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Diffstat (limited to 'src/3rdparty/llvm/include/llvm/ADT/iterator.h')
| -rw-r--r-- | src/3rdparty/llvm/include/llvm/ADT/iterator.h | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/src/3rdparty/llvm/include/llvm/ADT/iterator.h b/src/3rdparty/llvm/include/llvm/ADT/iterator.h new file mode 100644 index 0000000000..711f8f2216 --- /dev/null +++ b/src/3rdparty/llvm/include/llvm/ADT/iterator.h @@ -0,0 +1,339 @@ +//===- iterator.h - Utilities for using and defining iterators --*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ADT_ITERATOR_H +#define LLVM_ADT_ITERATOR_H + +#include "llvm/ADT/iterator_range.h" +#include <algorithm> +#include <cstddef> +#include <iterator> +#include <type_traits> +#include <utility> + +namespace llvm { + +/// \brief CRTP base class which implements the entire standard iterator facade +/// in terms of a minimal subset of the interface. +/// +/// Use this when it is reasonable to implement most of the iterator +/// functionality in terms of a core subset. If you need special behavior or +/// there are performance implications for this, you may want to override the +/// relevant members instead. +/// +/// Note, one abstraction that this does *not* provide is implementing +/// subtraction in terms of addition by negating the difference. Negation isn't +/// always information preserving, and I can see very reasonable iterator +/// designs where this doesn't work well. It doesn't really force much added +/// boilerplate anyways. +/// +/// Another abstraction that this doesn't provide is implementing increment in +/// terms of addition of one. These aren't equivalent for all iterator +/// categories, and respecting that adds a lot of complexity for little gain. +/// +/// Classes wishing to use `iterator_facade_base` should implement the following +/// methods: +/// +/// Forward Iterators: +/// (All of the following methods) +/// - DerivedT &operator=(const DerivedT &R); +/// - bool operator==(const DerivedT &R) const; +/// - const T &operator*() const; +/// - T &operator*(); +/// - DerivedT &operator++(); +/// +/// Bidirectional Iterators: +/// (All methods of forward iterators, plus the following) +/// - DerivedT &operator--(); +/// +/// Random-access Iterators: +/// (All methods of bidirectional iterators excluding the following) +/// - DerivedT &operator++(); +/// - DerivedT &operator--(); +/// (and plus the following) +/// - bool operator<(const DerivedT &RHS) const; +/// - DifferenceTypeT operator-(const DerivedT &R) const; +/// - DerivedT &operator+=(DifferenceTypeT N); +/// - DerivedT &operator-=(DifferenceTypeT N); +/// +template <typename DerivedT, typename IteratorCategoryT, typename T, + typename DifferenceTypeT = std::ptrdiff_t, typename PointerT = T *, + typename ReferenceT = T &> +class iterator_facade_base + : public std::iterator<IteratorCategoryT, T, DifferenceTypeT, PointerT, + ReferenceT> { +protected: + enum { + IsRandomAccess = std::is_base_of<std::random_access_iterator_tag, + IteratorCategoryT>::value, + IsBidirectional = std::is_base_of<std::bidirectional_iterator_tag, + IteratorCategoryT>::value, + }; + + /// A proxy object for computing a reference via indirecting a copy of an + /// iterator. This is used in APIs which need to produce a reference via + /// indirection but for which the iterator object might be a temporary. The + /// proxy preserves the iterator internally and exposes the indirected + /// reference via a conversion operator. + class ReferenceProxy { + friend iterator_facade_base; + + DerivedT I; + + ReferenceProxy(DerivedT I) : I(std::move(I)) {} + + public: + operator ReferenceT() const { return *I; } + }; + +public: + DerivedT operator+(DifferenceTypeT n) const { + static_assert(std::is_base_of<iterator_facade_base, DerivedT>::value, + "Must pass the derived type to this template!"); + static_assert( + IsRandomAccess, + "The '+' operator is only defined for random access iterators."); + DerivedT tmp = *static_cast<const DerivedT *>(this); + tmp += n; + return tmp; + } + friend DerivedT operator+(DifferenceTypeT n, const DerivedT &i) { + static_assert( + IsRandomAccess, + "The '+' operator is only defined for random access iterators."); + return i + n; + } + DerivedT operator-(DifferenceTypeT n) const { + static_assert( + IsRandomAccess, + "The '-' operator is only defined for random access iterators."); + DerivedT tmp = *static_cast<const DerivedT *>(this); + tmp -= n; + return tmp; + } + + DerivedT &operator++() { + static_assert(std::is_base_of<iterator_facade_base, DerivedT>::value, + "Must pass the derived type to this template!"); + return static_cast<DerivedT *>(this)->operator+=(1); + } + DerivedT operator++(int) { + DerivedT tmp = *static_cast<DerivedT *>(this); + ++*static_cast<DerivedT *>(this); + return tmp; + } + DerivedT &operator--() { + static_assert( + IsBidirectional, + "The decrement operator is only defined for bidirectional iterators."); + return static_cast<DerivedT *>(this)->operator-=(1); + } + DerivedT operator--(int) { + static_assert( + IsBidirectional, + "The decrement operator is only defined for bidirectional iterators."); + DerivedT tmp = *static_cast<DerivedT *>(this); + --*static_cast<DerivedT *>(this); + return tmp; + } + + bool operator!=(const DerivedT &RHS) const { + return !static_cast<const DerivedT *>(this)->operator==(RHS); + } + + bool operator>(const DerivedT &RHS) const { + static_assert( + IsRandomAccess, + "Relational operators are only defined for random access iterators."); + return !static_cast<const DerivedT *>(this)->operator<(RHS) && + !static_cast<const DerivedT *>(this)->operator==(RHS); + } + bool operator<=(const DerivedT &RHS) const { + static_assert( + IsRandomAccess, + "Relational operators are only defined for random access iterators."); + return !static_cast<const DerivedT *>(this)->operator>(RHS); + } + bool operator>=(const DerivedT &RHS) const { + static_assert( + IsRandomAccess, + "Relational operators are only defined for random access iterators."); + return !static_cast<const DerivedT *>(this)->operator<(RHS); + } + + PointerT operator->() { return &static_cast<DerivedT *>(this)->operator*(); } + PointerT operator->() const { + return &static_cast<const DerivedT *>(this)->operator*(); + } + ReferenceProxy operator[](DifferenceTypeT n) { + static_assert(IsRandomAccess, + "Subscripting is only defined for random access iterators."); + return ReferenceProxy(static_cast<DerivedT *>(this)->operator+(n)); + } + ReferenceProxy operator[](DifferenceTypeT n) const { + static_assert(IsRandomAccess, + "Subscripting is only defined for random access iterators."); + return ReferenceProxy(static_cast<const DerivedT *>(this)->operator+(n)); + } +}; + +/// \brief CRTP base class for adapting an iterator to a different type. +/// +/// This class can be used through CRTP to adapt one iterator into another. +/// Typically this is done through providing in the derived class a custom \c +/// operator* implementation. Other methods can be overridden as well. +template < + typename DerivedT, typename WrappedIteratorT, + typename IteratorCategoryT = + typename std::iterator_traits<WrappedIteratorT>::iterator_category, + typename T = typename std::iterator_traits<WrappedIteratorT>::value_type, + typename DifferenceTypeT = + typename std::iterator_traits<WrappedIteratorT>::difference_type, + typename PointerT = typename std::conditional< + std::is_same<T, typename std::iterator_traits< + WrappedIteratorT>::value_type>::value, + typename std::iterator_traits<WrappedIteratorT>::pointer, T *>::type, + typename ReferenceT = typename std::conditional< + std::is_same<T, typename std::iterator_traits< + WrappedIteratorT>::value_type>::value, + typename std::iterator_traits<WrappedIteratorT>::reference, T &>::type, + // Don't provide these, they are mostly to act as aliases below. + typename WrappedTraitsT = std::iterator_traits<WrappedIteratorT>> +class iterator_adaptor_base + : public iterator_facade_base<DerivedT, IteratorCategoryT, T, + DifferenceTypeT, PointerT, ReferenceT> { + using BaseT = typename iterator_adaptor_base::iterator_facade_base; + +protected: + WrappedIteratorT I; + + iterator_adaptor_base() = default; + + explicit iterator_adaptor_base(WrappedIteratorT u) : I(std::move(u)) { + static_assert(std::is_base_of<iterator_adaptor_base, DerivedT>::value, + "Must pass the derived type to this template!"); + } + + const WrappedIteratorT &wrapped() const { return I; } + +public: + using difference_type = DifferenceTypeT; + + DerivedT &operator+=(difference_type n) { + static_assert( + BaseT::IsRandomAccess, + "The '+=' operator is only defined for random access iterators."); + I += n; + return *static_cast<DerivedT *>(this); + } + DerivedT &operator-=(difference_type n) { + static_assert( + BaseT::IsRandomAccess, + "The '-=' operator is only defined for random access iterators."); + I -= n; + return *static_cast<DerivedT *>(this); + } + using BaseT::operator-; + difference_type operator-(const DerivedT &RHS) const { + static_assert( + BaseT::IsRandomAccess, + "The '-' operator is only defined for random access iterators."); + return I - RHS.I; + } + + // We have to explicitly provide ++ and -- rather than letting the facade + // forward to += because WrappedIteratorT might not support +=. + using BaseT::operator++; + DerivedT &operator++() { + ++I; + return *static_cast<DerivedT *>(this); + } + using BaseT::operator--; + DerivedT &operator--() { + static_assert( + BaseT::IsBidirectional, + "The decrement operator is only defined for bidirectional iterators."); + --I; + return *static_cast<DerivedT *>(this); + } + + bool operator==(const DerivedT &RHS) const { return I == RHS.I; } + bool operator<(const DerivedT &RHS) const { + static_assert( + BaseT::IsRandomAccess, + "Relational operators are only defined for random access iterators."); + return I < RHS.I; + } + + ReferenceT operator*() const { return *I; } +}; + +/// \brief An iterator type that allows iterating over the pointees via some +/// other iterator. +/// +/// The typical usage of this is to expose a type that iterates over Ts, but +/// which is implemented with some iterator over T*s: +/// +/// \code +/// using iterator = pointee_iterator<SmallVectorImpl<T *>::iterator>; +/// \endcode +template <typename WrappedIteratorT, + typename T = typename std::remove_reference< + decltype(**std::declval<WrappedIteratorT>())>::type> +struct pointee_iterator + : iterator_adaptor_base< + pointee_iterator<WrappedIteratorT>, WrappedIteratorT, + typename std::iterator_traits<WrappedIteratorT>::iterator_category, + T> { + pointee_iterator() = default; + template <typename U> + pointee_iterator(U &&u) + : pointee_iterator::iterator_adaptor_base(std::forward<U &&>(u)) {} + + T &operator*() const { return **this->I; } +}; + +template <typename RangeT, typename WrappedIteratorT = + decltype(std::begin(std::declval<RangeT>()))> +iterator_range<pointee_iterator<WrappedIteratorT>> +make_pointee_range(RangeT &&Range) { + using PointeeIteratorT = pointee_iterator<WrappedIteratorT>; + return make_range(PointeeIteratorT(std::begin(std::forward<RangeT>(Range))), + PointeeIteratorT(std::end(std::forward<RangeT>(Range)))); +} + +template <typename WrappedIteratorT, + typename T = decltype(&*std::declval<WrappedIteratorT>())> +class pointer_iterator + : public iterator_adaptor_base<pointer_iterator<WrappedIteratorT>, + WrappedIteratorT, T> { + mutable T Ptr; + +public: + pointer_iterator() = default; + + explicit pointer_iterator(WrappedIteratorT u) + : pointer_iterator::iterator_adaptor_base(std::move(u)) {} + + T &operator*() { return Ptr = &*this->I; } + const T &operator*() const { return Ptr = &*this->I; } +}; + +template <typename RangeT, typename WrappedIteratorT = + decltype(std::begin(std::declval<RangeT>()))> +iterator_range<pointer_iterator<WrappedIteratorT>> +make_pointer_range(RangeT &&Range) { + using PointerIteratorT = pointer_iterator<WrappedIteratorT>; + return make_range(PointerIteratorT(std::begin(std::forward<RangeT>(Range))), + PointerIteratorT(std::end(std::forward<RangeT>(Range)))); +} + +} // end namespace llvm + +#endif // LLVM_ADT_ITERATOR_H |