) 2015 Microsoft Corporation. All rights reserved.
   4 //
   5 // This code is licensed under the MIT License (MIT).
   6 //
   7 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   8 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   9 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  10 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  11 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  12 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  13 // THE SOFTWARE.
  14 //
  15 ///////////////////////////////////////////////////////////////////////////////
  16
  17 #ifndef GSL_NARROW_H
  18 #define GSL_NARROW_H
  19 #include <gsl/gsl_assert> // for Expects
  20 #include <gsl/gsl_util> // for narrow_cast
  21 namespace gsl
  22 {
  23 struct narrowing_error : public std::exception
  24 {
  25     const char* what() const noexcept override
  26     {
  27         return "narrowing_error";
  28     }
  29 };
  30
  31 // narrow() : a checked version of narrow_cast() that throws if the cast changed the value
  32 template <class T, class U>
  33 GSL_SUPPRESS(type.1) // NO-FORMAT: attribute
  34 GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // TODO: MSVC /analyze does not recognise noexcept(false)
  35 constexpr
  36 T narrow(U u) noexcept(false)
  37 {
  38     constexpr const bool is_different_signedness = (std::is_signed<T>::value != std::is_signed<U>::value);
  39
  40     const T t = narrow_cast<T>(u);
  41
  42     if (static_cast<U>(t) != u
  43         || (is_different_signedness
  44             && ((t < T{}) != (u < U{}))))
  45     {
  46         throw narrowing_error{};
  47     }
  48
  49     return t;
  50 }
  51 }
  52 #endif // GSL_NARROW_H