/****************************************************************************
 * include/nuttx/queue.h
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

#ifndef __INCLUDE_NUTTX_QUEUE_H
#define __INCLUDE_NUTTX_QUEUE_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <sys/types.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#ifdef CONFIG_LIBC_INLINE_QUEUE
#  ifndef STATIC_INLINE
#    define STATIC_INLINE static inline_function
#  endif
#else
#  define STATIC_INLINE
#endif

#define sq_init(q) \
  do \
    { \
      (q)->head = NULL; \
      (q)->tail = NULL; \
    } \
  while (0)

#define dq_init(q) \
  do \
    { \
      (q)->head = NULL; \
      (q)->tail = NULL; \
    } \
  while (0)

#define sq_move(q1,q2) \
  do \
    { \
      (q2)->head = (q1)->head; \
      (q2)->tail = (q1)->tail; \
      (q1)->head = NULL; \
      (q1)->tail = NULL; \
    } \
  while (0)

#define dq_move(q1,q2) \
  do \
    { \
      (q2)->head = (q1)->head; \
      (q2)->tail = (q1)->tail; \
      (q1)->head = NULL; \
      (q1)->tail = NULL; \
    } \
  while (0)

#define sq_addfirst(p, q) \
  do \
    { \
      FAR sq_entry_t *tmp_node = (p); \
      tmp_node->flink = (q)->head; \
      if (!(q)->head) \
        { \
          (q)->tail = tmp_node; \
        } \
      (q)->head = tmp_node; \
    } \
  while (0)

#define dq_addfirst(p, q) \
  do \
    { \
      FAR dq_entry_t *tmp_node = (p); \
      tmp_node->blink = NULL; \
      tmp_node->flink = (q)->head; \
      if (!(q)->head) \
        { \
          (q)->head = tmp_node; \
          (q)->tail = tmp_node; \
        } \
      else \
        { \
          (q)->head->blink = tmp_node; \
          (q)->head = tmp_node; \
        } \
    } \
  while (0)

#define sq_addlast(p, q) \
  do \
    { \
      FAR sq_entry_t *tmp_node = (p); \
      tmp_node->flink = NULL; \
      if (!(q)->head) \
        { \
          (q)->head = tmp_node; \
          (q)->tail = tmp_node; \
        } \
      else \
        { \
          (q)->tail->flink = tmp_node; \
          (q)->tail        = tmp_node; \
        } \
    } \
  while (0)

#define dq_addlast(p, q) \
  do \
    { \
      FAR dq_entry_t *tmp_node = (p); \
      tmp_node->flink = NULL; \
      tmp_node->blink = (q)->tail; \
      if (!(q)->head) \
        { \
          (q)->head = tmp_node; \
          (q)->tail = tmp_node; \
        } \
      else \
        { \
          (q)->tail->flink = tmp_node; \
          (q)->tail        = tmp_node; \
        } \
    } \
  while (0)

#define dq_addbefore(n, p, q) \
  do \
    { \
      FAR dq_entry_t *_tmp_node = (p); \
      if (!(q)->head || (n) == (q)->head) \
        { \
          dq_addfirst(_tmp_node, q); \
        } \
      else \
        { \
          FAR dq_entry_t *tmp_prev = (n)->blink; \
          _tmp_node->flink = (n); \
          _tmp_node->blink = tmp_prev; \
          tmp_prev->flink = _tmp_node; \
          (n)->blink = _tmp_node; \
        } \
    } \
  while (0)

#define sq_for_every(q, p) \
  for ((p) = (q)->head; (p) != NULL; (p) = (p)->flink)

#define sq_for_every_safe(q, p, tmp) \
  for((p) = (q)->head, (tmp) = (p) ? (p)->flink : NULL; \
      (p) != NULL; (p) = (tmp), (tmp) = (p) ? (p)->flink : NULL)

#define dq_for_every(q, p) sq_for_every(q, p)
#define dq_for_every_safe(q, p, tmp) sq_for_every_safe(q, p, tmp)

#define sq_rem(p, q) \
  do \
    { \
      FAR sq_entry_t *tmp_node = (p); \
      if ((q)->head && tmp_node) \
        { \
          if (tmp_node == (q)->head) \
            { \
              (q)->head = tmp_node->flink; \
              if (tmp_node == (q)->tail) \
                { \
                  (q)->tail = NULL; \
                } \
            } \
          else \
            { \
              FAR sq_entry_t *tmp_prev; \
              sq_for_every(q, tmp_prev) \
                { \
                  if (tmp_prev->flink == tmp_node) \
                    { \
                      sq_remafter(tmp_prev, q); \
                    } \
                } \
            } \
        } \
    } \
  while (0)

#define dq_rem(p, q) \
  do \
    { \
      FAR dq_entry_t *tmp_node = (p); \
      FAR dq_entry_t *tmp_prev = tmp_node->blink; \
      FAR dq_entry_t *tmp_next = tmp_node->flink; \
      if (!tmp_prev) \
        { \
          (q)->head = tmp_next; \
        } \
      else \
        { \
          tmp_prev->flink = tmp_next; \
        } \
      if (!tmp_next) \
        { \
          (q)->tail = tmp_prev; \
        } \
      else \
        { \
          tmp_next->blink = tmp_prev; \
        } \
      tmp_node->flink = NULL; \
      tmp_node->blink = NULL; \
    } \
  while (0)

#define sq_cat(q1, q2) \
  do \
    { \
      if (sq_empty(q2)) \
        { \
          sq_move(q1, q2); \
        } \
      else if (!sq_empty(q1)) \
        { \
          (q2)->tail->flink = (q1)->head; \
          (q2)->tail = (q1)->tail; \
          sq_init(q1); \
        } \
    } \
  while (0)

#define dq_cat(q1, q2) \
  do \
    { \
      if (dq_empty(q2)) \
        { \
          dq_move(q1, q2); \
        } \
      else if (!dq_empty(q1)) \
        { \
          (q2)->tail->flink = (q1)->head; \
          (q1)->head->blink = (q2)->tail; \
          (q2)->tail = (q1)->tail; \
          dq_init(q1); \
        } \
    } \
  while (0)

#define dq_split(p, q1, q2) \
  do \
    { \
      if (dq_peek(q1) == (p)) \
        { \
          dq_move(q1, q2); \
        } \
      else \
        { \
          (q2)->tail = (q1)->tail; \
          (q2)->head = (p); \
          (q1)->tail = (p)->blink; \
          (p)->blink = NULL; \
          if((q1)->tail) \
            { \
              (q1)->tail->flink = NULL; \
            } \
        } \
    } \
  while(0)

#define sq_next(p)  ((p)->flink)
#define dq_next(p)  ((p)->flink)
#define dq_prev(p)  ((p)->blink)

#define sq_empty(q) ((q)->head == NULL)
#define dq_empty(q) ((q)->head == NULL)

#define sq_peek(q)  ((q)->head)
#define dq_peek(q)  ((q)->head)

#define sq_tail(q)  ((q)->tail)
#define dq_tail(q)  ((q)->tail)

#define sq_inqueue(p, q) \
      ((p)->flink || sq_tail(q) == (p))
#define dq_inqueue(p, q) \
      ((p)->flink || dq_tail(q) == (p))

/* sq/dq_is_singular - tests whether a list has just one entry.  */

#define sq_is_singular(q) \
      (!sq_empty(q) && (q)->head->flink == NULL)

#define dq_is_singular(q) \
      (!dq_empty(q) && (q)->head->flink == NULL)

/****************************************************************************
 * Public Type Definitions
 ****************************************************************************/

struct sq_entry_s
{
  FAR struct sq_entry_s *flink;
};
typedef struct sq_entry_s sq_entry_t;

struct dq_entry_s
{
  FAR struct dq_entry_s *flink;
  FAR struct dq_entry_s *blink;
};
typedef struct dq_entry_s dq_entry_t;

struct sq_queue_s
{
  FAR sq_entry_t *head;
  FAR sq_entry_t *tail;
};
typedef struct sq_queue_s  sq_queue_t;

struct dq_queue_s
{
  FAR dq_entry_t *head;
  FAR dq_entry_t *tail;
};
typedef struct dq_queue_s dq_queue_t;

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/* Add nodes to queues */

#ifndef CONFIG_LIBC_INLINE_QUEUE
void sq_addafter(FAR sq_entry_t *prev, FAR sq_entry_t *node,
                 FAR sq_queue_t *queue);
#else
STATIC_INLINE void sq_addafter(FAR sq_entry_t *prev, FAR sq_entry_t *node,
                               FAR sq_queue_t *queue)
{
  if (!queue->head || prev == queue->tail)
    {
      sq_addlast(node, queue);
    }
  else
    {
      node->flink = prev->flink;
      prev->flink = node;
    }
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
void dq_addafter(FAR dq_entry_t *prev, FAR dq_entry_t *node,
                 FAR dq_queue_t *queue);
#else
STATIC_INLINE void dq_addafter(FAR dq_entry_t *prev, FAR dq_entry_t *node,
                               FAR dq_queue_t *queue)
{
  if (!queue->head || prev == queue->tail)
    {
      dq_addlast(node, queue);
    }
  else
    {
      FAR dq_entry_t *next = prev->flink;
      node->blink = prev;
      node->flink = next;
      next->blink = node;
      prev->flink = node;
    }
}
#endif

/* Remove nodes from queues */

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR sq_entry_t *sq_remafter(FAR sq_entry_t *node, FAR sq_queue_t *queue);
#else
STATIC_INLINE FAR sq_entry_t *sq_remafter(FAR sq_entry_t *node,
                                          FAR sq_queue_t *queue)
{
  FAR sq_entry_t *ret = node->flink;

  if (queue->head && ret)
    {
      if (queue->tail == ret)
        {
          queue->tail = node;
          node->flink = NULL;
        }
      else
        {
          node->flink = ret->flink;
        }

      ret->flink = NULL;
    }

  return ret;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR dq_entry_t *dq_remafter(FAR dq_entry_t *node, FAR dq_queue_t *queue);
#else
STATIC_INLINE FAR dq_entry_t *dq_remafter(FAR dq_entry_t *node,
                                          FAR dq_queue_t *queue)
{
  FAR dq_entry_t *ret = node->flink;

  if (queue->head != NULL && ret != NULL)
    {
      dq_rem(ret, queue);
    }

  return ret;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR sq_entry_t *sq_remlast(FAR sq_queue_t *queue);
#else
STATIC_INLINE FAR sq_entry_t *sq_remlast(FAR sq_queue_t *queue)
{
  FAR sq_entry_t *ret = queue->tail;

  if (ret)
    {
      if (queue->head == queue->tail)
        {
          queue->head = NULL;
          queue->tail = NULL;
        }
      else
        {
          FAR sq_entry_t *prev;
          for (prev = queue->head;
              prev && prev->flink != ret;
              prev = prev->flink);

          if (prev)
            {
              prev->flink = NULL;
              queue->tail = prev;
            }
        }

      ret->flink = NULL;
    }

  return ret;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR dq_entry_t *dq_remlast(FAR dq_queue_t *queue);
#else
STATIC_INLINE FAR dq_entry_t *dq_remlast(FAR dq_queue_t *queue)
{
  FAR dq_entry_t *ret = queue->tail;

  if (ret)
    {
      FAR dq_entry_t *prev = ret->blink;
      if (!prev)
        {
          queue->head = NULL;
          queue->tail = NULL;
        }
      else
        {
          queue->tail = prev;
          prev->flink = NULL;
        }

      ret->flink = NULL;
      ret->blink = NULL;
    }

  return ret;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR sq_entry_t *sq_remfirst(FAR sq_queue_t *queue);
#else
STATIC_INLINE FAR sq_entry_t *sq_remfirst(FAR sq_queue_t *queue)
{
  FAR sq_entry_t *ret = queue->head;

  if (ret)
    {
      queue->head = ret->flink;
      if (!queue->head)
        {
          queue->tail = NULL;
        }

      ret->flink = NULL;
    }

  return ret;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
FAR dq_entry_t *dq_remfirst(FAR dq_queue_t *queue);
#else
STATIC_INLINE FAR dq_entry_t *dq_remfirst(FAR dq_queue_t *queue)
{
  FAR dq_entry_t *ret = queue->head;

  if (ret)
    {
      FAR dq_entry_t *next = ret->flink;
      if (!next)
        {
          queue->head = NULL;
          queue->tail = NULL;
        }
      else
        {
          queue->head = next;
          next->blink = NULL;
        }

      ret->flink = NULL;
      ret->blink = NULL;
    }

  return ret;
}
#endif

/* Count nodes in queues */

#ifndef CONFIG_LIBC_INLINE_QUEUE
size_t sq_count(FAR sq_queue_t *queue);
#else
STATIC_INLINE size_t sq_count(FAR sq_queue_t *queue)
{
  FAR sq_entry_t *node;
  size_t count;

  for (node = queue->head, count = 0;
       node != NULL;
       node = node->flink, count++);

  return count;
}
#endif

#ifndef CONFIG_LIBC_INLINE_QUEUE
size_t dq_count(FAR dq_queue_t *queue);
#else
STATIC_INLINE size_t dq_count(FAR dq_queue_t *queue)
{
  FAR dq_entry_t *node;
  size_t count;

  for (node = queue->head, count = 0;
       node != NULL;
       node = node->flink, count++);

  return count;
}
#endif

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* __INCLUDE_NUTTX_QUEUE_H_ */