mirror of
https://github.com/XRPLF/rippled.git
synced 2025-12-06 17:27:55 +00:00
86 lines
2.7 KiB
C++
86 lines
2.7 KiB
C++
#ifndef XRPL_BASICS_SAFE_CAST_H_INCLUDED
|
|
#define XRPL_BASICS_SAFE_CAST_H_INCLUDED
|
|
|
|
#include <type_traits>
|
|
|
|
namespace xrpl {
|
|
|
|
// safe_cast adds compile-time checks to a static_cast to ensure that
|
|
// the destination can hold all values of the source. This is particularly
|
|
// handy when the source or destination is an enumeration type.
|
|
|
|
template <class Src, class Dest>
|
|
concept SafeToCast = (std::is_integral_v<Src> && std::is_integral_v<Dest>) &&
|
|
(std::is_signed<Src>::value || std::is_unsigned<Dest>::value) &&
|
|
(std::is_signed<Src>::value != std::is_signed<Dest>::value
|
|
? sizeof(Dest) > sizeof(Src)
|
|
: sizeof(Dest) >= sizeof(Src));
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_integral_v<Dest> && std::is_integral_v<Src>, Dest>
|
|
safe_cast(Src s) noexcept
|
|
{
|
|
static_assert(
|
|
std::is_signed_v<Dest> || std::is_unsigned_v<Src>,
|
|
"Cannot cast signed to unsigned");
|
|
constexpr unsigned not_same =
|
|
std::is_signed_v<Dest> != std::is_signed_v<Src>;
|
|
static_assert(
|
|
sizeof(Dest) >= sizeof(Src) + not_same,
|
|
"Destination is too small to hold all values of source");
|
|
return static_cast<Dest>(s);
|
|
}
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_enum_v<Dest> && std::is_integral_v<Src>, Dest>
|
|
safe_cast(Src s) noexcept
|
|
{
|
|
return static_cast<Dest>(safe_cast<std::underlying_type_t<Dest>>(s));
|
|
}
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_integral_v<Dest> && std::is_enum_v<Src>, Dest>
|
|
safe_cast(Src s) noexcept
|
|
{
|
|
return safe_cast<Dest>(static_cast<std::underlying_type_t<Src>>(s));
|
|
}
|
|
|
|
// unsafe_cast explicitly flags a static_cast as not necessarily able to hold
|
|
// all values of the source. It includes a compile-time check so that if
|
|
// underlying types become safe, it can be converted to a safe_cast.
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_integral_v<Dest> && std::is_integral_v<Src>, Dest>
|
|
unsafe_cast(Src s) noexcept
|
|
{
|
|
static_assert(
|
|
!SafeToCast<Src, Dest>,
|
|
"Only unsafe if casting signed to unsigned or "
|
|
"destination is too small");
|
|
return static_cast<Dest>(s);
|
|
}
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_enum_v<Dest> && std::is_integral_v<Src>, Dest>
|
|
unsafe_cast(Src s) noexcept
|
|
{
|
|
return static_cast<Dest>(unsafe_cast<std::underlying_type_t<Dest>>(s));
|
|
}
|
|
|
|
template <class Dest, class Src>
|
|
inline constexpr std::
|
|
enable_if_t<std::is_integral_v<Dest> && std::is_enum_v<Src>, Dest>
|
|
unsafe_cast(Src s) noexcept
|
|
{
|
|
return unsafe_cast<Dest>(static_cast<std::underlying_type_t<Src>>(s));
|
|
}
|
|
|
|
} // namespace xrpl
|
|
|
|
#endif
|