a2b3ab8f77
- implement `std::ranges::split_view` (last c++20 view) - Work in process on testing iterator/sentinel, but since we are getting closer to the deadline, I'd like to send the review early Differential Revision: https://reviews.llvm.org/D142063
87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// constexpr split_view(View base, Pattern pattern);
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#include <algorithm>
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#include <cassert>
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#include <ranges>
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#include <string_view>
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#include <utility>
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struct ViewWithCounting : std::ranges::view_base {
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int* times_copied = nullptr;
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int* times_moved = nullptr;
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constexpr ViewWithCounting(int& copies_ctr, int& moves_ctr) : times_copied(&copies_ctr), times_moved(&moves_ctr) {}
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constexpr ViewWithCounting(const ViewWithCounting& rhs)
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: times_copied(rhs.times_copied), times_moved(rhs.times_moved) {
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++(*times_copied);
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}
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constexpr ViewWithCounting(ViewWithCounting&& rhs) : times_copied(rhs.times_copied), times_moved(rhs.times_moved) {
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++(*times_moved);
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}
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constexpr const char* begin() const { return nullptr; }
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constexpr const char* end() const { return nullptr; }
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constexpr ViewWithCounting& operator=(const ViewWithCounting&) = default;
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constexpr ViewWithCounting& operator=(ViewWithCounting&&) = default;
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constexpr bool operator==(const ViewWithCounting&) const { return true; }
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};
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constexpr bool test() {
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{
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std::string_view input = "abc def";
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std::ranges::lazy_split_view<std::string_view, std::string_view> v(input, " ");
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assert(v.base() == input);
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assert(std::ranges::equal(*v.begin(), std::string_view{"abc"}));
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}
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// Make sure the arguments are moved, not copied.
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{
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using View = ViewWithCounting;
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using Pattern = ViewWithCounting;
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// Arguments are lvalues.
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{
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int view_copied = 0, view_moved = 0, pattern_copied = 0, pattern_moved = 0;
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View view(view_copied, view_moved);
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Pattern pattern(pattern_copied, pattern_moved);
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std::ranges::split_view<View, Pattern> v(view, pattern);
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assert(view_copied == 1); // The local variable is copied into the argument.
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assert(view_moved == 1);
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assert(pattern_copied == 1);
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assert(pattern_moved == 1);
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}
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// Arguments are rvalues.
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{
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int view_copied = 0, view_moved = 0, pattern_copied = 0, pattern_moved = 0;
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std::ranges::split_view<View, Pattern> v(View(view_copied, view_moved), Pattern(pattern_copied, pattern_moved));
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assert(view_copied == 0);
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assert(view_moved == 1);
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assert(pattern_copied == 0);
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assert(pattern_moved == 1);
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}
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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