///////    File: ArbList.C    ///////
#include "ArbList.h"

ArbList::~ArbList() {   free();  }

void ArbList::free() // private method
{       ArbCell* n, *p = head;
        while (p)
        {   n = p->next;
            delete p;
            p=n;
        }
}

int ArbList::shorten(int n)
{     while (n-- && head)
      {   ArbCell* tmp=head;
          head = head->next;
          delete(tmp);
      }
      return(- ++n);
}

int ArbList::remove(Arbent c)
{     ArbCell *tmp, *p = head;
      int count = 0;
      if ( p == NULL ) return(count);
      while (p->next)      // treat all but head cell
      {  if ( equal((p->next)->item, c) ) // call equal
         {   count++;
             tmp = p->next;
             p->next = tmp->next;
             delete(tmp); // free up store
         }
         else
                p = p->next;
      }
      if( equal(head->item, c) ) // treat head cell
      {  tmp = head;
         head = head->next;
         delete(tmp);
         count++;
      }
      return(count);        // number of items removed
}

int ArbList::put_on(Arbent c)
{     ArbCell* tmp = new ArbCell(c,head);
      if ( tmp )
      {  head = tmp;
         return(0);
      }
      else return(-1); // failed
}

// insert after entry e
int ArbList::insert(Arbent c, ArbCell* e)
{     ArbCell* tmp = new ArbCell(c,next(e));
      if ( tmp )
      {  if (e) e->next = tmp;
         else head = tmp;
         return(0);
      }
      else return(-1); // failed
}

ArbCell* ArbList::last()
{     ArbCell* p = head;
      while( p && p->next ) p =  p->next; 
      return(p);
}

ArbCell* ArbList::find(Arbent c)
{   for( ArbCell* p = head; p ; p = p->next )
       if( equal(p->item, c) )
           return(p);
    return(NULL);  // c not on list
}

int ArbList::substitute(Arbent r, Arbent s)
{   ArbCell* p = find(s);
    if ( p == NULL ) return(-1);  // s not on list
    p->item = r;
    return(0);
}

// display from p to end
void ArbList::display(ArbCell* p)
{   cout << "(";
    while ( p )
    {    dispfn(p->item);
         if ( p = p->next ) cout << " ";
    }
    cout << ")\n";
}