
/*
 
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Copyright 1992, 1993, 1994 Sun Microsystems, Inc.  Printed in the United
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This product is protected by copyright and distributed under the following
license restricting its use.
 
The Interface Definition Language Compiler Front End (CFE) is made
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notice on all media and documentation and the software program in which
this product is incorporated in whole or part. You may copy and extend
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distribution of Interface Definition Language CFE as permitted herein.
 
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and documentation for the Interface Definition Language CFE.
 
INTERFACE DEFINITION LANGUAGE CFE IS PROVIDED AS IS WITH NO WARRANTIES OF
ANY KIND INCLUDING THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS
FOR A PARTICULAR PURPOSE, NONINFRINGEMENT, OR ARISING FROM A COURSE OF
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 */


// utl_list.cc
//
// Implementation of generic single-linked lists

// NOTE: This list class only works correctly because we use single public
//       inheritance, as opposed to multiple inheritance or public virtual.
//  It relies on a type-unsafe cast from UTL_List to subclasses, which
//  will cease to operate correctly if you use either multiple or
//  public virtual inheritance.
//
//  For portability reasons we have decided to provide both this and
//  an implementation of the list classes in terms of templates. If
//  your compiler supports templates, please use the files in the
//  include/utl_tmpl and util/utl_tmpl directories instead of the
//  files by the same names in the include and util directories.

#include <idl.h>
#include <idl_extern.h>

/*
 * Constructor(s)
 */

UTL_List::UTL_List(UTL_List *c)
      : pd_cdr_data(c)
{}

/*
 * Private operations
 */

// Compute list length
long
UTL_List::list_length(long n)
{
   if (pd_cdr_data == NULL)
      return n;
   else
      return pd_cdr_data->list_length(n + 1);
}

/*
 * Public operations
 */

// Smash last cdr with l
void
UTL_List::nconc(UTL_List *l)
{
   if (pd_cdr_data == NULL)
      pd_cdr_data = l;
   else
      pd_cdr_data->nconc(l);
}

/*
 * Override this operation to copy lists of other types
 */ 
// Copy a list
UTL_List *
UTL_List::copy()
{
   if (pd_cdr_data == NULL)
      return new UTL_List(NULL);

   return new UTL_List(pd_cdr_data->copy());
}

// Get next list
UTL_List *
UTL_List::tail()
{
   return pd_cdr_data;
}

// Set next list
void
UTL_List::set_tail(UTL_List *l)
{
   pd_cdr_data = l;
}

// Compute list length
long
UTL_List::length()
{
   return list_length(1);
}

/*
 * Redefinition of inherited virtual operations
 */

// UTL_List active iterator

/*
 * Constructor
 */

UTL_ListActiveIterator::UTL_ListActiveIterator(UTL_List *s)
      : source(s)
{}

/*
 * Private operations
 */

/*
 * Public operations
 */

// Is iterator done?
long
UTL_ListActiveIterator::is_done()
{
   return (source == NULL) ? I_TRUE : I_FALSE;
}

// Advance to next item
void
UTL_ListActiveIterator::next()
{
   if (source != NULL)
      source = source->tail();
}

/*
 * Redefinition of inherited operations
 */

