text: // -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
  // Copyright (c) 2008, Google Inc.
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // ---
  // Author: Sanjay Ghemawat <opensource@google.com>
  //
  // Some very basic linked list functions for dealing with using void * as
  // storage.
  
  #ifndef TCMALLOC_LINKED_LIST_H_
  #define TCMALLOC_LINKED_LIST_H_
  
  #include <stddef.h>
  
  namespace tcmalloc {
  
  inline void *SLL_Next(void *t) {
    return *(reinterpret_cast<void**>(t));
  }
  
  inline void SLL_SetNext(void *t, void *n) {
    *(reinterpret_cast<void**>(t)) = n;
  }
  
  inline void SLL_Push(void **list, void *element) {
    SLL_SetNext(element, *list);
    *list = element;
  }
  
  inline void *SLL_Pop(void **list) {
    void *result = *list;
    *list = SLL_Next(*list);
    return result;
  }
  
  // Remove N elements from a linked list to which head points.  head will be
  // modified to point to the new head.  start and end will point to the first
  // and last nodes of the range.  Note that end will point to NULL after this
  // function is called.
  inline void SLL_PopRange(void **head, int N, void **start, void **end) {
    if (N == 0) {
      *start = NULL;
      *end = NULL;
      return;
    }
  
    void *tmp = *head;
    for (int i = 1; i < N; ++i) {
      tmp = SLL_Next(tmp);
    }
  
    *start = *head;
    *end = tmp;
    *head = SLL_Next(tmp);
    // Unlink range from list.
    SLL_SetNext(tmp, NULL);
  }
  
  inline void SLL_PushRange(void **head, void *start, void *end) {
    if (!start) return;
    SLL_SetNext(end, *head);
    *head = start;
  }
  
  inline size_t SLL_Size(void *head) {
    int count = 0;
    while (head) {
      count++;
      head = SLL_Next(head);
    }
    return count;
  }
  
  }  // namespace tcmalloc
  
  #endif  // TCMALLOC_LINKED_LIST_H_
  