//===- llvm/ADT/ilist_iterator.h - Intrusive List Iterator ------*- 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
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_ILIST_ITERATOR_H
#define LLVM_ADT_ILIST_ITERATOR_H
#include "llvm/ADT/ilist_node.h"
#include <cassert>
#include <cstddef>
#include <iterator>
#include <type_traits>
namespace llvm {
namespace ilist_detail {
/// Find const-correct node types.
template <class OptionsT, bool IsConst> struct IteratorTraits;
template <class OptionsT> struct IteratorTraits<OptionsT, false> {
using value_type = typename OptionsT::value_type;
using pointer = typename OptionsT::pointer;
using reference = typename OptionsT::reference;
using node_pointer = ilist_node_impl<OptionsT> *;
using node_reference = ilist_node_impl<OptionsT> &;
};
template <class OptionsT> struct IteratorTraits<OptionsT, true> {
using value_type = const typename OptionsT::value_type;
using pointer = typename OptionsT::const_pointer;
using reference = typename OptionsT::const_reference;
using node_pointer = const ilist_node_impl<OptionsT> *;
using node_reference = const ilist_node_impl<OptionsT> &;
};
template <bool IsReverse> struct IteratorHelper;
template <> struct IteratorHelper<false> : ilist_detail::NodeAccess {
using Access = ilist_detail::NodeAccess;
template <class T> static void increment(T *&I) { I = Access::getNext(*I); }
template <class T> static void decrement(T *&I) { I = Access::getPrev(*I); }
};
template <> struct IteratorHelper<true> : ilist_detail::NodeAccess {
using Access = ilist_detail::NodeAccess;
template <class T> static void increment(T *&I) { I = Access::getPrev(*I); }
template <class T> static void decrement(T *&I) { I = Access::getNext(*I); }
};
} // end namespace ilist_detail
/// Iterator for intrusive lists based on ilist_node.
template <class OptionsT, bool IsReverse, bool IsConst>
class ilist_iterator : ilist_detail::SpecificNodeAccess<OptionsT> {
friend ilist_iterator<OptionsT, IsReverse, !IsConst>;
friend ilist_iterator<OptionsT, !IsReverse, IsConst>;
friend ilist_iterator<OptionsT, !IsReverse, !IsConst>;
using Traits = ilist_detail::IteratorTraits<OptionsT, IsConst>;
using Access = ilist_detail::SpecificNodeAccess<OptionsT>;
public:
using value_type = typename Traits::value_type;
using pointer = typename Traits::pointer;
using reference = typename Traits::reference;
using difference_type = ptrdiff_t;
using iterator_category = std::bidirectional_iterator_tag;
using const_pointer = typename OptionsT::const_pointer;
using const_reference = typename OptionsT::const_reference;
private:
using node_pointer = typename Traits::node_pointer;
using node_reference = typename Traits::node_reference;
node_pointer NodePtr = nullptr;
public:
/// Create from an ilist_node.
explicit ilist_iterator(node_reference N) : NodePtr(&N) {}
explicit ilist_iterator(pointer NP) : NodePtr(Access::getNodePtr(NP)) {}
explicit ilist_iterator(reference NR) : NodePtr(Access::getNodePtr(&NR)) {}
ilist_iterator() = default;
// This is templated so that we can allow constructing a const iterator from
// a nonconst iterator...
template <bool RHSIsConst>
ilist_iterator(const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS,
std::enable_if_t<IsConst || !RHSIsConst, void *> = nullptr)
: NodePtr(RHS.NodePtr) {}
// This is templated so that we can allow assigning to a const iterator from
// a nonconst iterator...
template <bool RHSIsConst>
std::enable_if_t<IsConst || !RHSIsConst, ilist_iterator &>
operator=(const ilist_iterator<OptionsT, IsReverse, RHSIsConst> &RHS) {
NodePtr = RHS.NodePtr;
return *this;
}
/// Explicit conversion between forward/reverse iterators.
///
/// Translate between forward and reverse iterators without changing range
/// boundaries. The resulting iterator will dereference (and have a handle)
/// to the previous node, which is somewhat unexpected; but converting the
/// two endpoints in a range will give the same range in reverse.
///
/// This matches std::reverse_iterator conversions.
explicit ilist_iterator(
const ilist_iterator<OptionsT, !IsReverse, IsConst> &RHS)
: ilist_iterator(++RHS.getReverse()) {}
/// Get a reverse iterator to the same node.
///
/// Gives a reverse iterator that will dereference (and have a handle) to the
/// same node. Converting the endpoint iterators in a range will give a
/// different range; for range operations, use the explicit conversions.
ilist_iterator<OptionsT, !IsReverse, IsConst> getReverse() const {
if (NodePtr)
return ilist_iterator<OptionsT, !IsReverse, IsConst>(*NodePtr);
return ilist_iterator<OptionsT, !IsReverse, IsConst>();
}
/// Const-cast.
ilist_iterator<OptionsT, IsReverse, false> getNonConst() const {
if (NodePtr)
return ilist_iterator<OptionsT, IsReverse, false>(
const_cast<typename ilist_iterator<OptionsT, IsReverse,
false>::node_reference>(*NodePtr));
return ilist_iterator<OptionsT, IsReverse, false>();
}
// Accessors...
reference operator*() const {
assert(!NodePtr->isKnownSentinel());
return *Access::getValuePtr(NodePtr);
}
pointer operator->() const { return &operator*(); }
// Comparison operators
friend bool operator==(const ilist_iterator &LHS, const ilist_iterator &RHS) {
return LHS.NodePtr == RHS.NodePtr;
}
friend bool operator!=(const ilist_iterator &LHS, const ilist_iterator &RHS) {
return LHS.NodePtr != RHS.NodePtr;
}
// Increment and decrement operators...
ilist_iterator &operator--() {
NodePtr = IsReverse ? NodePtr->getNext() : NodePtr->getPrev();
return *this;
}
ilist_iterator &operator++() {
NodePtr = IsReverse ? NodePtr->getPrev() : NodePtr->getNext();
return *this;
}
ilist_iterator operator--(int) {
ilist_iterator tmp = *this;
--*this;
return tmp;
}
ilist_iterator operator++(int) {
ilist_iterator tmp = *this;
++*this;
return tmp;
}
/// Get the underlying ilist_node.
node_pointer getNodePtr() const { return static_cast<node_pointer>(NodePtr); }
/// Check for end. Only valid if ilist_sentinel_tracking<true>.
bool isEnd() const { return NodePtr ? NodePtr->isSentinel() : false; }
};
template <typename From> struct simplify_type;
/// Allow ilist_iterators to convert into pointers to a node automatically when
/// used by the dyn_cast, cast, isa mechanisms...
///
/// FIXME: remove this, since there is no implicit conversion to NodeTy.
template <class OptionsT, bool IsConst>
struct simplify_type<ilist_iterator<OptionsT, false, IsConst>> {
using iterator = ilist_iterator<OptionsT, false, IsConst>;
using SimpleType = typename iterator::pointer;
static SimpleType getSimplifiedValue(const iterator &Node) { return &*Node; }
};
template <class OptionsT, bool IsConst>
struct simplify_type<const ilist_iterator<OptionsT, false, IsConst>>
: simplify_type<ilist_iterator<OptionsT, false, IsConst>> {};
} // end namespace llvm
#endif // LLVM_ADT_ILIST_ITERATOR_H