slist.h

This software was done in part for a textbook on AI I ve written called _The Basis of AI_ (tentative

/*******************************************************************************
+
+  LEDA 3.5
+
+
+  slist.h
+
+
+  Copyright (c) 1995, 1996, 1997  by  LEDA Software GmbH
+  Postfach 151101, 66041 Saarbruecken, Germany
+  All rights reserved.
+ 
*******************************************************************************/


#ifndef LEDA_IMPL_SLIST_H
#define LEDA_IMPL_SLIST_H

//------------------------------------------------------------------------------
// simply linked lists
//------------------------------------------------------------------------------


#include <LEDA/basic.h>


class SLIST; 
class slink;

typedef slink* slist_item;

//------------------------------------------------------------------------------
// class slink 
//------------------------------------------------------------------------------

class __exportC slink {

  friend class __exportC SLIST;

  slink* succ;
  GenPtr e;

  slink(GenPtr a, slink* suc) { e = a; succ = suc; }

  LEDA_MEMORY(slink)

};


//------------------------------------------------------------------------------
// SLIST: base class for all simply linked Lists
//------------------------------------------------------------------------------

class __exportC SLIST {

   slink* h;                     //head
   slink* t;                     //tail
   int    count;                 //length of List

virtual void clear_el(GenPtr&) const {}
virtual void copy_el(GenPtr&)  const {}
virtual int  el_type_id() const { return UNKNOWN_TYPE_ID; }

public:

   int space()  const { return sizeof(SLIST) + count * sizeof(slink); }
   int length() const { return count; }
   bool empty()  const { return (count==0);}

   slink* insert(GenPtr, slink*);


   slink* push(GenPtr a)   
   { count++;
     h = new slink(a,h); 
     if (t==0) t = h;
     return h;
   }

   slink* append(GenPtr a)
   { count++;
     if (t) t = t->succ = new slink(a,0); 
     else   t = h = new slink(a,0); 
     return t;
   } 

   slink* first()               const { return h; }
   slink* first_item()          const { return h; }
   slink* last()                const { return t; }
   slink* last_item()           const { return t; }
   slink* next_item(slink* p)   const { return p ? p->succ : 0; }
   slink* succ(slink* l)        const { return l->succ; }
   slink* cyclic_succ(slink*)   const;

   void conc(SLIST&);

   GenPtr head()   const { return h ? h->e : 0;}
   GenPtr tail()   const { return t ? t->e : 0;}
   GenPtr pop();

   void del_succ(slink* p)    
   { slink* q = p->succ;
     if (q == t) t = p;
     p->succ = q->succ; 
     delete q;
     count--;
   }

   GenPtr  contents(slink* l)  const  { return l->e; }
   GenPtr& entry(slink* l)            { return l->e; }
   GenPtr& operator[](slink* l)       { return l->e; }
   GenPtr  operator[](slink* l) const { return l->e; }

   void clear();

   SLIST();    
   SLIST(GenPtr a);
   SLIST& operator=(const SLIST&); 
   SLIST(const SLIST&);
   virtual ~SLIST()     { clear(); }

};


#endif