/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * Copyright (C) 2011 STRATO AG
   * written by Arne Jansen <sensille@gmx.net>

   */

  #ifndef BTRFS_ULIST_H
  #define BTRFS_ULIST_H

  #include <linux/list.h>
  #include <linux/rbtree.h>

  /*
   * ulist is a generic data structure to hold a collection of unique u64
   * values. The only operations it supports is adding to the list and
   * enumerating it.
   * It is possible to store an auxiliary value along with the key.
   *

   */

  struct ulist_iterator {

  	struct list_head *cur_list;  /* hint to start search */

  };

  /*
   * element of the list
   */
  struct ulist_node {
  	u64 val;		/* value to store */

  	u64 aux;		/* auxiliary value saved along with the val */

  	struct list_head list;  /* used to link node */

  	struct rb_node rb_node;	/* used to speed up search */

  };
  
  struct ulist {
  	/*
  	 * number of elements stored in list
  	 */
  	unsigned long nnodes;

  	struct list_head nodes;

  	struct rb_root root;

  };
  
  void ulist_init(struct ulist *ulist);

  void ulist_release(struct ulist *ulist);

  void ulist_reinit(struct ulist *ulist);

  struct ulist *ulist_alloc(gfp_t gfp_mask);

  void ulist_free(struct ulist *ulist);

  int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  		    u64 *old_aux, gfp_t gfp_mask);

  int ulist_del(struct ulist *ulist, u64 val, u64 aux);

  
  /* just like ulist_add_merge() but take a pointer for the aux data */
  static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  				      void **old_aux, gfp_t gfp_mask)
  {
  #if BITS_PER_LONG == 32
  	u64 old64 = (uintptr_t)*old_aux;
  	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  	*old_aux = (void *)((uintptr_t)old64);
  	return ret;
  #else
  	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  #endif
  }

  struct ulist_node *ulist_next(struct ulist *ulist,
  			      struct ulist_iterator *uiter);

  #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)

  
  #endif