byte_stream.h

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/*
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
{

class byte_stream
{
   unsigned u_length;
   _byte_ * bp_in;
   _byte_ * bp_current;
   _byte_ * bp_end;
   bool o_valid;
public :
   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);
   }
   ~ byte_stream ()
   {
      if (bp_in)
         delete [] bp_in;
   }
   _byte_ b_top ()
   {
      return * bp_current;
   }
   _byte_ b_pop ()
   {
      if (! o_is_valid ())
         return 0;
      bp_current++;
      o_valid = (bp_current != bp_end);
      return * (bp_current - 1);
   }
   bool o_is_valid ()
   {
      return o_valid;
   }
   unsigned u_remain ()
   {
      return (unsigned) (bp_end - bp_current);
   }
   _byte_ b_forward (unsigned u_nb_char)
   {
      if (u_remain () > u_nb_char)
         return bp_current [u_nb_char];
      return 0;
   }
   const _byte_ * bp_get_backward (unsigned u_amount)
   {
      return bp_current - u_amount + 1;
   }
} ;

}

#endif

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