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*****************************************************************************/

/** @file ut/ut0list.cc
 A double-linked list

 Created 4/26/2006 Osku Salerma
 ************************************************************************/

#include "ut0list.h"

#include <stddef.h>

/** Create a new list.
 @return list */
ib_list_t *ib_list_create(void) {
  return (static_cast<ib_list_t *>(ut_zalloc_nokey(sizeof(ib_list_t))));
}

/** Free a list. */
void ib_list_free(ib_list_t *list) /*!< in: list */
{
  /* We don't check that the list is empty because it's entirely valid
  to e.g. have all the nodes allocated from a single heap that is then
  freed after the list itself is freed. */

  ut_free(list);
}

/** Add the data after the indicated node.
 @return new list node */
static ib_list_node_t *ib_list_add_after(
    ib_list_t *list,           /*!< in: list */
    ib_list_node_t *prev_node, /*!< in: node preceding new node (can
                               be NULL) */
    void *data,                /*!< in: data */
    mem_heap_t *heap)          /*!< in: memory heap to use */
{
  ib_list_node_t *node;

  node = static_cast<ib_list_node_t *>(mem_heap_alloc(heap, sizeof(*node)));

  node->data = data;

  if (!list->first) {
    /* Empty list. */

    ut_a(!prev_node);

    node->prev = NULL;
    node->next = NULL;

    list->first = node;
    list->last = node;
  } else if (!prev_node) {
    /* Start of list. */

    node->prev = NULL;
    node->next = list->first;

    list->first->prev = node;

    list->first = node;
  } else {
    /* Middle or end of list. */

    node->prev = prev_node;
    node->next = prev_node->next;

    prev_node->next = node;

    if (node->next) {
      node->next->prev = node;
    } else {
      list->last = node;
    }
  }

  return (node);
}

/** Add the data to the end of the list.
 @return new list node */
ib_list_node_t *ib_list_add_last(
    ib_list_t *list,  /*!< in: list */
    void *data,       /*!< in: data */
    mem_heap_t *heap) /*!< in: memory heap to use */
{
  return (ib_list_add_after(list, ib_list_get_last(list), data, heap));
}

/** Remove the node from the list. */
void ib_list_remove(ib_list_t *list,      /*!< in: list */
                    ib_list_node_t *node) /*!< in: node to remove */
{
  if (node->prev) {
    node->prev->next = node->next;
  } else {
    /* First item in list. */

    ut_ad(list->first == node);

    list->first = node->next;
  }

  if (node->next) {
    node->next->prev = node->prev;
  } else {
    /* Last item in list. */

    ut_ad(list->last == node);

    list->last = node->prev;
  }

  node->prev = node->next = NULL;
}