/*

www.sourceforge.net/projects/tinyxpath

Copyright (c) 2002-2004 Yves Berquin (yvesb@users.sourceforge.net)



This software is provided 'as-is', without any express or implied

warranty. In no event will the authors be held liable for any

damages arising from the use of this software.



Permission is granted to anyone to use this software for any

purpose, including commercial applications, and to alter it and

redistribute it freely, subject to the following restrictions:



1. The origin of this software must not be misrepresented; you must

not claim that you wrote the original software. If you use this

software in a product, an acknowledgment in the product documentation

would be appreciated but is not required.



2. Altered source versions must be plainly marked as such, and

must not be misrepresented as being the original software.



3. This notice may not be removed or altered from any source

distribution.

*/

#ifndef __TINYBYTESTREAM_H

#define __TINYBYTESTREAM_H



#include <string.h>

#include "lex_util.h"



namespace TinyXPath

{



//****************************************************************************

// Added by AndyO.

// Added ENGINE_API exports.

// Fixed const correctness issues.

#include "Engine/BPEEngineAPI.h"

//****************************************************************************



   /**

   A Byte stream class, very crude. The only purpose of this class is to walk in a byte stream,

   available at construction time.

*/

class ENGINE_API byte_stream

{

   /// Length of the total string, + 1

   unsigned u_length;

   /// Total string

   _byte_ * bp_in;

   /// Current read position

   _byte_ * bp_current;

   /// First invalid position

   _byte_ * bp_end;

   /// true when there are still some byte to read

   bool o_valid;

public :

   /// constructor

   byte_stream (const char * cp_in)

   {

      u_length = strlen (cp_in) + 1;

      bp_in = new _byte_ [u_length] ;

      memcpy (bp_in, cp_in, u_length);

      bp_current = bp_in;

      bp_end = bp_in + u_length - 1;

      o_valid = (bp_current != bp_end);

   }

   /// destructor

   ~ byte_stream ()

   {

      if (bp_in)

         delete [] bp_in;

   }

   /// Returns the byte on top 

   _byte_ b_top ()

   {

      return * bp_current;

   }

   /// Consumes one byte

   _byte_ b_pop ()

   {

      if (! o_is_valid ())

         return 0;

      bp_current++;

      o_valid = (bp_current != bp_end);

      return * (bp_current - 1);

   }

   /// true if there are still some byte to consume

   bool o_is_valid ()

   {

      return o_valid;

   }

   /// number of bytes still to consume

   unsigned u_remain ()

   {

      return (unsigned) (bp_end - bp_current);

   }

   /// peek a byte a little further down the stream

   _byte_ b_forward (unsigned u_nb_char)

   {

      if (u_remain () > u_nb_char)

         return bp_current [u_nb_char];

      return 0;

   }

   /// get a byte backward pointer to the stream 

   const _byte_ * bp_get_backward (unsigned u_amount)

   {

      return bp_current - u_amount + 1;

   }

} ;



}



#endif

