/* $Id: list.c,v 1.13 2003/06/15 10:05:55 sjoerd Exp $ */
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

#include "common.h"
#include "list.h"

/*
 *  Simple refcounted linked list implementation.
 *  Copyright (C) 2002-2006 Sjoerd Simons
 *
 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
*/

static void
list_node_ref(List * list, List_node * item) {
  item->refcount++;
}

static void
list_node_unref(List * list, List_node * item) {

  item->refcount--;
  if (item->refcount <= 0) {
    if (item->next != NULL) {
      item->next->prev = item->prev;
    }
    if (item->prev != NULL) {
      item->prev->next = item->next;
    }
    if (list->head == item) {
      list->head = item->next;
    }
    if (list->tail == item) {
      list->tail = item->prev;
    }
    free(item);
  }
}

static List_node *
list_new_node(void *data) {
  List_node *result = malloc(sizeof(List_node));

  assert(data != NULL);
  assert(result != NULL);

  memset(result, 0, sizeof(List_node));
  result->data = data;
  return result;
}

static void
list_del_node(List * list, List_node * item) {
  item->data = NULL;
  list->length--;
  list_node_unref(list, item);
}

List *
new_list(void) {
  List *result;

  result = malloc(sizeof(List));
  assert(result != NULL);
  memset(result, 0, sizeof(List));
  return result;
}

void
del_list(List * list) {
  List_ptr *ptr;

  ptr = new_list_ptr(list);
  if (list_ptr_first(ptr)) {
    do {
      list_ptr_del_current(ptr);
    } while (list_ptr_next(ptr));
  }
  del_list_ptr(ptr);
  free(list);
}

int
list_prepend(List * list, void *data) {
  List_node *n;

  n = list_new_node(data);
  list_node_ref(list, n);

  if (list->tail == NULL) {
    list->tail = n;
  } else {
    /* list->tail != NULL so list->head is also !NULL */
    n->next = list->head;
    list->head->prev = n;
  }
  list->head = n;
  list->length++;
  return TRUE;
}

int
list_append(List * list, void *data) {
  List_node *n;

  n = list_new_node(data);
  list_node_ref(list, n);

  if (list->head == NULL) {
    list->head = n;
  } else {
    /* list->head != NULL so list->tail is also !NULL */
    n->prev = list->tail;
    list->tail->next = n;
  }
  list->tail = n;
  list->length++;
  return TRUE;
}

int
list_cmp_data(void *data, void *user_data) {
  return data == user_data;
}

int
list_del(List * list, void *data) {
  List_ptr *ptr;

  ptr = new_list_ptr(list);
  if (!list_ptr_first(ptr)) {
    del_list_ptr(ptr);
    return FALSE;
  }

  do {
    if (list_ptr_get_data(ptr) == data) {
      list_ptr_del_current(ptr);
      del_list_ptr(ptr);
      return TRUE;
    }
  } while (list_ptr_next(ptr));

  del_list_ptr(ptr);
  return FALSE;
}

void *
list_search(List * list, ListFunc cmp_func, void *user_data) {
  List_ptr *ptr;
  void *data;

  ptr = new_list_ptr(list);
  if (!list_ptr_first(ptr)) {
    del_list_ptr(ptr);
    return NULL;
  }

  do {
    data = list_ptr_get_data(ptr);
    if (cmp_func(data, user_data)) {
      del_list_ptr(ptr);
      return data;
    }
  } while (list_ptr_next(ptr));
  del_list_ptr(ptr);
  return NULL;
}

int
list_foreach(List * list, ListFunc do_func, void *user_data) {
  List_ptr *ptr;
  void *data;

  ptr = new_list_ptr(list);
  if (!list_ptr_first(ptr)) {
    del_list_ptr(ptr);
    return TRUE;
  }

  do {
    data = list_ptr_get_data(ptr);
    if (!do_func(data, user_data)) {
      del_list_ptr(ptr);
      return FALSE;
    }
  } while (list_ptr_next(ptr));
  del_list_ptr(ptr);
  return TRUE;
}


List_ptr *
new_list_ptr(List * list) {
  List_ptr *result;

  result = malloc(sizeof(List_ptr));
  assert(result != NULL);
  result->list = list;
  result->current = NULL;
  return result;
}

void
del_list_ptr(List_ptr * ptr) {
  if (ptr->current != NULL) {
    list_node_unref(ptr->list, ptr->current);
  }
  free(ptr);
}

List_ptr *
list_ptr_dup(List_ptr * ptr) {
  List_ptr *result;

  result = malloc(sizeof(List_ptr));
  assert(result != NULL);
  memcpy(result, ptr, sizeof(List_ptr));
  list_node_ref(result->list, result->current);
  return result;
}

void *
list_ptr_get_data(List_ptr * ptr) {
  return ptr->current == NULL ? NULL : ptr->current->data;
}

void
list_ptr_del_current(List_ptr * ptr) {
  if (ptr->current != NULL && ptr->current->data != NULL) {
    list_del_node(ptr->list, ptr->current);
  }
}

static int
list_ptr_getend(List_ptr * ptr, int head) {
  List_node *next;

  if (head) {
    next = ptr->list->head;
  } else {
    next = ptr->list->tail;
  }

  while (next != NULL && next->data == NULL) {
    if (head) {
      next = next->next;
    } else {
      next = next->prev;
    }
  }
  if (next == NULL) {
    return FALSE;
  }
  if (ptr->current != NULL) {
    list_node_unref(ptr->list, ptr->current);
  }
  ptr->current = next;
  list_node_ref(ptr->list, ptr->current);
  return TRUE;
}

int
list_ptr_first(List_ptr * ptr) {
  return list_ptr_getend(ptr, TRUE);
}

int
list_ptr_last(List_ptr * ptr) {
  return list_ptr_getend(ptr, FALSE);
}

static int
list_ptr_step(List_ptr * ptr, int forward) {
  List_node *next;

  if (ptr->current == NULL) {
    return FALSE;
  }
  next = ptr->current->next;
  while (next != NULL && next->data == NULL) {
    if (forward) {
      next = next->next;
    } else {
      next = next->prev;
    }
  }
  if (next == NULL) {
    return FALSE;
  }

  list_node_unref(ptr->list, ptr->current);
  ptr->current = next;
  list_node_ref(ptr->list, ptr->current);
  return TRUE;
}

int
list_ptr_next(List_ptr * ptr) {
  return list_ptr_step(ptr, TRUE);
}

int
list_ptr_prev(List_ptr * ptr) {
  return list_ptr_step(ptr, FALSE);
}

void *
list_pop(List *list) {
  void *result;
  List_node *node;

  for (node = list->head; node != NULL && node->data == NULL; 
       node = node->next);

  if (node == NULL)
    return NULL;

  result = node->data;
  list_del_node(list,node);

  return result;
}

int 
list_length(List *list) {
  return list->length;
}

void
list_swapnodes(List_node *node0,List_node *node1) {
  List_node *tmp;

  if (node0->next == node1) {
    node0->next = node1->next;
    node1->next = node0;

    tmp = node0->prev;
    node0->prev = node1;
    node1->prev  = tmp;
  } else if (node1->next == node0) {
    node1->next = node0->next;
    node0->next = node1;

    tmp = node1->prev;
    node1->prev = node0;
    node0->prev = tmp;
  } else {
    tmp = node1->next;
    node1->next = node0->next;
    node0->next = tmp;

    tmp = node1->prev;
    node1->prev = node0->prev;
    node0->prev = tmp;
  }

  if (node1->next != NULL) {
    node1->next->prev = node1;
  }
  if (node0->next != NULL) {
    node0->next->prev = node0;
  }
  if (node0->prev != NULL) {
    node0->prev->next = node0;
  }
  if (node1->prev != NULL) {
    node1->prev->next = node1;
  }
}

List_node *
list_partition(ListSortFunc func,List_node **snode, 
               List_node **enode,void *user_data) {
  List_node *node;
  List_node *tmp;
  List_node *pivot = *enode;
  List_node *pivotpoint = *snode;;

  for (node = *snode ; node != *enode; node = node->next) {
    if (func(node->data,pivot->data,user_data) <= 0) {
      if (node != pivotpoint) {
        list_swapnodes(node,pivotpoint);
        if (*snode == pivotpoint) {
          *snode = node;
        } else if (*snode == node) {
          *snode = pivotpoint;
        }
      }
      tmp = pivotpoint;
      pivotpoint = node->next;
      node = tmp;
    }
  }
  list_swapnodes(pivot,pivotpoint); 
  if (*snode == pivotpoint) {
    *snode = pivot;
  }
  *enode = pivotpoint;
  return pivot;
}

int 
list_do_sort(ListSortFunc func,
                 List_node *snode, List_node *enode,void *user_data) {
  List_node *node;
  if (snode != NULL && enode != NULL && 
      snode->prev != enode && snode != enode) {

      node = list_partition(func,&snode,&enode,user_data);
      list_do_sort(func,snode,node->prev,user_data);
      list_do_sort(func,node->next,enode,user_data);
  }
  return TRUE;
}
int
list_sort(List *list,ListSortFunc func,void *user_data) {
  List_node *node;

  if (list->length == 0)
    return TRUE;

  list_do_sort(func,list->head,list->tail,user_data);

  /* fix -> head pointer */
  for (node = list->head; node->prev != NULL; node = node->prev)
    ;
  list->head = node;
  /* fix ->tail pointer */
  for (node = list->tail; node->next != NULL; node = node->next)
    ;
  list->tail = node;

  return TRUE;
}