// Source:        dblist.cpp  
// Author:        Michele Estebon
// Date:          11/26/96
// For:           CS1704: Introduction to Data Structures and Software Design
// Last revision: 11/26/96

/**************************************************************************************
   Low Level Double linked list operations for pointer implementaion
        
   Provided functions:
       (public functions)
***************************************************************************************/

/*-- INCLUDES ------------------------------------------------------------------------*/       

#include "dblist.h"
#include "listglob.h"
#include <string.h>


/*-- TYPE DEFINITIONS ----------------------------------------------------------------*/       

// located in dblist.h 

//***************** LINKED LIST OPERATIONS  *******************************************

void GetLabel( nodeptr List, labeltype& flabel)
{  
    if (List != null)
        strcpy(flabel, List->label); 
}

void RefctDec( nodeptr& List )
{
    if (List != null)
        List->refct--;
}

void RefctInc( nodeptr& List)
{
    if (List != null)
        List->refct++;
}

void GetCode( nodeptr List, codetype& fcode)
{
    if (List != null)
        fcode = List->code;
}

void SetRefct( nodeptr& List, int ct)
{
    if (List != null)
        List->refct = ct;
}

int GetRefct( nodeptr List )
{
    if (List!= null)
        return (List->refct);
    else return (-1);
}

void GetElements( nodeptr N, keytype &fname, labeltype &lbl, codetype &cde, int &refcount )
{
    strcpy(fname, N->name);
    strcpy(lbl, N->label);
    cde = N->code;
    refcount = N->refct; 
}

void SetNextLink( nodeptr N, nodeptr A)
	{	N->next = A;   }

void SetPrevLink( nodeptr N, nodeptr A )
	{   N->prev = A;   }
 
nodeptr GetNextLink( nodeptr N )
	{   return (N->next);  }

nodeptr GetPrevLink( nodeptr N)
	{   return (N->prev);  }

void AssignItem( nodeptr N, keytype nuname, labeltype nulabel, codetype nucode )
{
	strcpy(N->name, nuname);
	strcpy(N->label, nulabel);
	N->code  = nucode;
}
 
void AssignName( nodeptr N, keytype newname )
{
    strcpy( N->name, newname );
}
 
void AssignLabel( nodeptr N, labeltype newlabel )
{
    strcpy( N->label, newlabel );
}

void AssignCode( nodeptr N, codetype newcode )
{
    N->code = newcode;
}

void GetItem( nodeptr List, keytype& key1 )
{
	strcpy( key1, List->name);
}
 
void AllocateNew( nodeptr& newnode)
{
	newnode = new node; 
	SetPrevLink( newnode, NULL );
	SetNextLink( newnode, NULL );

}
 
void FreeNode( nodeptr oldnode )
{
	delete oldnode;
}
 
void InitList( void )
{
	// none needed for pointer implementation
}

Boolean GreaterThan( keytype key1, keytype key2)
{
	// works for strings
	return ( strcmp(key1, key2) > 0  );
}

Boolean EqualTo( keytype key1, keytype key2)
{
	// works only for strings
	return ( strcmp( key1, key2) == 0 );
}