/*

  silcdlist.h

  Author: Pekka Riikonen <priikone@poseidon.pspt.fi>

  Copyright (C) 2000 Pekka Riikonen

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
  
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

*/

#ifndef SILDCLIST_H
#define SILDCLIST_H

#include "silclist.h"

/*
   SILC Dynamic List API

   SILC Dynamic List API can be used to add opaque contexts to list that will
   automatically allocate list entries.  Normal SILC List API cannot be used
   for this purpose because in that case the context passed to the list must
   be defined as list structure already.  This is not the case in SilcDList.

   This is slower than SilcList because this requires one extra memory 
   allocation when adding new entries to the list.  The context is probably
   allocated already and the new list entry requires one additional memory 
   allocation.  The memory allocation and free'ing is done automatically in
   the API and does not show to the caller.

   I left sorting functions out because I don't know whether we need them.
   If needed, just copy them from silclist.h

*/

/* SilcDList object. This is the actual SilcDList object that is used by
   application. Application defines this object and adds context's to this
   list with functions defined below. */
typedef struct {
  SilcList list;
} *SilcDList;

/* SilcDListEntry structure, one entry in the list. This MUST NOT be used
   directly by the application. */
typedef struct SilcDListEntryStruct {
  void *context;
  struct SilcDListEntryStruct *next;
} *SilcDListEntry;

/* Initializes SilcDList. */

static inline
SilcDList silc_dlist_init()
{
  SilcDList list;

  list = (SilcDList)silc_calloc(1, sizeof(*list));
  silc_list_init(list->list, struct SilcDListEntryStruct, next);

  return list;
}

/* Uninits and free's all memory. Must be called to free memory. Does NOT
   free the contexts saved by caller. */

static inline
void silc_dlist_uninit(SilcDList list)
{
  if (list) {
    SilcDListEntry e;
    silc_list_start(list->list);
    while ((e = (SilcDListEntry)silc_list_get(list->list)) != SILC_LIST_END) {
      silc_list_del(list->list, e);
      silc_free(e);
    }
    silc_free(list);
  }
}

/* Return the number of entries in the list */

static inline
int silc_dlist_count(SilcDList list)
{
  return silc_list_count(list->list);
}

/* Set the start of the list. This prepares the list for traversing entries
   from the start of the list. */

static inline
void silc_dlist_start(SilcDList list)
{
  silc_list_start(list->list);
}

/* Adds new entry to the list. This is the default function to add new
   entries to the list. */

static inline
void silc_dlist_add(SilcDList list, void *context)
{
  SilcDListEntry e = (SilcDListEntry)silc_calloc(1, sizeof(*e));
  e->context = context;
  silc_list_add(list->list, e);
}

/* Remove entry from the list. Returns < 0 on error, 0 otherwise. */

static inline
void silc_dlist_del(SilcDList list, void *context)
{
  SilcDListEntry e;

  silc_list_start(list->list);
  while ((e = (SilcDListEntry)silc_list_get(list->list)) != SILC_LIST_END) {
    if (e->context == context) {
      silc_list_del(list->list, e);
      silc_free(e);
      break;
    }
  }
}

/* Returns current entry from the list and moves the list pointer forward
   so that calling this next time returns the next entry from the list. This
   can be used to traverse the list. Return SILC_LIST_END when the entire
   list has ben traversed. Later, silc_list_start must be called again when 
   re-starting list traversing. Example:

   // Traverse the list from the beginning to the end 
   silc_dlist_start(list)
   while ((entry = silc_dlist_get(list)) != SILC_LIST_END) {
     ...
   }
   
*/
static inline
void *silc_dlist_get(SilcDList list)
{
  SilcDListEntry e = (SilcDListEntry)silc_list_get(list->list);
  if (e != SILC_LIST_END)
    return e->context;
  return SILC_LIST_END;
}

#endif