//===- llvm/ADT/ilist_base.h - Intrusive List Base --------------*- 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_BASE_H
 
#define LLVM_ADT_ILIST_BASE_H
 
 
 
#include "llvm/ADT/ilist_node_base.h"
 
#include <cassert>
 
 
 
namespace llvm {
 
 
 
/// Implementations of list algorithms using ilist_node_base.
 
template <bool EnableSentinelTracking> class ilist_base {
 
public:
 
  using node_base_type = ilist_node_base<EnableSentinelTracking>;
 
 
 
  static void insertBeforeImpl(node_base_type &Next, node_base_type &N) {
 
    node_base_type &Prev = *Next.getPrev();
 
    N.setNext(&Next);
 
    N.setPrev(&Prev);
 
    Prev.setNext(&N);
 
    Next.setPrev(&N);
 
  }
 
 
 
  static void removeImpl(node_base_type &N) {
 
    node_base_type *Prev = N.getPrev();
 
    node_base_type *Next = N.getNext();
 
    Next->setPrev(Prev);
 
    Prev->setNext(Next);
 
 
 
    // Not strictly necessary, but helps catch a class of bugs.
 
    N.setPrev(nullptr);
 
    N.setNext(nullptr);
 
  }
 
 
 
  static void removeRangeImpl(node_base_type &First, node_base_type &Last) {
 
    node_base_type *Prev = First.getPrev();
 
    node_base_type *Final = Last.getPrev();
 
    Last.setPrev(Prev);
 
    Prev->setNext(&Last);
 
 
 
    // Not strictly necessary, but helps catch a class of bugs.
 
    First.setPrev(nullptr);
 
    Final->setNext(nullptr);
 
  }
 
 
 
  static void transferBeforeImpl(node_base_type &Next, node_base_type &First,
 
                                 node_base_type &Last) {
 
    if (&Next == &Last || &First == &Last)
 
      return;
 
 
 
    // Position cannot be contained in the range to be transferred.
 
    assert(&Next != &First &&
 
           // Check for the most common mistake.
 
           "Insertion point can't be one of the transferred nodes");
 
 
 
    node_base_type &Final = *Last.getPrev();
 
 
 
    // Detach from old list/position.
 
    First.getPrev()->setNext(&Last);
 
    Last.setPrev(First.getPrev());
 
 
 
    // Splice [First, Final] into its new list/position.
 
    node_base_type &Prev = *Next.getPrev();
 
    Final.setNext(&Next);
 
    First.setPrev(&Prev);
 
    Prev.setNext(&First);
 
    Next.setPrev(&Final);
 
  }
 
 
 
  template <class T> static void insertBefore(T &Next, T &N) {
 
    insertBeforeImpl(Next, N);
 
  }
 
 
 
  template <class T> static void remove(T &N) { removeImpl(N); }
 
  template <class T> static void removeRange(T &First, T &Last) {
 
    removeRangeImpl(First, Last);
 
  }
 
 
 
  template <class T> static void transferBefore(T &Next, T &First, T &Last) {
 
    transferBeforeImpl(Next, First, Last);
 
  }
 
};
 
 
 
} // end namespace llvm
 
 
 
#endif // LLVM_ADT_ILIST_BASE_H