narrow: Also check if a value has changed sign after cast.

Fixes https://github.com/Microsoft/GSL/issues/222.
This commit is contained in:
Paweł Bylica 2016-02-08 12:34:21 +01:00
parent 0be53d99ef
commit 6a4f2512b7
2 changed files with 50 additions and 37 deletions

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@ -1,17 +1,17 @@
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
// //
// Copyright (c) 2015 Microsoft Corporation. All rights reserved. // Copyright (c) 2015 Microsoft Corporation. All rights reserved.
// //
// This code is licensed under the MIT License (MIT). // This code is licensed under the MIT License (MIT).
// //
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE. // THE SOFTWARE.
// //
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
#pragma once #pragma once
@ -28,13 +28,13 @@
// No MSVC does constexpr fully yet // No MSVC does constexpr fully yet
#pragma push_macro("constexpr") #pragma push_macro("constexpr")
#define constexpr #define constexpr
// MSVC 2013 workarounds // MSVC 2013 workarounds
#if _MSC_VER <= 1800 #if _MSC_VER <= 1800
// noexcept is not understood // noexcept is not understood
#pragma push_macro("noexcept") #pragma push_macro("noexcept")
#define noexcept #define noexcept
// turn off some misguided warnings // turn off some misguided warnings
#pragma warning(push) #pragma warning(push)
@ -63,7 +63,7 @@ public:
final_act(final_act&& other) noexcept final_act(final_act&& other) noexcept
: f_(std::move(other.f_)), invoke_(other.invoke_) : f_(std::move(other.f_)), invoke_(other.invoke_)
{ other.invoke_ = false; } { other.invoke_ = false; }
final_act(const final_act&) = delete; final_act(const final_act&) = delete;
final_act& operator=(const final_act&) = delete; final_act& operator=(const final_act&) = delete;
@ -93,12 +93,12 @@ struct narrowing_error : public std::exception {};
// narrow() : a checked version of narrow_cast() that throws if the cast changed the value // narrow() : a checked version of narrow_cast() that throws if the cast changed the value
template<class T, class U> template<class T, class U>
inline T narrow(U u) inline T narrow(U u)
{ T t = narrow_cast<T>(u); if (static_cast<U>(t) != u) throw narrowing_error(); return t; } { T t = narrow_cast<T>(u); if (static_cast<U>(t) != u || (t < T{}) != (u < U{})) throw narrowing_error(); return t; }
// //
// at() - Bounds-checked way of accessing static arrays, std::array, std::vector // at() - Bounds-checked way of accessing static arrays, std::array, std::vector
// //
template <class T, size_t N> template <class T, size_t N>
constexpr T& at(T(&arr)[N], size_t index) constexpr T& at(T(&arr)[N], size_t index)
{ Expects(index < N); return arr[index]; } { Expects(index < N); return arr[index]; }
@ -122,7 +122,7 @@ constexpr typename Cont::value_type& at(Cont& cont, size_t index)
#undef noexcept #undef noexcept
#pragma pop_macro("noexcept") #pragma pop_macro("noexcept")
#pragma warning(pop) #pragma warning(pop)
#endif // _MSC_VER <= 1800 #endif // _MSC_VER <= 1800

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@ -1,20 +1,20 @@
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
// //
// Copyright (c) 2015 Microsoft Corporation. All rights reserved. // Copyright (c) 2015 Microsoft Corporation. All rights reserved.
// //
// This code is licensed under the MIT License (MIT). // This code is licensed under the MIT License (MIT).
// //
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE. // THE SOFTWARE.
// //
/////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////
#include <UnitTest++/UnitTest++.h> #include <UnitTest++/UnitTest++.h>
#include <gsl.h> #include <gsl.h>
#include <functional> #include <functional>
@ -95,8 +95,21 @@ SUITE(utils_tests)
char c = narrow<char>(n); char c = narrow<char>(n);
CHECK(c == 120); CHECK(c == 120);
n = 300; n = 300;
CHECK_THROW(narrow<char>(n), narrowing_error); CHECK_THROW(narrow<char>(n), narrowing_error);
const auto int32_max = std::numeric_limits<int32_t>::max();
const auto int32_min = std::numeric_limits<int32_t>::min();
CHECK(narrow<uint32_t>(int32_t(0)) == 0);
CHECK(narrow<uint32_t>(int32_t(1)) == 1);
CHECK(narrow<uint32_t>(int32_max) == int32_max);
CHECK_THROW(narrow<uint32_t>(int32_t(-1)), narrowing_error);
CHECK_THROW(narrow<uint32_t>(int32_min), narrowing_error);
n = -42;
CHECK_THROW(narrow<unsigned>(n), narrowing_error);
} }
} }