%TITLE	'HG$PUT_OUTPUT'
MODULE	HG$PUT_OUTPUT (IDENT = '01-000') =
BEGIN
!++
!
!  Facility:	I/O routines
!
!  Author:	Hunter Goatley
!		goathunter@WKUVX1.BITNET
!
!  Date:	March 13, 1992
!
!  Abstract:
!
!	This file contains the routines necessary to provide TYPE/PAGE
!	emulation.  It is useful for pausing screenfuls of output so that
!	the text doesn't scroll off the screen before the user has a chance
!	to read it.
!
!  Modified by:
!
!	01-000		Hunter Goatley		13-MAR-1992 07:59
!		Genesis.
!
!--
LIBRARY 'SYS$LIBRARY:STARLET';

SWITCHES ADDRESSING_MODE (EXTERNAL = GENERAL, NONEXTERNAL = WORD_RELATIVE);

FORWARD ROUTINE
	hg$put_output,				!The output routine
	hg$put_outexh;				!The exit handler

EXTERNAL ROUTINE
	LIB$PUT_OUTPUT,				!Write to SYS$OUTPUT
	SMG$CREATE_PASTEBOARD,			!Create an SMG$ pasteboard
	SMG$CREATE_VIRTUAL_DISPLAY,		!Create an SMG$ virtual display
	SMG$CREATE_VIRTUAL_KEYBOARD,		!Create an SMG$ keyboard
	SMG$DELETE_PASTEBOARD,			!Delete an SMG$ pasteboard
	SMG$DELETE_VIRTUAL_DISPLAY,		!Delete an SMG$ virtual display
	SMG$DELETE_VIRTUAL_KEYBOARD,		!Delete an SMG$ keyboard
	SMG$ERASE_CHARS,			!Erase characters from display
	SMG$PASTE_VIRTUAL_DISPLAY,		!Paste a virtual display
	SMG$PUT_CHARS,				!Write characters to a display
	SMG$PUT_LINE,				!Write a line to a display
	SMG$READ_KEYSTROKE,			!Read a key from the keyboard
	SMG$UNPASTE_VIRTUAL_DISPLAY;		!Unpaste a virtual display

LITERAL
	txt$c_bufsiz	= 256,
	true		= 1,
	false		= 0;

MACRO
	$STATICDESC (len, addr) =	!Static descriptor declaration
		$BBLOCK[DSC$C_S_BLN]
		PRESET	([DSC$W_LENGTH] = len,
			 [DSC$B_DTYPE]	= DSC$K_DTYPE_T,
			 [DSC$B_CLASS]	= DSC$K_CLASS_S,
			 [DSC$A_POINTER]= addr)
	%;


%SBTTL	'HG$PUT_OUTPUT'
GLOBAL ROUTINE hg$put_output (string_a) =
BEGIN
!+
!
!  Routine:	PUT_OUTPUT
!
!  Functional Description:
!
!	This routine is called to write a line to SYS$OUTPUT.  It keeps
!	track of how many lines have been displayed and prompts the user
!	to press [RETURN] if a full-screen is displayed.
!
!	For terminals, SMG$ is used to manage the screen.  If SYS$OUTPUT
!	is not a terminal (i.e., a file), LIB$PUT_OUTPUT is used and no
!	checks on the line count are made.
!
!  Environment:
!
!	User mode.
!
!  Formal parameters:
!
!	string_a	- Address of string descriptor for output string
!
!  Implicit inputs:
!
!	fao_out, line, module_header, header_buff
!
!  Outputs:
!
!	None.
!
!  Returns:
!
!	R0	- Status
!
!-
BIND
	string		= .string_a	: $BBLOCK;

BIND
	sys$output	= %ASCID'SYS$OUTPUT',
	key_prompt	= %ASCID'Press RETURN to continue, CTRL-Z to exit';

OWN
	vd1,					!Main text virtual display
	vd2,					!"Press RETURN...." display
	pb,					!The pasteboard
	kb,					!The keyboard
	rows,					!The number of rows in pb
	columns,				!The number of columns in pb
	key_prompt_col,				!The column number for prompt
	terminal,				!Terminal flag (true/false)
	line_count,				!Number of lines printed
	exit_status,				!Exit status for exit handler
	iosb		: $BBLOCK[8],		!I/O status block
	exh_block	: VECTOR[8,LONG]
		INITIAL (0, hg$put_outexh, 5, exit_status, vd1, vd2, pb, kb);

REGISTER
	status;					!The status

  !
  !  The first time this routine is called, call $GETDVI to see if
  !  SYS$OUTPUT is a terminal or not.  If it is, then make the appropriate
  !  SMG$ calls to set up the pasteboard and the virtual displays.
  !
  IF (.rows EQLU 0)
  THEN
     BEGIN
     status = SMG$CREATE_PASTEBOARD (pb, sys$output, rows, columns,
			0, terminal);

     terminal = (IF (.terminal EQLU SMG$K_VTTERMTABLE)	!Is it a terminal?
		 THEN					!Set flag to true or
		    true				!... false for fast
		 ELSE					!... checking later on
		    false);				!...
     IF .terminal					!If terminal, then get
     THEN						!... the page size
	IF (.rows GTRU 4)			!If there are at least 4 rows
	THEN					!... on the screen, then use
	   BEGIN				!... SMG for the output
	   rows = .rows - 2;			!Leave two lines for the prompt
	   status = SMG$CREATE_VIRTUAL_DISPLAY (rows, columns, vd1);
	   rows = .rows - 1;	!Display last line at top after scroll
	   status = SMG$CREATE_VIRTUAL_DISPLAY (%REF(1), columns, vd2);
	   status = SMG$PASTE_VIRTUAL_DISPLAY (vd1, pb, %REF(1), %REF(1));
	   status = SMG$PASTE_VIRTUAL_DISPLAY (vd2, pb, %REF(.rows+3), %REF(1));
	   status = SMG$CREATE_VIRTUAL_KEYBOARD (kb);
	   key_prompt_col = (.columns-.key_prompt<0,16,0>) / 2;
	   status = $DCLEXH (DESBLK = exh_block);
	   END
	ELSE
	   terminal = false;				!Set no terminal

     IF NOT(.terminal)					!If it's not a terminal,
     THEN						!... delete the SMG$
	status = SMG$DELETE_PASTEBOARD (pb, %REF(0));	!... pasteboard

     line_count = 0;					!Initialize the count
     END;

  !
  !  Now we're ready to write the string to SYS$OUTPUT.
  !
  !  If SYS$OUTPUT is a terminal, add a <LF><CR> pair to the string and
  !  write it using $QIOW.  If we hit the maximum number of lines to display,
  !  then prompt the user to press a key before returning.
  !
  !  If SYS$OUTPUT is *not* a terminal, just use LIB$PUT_OUTPUT.
  !
  IF .terminal
  THEN
     BEGIN
     status = SMG$PUT_LINE (vd1, string);		!Write string to vd1
     line_count = .line_count + 1;			!Bump number of lines
     !
     !  If the number of lines written is equal to the page length - 2,
     !  then prompt the user to press a key before continuing....
     !
     IF (.line_count EQLU .rows)
     THEN
	BEGIN
	LOCAL	key_pressed;
	status = SMG$PUT_CHARS (vd2, key_prompt, %REF(1),
				key_prompt_col,0,
				UPLIT(SMG$M_REVERSE));
	status = SMG$READ_KEYSTROKE (kb, key_pressed);
	status = SMG$ERASE_CHARS (vd2, %REF(.key_prompt<0,16,0>), %REF(1),
				   key_prompt_col);
	!
	!  Exit the program (via $EXIT) if any key other than RETURN or
	!  SPACE was typed (SPACE is accepted for "more" compatibility).
	!
	IF ((.key_pressed<0,16,0> NEQU SMG$K_TRM_CR) AND
	    (.key_pressed<0,16,0> NEQU SMG$K_TRM_SPACE))
	THEN
	   $EXIT (CODE = SS$_NORMAL);
	line_count = 0;					!And reset line counter
	END;
     END
  ELSE							!Not a terminal, so
     LIB$PUT_OUTPUT (string);				!... just use LIB$ rtn


  RETURN (SS$_NORMAL);					!Always return success

END;


ROUTINE hg$put_outexh (estatus_a, vd1_a, vd2_a, pb_a, kb_a) =
BEGIN
!++
!
!  Routine:	HG$PUT_OUTEXH
!
!  Abstract:
!
!	This routine is established as an exit handler to delete the
!	pasteboard and the keyboard.  The virtual displays are not deleted,
!	though, because the screen is cleared if they are.
!
!--
BIND
	estatus	= .estatus_a,
	vd1	= .vd1_a,
	vd2	= .vd2_a,
	pb	= .pb_a,
	kb	= .kb_a;

REGISTER
	status;

  !
  !If the virtual displays are deleted, the text disappears---just let
  !the image rundown free up the memory.....
  !
!  status = SMG$DELETE_VIRTUAL_DISPLAY (vd1);
!  status = SMG$DELETE_VIRTUAL_DISPLAY (vd2);
  status = SMG$DELETE_VIRTUAL_KEYBOARD (kb);
  RETURN (SMG$DELETE_PASTEBOARD (pb, %REF(0)));

END;

END
ELUDOM