jeanlemotan
32 lines
600 B
C++
32 lines
600 B
C++
#pragma once
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#include "tl/detail/prologue.h"
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#include "tl/plain_crash.h"
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#include "tl/type_traits.h"
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namespace tl
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{
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namespace detail
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{
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template <class T, class U>
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struct is_same_signedness : integral_constant<bool, is_signed<T>::value == is_signed<U>::value>
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{
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};
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}
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template <class T, class U>
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T narrow(U u) noexcept
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{
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T t = static_cast<T>(u);
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if (static_cast<U>(t) != u)
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TL_PLAIN_CRASH("Narrowing error");
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if (!detail::is_same_signedness<T, U>::value && ((t < T{}) != (u < U{})))
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TL_PLAIN_CRASH("Narrowing error");
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return t;
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}
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}
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