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/*
* (C) 1998-1999 Murat Deligonul
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "linkedlist.h"
#include <stdio.h>
#include <stdlib.h>
/*
* Optional last argument returns idx of last found node.
*/
__list_core::node * __list_core::find_by_idx(int idx, int * pt) const
{
int target = 0;
for (node * current = _first; current; current = current->next, target++)
{
if (target == idx)
{
if (pt)
*pt = target;
return current;
}
}
if (pt)
*pt = target;
return NULL;
}
__list_core::__list_core(void * init_data)
{
_last = _first = NULL;
num_nodes = 0;
if (init_data)
add(init_data);
}
/*
* Destroy everything
*/
__list_core::~__list_core(void)
{
while (_first)
remove(0);
}
/*
* Add an element to the end of the list
*/
int __list_core::add(void * data)
{
node * n = new node;
if (!_first)
_first = n;
if (_last)
_last->next = n;
n->data = data;
n->prev = _last;
n->next = NULL;
_last = n;
return (++num_nodes);
}
/*
* Insert at arbitrary position, or at
* begining of list if none specified.
* Takes elements place at idx. Moves that element up one.
* Does not work for adding to an end (right now); use add() for that.
*
* Return: new number of elements (0 on error)
*/
int __list_core::insert(void * data, int idx /* = 0 */)
{
int target = 0;
node * current = find_by_idx(idx , &target);
if (target != idx)
return 0;
node * n = new node;
n->data = data;
if (current)
{
if (current->prev)
current->prev->next = n;
n->prev = current->prev;
n->next = current;
current->prev = n;
}
else {
n->prev = NULL;
n->next = NULL;
}
if (!n->prev)
_first = n;
if (!n->next)
_last = n;
return (++num_nodes);
}
/*
* Get element[idx], but do not remove it.
* Use remove() if you want to remove it.
*/
void * __list_core::get(int idx)
{
node * n = find_by_idx(idx);
return n ? n->data : NULL;
}
/*
* Get element[idx] and remove it
*/
void * __list_core::remove(int idx)
{
node * n = find_by_idx(idx);
void * d;
if (!n)
return NULL;
d = n->data;
if (n->prev)
n->prev->next = n->next;
if (n->next)
n->next->prev = n->prev;
if (!n->prev)
_first = n->next;
if (!n->next)
_last = n->prev;
delete n;
num_nodes--;
return d;
}
bool __list_core::remove(void * data)
{
int idx = 0;
for (node * n = _first; n; n = n->next, idx++)
if (n->data == data)
return remove(idx), true;
return false;
}
/*
* Get the currently pointed item.
* Optional integer argument:
* -1: get previous item
* 1: get next item
* 0: get current
*/
void *__list_iter::get(int w)
{
if (current)
{
if (w == -1 && current->prev)
return current->prev->data;
else if (w == 1 && current->next)
return current->next->data;
return current->data;
}
return NULL;
}
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