/*
* inserts a thing after the thing in index
* NOTE: index must represent a valid index
*/
int insert_thing_after(
resizable_array *ra,
void *thing,
int index)
{
int rc;
int next;
/* check if the array must be resized */
if ((rc = check_and_resize(ra)) != PBSE_NONE)
{
return(-1);
}
/* insert this element */
ra->slots[ra->next_slot].item = thing;
/* save the insertion point */
rc = ra->next_slot;
/* move pointers around */
ra->slots[rc].prev = index;
next = ra->slots[index].next;
ra->slots[rc].next = next;
ra->slots[index].next = rc;
if (next != 0)
{
ra->slots[next].prev = rc;
}
/* update the last index if needed */
if (ra->last == index)
ra->last = rc;
/* increase the count */
ra->num++;
update_next_slot(ra);
return(rc);
} /* END insert_thing_after() */
int insert_thing(
resizable_array *ra,
void *thing)
{
int rc;
/* check if the array must be resized */
if ((rc = check_and_resize(ra)) != PBSE_NONE)
{
return(-1);
}
ra->slots[ra->next_slot].item = thing;
/* save the insertion point */
rc = ra->next_slot;
/* handle the backwards pointer, next pointer is left at zero */
ra->slots[rc].prev = ra->last;
/* make sure the empty slot points to the next occupied slot */
if (ra->last == ALWAYS_EMPTY_INDEX)
{
ra->slots[ALWAYS_EMPTY_INDEX].next = rc;
}
/* update the last index */
ra->slots[ra->last].next = rc;
ra->last = rc;
/* update the new item's next index */
ra->slots[rc].next = ALWAYS_EMPTY_INDEX;
/* increase the count */
ra->num++;
update_next_slot(ra);
return(rc);
} /* END insert_thing() */
int insert_thing_before(
resizable_array *ra,
void *thing,
int index)
{
int rc;
int prev;
/* check if the array must be resized */
if ((rc = check_and_resize(ra)) != PBSE_NONE)
{
return(-1);
}
/* insert this element */
ra->slots[ra->next_slot].item = thing;
/* save the insertion point */
rc = ra->next_slot;
/* move pointers around */
prev = ra->slots[index].prev;
ra->slots[rc].next = index;
ra->slots[rc].prev = prev;
ra->slots[index].prev = rc;
ra->slots[prev].next = rc;
/* increase the count */
ra->num++;
update_next_slot(ra);
return(rc);
} /* END insert_thing_before() */
