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cast: use concepts to constrain narrow

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This commit is contained in:
Danny Robson 2020-02-27 11:49:41 +11:00
parent 5d0b75d129
commit 6cf54f6f14
1 changed files with 8 additions and 10 deletions
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18
cast.hpp
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@ -8,6 +8,8 @@
#pragma once
#include "concepts.hpp"
#include "debug/assert.hpp"
#include "debug/validate.hpp"
#include "platform.hpp"
@ -72,17 +74,13 @@ namespace cruft::cast {
/// Identity casts are allowed so as to simplify the use of this routine
/// in template code.
template <
typename NarrowT,
typename WideT,
typename = std::enable_if_t<
std::is_arithmetic_v<NarrowT> &&
std::is_arithmetic_v<WideT> &&
std::is_signed_v<NarrowT> == std::is_signed_v<WideT> &&
std::is_floating_point_v<NarrowT> == std::is_floating_point_v<WideT> &&
sizeof (NarrowT) <= sizeof (WideT),
void
>
concepts::arithmetic NarrowT,
concepts::arithmetic WideT
>
requires
(std::is_signed_v<NarrowT> == std::is_signed_v<WideT>) &&
(std::is_floating_point_v<NarrowT> == std::is_floating_point_v<WideT>) &&
(sizeof (NarrowT) <= sizeof (WideT))
constexpr NarrowT
narrow (const WideT &val)
{