public inbox for gcc-cvs@sourceware.org help / color / mirror / Atom feed
From: Patrick Palka <ppalka@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-2896] libstdc++: Implement P1994R1 changes to ranges::elements_view Date: Thu, 27 Aug 2020 01:53:29 +0000 (GMT) [thread overview] Message-ID: <20200827015329.25721384C004@sourceware.org> (raw) https://gcc.gnu.org/g:97ab5daa6c1186d3b10872cc1d5b05da247d102c commit r11-2896-g97ab5daa6c1186d3b10872cc1d5b05da247d102c Author: Patrick Palka <ppalka@redhat.com> Date: Wed Aug 26 21:49:51 2020 -0400 libstdc++: Implement P1994R1 changes to ranges::elements_view The example from the paper doesn't compile without the proposed resolution for LWG 3406, so we'll add a testcase for this once the proposed resolution is implemented. libstdc++-v3/ChangeLog: * include/std/ranges (elements_view::end): Replace these two overloads with four new overloads. (elements_view::_Iterator::operator==): Remove. (elements_view::_Iterator::operator-): Likewise. (elements_view::_Sentinel): Define. Diff: --- libstdc++-v3/include/std/ranges | 74 +++++++++++++++++++++++++++++++++-------- 1 file changed, 60 insertions(+), 14 deletions(-) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 9d22b138082..efa8d2cf9f4 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -3366,12 +3366,20 @@ namespace views { return _Iterator<true>(ranges::begin(_M_base)); } constexpr auto - end() requires (!__detail::__simple_view<_Vp>) - { return ranges::end(_M_base); } + end() + { return _Sentinel<false>{ranges::end(_M_base)}; } constexpr auto - end() const requires __detail::__simple_view<_Vp> - { return ranges::end(_M_base); } + end() requires common_range<_Vp> + { return _Iterator<false>{ranges::end(_M_base)}; } + + constexpr auto + end() const requires range<const _Vp> + { return _Sentinel<true>{ranges::end(_M_base)}; } + + constexpr auto + end() const requires common_range<const _Vp> + { return _Iterator<true>{ranges::end(_M_base)}; } constexpr auto size() requires sized_range<_Vp> @@ -3382,6 +3390,9 @@ namespace views { return ranges::size(_M_base); } private: + template<bool _Const> + struct _Sentinel; + template<bool _Const> struct _Iterator { @@ -3484,10 +3495,6 @@ namespace views requires equality_comparable<iterator_t<_Base>> { return __x._M_current == __y._M_current; } - friend constexpr bool - operator==(const _Iterator& __x, const sentinel_t<_Base>& __y) - { return __x._M_current == __y; } - friend constexpr bool operator<(const _Iterator& __x, const _Iterator& __y) requires random_access_range<_Base> @@ -3536,15 +3543,54 @@ namespace views requires random_access_range<_Base> { return __x._M_current - __y._M_current; } - friend constexpr difference_type - operator-(const _Iterator<_Const>& __x, const sentinel_t<_Base>& __y) + friend _Sentinel<_Const>; + }; + + template<bool _Const> + struct _Sentinel + { + private: + constexpr bool + _M_equal(const _Iterator<_Const>& __x) const + { return __x._M_current == _M_end; } + + using _Base = __detail::__maybe_const_t<_Const, _Vp>; + sentinel_t<_Base> _M_end = sentinel_t<_Base>(); + + public: + _Sentinel() = default; + + constexpr explicit + _Sentinel(sentinel_t<_Base> __end) + : _M_end(std::move(__end)) + { } + + constexpr + _Sentinel(_Sentinel<!_Const> __other) + requires _Const + && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>> + : _M_end(std::move(__other._M_end)) + { } + + constexpr sentinel_t<_Base> + base() const + { return _M_end; } + + friend constexpr bool + operator==(const _Iterator<_Const>& __x, const _Sentinel& __y) + { return __y._M_equal(__x); } + + friend constexpr range_difference_t<_Base> + operator-(const _Iterator<_Const>& __x, const _Sentinel& __y) requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>> - { return __x._M_current - __y; } + { return __x._M_current - __y._M_end; } - friend constexpr difference_type - operator-(const sentinel_t<_Base>& __x, const _Iterator<_Const>& __y) + friend constexpr range_difference_t<_Base> + operator-(const _Sentinel& __x, const _Iterator<_Const>& __y) requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base>> - { return -(__y - __x); } + { return __x._M_end - __y._M_current; } + + friend _Sentinel<!_Const>; }; _Vp _M_base = _Vp();
reply other threads:[~2020-08-27 1:53 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20200827015329.25721384C004@sourceware.org \ --to=ppalka@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ --cc=libstdc++-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).