/*

COPYRIGHT

Copyright 1992, 1993, 1994 Sun Microsystems, Inc.  Printed in the United
States of America.  All Rights Reserved.

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
available for your use provided that you include this license and copyright
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
functionality (but may not remove functionality) of the Interface
Definition Language CFE without charge, but you are not authorized to
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program developed by you or with the express written consent of Sun
Microsystems, Inc. ("Sun").

The names of Sun Microsystems, Inc. and any of its subsidiaries or
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distribution of Interface Definition Language CFE as permitted herein.

This license is effective until terminated by Sun for failure to comply
with this license.  Upon termination, you shall destroy or return all code
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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INTERFACE DEFINITION LANGUAGE CFE IS PROVIDED WITH NO SUPPORT AND WITHOUT
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 */

#ifndef _UTL_STACK_UTL_STACK_HH
#define _UTL_STACK_UTL_STACK_HH

#pragma ident "%@(#)utl_stack.hh	1.36% %92/06/10% Sun Microsystems"

// utl_stack.hh - Defines the UTL_ScopeStack class - a stack of scopes
//
// UTL_ScopeStack implements scope nesting

/*
** DEPENDENCIES: utl_scope.hh
**
** USE: Included from util.hh
*/

// Forward declaration of active iterator for UTL_ScopeStack
class	UTL_ScopeStackActiveIterator;

class	UTL_ScopeStack
{
public:
  // Operations

  // Constructor and destructor
  UTL_ScopeStack();
  virtual ~UTL_ScopeStack();

  // Return top element
  virtual UTL_Scope		*top();

  // Pop top element
  virtual void			pop();

  // Clear entire stack
  virtual void			clear();

  // Push an element on the stack and return stack
  virtual UTL_ScopeStack	*push(UTL_Scope *el);

  // How deep is the stack now?
  virtual unsigned long		depth();

  // Return bottom element
  virtual UTL_Scope		*bottom();

  // Return (top - 1) element
  virtual UTL_Scope		*next_to_top();

  // return topmost non-NULL element
  virtual UTL_Scope		*top_non_null();

private:
  // Data
  UTL_Scope			**pd_stack_data;	// Store scopes stack
  unsigned long			pd_stack_data_nalloced;	// How many allocated?
  unsigned long			pd_stack_top;		// How many used?

  // Friend active iterator class for UTL_ScopeStack
  friend class			UTL_ScopeStackActiveIterator;
};

// Active iterator for UTL_ScopeStack
class	UTL_ScopeStackActiveIterator
{
public:
  // Operations

  // Constructor
  UTL_ScopeStackActiveIterator(UTL_ScopeStack *s);

  // Advance to next element
  virtual void			next();

  // Get current item
  virtual UTL_Scope		*item();

  // Is the iteration finished?
  virtual long			is_done();

private:
  // Data
  UTL_ScopeStack		*source;	// On what to iterate?
  long				il;		// Where are we in iteration?
};

#endif           // _UTL_STACK_UTL_STACK_HH