From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1059) id 23BC4394C803; Fri, 28 Aug 2020 16:07:40 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 23BC4394C803 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1598630860; bh=PYHLnkwjTQoStAczdfaJK/Dka2Vfwc0wQWMNP6hT96U=; h=From:To:Subject:Date:From; b=hcWV0Ko7mBzB2UmIiQhPW8d6RLxuKovFbtb+O7f7m1nQQRkTGWmfDktzp9S/RWAmQ 7IOlW6EAF54EA4K+1U3YyQwiMfYrTdJkJel+RB4SKxv0ZdzSmeFElATx9P+Vjiy5at fYFO2rNwExVNIQQDfyK2Rjxf8Y4pYv/yM/zK4qx0= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Nathan Sidwell To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc/devel/c++-modules] libstdc++: Implement P1994R1 changes to ranges::elements_view X-Act-Checkin: gcc X-Git-Author: Patrick Palka X-Git-Refname: refs/heads/devel/c++-modules X-Git-Oldrev: 57ea089421a3cfce936f91f3c0c92bf95ac71da1 X-Git-Newrev: 97ab5daa6c1186d3b10872cc1d5b05da247d102c Message-Id: <20200828160740.23BC4394C803@sourceware.org> Date: Fri, 28 Aug 2020 16:07:40 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Aug 2020 16:07:40 -0000 https://gcc.gnu.org/g:97ab5daa6c1186d3b10872cc1d5b05da247d102c commit 97ab5daa6c1186d3b10872cc1d5b05da247d102c Author: Patrick Palka 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(ranges::begin(_M_base)); } constexpr auto - end() requires (!__detail::__simple_view<_Vp>) - { return ranges::end(_M_base); } + end() + { return _Sentinel{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{ranges::end(_M_base)}; } + + constexpr auto + end() const requires range + { return _Sentinel{ranges::end(_M_base)}; } + + constexpr auto + end() const requires common_range + { return _Iterator{ranges::end(_M_base)}; } constexpr auto size() requires sized_range<_Vp> @@ -3382,6 +3390,9 @@ namespace views { return ranges::size(_M_base); } private: + template + struct _Sentinel; + template struct _Iterator { @@ -3484,10 +3495,6 @@ namespace views requires equality_comparable> { 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 + 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 __other) + requires _Const + && convertible_to, 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, 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, iterator_t<_Base>> - { return -(__y - __x); } + { return __x._M_end - __y._M_current; } + + friend _Sentinel; }; _Vp _M_base = _Vp();