--- /dev/null
+#ifndef LINKLIST_H
+#define LINKLIST_H
+
+template<class TYPE> class List;
+
+template<class TYPE>
+class ListItem {
+public:
+ TYPE *previous, *next;
+ List<TYPE> *owner;
+
+ int get_item_number() { return !owner ? -1 : owner->number_of(this); }
+ ListItem() { owner = 0; previous = next = 0; }
+ ListItem(List<TYPE> &me) { owner = me; previous = next = 0; }
+ virtual ~ListItem() { if( owner ) owner->remove_pointer(this); }
+};
+
+template<class TYPE>
+class List {
+ TYPE *split(int (*cmpr)(TYPE *a, TYPE *b),TYPE *l, TYPE *r);
+ void sort(int (*cmpr)(TYPE *a, TYPE *b),TYPE *ll, TYPE *rr);
+ static int cmpr(TYPE *a, TYPE *b) {
+ if( *a == *b ) return 0;
+ return *a > *b ? 1 : -1;
+ }
+public:
+ TYPE *first, *last;
+ void remove(TYPE *item) { if(item) delete item; }
+ void remove_pointer(ListItem<TYPE> *item);
+ TYPE *append(TYPE *new_item);
+ TYPE *append() { return append(new TYPE()); }
+ TYPE *insert_before(TYPE *here, TYPE *item);
+ TYPE *insert_before(TYPE *here) { return insert_before(here, new TYPE()); }
+ TYPE *insert_after(TYPE *here, TYPE *item);
+ TYPE *insert_after(TYPE *here) { return insert_after(here, new TYPE()); }
+ int total() { TYPE *p=first; int n=0; while(p) { p=p->next; ++n; } return n; }
+ TYPE *get_item_number(int i) { TYPE *p=first;
+ while(p && i>0) { --i; p=p->next; }
+ return p;
+ }
+ TYPE &operator[](int i) { return *get_item_number(i); }
+ int number_of(TYPE *item) { TYPE *p=first; int i=0;
+ while(p && p!=item) { ++i; p=p->next; }
+ return p ? i : -1;
+ }
+ void swap(TYPE *item1, TYPE *item2);
+ void sort(int (*cmp)(TYPE *a, TYPE *b) = 0) {
+ return sort(cmp ? cmp : cmpr,0,0); }
+ List() { first = last = 0; }
+ virtual ~List() { while(last) delete last; }
+};
+
+// convenience macros
+#define PREVIOUS current->previous
+#define NEXT current->next
+
+template<class TYPE>
+TYPE* List<TYPE>::append(TYPE *item)
+{
+ item->owner = this; item->next = 0;
+ if( !last ) { item->previous = 0; first = item; }
+ else { item->previous = last; last->next = item; }
+ return last = item;
+}
+
+template<class TYPE>
+TYPE* List<TYPE>::insert_before(TYPE *here, TYPE *item)
+{
+ if( !here || !last ) return append(item);
+ item->owner = this; item->next = here;
+ *( !(item->previous=here->previous) ? &first : &here->previous->next ) = item;
+ return here->previous = item;
+}
+
+template<class TYPE>
+TYPE* List<TYPE>::insert_after(TYPE *here, TYPE *item)
+{
+ if( !here || !last ) return append(item);
+ item->owner = this; item->previous = here;
+ *( !(item->next=here->next) ? &last : &here->next->previous ) = item;
+ return here->next = item;
+}
+
+
+template<class TYPE>
+void List<TYPE>::remove_pointer(ListItem<TYPE> *item)
+{
+ if( !item ) return;
+ TYPE *previous = item->previous, *next = item->next;
+ *( previous ? &previous->next : &first ) = next;
+ *( next ? &next->previous : &last ) = previous;
+ item->owner = 0;
+}
+
+template<class TYPE>
+void List<TYPE>::swap(TYPE *item1, TYPE *item2)
+{
+ if( item1 == item2 ) return;
+ TYPE *item1_previous = item1->previous, *item1_next = item1->next;
+ TYPE *item2_previous = item2->previous, *item2_next = item2->next;
+ *( item1_previous ? &item1_previous->next : &first ) = item2;
+ *( item1_next ? &item1_next->previous : &last ) = item2;
+ *( item2_previous ? &item2_previous->next : &first ) = item1;
+ *( item2_next ? &item2_next->previous : &last ) = item1;
+ item1->previous = item2_previous == item1 ? item2 : item2_previous;
+ item1->next = item2_next == item1 ? item2 : item2_next;
+ item2->previous = item1_previous == item2 ? item1 : item1_previous;
+ item2->next = item1_next == item2 ? item1 : item1_next;
+}
+
+template<class TYPE>
+TYPE *List<TYPE>::split(int (*cmpr)(TYPE *a, TYPE *b), TYPE *l, TYPE *r)
+{
+ for(;;) {
+ while( cmpr(r,l) >= 0 ) if( (l=l->next) == r ) return r;
+ swap(l, r);
+ while( cmpr(l,r) >= 0 ) if( r == (l=l->previous) ) return r;
+ swap(l, r);
+ }
+}
+
+template<class TYPE>
+void List<TYPE>::sort(int (*cmpr)(TYPE *a, TYPE *b), TYPE *ll, TYPE *rr)
+{
+ for(;;) {
+ TYPE *l = !ll ? first : ll->next;
+ if( l == rr ) return;
+ TYPE *r = !rr ? last : rr->previous;
+ if( l == r ) return;
+ TYPE *m = split(cmpr, l, r);
+ sort(cmpr, ll, m);
+ ll = m;
+ }
+}
+
+#endif