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pragma once replaced

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added constexpr
This commit is contained in:
Marius Bancila 2022-02-23 18:24:00 +02:00
parent 5c538cca02
commit cdebc5b78d
2 changed files with 28 additions and 45 deletions
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52
P0959.md
View File

@ -105,6 +105,7 @@ P0959R2 was discussed by LEWGI in Kona with the following feedback:
Based on this feedback and further considerations, the following changes have been done in this version:
* Added detailed explanation of the algorithms for generating uuids.
* `from_string()` and non-member `swap()` declared with `noexcept`.
* `from_string()` and `is_valid_uuid()` declared with `constexpr`.
* The `uuid` type is now defined as a class.
* Added an exposition-only member to hint and the possible internal representation of the uuid data.
* Added `uuid` constructors from arrays.
@ -506,21 +507,11 @@ namespace std {
constexpr std::strong_ordering operator<=>(uuid const&) const noexcept = default;
template<class CharT = char>
static bool is_valid_uuid(CharT const * str) noexcept;
template<typename StringType>
constexpr static bool is_valid_uuid(StringType const & str) noexcept;
template<class CharT = char,
class Traits = std::char_traits<CharT>,
class Allocator = std::allocator<CharT>>
static bool is_valid_uuid(std::basic_string<CharT, Traits, Allocator> const & str) noexcept;
template<class CharT = char>
static uuid from_string(CharT const * str) noexcept;
template<class CharT = char,
class Traits = std::char_traits<CharT>,
class Allocator = std::allocator<CharT>>
static uuid from_string(std::basic_string<CharT, Traits, Allocator> const & str) noexcept;
template<typename StringType>
constexpr static uuid from_string(StringType const & str) noexcept;
private:
template <class Elem, class Traits>
friend std::basic_ostream<Elem, Traits> & operator<<(std::basic_ostream<Elem, Traits> &s, uuid const & id);
@ -598,13 +589,8 @@ namespace std {
public:
explicit uuid_name_generator(uuid const& namespace_uuid) noexcept;
template<class CharT = char>
uuid operator()(CharT const * name);
template<class CharT = char,
class Traits = std::char_traits<CharT>,
class Allocator = std::allocator<CharT>>
uuid operator()(std::basic_string<CharT, Traits, Allocator> const & name);
template<typename StringType>
uuid operator()(StringType const & name);
};
}
```
@ -714,21 +700,11 @@ namespace std {
constexpr std::span<std::byte const, 16> as_bytes() const;
template<class CharT = char>
static bool is_valid_uuid(CharT const * str) noexcept;
template<typename StringType>
constexpr static bool is_valid_uuid(StringType const & str) noexcept;
template<class CharT = char,
class Traits = std::char_traits<CharT>,
class Allocator = std::allocator<CharT>>
static bool is_valid_uuid(std::basic_string<CharT, Traits, Allocator> const & str) noexcept;
template<class CharT = char>
static uuid from_string(CharT const * str) noexcept;
template<class CharT = char,
class Traits = std::char_traits<CharT>,
class Allocator = std::allocator<CharT>>
static uuid from_string(std::basic_string<CharT, Traits, Allocator> const & str) noexcept;
template<typename StringType>
constexpr static uuid from_string(StringType const & str) noexcept;
private:
template <class Elem, class Traits>
friend std::basic_ostream<Elem, Traits> & operator<<(std::basic_ostream<Elem, Traits> &s, uuid const & id);
@ -841,6 +817,12 @@ auto id1 = uuid::from_string<char, std::char_traits<char>>(
std::string str{ "47183823-2574-4bfd-b411-99ed177d3e43" };
auto id2 = uuid::from_string<char, std::char_traits<char>>(str); // [2]
```
However, to simplify the definition, these two overloads have been replaced with a single one:
```
template <typename StringType>
constexpr static std::optional<uuid> from_string(StringType const & str);
```
The `is_valid_uuid()` function and the `uuid_name_generator`'s call operator are now defined in the same manner.
#### Need more explanations about the choices of ordering and how the RFC works in that regard.

17
include/uuid.h
View File

@ -1,4 +1,5 @@
#pragma once
#ifndef STDUUID_H
#define STDUUID_H
#include <cstring>
#include <string>
@ -62,7 +63,7 @@ namespace uuids
namespace detail
{
template <typename TChar>
constexpr inline unsigned char hex2char(TChar const ch)
constexpr inline unsigned char hex2char(TChar const ch) noexcept
{
if (ch >= static_cast<TChar>('0') && ch <= static_cast<TChar>('9'))
return static_cast<unsigned char>(ch - static_cast<TChar>('0'));
@ -74,7 +75,7 @@ namespace uuids
}
template <typename TChar>
constexpr inline bool is_hex(TChar const ch)
constexpr inline bool is_hex(TChar const ch) noexcept
{
return
(ch >= static_cast<TChar>('0') && ch <= static_cast<TChar>('9')) ||
@ -83,17 +84,15 @@ namespace uuids
}
template <typename TChar>
constexpr std::basic_string_view<TChar> to_string_view(TChar const * str)
constexpr std::basic_string_view<TChar> to_string_view(TChar const * str) noexcept
{
if (str) return str;
return {};
}
template <typename StringType>
constexpr std::basic_string_view<
typename StringType::value_type,
typename StringType::traits_type>
to_string_view(StringType const & str)
constexpr std::basic_string_view<typename StringType::value_type, typename StringType::traits_type>
to_string_view(StringType const & str) noexcept
{
return str;
}
@ -947,3 +946,5 @@ namespace std
}
};
}
#endif /* STDUUID_H */