Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- 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