| //===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains some templates that are useful if you are working with the |
| // STL at all. |
| // |
| // No library is required when using these functions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ADT_STLEXTRAS_H |
| #define LLVM_ADT_STLEXTRAS_H |
| |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/ADT/STLForwardCompat.h" |
| #include "llvm/ADT/iterator.h" |
| #include "llvm/ADT/iterator_range.h" |
| #include "llvm/Config/abi-breaking.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include <algorithm> |
| #include <cassert> |
| #include <cstddef> |
| #include <cstdint> |
| #include <cstdlib> |
| #include <functional> |
| #include <initializer_list> |
| #include <iterator> |
| #include <limits> |
| #include <memory> |
| #include <tuple> |
| #include <type_traits> |
| #include <utility> |
| |
| #ifdef EXPENSIVE_CHECKS |
| #include <random> // for std::mt19937 |
| #endif |
| |
| namespace llvm { |
| |
| // Only used by compiler if both template types are the same. Useful when |
| // using SFINAE to test for the existence of member functions. |
| template <typename T, T> struct SameType; |
| |
| namespace detail { |
| |
| template <typename RangeT> |
| using IterOfRange = decltype(std::begin(std::declval<RangeT &>())); |
| |
| template <typename RangeT> |
| using ValueOfRange = typename std::remove_reference<decltype( |
| *std::begin(std::declval<RangeT &>()))>::type; |
| |
| } // end namespace detail |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <type_traits> |
| //===----------------------------------------------------------------------===// |
| |
| template <typename T> struct make_const_ptr { |
| using type = |
| typename std::add_pointer<typename std::add_const<T>::type>::type; |
| }; |
| |
| template <typename T> struct make_const_ref { |
| using type = typename std::add_lvalue_reference< |
| typename std::add_const<T>::type>::type; |
| }; |
| |
| namespace detail { |
| template <typename...> using void_t = void; |
| template <class, template <class...> class Op, class... Args> struct detector { |
| using value_t = std::false_type; |
| }; |
| template <template <class...> class Op, class... Args> |
| struct detector<void_t<Op<Args...>>, Op, Args...> { |
| using value_t = std::true_type; |
| }; |
| } // end namespace detail |
| |
| /// Detects if a given trait holds for some set of arguments 'Args'. |
| /// For example, the given trait could be used to detect if a given type |
| /// has a copy assignment operator: |
| /// template<class T> |
| /// using has_copy_assign_t = decltype(std::declval<T&>() |
| /// = std::declval<const T&>()); |
| /// bool fooHasCopyAssign = is_detected<has_copy_assign_t, FooClass>::value; |
| template <template <class...> class Op, class... Args> |
| using is_detected = typename detail::detector<void, Op, Args...>::value_t; |
| |
| namespace detail { |
| template <typename Callable, typename... Args> |
| using is_invocable = |
| decltype(std::declval<Callable &>()(std::declval<Args>()...)); |
| } // namespace detail |
| |
| /// Check if a Callable type can be invoked with the given set of arg types. |
| template <typename Callable, typename... Args> |
| using is_invocable = is_detected<detail::is_invocable, Callable, Args...>; |
| |
| /// This class provides various trait information about a callable object. |
| /// * To access the number of arguments: Traits::num_args |
| /// * To access the type of an argument: Traits::arg_t<Index> |
| /// * To access the type of the result: Traits::result_t |
| template <typename T, bool isClass = std::is_class<T>::value> |
| struct function_traits : public function_traits<decltype(&T::operator())> {}; |
| |
| /// Overload for class function types. |
| template <typename ClassType, typename ReturnType, typename... Args> |
| struct function_traits<ReturnType (ClassType::*)(Args...) const, false> { |
| /// The number of arguments to this function. |
| enum { num_args = sizeof...(Args) }; |
| |
| /// The result type of this function. |
| using result_t = ReturnType; |
| |
| /// The type of an argument to this function. |
| template <size_t Index> |
| using arg_t = typename std::tuple_element<Index, std::tuple<Args...>>::type; |
| }; |
| /// Overload for class function types. |
| template <typename ClassType, typename ReturnType, typename... Args> |
| struct function_traits<ReturnType (ClassType::*)(Args...), false> |
| : function_traits<ReturnType (ClassType::*)(Args...) const> {}; |
| /// Overload for non-class function types. |
| template <typename ReturnType, typename... Args> |
| struct function_traits<ReturnType (*)(Args...), false> { |
| /// The number of arguments to this function. |
| enum { num_args = sizeof...(Args) }; |
| |
| /// The result type of this function. |
| using result_t = ReturnType; |
| |
| /// The type of an argument to this function. |
| template <size_t i> |
| using arg_t = typename std::tuple_element<i, std::tuple<Args...>>::type; |
| }; |
| /// Overload for non-class function type references. |
| template <typename ReturnType, typename... Args> |
| struct function_traits<ReturnType (&)(Args...), false> |
| : public function_traits<ReturnType (*)(Args...)> {}; |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <functional> |
| //===----------------------------------------------------------------------===// |
| |
| template <class Ty> struct identity { |
| using argument_type = Ty; |
| |
| Ty &operator()(Ty &self) const { |
| return self; |
| } |
| const Ty &operator()(const Ty &self) const { |
| return self; |
| } |
| }; |
| |
| /// An efficient, type-erasing, non-owning reference to a callable. This is |
| /// intended for use as the type of a function parameter that is not used |
| /// after the function in question returns. |
| /// |
| /// This class does not own the callable, so it is not in general safe to store |
| /// a function_ref. |
| template<typename Fn> class function_ref; |
| |
| template<typename Ret, typename ...Params> |
| class function_ref<Ret(Params...)> { |
| Ret (*callback)(intptr_t callable, Params ...params) = nullptr; |
| intptr_t callable; |
| |
| template<typename Callable> |
| static Ret callback_fn(intptr_t callable, Params ...params) { |
| return (*reinterpret_cast<Callable*>(callable))( |
| std::forward<Params>(params)...); |
| } |
| |
| public: |
| function_ref() = default; |
| function_ref(std::nullptr_t) {} |
| |
| template <typename Callable> |
| function_ref( |
| Callable &&callable, |
| // This is not the copy-constructor. |
| std::enable_if_t<!std::is_same<remove_cvref_t<Callable>, |
| function_ref>::value> * = nullptr, |
| // Functor must be callable and return a suitable type. |
| std::enable_if_t<std::is_void<Ret>::value || |
| std::is_convertible<decltype(std::declval<Callable>()( |
| std::declval<Params>()...)), |
| Ret>::value> * = nullptr) |
| : callback(callback_fn<typename std::remove_reference<Callable>::type>), |
| callable(reinterpret_cast<intptr_t>(&callable)) {} |
| |
| Ret operator()(Params ...params) const { |
| return callback(callable, std::forward<Params>(params)...); |
| } |
| |
| explicit operator bool() const { return callback; } |
| }; |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <iterator> |
| //===----------------------------------------------------------------------===// |
| |
| namespace adl_detail { |
| |
| using std::begin; |
| |
| template <typename ContainerTy> |
| decltype(auto) adl_begin(ContainerTy &&container) { |
| return begin(std::forward<ContainerTy>(container)); |
| } |
| |
| using std::end; |
| |
| template <typename ContainerTy> |
| decltype(auto) adl_end(ContainerTy &&container) { |
| return end(std::forward<ContainerTy>(container)); |
| } |
| |
| using std::swap; |
| |
| template <typename T> |
| void adl_swap(T &&lhs, T &&rhs) noexcept(noexcept(swap(std::declval<T>(), |
| std::declval<T>()))) { |
| swap(std::forward<T>(lhs), std::forward<T>(rhs)); |
| } |
| |
| } // end namespace adl_detail |
| |
| template <typename ContainerTy> |
| decltype(auto) adl_begin(ContainerTy &&container) { |
| return adl_detail::adl_begin(std::forward<ContainerTy>(container)); |
| } |
| |
| template <typename ContainerTy> |
| decltype(auto) adl_end(ContainerTy &&container) { |
| return adl_detail::adl_end(std::forward<ContainerTy>(container)); |
| } |
| |
| template <typename T> |
| void adl_swap(T &&lhs, T &&rhs) noexcept( |
| noexcept(adl_detail::adl_swap(std::declval<T>(), std::declval<T>()))) { |
| adl_detail::adl_swap(std::forward<T>(lhs), std::forward<T>(rhs)); |
| } |
| |
| /// Test whether \p RangeOrContainer is empty. Similar to C++17 std::empty. |
| template <typename T> |
| constexpr bool empty(const T &RangeOrContainer) { |
| return adl_begin(RangeOrContainer) == adl_end(RangeOrContainer); |
| } |
| |
| /// Returns true if the given container only contains a single element. |
| template <typename ContainerTy> bool hasSingleElement(ContainerTy &&C) { |
| auto B = std::begin(C), E = std::end(C); |
| return B != E && std::next(B) == E; |
| } |
| |
| /// Return a range covering \p RangeOrContainer with the first N elements |
| /// excluded. |
| template <typename T> auto drop_begin(T &&RangeOrContainer, size_t N = 1) { |
| return make_range(std::next(adl_begin(RangeOrContainer), N), |
| adl_end(RangeOrContainer)); |
| } |
| |
| // mapped_iterator - This is a simple iterator adapter that causes a function to |
| // be applied whenever operator* is invoked on the iterator. |
| |
| template <typename ItTy, typename FuncTy, |
| typename FuncReturnTy = |
| decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))> |
| class mapped_iterator |
| : public iterator_adaptor_base< |
| mapped_iterator<ItTy, FuncTy>, ItTy, |
| typename std::iterator_traits<ItTy>::iterator_category, |
| typename std::remove_reference<FuncReturnTy>::type> { |
| public: |
| mapped_iterator(ItTy U, FuncTy F) |
| : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {} |
| |
| ItTy getCurrent() { return this->I; } |
| |
| FuncReturnTy operator*() const { return F(*this->I); } |
| |
| private: |
| FuncTy F; |
| }; |
| |
| // map_iterator - Provide a convenient way to create mapped_iterators, just like |
| // make_pair is useful for creating pairs... |
| template <class ItTy, class FuncTy> |
| inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) { |
| return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F)); |
| } |
| |
| template <class ContainerTy, class FuncTy> |
| auto map_range(ContainerTy &&C, FuncTy F) { |
| return make_range(map_iterator(C.begin(), F), map_iterator(C.end(), F)); |
| } |
| |
| /// Helper to determine if type T has a member called rbegin(). |
| template <typename Ty> class has_rbegin_impl { |
| using yes = char[1]; |
| using no = char[2]; |
| |
| template <typename Inner> |
| static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr); |
| |
| template <typename> |
| static no& test(...); |
| |
| public: |
| static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes); |
| }; |
| |
| /// Metafunction to determine if T& or T has a member called rbegin(). |
| template <typename Ty> |
| struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> { |
| }; |
| |
| // Returns an iterator_range over the given container which iterates in reverse. |
| // Note that the container must have rbegin()/rend() methods for this to work. |
| template <typename ContainerTy> |
| auto reverse(ContainerTy &&C, |
| std::enable_if_t<has_rbegin<ContainerTy>::value> * = nullptr) { |
| return make_range(C.rbegin(), C.rend()); |
| } |
| |
| // Returns a std::reverse_iterator wrapped around the given iterator. |
| template <typename IteratorTy> |
| std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) { |
| return std::reverse_iterator<IteratorTy>(It); |
| } |
| |
| // Returns an iterator_range over the given container which iterates in reverse. |
| // Note that the container must have begin()/end() methods which return |
| // bidirectional iterators for this to work. |
| template <typename ContainerTy> |
| auto reverse(ContainerTy &&C, |
| std::enable_if_t<!has_rbegin<ContainerTy>::value> * = nullptr) { |
| return make_range(llvm::make_reverse_iterator(std::end(C)), |
| llvm::make_reverse_iterator(std::begin(C))); |
| } |
| |
| /// An iterator adaptor that filters the elements of given inner iterators. |
| /// |
| /// The predicate parameter should be a callable object that accepts the wrapped |
| /// iterator's reference type and returns a bool. When incrementing or |
| /// decrementing the iterator, it will call the predicate on each element and |
| /// skip any where it returns false. |
| /// |
| /// \code |
| /// int A[] = { 1, 2, 3, 4 }; |
| /// auto R = make_filter_range(A, [](int N) { return N % 2 == 1; }); |
| /// // R contains { 1, 3 }. |
| /// \endcode |
| /// |
| /// Note: filter_iterator_base implements support for forward iteration. |
| /// filter_iterator_impl exists to provide support for bidirectional iteration, |
| /// conditional on whether the wrapped iterator supports it. |
| template <typename WrappedIteratorT, typename PredicateT, typename IterTag> |
| class filter_iterator_base |
| : public iterator_adaptor_base< |
| filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>, |
| WrappedIteratorT, |
| typename std::common_type< |
| IterTag, typename std::iterator_traits< |
| WrappedIteratorT>::iterator_category>::type> { |
| using BaseT = iterator_adaptor_base< |
| filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>, |
| WrappedIteratorT, |
| typename std::common_type< |
| IterTag, typename std::iterator_traits< |
| WrappedIteratorT>::iterator_category>::type>; |
| |
| protected: |
| WrappedIteratorT End; |
| PredicateT Pred; |
| |
| void findNextValid() { |
| while (this->I != End && !Pred(*this->I)) |
| BaseT::operator++(); |
| } |
| |
| // Construct the iterator. The begin iterator needs to know where the end |
| // is, so that it can properly stop when it gets there. The end iterator only |
| // needs the predicate to support bidirectional iteration. |
| filter_iterator_base(WrappedIteratorT Begin, WrappedIteratorT End, |
| PredicateT Pred) |
| : BaseT(Begin), End(End), Pred(Pred) { |
| findNextValid(); |
| } |
| |
| public: |
| using BaseT::operator++; |
| |
| filter_iterator_base &operator++() { |
| BaseT::operator++(); |
| findNextValid(); |
| return *this; |
| } |
| }; |
| |
| /// Specialization of filter_iterator_base for forward iteration only. |
| template <typename WrappedIteratorT, typename PredicateT, |
| typename IterTag = std::forward_iterator_tag> |
| class filter_iterator_impl |
| : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> { |
| using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>; |
| |
| public: |
| filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End, |
| PredicateT Pred) |
| : BaseT(Begin, End, Pred) {} |
| }; |
| |
| /// Specialization of filter_iterator_base for bidirectional iteration. |
| template <typename WrappedIteratorT, typename PredicateT> |
| class filter_iterator_impl<WrappedIteratorT, PredicateT, |
| std::bidirectional_iterator_tag> |
| : public filter_iterator_base<WrappedIteratorT, PredicateT, |
| std::bidirectional_iterator_tag> { |
| using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, |
| std::bidirectional_iterator_tag>; |
| void findPrevValid() { |
| while (!this->Pred(*this->I)) |
| BaseT::operator--(); |
| } |
| |
| public: |
| using BaseT::operator--; |
| |
| filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End, |
| PredicateT Pred) |
| : BaseT(Begin, End, Pred) {} |
| |
| filter_iterator_impl &operator--() { |
| BaseT::operator--(); |
| findPrevValid(); |
| return *this; |
| } |
| }; |
| |
| namespace detail { |
| |
| template <bool is_bidirectional> struct fwd_or_bidi_tag_impl { |
| using type = std::forward_iterator_tag; |
| }; |
| |
| template <> struct fwd_or_bidi_tag_impl<true> { |
| using type = std::bidirectional_iterator_tag; |
| }; |
| |
| /// Helper which sets its type member to forward_iterator_tag if the category |
| /// of \p IterT does not derive from bidirectional_iterator_tag, and to |
| /// bidirectional_iterator_tag otherwise. |
| template <typename IterT> struct fwd_or_bidi_tag { |
| using type = typename fwd_or_bidi_tag_impl<std::is_base_of< |
| std::bidirectional_iterator_tag, |
| typename std::iterator_traits<IterT>::iterator_category>::value>::type; |
| }; |
| |
| } // namespace detail |
| |
| /// Defines filter_iterator to a suitable specialization of |
| /// filter_iterator_impl, based on the underlying iterator's category. |
| template <typename WrappedIteratorT, typename PredicateT> |
| using filter_iterator = filter_iterator_impl< |
| WrappedIteratorT, PredicateT, |
| typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>; |
| |
| /// Convenience function that takes a range of elements and a predicate, |
| /// and return a new filter_iterator range. |
| /// |
| /// FIXME: Currently if RangeT && is a rvalue reference to a temporary, the |
| /// lifetime of that temporary is not kept by the returned range object, and the |
| /// temporary is going to be dropped on the floor after the make_iterator_range |
| /// full expression that contains this function call. |
| template <typename RangeT, typename PredicateT> |
| iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>> |
| make_filter_range(RangeT &&Range, PredicateT Pred) { |
| using FilterIteratorT = |
| filter_iterator<detail::IterOfRange<RangeT>, PredicateT>; |
| return make_range( |
| FilterIteratorT(std::begin(std::forward<RangeT>(Range)), |
| std::end(std::forward<RangeT>(Range)), Pred), |
| FilterIteratorT(std::end(std::forward<RangeT>(Range)), |
| std::end(std::forward<RangeT>(Range)), Pred)); |
| } |
| |
| /// A pseudo-iterator adaptor that is designed to implement "early increment" |
| /// style loops. |
| /// |
| /// This is *not a normal iterator* and should almost never be used directly. It |
| /// is intended primarily to be used with range based for loops and some range |
| /// algorithms. |
| /// |
| /// The iterator isn't quite an `OutputIterator` or an `InputIterator` but |
| /// somewhere between them. The constraints of these iterators are: |
| /// |
| /// - On construction or after being incremented, it is comparable and |
| /// dereferencable. It is *not* incrementable. |
| /// - After being dereferenced, it is neither comparable nor dereferencable, it |
| /// is only incrementable. |
| /// |
| /// This means you can only dereference the iterator once, and you can only |
| /// increment it once between dereferences. |
| template <typename WrappedIteratorT> |
| class early_inc_iterator_impl |
| : public iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>, |
| WrappedIteratorT, std::input_iterator_tag> { |
| using BaseT = |
| iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>, |
| WrappedIteratorT, std::input_iterator_tag>; |
| |
| using PointerT = typename std::iterator_traits<WrappedIteratorT>::pointer; |
| |
| protected: |
| #if LLVM_ENABLE_ABI_BREAKING_CHECKS |
| bool IsEarlyIncremented = false; |
| #endif |
| |
| public: |
| early_inc_iterator_impl(WrappedIteratorT I) : BaseT(I) {} |
| |
| using BaseT::operator*; |
| decltype(*std::declval<WrappedIteratorT>()) operator*() { |
| #if LLVM_ENABLE_ABI_BREAKING_CHECKS |
| assert(!IsEarlyIncremented && "Cannot dereference twice!"); |
| IsEarlyIncremented = true; |
| #endif |
| return *(this->I)++; |
| } |
| |
| using BaseT::operator++; |
| early_inc_iterator_impl &operator++() { |
| #if LLVM_ENABLE_ABI_BREAKING_CHECKS |
| assert(IsEarlyIncremented && "Cannot increment before dereferencing!"); |
| IsEarlyIncremented = false; |
| #endif |
| return *this; |
| } |
| |
| friend bool operator==(const early_inc_iterator_impl &LHS, |
| const early_inc_iterator_impl &RHS) { |
| #if LLVM_ENABLE_ABI_BREAKING_CHECKS |
| assert(!LHS.IsEarlyIncremented && "Cannot compare after dereferencing!"); |
| #endif |
| return (const BaseT &)LHS == (const BaseT &)RHS; |
| } |
| }; |
| |
| /// Make a range that does early increment to allow mutation of the underlying |
| /// range without disrupting iteration. |
| /// |
| /// The underlying iterator will be incremented immediately after it is |
| /// dereferenced, allowing deletion of the current node or insertion of nodes to |
| /// not disrupt iteration provided they do not invalidate the *next* iterator -- |
| /// the current iterator can be invalidated. |
| /// |
| /// This requires a very exact pattern of use that is only really suitable to |
| /// range based for loops and other range algorithms that explicitly guarantee |
| /// to dereference exactly once each element, and to increment exactly once each |
| /// element. |
| template <typename RangeT> |
| iterator_range<early_inc_iterator_impl<detail::IterOfRange<RangeT>>> |
| make_early_inc_range(RangeT &&Range) { |
| using EarlyIncIteratorT = |
| early_inc_iterator_impl<detail::IterOfRange<RangeT>>; |
| return make_range(EarlyIncIteratorT(std::begin(std::forward<RangeT>(Range))), |
| EarlyIncIteratorT(std::end(std::forward<RangeT>(Range)))); |
| } |
| |
| // forward declarations required by zip_shortest/zip_first/zip_longest |
| template <typename R, typename UnaryPredicate> |
| bool all_of(R &&range, UnaryPredicate P); |
| template <typename R, typename UnaryPredicate> |
| bool any_of(R &&range, UnaryPredicate P); |
| |
| namespace detail { |
| |
| using std::declval; |
| |
| // We have to alias this since inlining the actual type at the usage site |
| // in the parameter list of iterator_facade_base<> below ICEs MSVC 2017. |
| template<typename... Iters> struct ZipTupleType { |
| using type = std::tuple<decltype(*declval<Iters>())...>; |
| }; |
| |
| template <typename ZipType, typename... Iters> |
| using zip_traits = iterator_facade_base< |
| ZipType, typename std::common_type<std::bidirectional_iterator_tag, |
| typename std::iterator_traits< |
| Iters>::iterator_category...>::type, |
| // ^ TODO: Implement random access methods. |
| typename ZipTupleType<Iters...>::type, |
| typename std::iterator_traits<typename std::tuple_element< |
| 0, std::tuple<Iters...>>::type>::difference_type, |
| // ^ FIXME: This follows boost::make_zip_iterator's assumption that all |
| // inner iterators have the same difference_type. It would fail if, for |
| // instance, the second field's difference_type were non-numeric while the |
| // first is. |
| typename ZipTupleType<Iters...>::type *, |
| typename ZipTupleType<Iters...>::type>; |
| |
| template <typename ZipType, typename... Iters> |
| struct zip_common : public zip_traits<ZipType, Iters...> { |
| using Base = zip_traits<ZipType, Iters...>; |
| using value_type = typename Base::value_type; |
| |
| std::tuple<Iters...> iterators; |
| |
| protected: |
| template <size_t... Ns> value_type deref(std::index_sequence<Ns...>) const { |
| return value_type(*std::get<Ns>(iterators)...); |
| } |
| |
| template <size_t... Ns> |
| decltype(iterators) tup_inc(std::index_sequence<Ns...>) const { |
| return std::tuple<Iters...>(std::next(std::get<Ns>(iterators))...); |
| } |
| |
| template <size_t... Ns> |
| decltype(iterators) tup_dec(std::index_sequence<Ns...>) const { |
| return std::tuple<Iters...>(std::prev(std::get<Ns>(iterators))...); |
| } |
| |
| public: |
| zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {} |
| |
| value_type operator*() { return deref(std::index_sequence_for<Iters...>{}); } |
| |
| const value_type operator*() const { |
| return deref(std::index_sequence_for<Iters...>{}); |
| } |
| |
| ZipType &operator++() { |
| iterators = tup_inc(std::index_sequence_for<Iters...>{}); |
| return *reinterpret_cast<ZipType *>(this); |
| } |
| |
| ZipType &operator--() { |
| static_assert(Base::IsBidirectional, |
| "All inner iterators must be at least bidirectional."); |
| iterators = tup_dec(std::index_sequence_for<Iters...>{}); |
| return *reinterpret_cast<ZipType *>(this); |
| } |
| }; |
| |
| template <typename... Iters> |
| struct zip_first : public zip_common<zip_first<Iters...>, Iters...> { |
| using Base = zip_common<zip_first<Iters...>, Iters...>; |
| |
| bool operator==(const zip_first<Iters...> &other) const { |
| return std::get<0>(this->iterators) == std::get<0>(other.iterators); |
| } |
| |
| zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {} |
| }; |
| |
| template <typename... Iters> |
| class zip_shortest : public zip_common<zip_shortest<Iters...>, Iters...> { |
| template <size_t... Ns> |
| bool test(const zip_shortest<Iters...> &other, |
| std::index_sequence<Ns...>) const { |
| return all_of(std::initializer_list<bool>{std::get<Ns>(this->iterators) != |
| std::get<Ns>(other.iterators)...}, |
| identity<bool>{}); |
| } |
| |
| public: |
| using Base = zip_common<zip_shortest<Iters...>, Iters...>; |
| |
| zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {} |
| |
| bool operator==(const zip_shortest<Iters...> &other) const { |
| return !test(other, std::index_sequence_for<Iters...>{}); |
| } |
| }; |
| |
| template <template <typename...> class ItType, typename... Args> class zippy { |
| public: |
| using iterator = ItType<decltype(std::begin(std::declval<Args>()))...>; |
| using iterator_category = typename iterator::iterator_category; |
| using value_type = typename iterator::value_type; |
| using difference_type = typename iterator::difference_type; |
| using pointer = typename iterator::pointer; |
| using reference = typename iterator::reference; |
| |
| private: |
| std::tuple<Args...> ts; |
| |
| template <size_t... Ns> |
| iterator begin_impl(std::index_sequence<Ns...>) const { |
| return iterator(std::begin(std::get<Ns>(ts))...); |
| } |
| template <size_t... Ns> iterator end_impl(std::index_sequence<Ns...>) const { |
| return iterator(std::end(std::get<Ns>(ts))...); |
| } |
| |
| public: |
| zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {} |
| |
| iterator begin() const { |
| return begin_impl(std::index_sequence_for<Args...>{}); |
| } |
| iterator end() const { return end_impl(std::index_sequence_for<Args...>{}); } |
| }; |
| |
| } // end namespace detail |
| |
| /// zip iterator for two or more iteratable types. |
| template <typename T, typename U, typename... Args> |
| detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u, |
| Args &&... args) { |
| return detail::zippy<detail::zip_shortest, T, U, Args...>( |
| std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...); |
| } |
| |
| /// zip iterator that, for the sake of efficiency, assumes the first iteratee to |
| /// be the shortest. |
| template <typename T, typename U, typename... Args> |
| detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u, |
| Args &&... args) { |
| return detail::zippy<detail::zip_first, T, U, Args...>( |
| std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...); |
| } |
| |
| namespace detail { |
| template <typename Iter> |
| Iter next_or_end(const Iter &I, const Iter &End) { |
| if (I == End) |
| return End; |
| return std::next(I); |
| } |
| |
| template <typename Iter> |
| auto deref_or_none(const Iter &I, const Iter &End) -> llvm::Optional< |
| std::remove_const_t<std::remove_reference_t<decltype(*I)>>> { |
| if (I == End) |
| return None; |
| return *I; |
| } |
| |
| template <typename Iter> struct ZipLongestItemType { |
| using type = |
| llvm::Optional<typename std::remove_const<typename std::remove_reference< |
| decltype(*std::declval<Iter>())>::type>::type>; |
| }; |
| |
| template <typename... Iters> struct ZipLongestTupleType { |
| using type = std::tuple<typename ZipLongestItemType<Iters>::type...>; |
| }; |
| |
| template <typename... Iters> |
| class zip_longest_iterator |
| : public iterator_facade_base< |
| zip_longest_iterator<Iters...>, |
| typename std::common_type< |
| std::forward_iterator_tag, |
| typename std::iterator_traits<Iters>::iterator_category...>::type, |
| typename ZipLongestTupleType<Iters...>::type, |
| typename std::iterator_traits<typename std::tuple_element< |
| 0, std::tuple<Iters...>>::type>::difference_type, |
| typename ZipLongestTupleType<Iters...>::type *, |
| typename ZipLongestTupleType<Iters...>::type> { |
| public: |
| using value_type = typename ZipLongestTupleType<Iters...>::type; |
| |
| private: |
| std::tuple<Iters...> iterators; |
| std::tuple<Iters...> end_iterators; |
| |
| template <size_t... Ns> |
| bool test(const zip_longest_iterator<Iters...> &other, |
| std::index_sequence<Ns...>) const { |
| return llvm::any_of( |
| std::initializer_list<bool>{std::get<Ns>(this->iterators) != |
| std::get<Ns>(other.iterators)...}, |
| identity<bool>{}); |
| } |
| |
| template <size_t... Ns> value_type deref(std::index_sequence<Ns...>) const { |
| return value_type( |
| deref_or_none(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...); |
| } |
| |
| template <size_t... Ns> |
| decltype(iterators) tup_inc(std::index_sequence<Ns...>) const { |
| return std::tuple<Iters...>( |
| next_or_end(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...); |
| } |
| |
| public: |
| zip_longest_iterator(std::pair<Iters &&, Iters &&>... ts) |
| : iterators(std::forward<Iters>(ts.first)...), |
| end_iterators(std::forward<Iters>(ts.second)...) {} |
| |
| value_type operator*() { return deref(std::index_sequence_for<Iters...>{}); } |
| |
| value_type operator*() const { |
| return deref(std::index_sequence_for<Iters...>{}); |
| } |
| |
| zip_longest_iterator<Iters...> &operator++() { |
| iterators = tup_inc(std::index_sequence_for<Iters...>{}); |
| return *this; |
| } |
| |
| bool operator==(const zip_longest_iterator<Iters...> &other) const { |
| return !test(other, std::index_sequence_for<Iters...>{}); |
| } |
| }; |
| |
| template <typename... Args> class zip_longest_range { |
| public: |
| using iterator = |
| zip_longest_iterator<decltype(adl_begin(std::declval<Args>()))...>; |
| using iterator_category = typename iterator::iterator_category; |
| using value_type = typename iterator::value_type; |
| using difference_type = typename iterator::difference_type; |
| using pointer = typename iterator::pointer; |
| using reference = typename iterator::reference; |
| |
| private: |
| std::tuple<Args...> ts; |
| |
| template <size_t... Ns> |
| iterator begin_impl(std::index_sequence<Ns...>) const { |
| return iterator(std::make_pair(adl_begin(std::get<Ns>(ts)), |
| adl_end(std::get<Ns>(ts)))...); |
| } |
| |
| template <size_t... Ns> iterator end_impl(std::index_sequence<Ns...>) const { |
| return iterator(std::make_pair(adl_end(std::get<Ns>(ts)), |
| adl_end(std::get<Ns>(ts)))...); |
| } |
| |
| public: |
| zip_longest_range(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {} |
| |
| iterator begin() const { |
| return begin_impl(std::index_sequence_for<Args...>{}); |
| } |
| iterator end() const { return end_impl(std::index_sequence_for<Args...>{}); } |
| }; |
| } // namespace detail |
| |
| /// Iterate over two or more iterators at the same time. Iteration continues |
| /// until all iterators reach the end. The llvm::Optional only contains a value |
| /// if the iterator has not reached the end. |
| template <typename T, typename U, typename... Args> |
| detail::zip_longest_range<T, U, Args...> zip_longest(T &&t, U &&u, |
| Args &&... args) { |
| return detail::zip_longest_range<T, U, Args...>( |
| std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...); |
| } |
| |
| /// Iterator wrapper that concatenates sequences together. |
| /// |
| /// This can concatenate different iterators, even with different types, into |
| /// a single iterator provided the value types of all the concatenated |
| /// iterators expose `reference` and `pointer` types that can be converted to |
| /// `ValueT &` and `ValueT *` respectively. It doesn't support more |
| /// interesting/customized pointer or reference types. |
| /// |
| /// Currently this only supports forward or higher iterator categories as |
| /// inputs and always exposes a forward iterator interface. |
| template <typename ValueT, typename... IterTs> |
| class concat_iterator |
| : public iterator_facade_base<concat_iterator<ValueT, IterTs...>, |
| std::forward_iterator_tag, ValueT> { |
| using BaseT = typename concat_iterator::iterator_facade_base; |
| |
| /// We store both the current and end iterators for each concatenated |
| /// sequence in a tuple of pairs. |
| /// |
| /// Note that something like iterator_range seems nice at first here, but the |
| /// range properties are of little benefit and end up getting in the way |
| /// because we need to do mutation on the current iterators. |
| std::tuple<IterTs...> Begins; |
| std::tuple<IterTs...> Ends; |
| |
| /// Attempts to increment a specific iterator. |
| /// |
| /// Returns true if it was able to increment the iterator. Returns false if |
| /// the iterator is already at the end iterator. |
| template <size_t Index> bool incrementHelper() { |
| auto &Begin = std::get<Index>(Begins); |
| auto &End = std::get<Index>(Ends); |
| if (Begin == End) |
| return false; |
| |
| ++Begin; |
| return true; |
| } |
| |
| /// Increments the first non-end iterator. |
| /// |
| /// It is an error to call this with all iterators at the end. |
| template <size_t... Ns> void increment(std::index_sequence<Ns...>) { |
| // Build a sequence of functions to increment each iterator if possible. |
| bool (concat_iterator::*IncrementHelperFns[])() = { |
| &concat_iterator::incrementHelper<Ns>...}; |
| |
| // Loop over them, and stop as soon as we succeed at incrementing one. |
| for (auto &IncrementHelperFn : IncrementHelperFns) |
| if ((this->*IncrementHelperFn)()) |
| return; |
| |
| llvm_unreachable("Attempted to increment an end concat iterator!"); |
| } |
| |
| /// Returns null if the specified iterator is at the end. Otherwise, |
| /// dereferences the iterator and returns the address of the resulting |
| /// reference. |
| template <size_t Index> ValueT *getHelper() const { |
| auto &Begin = std::get<Index>(Begins); |
| auto &End = std::get<Index>(Ends); |
| if (Begin == End) |
| return nullptr; |
| |
| return &*Begin; |
| } |
| |
| /// Finds the first non-end iterator, dereferences, and returns the resulting |
| /// reference. |
| /// |
| /// It is an error to call this with all iterators at the end. |
| template <size_t... Ns> ValueT &get(std::index_sequence<Ns...>) const { |
| // Build a sequence of functions to get from iterator if possible. |
| ValueT *(concat_iterator::*GetHelperFns[])() const = { |
| &concat_iterator::getHelper<Ns>...}; |
| |
| // Loop over them, and return the first result we find. |
| for (auto &GetHelperFn : GetHelperFns) |
| if (ValueT *P = (this->*GetHelperFn)()) |
| return *P; |
| |
| llvm_unreachable("Attempted to get a pointer from an end concat iterator!"); |
| } |
| |
| public: |
| /// Constructs an iterator from a sequence of ranges. |
| /// |
| /// We need the full range to know how to switch between each of the |
| /// iterators. |
| template <typename... RangeTs> |
| explicit concat_iterator(RangeTs &&... Ranges) |
| : Begins(std::begin(Ranges)...), Ends(std::end(Ranges)...) {} |
| |
| using BaseT::operator++; |
| |
| concat_iterator &operator++() { |
| increment(std::index_sequence_for<IterTs...>()); |
| return *this; |
| } |
| |
| ValueT &operator*() const { |
| return get(std::index_sequence_for<IterTs...>()); |
| } |
| |
| bool operator==(const concat_iterator &RHS) const { |
| return Begins == RHS.Begins && Ends == RHS.Ends; |
| } |
| }; |
| |
| namespace detail { |
| |
| /// Helper to store a sequence of ranges being concatenated and access them. |
| /// |
| /// This is designed to facilitate providing actual storage when temporaries |
| /// are passed into the constructor such that we can use it as part of range |
| /// based for loops. |
| template <typename ValueT, typename... RangeTs> class concat_range { |
| public: |
| using iterator = |
| concat_iterator<ValueT, |
| decltype(std::begin(std::declval<RangeTs &>()))...>; |
| |
| private: |
| std::tuple<RangeTs...> Ranges; |
| |
| template <size_t... Ns> iterator begin_impl(std::index_sequence<Ns...>) { |
| return iterator(std::get<Ns>(Ranges)...); |
| } |
| template <size_t... Ns> iterator end_impl(std::index_sequence<Ns...>) { |
| return iterator(make_range(std::end(std::get<Ns>(Ranges)), |
| std::end(std::get<Ns>(Ranges)))...); |
| } |
| |
| public: |
| concat_range(RangeTs &&... Ranges) |
| : Ranges(std::forward<RangeTs>(Ranges)...) {} |
| |
| iterator begin() { return begin_impl(std::index_sequence_for<RangeTs...>{}); } |
| iterator end() { return end_impl(std::index_sequence_for<RangeTs...>{}); } |
| }; |
| |
| } // end namespace detail |
| |
| /// Concatenated range across two or more ranges. |
| /// |
| /// The desired value type must be explicitly specified. |
| template <typename ValueT, typename... RangeTs> |
| detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) { |
| static_assert(sizeof...(RangeTs) > 1, |
| "Need more than one range to concatenate!"); |
| return detail::concat_range<ValueT, RangeTs...>( |
| std::forward<RangeTs>(Ranges)...); |
| } |
| |
| /// A utility class used to implement an iterator that contains some base object |
| /// and an index. The iterator moves the index but keeps the base constant. |
| template <typename DerivedT, typename BaseT, typename T, |
| typename PointerT = T *, typename ReferenceT = T &> |
| class indexed_accessor_iterator |
| : public llvm::iterator_facade_base<DerivedT, |
| std::random_access_iterator_tag, T, |
| std::ptrdiff_t, PointerT, ReferenceT> { |
| public: |
| ptrdiff_t operator-(const indexed_accessor_iterator &rhs) const { |
| assert(base == rhs.base && "incompatible iterators"); |
| return index - rhs.index; |
| } |
| bool operator==(const indexed_accessor_iterator &rhs) const { |
| return base == rhs.base && index == rhs.index; |
| } |
| bool operator<(const indexed_accessor_iterator &rhs) const { |
| assert(base == rhs.base && "incompatible iterators"); |
| return index < rhs.index; |
| } |
| |
| DerivedT &operator+=(ptrdiff_t offset) { |
| this->index += offset; |
| return static_cast<DerivedT &>(*this); |
| } |
| DerivedT &operator-=(ptrdiff_t offset) { |
| this->index -= offset; |
| return static_cast<DerivedT &>(*this); |
| } |
| |
| /// Returns the current index of the iterator. |
| ptrdiff_t getIndex() const { return index; } |
| |
| /// Returns the current base of the iterator. |
| const BaseT &getBase() const { return base; } |
| |
| protected: |
| indexed_accessor_iterator(BaseT base, ptrdiff_t index) |
| : base(base), index(index) {} |
| BaseT base; |
| ptrdiff_t index; |
| }; |
| |
| namespace detail { |
| /// The class represents the base of a range of indexed_accessor_iterators. It |
| /// provides support for many different range functionalities, e.g. |
| /// drop_front/slice/etc.. Derived range classes must implement the following |
| /// static methods: |
| /// * ReferenceT dereference_iterator(const BaseT &base, ptrdiff_t index) |
| /// - Dereference an iterator pointing to the base object at the given |
| /// index. |
| /// * BaseT offset_base(const BaseT &base, ptrdiff_t index) |
| /// - Return a new base that is offset from the provide base by 'index' |
| /// elements. |
| template <typename DerivedT, typename BaseT, typename T, |
| typename PointerT = T *, typename ReferenceT = T &> |
| class indexed_accessor_range_base { |
| public: |
| using RangeBaseT = |
| indexed_accessor_range_base<DerivedT, BaseT, T, PointerT, ReferenceT>; |
| |
| /// An iterator element of this range. |
| class iterator : public indexed_accessor_iterator<iterator, BaseT, T, |
| PointerT, ReferenceT> { |
| public: |
| // Index into this iterator, invoking a static method on the derived type. |
| ReferenceT operator*() const { |
| return DerivedT::dereference_iterator(this->getBase(), this->getIndex()); |
| } |
| |
| private: |
| iterator(BaseT owner, ptrdiff_t curIndex) |
| : indexed_accessor_iterator<iterator, BaseT, T, PointerT, ReferenceT>( |
| owner, curIndex) {} |
| |
| /// Allow access to the constructor. |
| friend indexed_accessor_range_base<DerivedT, BaseT, T, PointerT, |
| ReferenceT>; |
| }; |
| |
| indexed_accessor_range_base(iterator begin, iterator end) |
| : base(offset_base(begin.getBase(), begin.getIndex())), |
| count(end.getIndex() - begin.getIndex()) {} |
| indexed_accessor_range_base(const iterator_range<iterator> &range) |
| : indexed_accessor_range_base(range.begin(), range.end()) {} |
| indexed_accessor_range_base(BaseT base, ptrdiff_t count) |
| : base(base), count(count) {} |
| |
| iterator begin() const { return iterator(base, 0); } |
| iterator end() const { return iterator(base, count); } |
| ReferenceT operator[](size_t Index) const { |
| assert(Index < size() && "invalid index for value range"); |
| return DerivedT::dereference_iterator(base, static_cast<ptrdiff_t>(Index)); |
| } |
| ReferenceT front() const { |
| assert(!empty() && "expected non-empty range"); |
| return (*this)[0]; |
| } |
| ReferenceT back() const { |
| assert(!empty() && "expected non-empty range"); |
| return (*this)[size() - 1]; |
| } |
| |
| /// Compare this range with another. |
| template <typename OtherT> bool operator==(const OtherT &other) const { |
| return size() == |
| static_cast<size_t>(std::distance(other.begin(), other.end())) && |
| std::equal(begin(), end(), other.begin()); |
| } |
| template <typename OtherT> bool operator!=(const OtherT &other) const { |
| return !(*this == other); |
| } |
| |
| /// Return the size of this range. |
| size_t size() const { return count; } |
| |
| /// Return if the range is empty. |
| bool empty() const { return size() == 0; } |
| |
| /// Drop the first N elements, and keep M elements. |
| DerivedT slice(size_t n, size_t m) const { |
| assert(n + m <= size() && "invalid size specifiers"); |
| return DerivedT(offset_base(base, n), m); |
| } |
| |
| /// Drop the first n elements. |
| DerivedT drop_front(size_t n = 1) const { |
| assert(size() >= n && "Dropping more elements than exist"); |
| return slice(n, size() - n); |
| } |
| /// Drop the last n elements. |
| DerivedT drop_back(size_t n = 1) const { |
| assert(size() >= n && "Dropping more elements than exist"); |
| return DerivedT(base, size() - n); |
| } |
| |
| /// Take the first n elements. |
| DerivedT take_front(size_t n = 1) const { |
| return n < size() ? drop_back(size() - n) |
| : static_cast<const DerivedT &>(*this); |
| } |
| |
| /// Take the last n elements. |
| DerivedT take_back(size_t n = 1) const { |
| return n < size() ? drop_front(size() - n) |
| : static_cast<const DerivedT &>(*this); |
| } |
| |
| /// Allow conversion to any type accepting an iterator_range. |
| template <typename RangeT, typename = std::enable_if_t<std::is_constructible< |
| RangeT, iterator_range<iterator>>::value>> |
| operator RangeT() const { |
| return RangeT(iterator_range<iterator>(*this)); |
| } |
| |
| /// Returns the base of this range. |
| const BaseT &getBase() const { return base; } |
| |
| private: |
| /// Offset the given base by the given amount. |
| static BaseT offset_base(const BaseT &base, size_t n) { |
| return n == 0 ? base : DerivedT::offset_base(base, n); |
| } |
| |
| protected: |
| indexed_accessor_range_base(const indexed_accessor_range_base &) = default; |
| indexed_accessor_range_base(indexed_accessor_range_base &&) = default; |
| indexed_accessor_range_base & |
| operator=(const indexed_accessor_range_base &) = default; |
| |
| /// The base that owns the provided range of values. |
| BaseT base; |
| /// The size from the owning range. |
| ptrdiff_t count; |
| }; |
| } // end namespace detail |
| |
| /// This class provides an implementation of a range of |
| /// indexed_accessor_iterators where the base is not indexable. Ranges with |
| /// bases that are offsetable should derive from indexed_accessor_range_base |
| /// instead. Derived range classes are expected to implement the following |
| /// static method: |
| /// * ReferenceT dereference(const BaseT &base, ptrdiff_t index) |
| /// - Dereference an iterator pointing to a parent base at the given index. |
| template <typename DerivedT, typename BaseT, typename T, |
| typename PointerT = T *, typename ReferenceT = T &> |
| class indexed_accessor_range |
| : public detail::indexed_accessor_range_base< |
| DerivedT, std::pair<BaseT, ptrdiff_t>, T, PointerT, ReferenceT> { |
| public: |
| indexed_accessor_range(BaseT base, ptrdiff_t startIndex, ptrdiff_t count) |
| : detail::indexed_accessor_range_base< |
| DerivedT, std::pair<BaseT, ptrdiff_t>, T, PointerT, ReferenceT>( |
| std::make_pair(base, startIndex), count) {} |
| using detail::indexed_accessor_range_base< |
| DerivedT, std::pair<BaseT, ptrdiff_t>, T, PointerT, |
| ReferenceT>::indexed_accessor_range_base; |
| |
| /// Returns the current base of the range. |
| const BaseT &getBase() const { return this->base.first; } |
| |
| /// Returns the current start index of the range. |
| ptrdiff_t getStartIndex() const { return this->base.second; } |
| |
| /// See `detail::indexed_accessor_range_base` for details. |
| static std::pair<BaseT, ptrdiff_t> |
| offset_base(const std::pair<BaseT, ptrdiff_t> &base, ptrdiff_t index) { |
| // We encode the internal base as a pair of the derived base and a start |
| // index into the derived base. |
| return std::make_pair(base.first, base.second + index); |
| } |
| /// See `detail::indexed_accessor_range_base` for details. |
| static ReferenceT |
| dereference_iterator(const std::pair<BaseT, ptrdiff_t> &base, |
| ptrdiff_t index) { |
| return DerivedT::dereference(base.first, base.second + index); |
| } |
| }; |
| |
| /// Given a container of pairs, return a range over the first elements. |
| template <typename ContainerTy> auto make_first_range(ContainerTy &&c) { |
| return llvm::map_range( |
| std::forward<ContainerTy>(c), |
| [](decltype((*std::begin(c))) elt) -> decltype((elt.first)) { |
| return elt.first; |
| }); |
| } |
| |
| /// Given a container of pairs, return a range over the second elements. |
| template <typename ContainerTy> auto make_second_range(ContainerTy &&c) { |
| return llvm::map_range( |
| std::forward<ContainerTy>(c), |
| [](decltype((*std::begin(c))) elt) -> decltype((elt.second)) { |
| return elt.second; |
| }); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <utility> |
| //===----------------------------------------------------------------------===// |
| |
| /// Function object to check whether the first component of a std::pair |
| /// compares less than the first component of another std::pair. |
| struct less_first { |
| template <typename T> bool operator()(const T &lhs, const T &rhs) const { |
| return lhs.first < rhs.first; |
| } |
| }; |
| |
| /// Function object to check whether the second component of a std::pair |
| /// compares less than the second component of another std::pair. |
| struct less_second { |
| template <typename T> bool operator()(const T &lhs, const T &rhs) const { |
| return lhs.second < rhs.second; |
| } |
| }; |
| |
| /// \brief Function object to apply a binary function to the first component of |
| /// a std::pair. |
| template<typename FuncTy> |
| struct on_first { |
| FuncTy func; |
| |
| template <typename T> |
| decltype(auto) operator()(const T &lhs, const T &rhs) const { |
| return func(lhs.first, rhs.first); |
| } |
| }; |
| |
| /// Utility type to build an inheritance chain that makes it easy to rank |
| /// overload candidates. |
| template <int N> struct rank : rank<N - 1> {}; |
| template <> struct rank<0> {}; |
| |
| /// traits class for checking whether type T is one of any of the given |
| /// types in the variadic list. |
| template <typename T, typename... Ts> |
| using is_one_of = disjunction<std::is_same<T, Ts>...>; |
| |
| /// traits class for checking whether type T is a base class for all |
| /// the given types in the variadic list. |
| template <typename T, typename... Ts> |
| using are_base_of = conjunction<std::is_base_of<T, Ts>...>; |
| |
| namespace detail { |
| template <typename... Ts> struct Visitor; |
| |
| template <typename HeadT, typename... TailTs> |
| struct Visitor<HeadT, TailTs...> : remove_cvref_t<HeadT>, Visitor<TailTs...> { |
| explicit constexpr Visitor(HeadT &&Head, TailTs &&...Tail) |
| : remove_cvref_t<HeadT>(std::forward<HeadT>(Head)), |
| Visitor<TailTs...>(std::forward<TailTs>(Tail)...) {} |
| using remove_cvref_t<HeadT>::operator(); |
| using Visitor<TailTs...>::operator(); |
| }; |
| |
| template <typename HeadT> struct Visitor<HeadT> : remove_cvref_t<HeadT> { |
| explicit constexpr Visitor(HeadT &&Head) |
| : remove_cvref_t<HeadT>(std::forward<HeadT>(Head)) {} |
| using remove_cvref_t<HeadT>::operator(); |
| }; |
| } // namespace detail |
| |
| /// Returns an opaquely-typed Callable object whose operator() overload set is |
| /// the sum of the operator() overload sets of each CallableT in CallableTs. |
| /// |
| /// The type of the returned object derives from each CallableT in CallableTs. |
| /// The returned object is constructed by invoking the appropriate copy or move |
| /// constructor of each CallableT, as selected by overload resolution on the |
| /// corresponding argument to makeVisitor. |
| /// |
| /// Example: |
| /// |
| /// \code |
| /// auto visitor = makeVisitor([](auto) { return "unhandled type"; }, |
| /// [](int i) { return "int"; }, |
| /// [](std::string s) { return "str"; }); |
| /// auto a = visitor(42); // `a` is now "int". |
| /// auto b = visitor("foo"); // `b` is now "str". |
| /// auto c = visitor(3.14f); // `c` is now "unhandled type". |
| /// \endcode |
| /// |
| /// Example of making a visitor with a lambda which captures a move-only type: |
| /// |
| /// \code |
| /// std::unique_ptr<FooHandler> FH = /* ... */; |
| /// auto visitor = makeVisitor( |
| /// [FH{std::move(FH)}](Foo F) { return FH->handle(F); }, |
| /// [](int i) { return i; }, |
| /// [](std::string s) { return atoi(s); }); |
| /// \endcode |
| template <typename... CallableTs> |
| constexpr decltype(auto) makeVisitor(CallableTs &&...Callables) { |
| return detail::Visitor<CallableTs...>(std::forward<CallableTs>(Callables)...); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions for arrays |
| //===----------------------------------------------------------------------===// |
| |
| // We have a copy here so that LLVM behaves the same when using different |
| // standard libraries. |
| template <class Iterator, class RNG> |
| void shuffle(Iterator first, Iterator last, RNG &&g) { |
| // It would be better to use a std::uniform_int_distribution, |
| // but that would be stdlib dependent. |
| typedef |
| typename std::iterator_traits<Iterator>::difference_type difference_type; |
| for (auto size = last - first; size > 1; ++first, (void)--size) { |
| difference_type offset = g() % size; |
| // Avoid self-assignment due to incorrect assertions in libstdc++ |
| // containers (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85828). |
| if (offset != difference_type(0)) |
| std::iter_swap(first, first + offset); |
| } |
| } |
| |
| /// Find the length of an array. |
| template <class T, std::size_t N> |
| constexpr inline size_t array_lengthof(T (&)[N]) { |
| return N; |
| } |
| |
| /// Adapt std::less<T> for array_pod_sort. |
| template<typename T> |
| inline int array_pod_sort_comparator(const void *P1, const void *P2) { |
| if (std::less<T>()(*reinterpret_cast<const T*>(P1), |
| *reinterpret_cast<const T*>(P2))) |
| return -1; |
| if (std::less<T>()(*reinterpret_cast<const T*>(P2), |
| *reinterpret_cast<const T*>(P1))) |
| return 1; |
| return 0; |
| } |
| |
| /// get_array_pod_sort_comparator - This is an internal helper function used to |
| /// get type deduction of T right. |
| template<typename T> |
| inline int (*get_array_pod_sort_comparator(const T &)) |
| (const void*, const void*) { |
| return array_pod_sort_comparator<T>; |
| } |
| |
| #ifdef EXPENSIVE_CHECKS |
| namespace detail { |
| |
| inline unsigned presortShuffleEntropy() { |
| static unsigned Result(std::random_device{}()); |
| return Result; |
| } |
| |
| template <class IteratorTy> |
| inline void presortShuffle(IteratorTy Start, IteratorTy End) { |
| std::mt19937 Generator(presortShuffleEntropy()); |
| llvm::shuffle(Start, End, Generator); |
| } |
| |
| } // end namespace detail |
| #endif |
| |
| /// array_pod_sort - This sorts an array with the specified start and end |
| /// extent. This is just like std::sort, except that it calls qsort instead of |
| /// using an inlined template. qsort is slightly slower than std::sort, but |
| /// most sorts are not performance critical in LLVM and std::sort has to be |
| /// template instantiated for each type, leading to significant measured code |
| /// bloat. This function should generally be used instead of std::sort where |
| /// possible. |
| /// |
| /// This function assumes that you have simple POD-like types that can be |
| /// compared with std::less and can be moved with memcpy. If this isn't true, |
| /// you should use std::sort. |
| /// |
| /// NOTE: If qsort_r were portable, we could allow a custom comparator and |
| /// default to std::less. |
| template<class IteratorTy> |
| inline void array_pod_sort(IteratorTy Start, IteratorTy End) { |
| // Don't inefficiently call qsort with one element or trigger undefined |
| // behavior with an empty sequence. |
| auto NElts = End - Start; |
| if (NElts <= 1) return; |
| #ifdef EXPENSIVE_CHECKS |
| detail::presortShuffle<IteratorTy>(Start, End); |
| #endif |
| qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start)); |
| } |
| |
| template <class IteratorTy> |
| inline void array_pod_sort( |
| IteratorTy Start, IteratorTy End, |
| int (*Compare)( |
| const typename std::iterator_traits<IteratorTy>::value_type *, |
| const typename std::iterator_traits<IteratorTy>::value_type *)) { |
| // Don't inefficiently call qsort with one element or trigger undefined |
| // behavior with an empty sequence. |
| auto NElts = End - Start; |
| if (NElts <= 1) return; |
| #ifdef EXPENSIVE_CHECKS |
| detail::presortShuffle<IteratorTy>(Start, End); |
| #endif |
| qsort(&*Start, NElts, sizeof(*Start), |
| reinterpret_cast<int (*)(const void *, const void *)>(Compare)); |
| } |
| |
| namespace detail { |
| template <typename T> |
| // We can use qsort if the iterator type is a pointer and the underlying value |
| // is trivially copyable. |
| using sort_trivially_copyable = conjunction< |
| std::is_pointer<T>, |
| std::is_trivially_copyable<typename std::iterator_traits<T>::value_type>>; |
| } // namespace detail |
| |
| // Provide wrappers to std::sort which shuffle the elements before sorting |
| // to help uncover non-deterministic behavior (PR35135). |
| template <typename IteratorTy, |
| std::enable_if_t<!detail::sort_trivially_copyable<IteratorTy>::value, |
| int> = 0> |
| inline void sort(IteratorTy Start, IteratorTy End) { |
| #ifdef EXPENSIVE_CHECKS |
| detail::presortShuffle<IteratorTy>(Start, End); |
| #endif |
| std::sort(Start, End); |
| } |
| |
| // Forward trivially copyable types to array_pod_sort. This avoids a large |
| // amount of code bloat for a minor performance hit. |
| template <typename IteratorTy, |
| std::enable_if_t<detail::sort_trivially_copyable<IteratorTy>::value, |
| int> = 0> |
| inline void sort(IteratorTy Start, IteratorTy End) { |
| array_pod_sort(Start, End); |
| } |
| |
| template <typename Container> inline void sort(Container &&C) { |
| llvm::sort(adl_begin(C), adl_end(C)); |
| } |
| |
| template <typename IteratorTy, typename Compare> |
| inline void sort(IteratorTy Start, IteratorTy End, Compare Comp) { |
| #ifdef EXPENSIVE_CHECKS |
| detail::presortShuffle<IteratorTy>(Start, End); |
| #endif |
| std::sort(Start, End, Comp); |
| } |
| |
| template <typename Container, typename Compare> |
| inline void sort(Container &&C, Compare Comp) { |
| llvm::sort(adl_begin(C), adl_end(C), Comp); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <algorithm> |
| //===----------------------------------------------------------------------===// |
| |
| /// Get the size of a range. This is a wrapper function around std::distance |
| /// which is only enabled when the operation is O(1). |
| template <typename R> |
| auto size(R &&Range, |
| std::enable_if_t< |
| std::is_base_of<std::random_access_iterator_tag, |
| typename std::iterator_traits<decltype( |
| Range.begin())>::iterator_category>::value, |
| void> * = nullptr) { |
| return std::distance(Range.begin(), Range.end()); |
| } |
| |
| /// Provide wrappers to std::for_each which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename UnaryFunction> |
| UnaryFunction for_each(R &&Range, UnaryFunction F) { |
| return std::for_each(adl_begin(Range), adl_end(Range), F); |
| } |
| |
| /// Provide wrappers to std::all_of which take ranges instead of having to pass |
| /// begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| bool all_of(R &&Range, UnaryPredicate P) { |
| return std::all_of(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::any_of which take ranges instead of having to pass |
| /// begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| bool any_of(R &&Range, UnaryPredicate P) { |
| return std::any_of(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::none_of which take ranges instead of having to pass |
| /// begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| bool none_of(R &&Range, UnaryPredicate P) { |
| return std::none_of(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::find which take ranges instead of having to pass |
| /// begin/end explicitly. |
| template <typename R, typename T> auto find(R &&Range, const T &Val) { |
| return std::find(adl_begin(Range), adl_end(Range), Val); |
| } |
| |
| /// Provide wrappers to std::find_if which take ranges instead of having to pass |
| /// begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| auto find_if(R &&Range, UnaryPredicate P) { |
| return std::find_if(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| template <typename R, typename UnaryPredicate> |
| auto find_if_not(R &&Range, UnaryPredicate P) { |
| return std::find_if_not(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::remove_if which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| auto remove_if(R &&Range, UnaryPredicate P) { |
| return std::remove_if(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::copy_if which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename OutputIt, typename UnaryPredicate> |
| OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) { |
| return std::copy_if(adl_begin(Range), adl_end(Range), Out, P); |
| } |
| |
| template <typename R, typename OutputIt> |
| OutputIt copy(R &&Range, OutputIt Out) { |
| return std::copy(adl_begin(Range), adl_end(Range), Out); |
| } |
| |
| /// Provide wrappers to std::move which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename OutputIt> |
| OutputIt move(R &&Range, OutputIt Out) { |
| return std::move(adl_begin(Range), adl_end(Range), Out); |
| } |
| |
| /// Wrapper function around std::find to detect if an element exists |
| /// in a container. |
| template <typename R, typename E> |
| bool is_contained(R &&Range, const E &Element) { |
| return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range); |
| } |
| |
| /// Wrapper function around std::is_sorted to check if elements in a range \p R |
| /// are sorted with respect to a comparator \p C. |
| template <typename R, typename Compare> bool is_sorted(R &&Range, Compare C) { |
| return std::is_sorted(adl_begin(Range), adl_end(Range), C); |
| } |
| |
| /// Wrapper function around std::is_sorted to check if elements in a range \p R |
| /// are sorted in non-descending order. |
| template <typename R> bool is_sorted(R &&Range) { |
| return std::is_sorted(adl_begin(Range), adl_end(Range)); |
| } |
| |
| /// Wrapper function around std::count to count the number of times an element |
| /// \p Element occurs in the given range \p Range. |
| template <typename R, typename E> auto count(R &&Range, const E &Element) { |
| return std::count(adl_begin(Range), adl_end(Range), Element); |
| } |
| |
| /// Wrapper function around std::count_if to count the number of times an |
| /// element satisfying a given predicate occurs in a range. |
| template <typename R, typename UnaryPredicate> |
| auto count_if(R &&Range, UnaryPredicate P) { |
| return std::count_if(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Wrapper function around std::transform to apply a function to a range and |
| /// store the result elsewhere. |
| template <typename R, typename OutputIt, typename UnaryFunction> |
| OutputIt transform(R &&Range, OutputIt d_first, UnaryFunction F) { |
| return std::transform(adl_begin(Range), adl_end(Range), d_first, F); |
| } |
| |
| /// Provide wrappers to std::partition which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename UnaryPredicate> |
| auto partition(R &&Range, UnaryPredicate P) { |
| return std::partition(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| /// Provide wrappers to std::lower_bound which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename T> auto lower_bound(R &&Range, T &&Value) { |
| return std::lower_bound(adl_begin(Range), adl_end(Range), |
| std::forward<T>(Value)); |
| } |
| |
| template <typename R, typename T, typename Compare> |
| auto lower_bound(R &&Range, T &&Value, Compare C) { |
| return std::lower_bound(adl_begin(Range), adl_end(Range), |
| std::forward<T>(Value), C); |
| } |
| |
| /// Provide wrappers to std::upper_bound which take ranges instead of having to |
| /// pass begin/end explicitly. |
| template <typename R, typename T> auto upper_bound(R &&Range, T &&Value) { |
| return std::upper_bound(adl_begin(Range), adl_end(Range), |
| std::forward<T>(Value)); |
| } |
| |
| template <typename R, typename T, typename Compare> |
| auto upper_bound(R &&Range, T &&Value, Compare C) { |
| return std::upper_bound(adl_begin(Range), adl_end(Range), |
| std::forward<T>(Value), C); |
| } |
| |
| template <typename R> |
| void stable_sort(R &&Range) { |
| std::stable_sort(adl_begin(Range), adl_end(Range)); |
| } |
| |
| template <typename R, typename Compare> |
| void stable_sort(R &&Range, Compare C) { |
| std::stable_sort(adl_begin(Range), adl_end(Range), C); |
| } |
| |
| /// Binary search for the first iterator in a range where a predicate is false. |
| /// Requires that C is always true below some limit, and always false above it. |
| template <typename R, typename Predicate, |
| typename Val = decltype(*adl_begin(std::declval<R>()))> |
| auto partition_point(R &&Range, Predicate P) { |
| return std::partition_point(adl_begin(Range), adl_end(Range), P); |
| } |
| |
| template<typename Range, typename Predicate> |
| auto unique(Range &&R, Predicate P) { |
| return std::unique(adl_begin(R), adl_end(R), P); |
| } |
| |
| /// Wrapper function around std::equal to detect if all elements |
| /// in a container are same. |
| template <typename R> |
| bool is_splat(R &&Range) { |
| size_t range_size = size(Range); |
| return range_size != 0 && (range_size == 1 || |
| std::equal(adl_begin(Range) + 1, adl_end(Range), adl_begin(Range))); |
| } |
| |
| /// Provide a container algorithm similar to C++ Library Fundamentals v2's |
| /// `erase_if` which is equivalent to: |
| /// |
| /// C.erase(remove_if(C, pred), C.end()); |
| /// |
| /// This version works for any container with an erase method call accepting |
| /// two iterators. |
| template <typename Container, typename UnaryPredicate> |
| void erase_if(Container &C, UnaryPredicate P) { |
| C.erase(remove_if(C, P), C.end()); |
| } |
| |
| /// Wrapper function to remove a value from a container: |
| /// |
| /// C.erase(remove(C.begin(), C.end(), V), C.end()); |
| template <typename Container, typename ValueType> |
| void erase_value(Container &C, ValueType V) { |
| C.erase(std::remove(C.begin(), C.end(), V), C.end()); |
| } |
| |
| /// Wrapper function to append a range to a container. |
| /// |
| /// C.insert(C.end(), R.begin(), R.end()); |
| template <typename Container, typename Range> |
| inline void append_range(Container &C, Range &&R) { |
| C.insert(C.end(), R.begin(), R.end()); |
| } |
| |
| /// Given a sequence container Cont, replace the range [ContIt, ContEnd) with |
| /// the range [ValIt, ValEnd) (which is not from the same container). |
| template<typename Container, typename RandomAccessIterator> |
| void replace(Container &Cont, typename Container::iterator ContIt, |
| typename Container::iterator ContEnd, RandomAccessIterator ValIt, |
| RandomAccessIterator ValEnd) { |
| while (true) { |
| if (ValIt == ValEnd) { |
| Cont.erase(ContIt, ContEnd); |
| return; |
| } else if (ContIt == ContEnd) { |
| Cont.insert(ContIt, ValIt, ValEnd); |
| return; |
| } |
| *ContIt++ = *ValIt++; |
| } |
| } |
| |
| /// Given a sequence container Cont, replace the range [ContIt, ContEnd) with |
| /// the range R. |
| template<typename Container, typename Range = std::initializer_list< |
| typename Container::value_type>> |
| void replace(Container &Cont, typename Container::iterator ContIt, |
| typename Container::iterator ContEnd, Range R) { |
| replace(Cont, ContIt, ContEnd, R.begin(), R.end()); |
| } |
| |
| /// An STL-style algorithm similar to std::for_each that applies a second |
| /// functor between every pair of elements. |
| /// |
| /// This provides the control flow logic to, for example, print a |
| /// comma-separated list: |
| /// \code |
| /// interleave(names.begin(), names.end(), |
| /// [&](StringRef name) { os << name; }, |
| /// [&] { os << ", "; }); |
| /// \endcode |
| template <typename ForwardIterator, typename UnaryFunctor, |
| typename NullaryFunctor, |
| typename = typename std::enable_if< |
| !std::is_constructible<StringRef, UnaryFunctor>::value && |
| !std::is_constructible<StringRef, NullaryFunctor>::value>::type> |
| inline void interleave(ForwardIterator begin, ForwardIterator end, |
| UnaryFunctor each_fn, NullaryFunctor between_fn) { |
| if (begin == end) |
| return; |
| each_fn(*begin); |
| ++begin; |
| for (; begin != end; ++begin) { |
| between_fn(); |
| each_fn(*begin); |
| } |
| } |
| |
| template <typename Container, typename UnaryFunctor, typename NullaryFunctor, |
| typename = typename std::enable_if< |
| !std::is_constructible<StringRef, UnaryFunctor>::value && |
| !std::is_constructible<StringRef, NullaryFunctor>::value>::type> |
| inline void interleave(const Container &c, UnaryFunctor each_fn, |
| NullaryFunctor between_fn) { |
| interleave(c.begin(), c.end(), each_fn, between_fn); |
| } |
| |
| /// Overload of interleave for the common case of string separator. |
| template <typename Container, typename UnaryFunctor, typename StreamT, |
| typename T = detail::ValueOfRange<Container>> |
| inline void interleave(const Container &c, StreamT &os, UnaryFunctor each_fn, |
| const StringRef &separator) { |
| interleave(c.begin(), c.end(), each_fn, [&] { os << separator; }); |
| } |
| template <typename Container, typename StreamT, |
| typename T = detail::ValueOfRange<Container>> |
| inline void interleave(const Container &c, StreamT &os, |
| const StringRef &separator) { |
| interleave( |
| c, os, [&](const T &a) { os << a; }, separator); |
| } |
| |
| template <typename Container, typename UnaryFunctor, typename StreamT, |
| typename T = detail::ValueOfRange<Container>> |
| inline void interleaveComma(const Container &c, StreamT &os, |
| UnaryFunctor each_fn) { |
| interleave(c, os, each_fn, ", "); |
| } |
| template <typename Container, typename StreamT, |
| typename T = detail::ValueOfRange<Container>> |
| inline void interleaveComma(const Container &c, StreamT &os) { |
| interleaveComma(c, os, [&](const T &a) { os << a; }); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <memory> |
| //===----------------------------------------------------------------------===// |
| |
| struct FreeDeleter { |
| void operator()(void* v) { |
| ::free(v); |
| } |
| }; |
| |
| template<typename First, typename Second> |
| struct pair_hash { |
| size_t operator()(const std::pair<First, Second> &P) const { |
| return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second); |
| } |
| }; |
| |
| /// Binary functor that adapts to any other binary functor after dereferencing |
| /// operands. |
| template <typename T> struct deref { |
| T func; |
| |
| // Could be further improved to cope with non-derivable functors and |
| // non-binary functors (should be a variadic template member function |
| // operator()). |
| template <typename A, typename B> auto operator()(A &lhs, B &rhs) const { |
| assert(lhs); |
| assert(rhs); |
| return func(*lhs, *rhs); |
| } |
| }; |
| |
| namespace detail { |
| |
| template <typename R> class enumerator_iter; |
| |
| template <typename R> struct result_pair { |
| using value_reference = |
| typename std::iterator_traits<IterOfRange<R>>::reference; |
| |
| friend class enumerator_iter<R>; |
| |
| result_pair() = default; |
| result_pair(std::size_t Index, IterOfRange<R> Iter) |
| : Index(Index), Iter(Iter) {} |
| |
| result_pair(const result_pair<R> &Other) |
| : Index(Other.Index), Iter(Other.Iter) {} |
| result_pair &operator=(const result_pair &Other) { |
| Index = Other.Index; |
| Iter = Other.Iter; |
| return *this; |
| } |
| |
| std::size_t index() const { return Index; } |
| const value_reference value() const { return *Iter; } |
| value_reference value() { return *Iter; } |
| |
| private: |
| std::size_t Index = std::numeric_limits<std::size_t>::max(); |
| IterOfRange<R> Iter; |
| }; |
| |
| template <typename R> |
| class enumerator_iter |
| : public iterator_facade_base< |
| enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>, |
| typename std::iterator_traits<IterOfRange<R>>::difference_type, |
| typename std::iterator_traits<IterOfRange<R>>::pointer, |
| typename std::iterator_traits<IterOfRange<R>>::reference> { |
| using result_type = result_pair<R>; |
| |
| public: |
| explicit enumerator_iter(IterOfRange<R> EndIter) |
| : Result(std::numeric_limits<size_t>::max(), EndIter) {} |
| |
| enumerator_iter(std::size_t Index, IterOfRange<R> Iter) |
| : Result(Index, Iter) {} |
| |
| result_type &operator*() { return Result; } |
| const result_type &operator*() const { return Result; } |
| |
| enumerator_iter &operator++() { |
| assert(Result.Index != std::numeric_limits<size_t>::max()); |
| ++Result.Iter; |
| ++Result.Index; |
| return *this; |
| } |
| |
| bool operator==(const enumerator_iter &RHS) const { |
| // Don't compare indices here, only iterators. It's possible for an end |
| // iterator to have different indices depending on whether it was created |
| // by calling std::end() versus incrementing a valid iterator. |
| return Result.Iter == RHS.Result.Iter; |
| } |
| |
| enumerator_iter(const enumerator_iter &Other) : Result(Other.Result) {} |
| enumerator_iter &operator=(const enumerator_iter &Other) { |
| Result = Other.Result; |
| return *this; |
| } |
| |
| private: |
| result_type Result; |
| }; |
| |
| template <typename R> class enumerator { |
| public: |
| explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {} |
| |
| enumerator_iter<R> begin() { |
| return enumerator_iter<R>(0, std::begin(TheRange)); |
| } |
| |
| enumerator_iter<R> end() { |
| return enumerator_iter<R>(std::end(TheRange)); |
| } |
| |
| private: |
| R TheRange; |
| }; |
| |
| } // end namespace detail |
| |
| /// Given an input range, returns a new range whose values are are pair (A,B) |
| /// such that A is the 0-based index of the item in the sequence, and B is |
| /// the value from the original sequence. Example: |
| /// |
| /// std::vector<char> Items = {'A', 'B', 'C', 'D'}; |
| /// for (auto X : enumerate(Items)) { |
| /// printf("Item %d - %c\n", X.index(), X.value()); |
| /// } |
| /// |
| /// Output: |
| /// Item 0 - A |
| /// Item 1 - B |
| /// Item 2 - C |
| /// Item 3 - D |
| /// |
| template <typename R> detail::enumerator<R> enumerate(R &&TheRange) { |
| return detail::enumerator<R>(std::forward<R>(TheRange)); |
| } |
| |
| namespace detail { |
| |
| template <typename F, typename Tuple, std::size_t... I> |
| decltype(auto) apply_tuple_impl(F &&f, Tuple &&t, std::index_sequence<I...>) { |
| return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...); |
| } |
| |
| } // end namespace detail |
| |
| /// Given an input tuple (a1, a2, ..., an), pass the arguments of the |
| /// tuple variadically to f as if by calling f(a1, a2, ..., an) and |
| /// return the result. |
| template <typename F, typename Tuple> |
| decltype(auto) apply_tuple(F &&f, Tuple &&t) { |
| using Indices = std::make_index_sequence< |
| std::tuple_size<typename std::decay<Tuple>::type>::value>; |
| |
| return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t), |
| Indices{}); |
| } |
| |
| /// Return true if the sequence [Begin, End) has exactly N items. Runs in O(N) |
| /// time. Not meant for use with random-access iterators. |
| /// Can optionally take a predicate to filter lazily some items. |
| template <typename IterTy, |
| typename Pred = bool (*)(const decltype(*std::declval<IterTy>()) &)> |
| bool hasNItems( |
| IterTy &&Begin, IterTy &&End, unsigned N, |
| Pred &&ShouldBeCounted = |
| [](const decltype(*std::declval<IterTy>()) &) { return true; }, |
| std::enable_if_t< |
| !std::is_base_of<std::random_access_iterator_tag, |
| typename std::iterator_traits<std::remove_reference_t< |
| decltype(Begin)>>::iterator_category>::value, |
| void> * = nullptr) { |
| for (; N; ++Begin) { |
| if (Begin == End) |
| return false; // Too few. |
| N -= ShouldBeCounted(*Begin); |
| } |
| for (; Begin != End; ++Begin) |
| if (ShouldBeCounted(*Begin)) |
| return false; // Too many. |
| return true; |
| } |
| |
| /// Return true if the sequence [Begin, End) has N or more items. Runs in O(N) |
| /// time. Not meant for use with random-access iterators. |
| /// Can optionally take a predicate to lazily filter some items. |
| template <typename IterTy, |
| typename Pred = bool (*)(const decltype(*std::declval<IterTy>()) &)> |
| bool hasNItemsOrMore( |
| IterTy &&Begin, IterTy &&End, unsigned N, |
| Pred &&ShouldBeCounted = |
| [](const decltype(*std::declval<IterTy>()) &) { return true; }, |
| std::enable_if_t< |
| !std::is_base_of<std::random_access_iterator_tag, |
| typename std::iterator_traits<std::remove_reference_t< |
| decltype(Begin)>>::iterator_category>::value, |
| void> * = nullptr) { |
| for (; N; ++Begin) { |
| if (Begin == End) |
| return false; // Too few. |
| N -= ShouldBeCounted(*Begin); |
| } |
| return true; |
| } |
| |
| /// Returns true if the sequence [Begin, End) has N or less items. Can |
| /// optionally take a predicate to lazily filter some items. |
| template <typename IterTy, |
| typename Pred = bool (*)(const decltype(*std::declval<IterTy>()) &)> |
| bool hasNItemsOrLess( |
| IterTy &&Begin, IterTy &&End, unsigned N, |
| Pred &&ShouldBeCounted = [](const decltype(*std::declval<IterTy>()) &) { |
| return true; |
| }) { |
| assert(N != std::numeric_limits<unsigned>::max()); |
| return !hasNItemsOrMore(Begin, End, N + 1, ShouldBeCounted); |
| } |
| |
| /// Returns true if the given container has exactly N items |
| template <typename ContainerTy> bool hasNItems(ContainerTy &&C, unsigned N) { |
| return hasNItems(std::begin(C), std::end(C), N); |
| } |
| |
| /// Returns true if the given container has N or more items |
| template <typename ContainerTy> |
| bool hasNItemsOrMore(ContainerTy &&C, unsigned N) { |
| return hasNItemsOrMore(std::begin(C), std::end(C), N); |
| } |
| |
| /// Returns true if the given container has N or less items |
| template <typename ContainerTy> |
| bool hasNItemsOrLess(ContainerTy &&C, unsigned N) { |
| return hasNItemsOrLess(std::begin(C), std::end(C), N); |
| } |
| |
| /// Returns a raw pointer that represents the same address as the argument. |
| /// |
| /// This implementation can be removed once we move to C++20 where it's defined |
| /// as std::to_address(). |
| /// |
| /// The std::pointer_traits<>::to_address(p) variations of these overloads has |
| /// not been implemented. |
| template <class Ptr> auto to_address(const Ptr &P) { return P.operator->(); } |
| template <class T> constexpr T *to_address(T *P) { return P; } |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_ADT_STLEXTRAS_H |