/** \brief Rewind the lexer input to the state specified by the supplied mark.
 * 
 * \param[in] input Input stream context pointer
 *
 * \remark
 * Assumes ASCII (or at least, 8 Bit) input stream.
 */
static void
antlr3AsciiSeek	(pANTLR3_INT_STREAM is, ANTLR3_MARKER seekPoint)
{
	ANTLR3_INT32   count;
	pANTLR3_INPUT_STREAM input;

	input   = ANTLR3_FUNC_PTR(((pANTLR3_INPUT_STREAM) is->super));

	/* If the requested seek point is less than the current
	* input point, then we assume that we are resetting from a mark
	* and do not need to scan, but can just set to there.
	*/
	if	(seekPoint <= (ANTLR3_MARKER)(input->nextChar))
	{
		input->nextChar	= ((pANTLR3_UINT8) seekPoint);
	}
	else
	{
		count	= (ANTLR3_UINT32)(seekPoint - (ANTLR3_MARKER)(input->nextChar));

		while (count--)
		{
			is->consume(is);
		}
	}
}

/// \brief Rewind the lexer input to the state specified by the supplied mark.
///
/// \param[in] input Input stream context pointer
///
/// \remark
/// Assumes ASCII (or at least, 8 Bit) input stream.
///
static void
antlr3UCS2Seek	(pANTLR3_INT_STREAM is, ANTLR3_MARKER seekPoint)
{
	ANTLR3_INT32   count;
	pANTLR3_INPUT_STREAM input;

	input   = ((pANTLR3_INPUT_STREAM) is->super);

	// If the requested seek point is less than the current
	// input point, then we assume that we are resetting from a mark
	// and do not need to scan, but can just set to there.
	//
	if	(seekPoint <= (ANTLR3_MARKER)(input->nextChar))
	{
		input->nextChar	= (void *)seekPoint;
	}
	else
	{
		count	= (ANTLR3_UINT32)((seekPoint - (ANTLR3_MARKER)(input->nextChar)) / 2); // 16 bits per character in UCS2

		while (count--)
		{
			is->consume(is);
		}
	}
}

static void		    
dbgRewindStream	(pANTLR3_INT_STREAM is, ANTLR3_MARKER marker)
{
    pANTLR3_TOKEN_STREAM	ts;

    ts	    = (pANTLR3_TOKEN_STREAM)	    is->super;

	ts->debugger->rewind(ts->debugger, marker);

    is->seek(is, (ANTLR3_UINT32)(marker));
}

/// Debug only method to flag consumption of initial off-channel
/// tokens in the input stream
///
static void
consumeInitialHiddenTokens(pANTLR3_INT_STREAM is)
{
	ANTLR3_MARKER	first;
	ANTLR3_INT32	i;
	pANTLR3_TOKEN_STREAM	ts;

	ts	    = (pANTLR3_TOKEN_STREAM)	    is->super;
	first	= is->index(is);

	for	(i=0; i<first; i++)
	{
		ts->debugger->consumeHiddenToken(ts->debugger, ts->get(ts, i));
	}

	ts->initialStreamState = ANTLR3_FALSE;

}

static  void
rewindLast      (pANTLR3_INT_STREAM is)
{
   is->seek(is, is->lastMarker);
}