/*
======================================================================
list.c

Generic linked list operations.

Ernie Wright  17 Sep 00
====================================================================== */

#include <stdio.h>
#include <stdlib.h>
#include <lwo2.h>


/*
======================================================================
lwListFree()

Free the items in a list.
====================================================================== */

void lwListFree( void *list, void ( *freeNode )( void * ))
{
   lwNode *node, *next;

   node = ( lwNode * ) list;
   while ( node ) {
      next = node->next;
      freeNode( node );
      node = next;
   }
}


/*
======================================================================
lwListAdd()

Append a node to a list.
====================================================================== */

void lwListAdd( void **list, void *node )
{
   lwNode *head, *tail;

   head = *(( lwNode ** ) list );
   if ( !head ) {
      *list = node;
      return;
   }
   while ( head ) {
      tail = head;
      head = head->next;
   }
   tail->next = ( lwNode * ) node;
   (( lwNode * ) node )->prev = tail;
}


/*
======================================================================
lwListInsert()

Insert a node into a list in sorted order.
====================================================================== */

void lwListInsert( void **vlist, void *vitem, int ( *compare )( void *, void * ))
{
   lwNode **list, *item, *node, *prev;

   if ( !*vlist ) {
      *vlist = vitem;
      return;
   }

   list = ( lwNode ** ) vlist;
   item = ( lwNode * ) vitem;
   node = *list;
   prev = NULL;

   while ( node ) {
      if ( 0 < compare( node, item )) break;
      prev = node;
      node = node->next;
   }

   if ( !prev ) {
      *list = item;
      node->prev = item;
      item->next = node;
   }
   else if ( !node ) {
      prev->next = item;
      item->prev = prev;
   }
   else {
      item->next = node;
      item->prev = prev;
      prev->next = item;
      node->prev = item;
   }
}