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 %TITLE 'SCRCOMCUR - compute cursor position'
MODULE SCRCOMCUR (				! Compute cursor position
		IDENT = '3-001'			! File: SCRCOMCUR.BLI Edit: GB3001
		) =
BEGIN
!
!			  COPYRIGHT (c) 1981, 1985 BY
!	      DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.
!		ALL RIGHTS RESERVED.
!
! THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND  COPIED
! ONLY  IN  ACCORDANCE  WITH  THE  TERMS  OF  SUCH  LICENSE AND WITH THE
! INCLUSION OF THE ABOVE COPYRIGHT NOTICE.  THIS SOFTWARE OR  ANY  OTHER
! COPIES  THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
! OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF  THE  SOFTWARE  IS  HEREBY
! TRANSFERRED.
!
! THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE  WITHOUT  NOTICE
! AND  SHOULD  NOT  BE  CONSTRUED  AS  A COMMITMENT BY DIGITAL EQUIPMENT
! CORPORATION.
!
! DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR  RELIABILITY  OF  ITS
! SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
!

!++
! FACILITY:	EDT -- The DEC Standard Editor
!
! ABSTRACT:
!
!	This module computes the current cursor position.
!
! ENVIRONMENT:	Runs at any access mode - AST reentrant
!
! AUTHOR: Bob Kushlis, CREATION DATE: September 8, 1979
!
! MODIFIED BY:
!
! 1-001	- Original.  DJS 12-Feb-1981.  This module was created by
!	extracting the routine EDT$$SC_CPUCSPOS  from module SCREEN.
! 1-002	- Regularize headers.  JBS 13-Mar-1981
! 1-003	- Rewrite for new screen logic.  JBS 12-Oct-1982
! 1-004	- Fix a couple of minor bugs.  JBS 13-Oct-1982
! 1-005	- Fix call to EDT$$FMT_CHWID.  JBS 13-Oct-1982
! 1-006	- Fix problem with SHL.  JBS 27-Oct-1982
! 1-007	- Fix the cursor position in NOTRUNCATE mode.  JBS 09-Nov-1982
! 1-008	- Fix the cursor positioning again.  JBS 10-Nov-1982
! 1-009	- Change the handling of SHF.  JBS 14-Dec-1982
! 1-010	- Correct tab at front of continued line.  JBS 15-Dec-1982
!--

%SBTTL 'Declarations'
!
! TABLE OF CONTENTS:
!

REQUIRE 'EDTSRC:TRAROUNAM';

FORWARD ROUTINE
    EDT$$SC_CPUCSPOS : NOVALUE;

!
! INCLUDE FILES:
!

REQUIRE 'EDTSRC:EDTREQ';

!
! MACROS:
!
!	NONE
!
! EQUATED SYMBOLS:
!
!	NONE
!
! OWN STORAGE:
!
!	NONE
!
! EXTERNAL REFERENCES:
!
!	In the routine

%SBTTL 'EDT$$SC_CPUCSPOS  - compute cursor position'

GLOBAL ROUTINE EDT$$SC_CPUCSPOS (		! Compute cursor position
    LINE, 					! Where to return line number
    COLUMN					! Where to return column number
    ) : NOVALUE =

!++
! FUNCTIONAL DESCRIPTION:
!
!	This routine computes the current cursor position returning the line
!	and column numbers in the ref parameters LINE and COLUMN.
!
! FORMAL PARAMETERS:
!
!  LINE			Cursor's relative line number
!
!  COLUMN			Cursor's column number
!
! IMPLICIT INPUTS:
!
!	SHF
!	TI_WID
!	TRUN
!	LN_BUF
!	LN_PTR
!	LN_END
!
! IMPLICIT OUTPUTS:
!
!	NONE
!
! ROUTINE VALUE:
!
!	NONE
!
! SIDE EFFECTS:
!
!	NONE
!
!--

    BEGIN

    EXTERNAL ROUTINE
	EDT$$FMT_CHWID;				! Compute the width of a character

    EXTERNAL
	SHF,				! The number of columns shifted.
	TI_WID,				! Width of terminal line.
	TRUN,				! Truncate or wrap long lines.
	LN_BUF,				! Current line buffer.
	LN_PTR,				! Current character pointer.
	LN_END;				! End of line

    LOCAL
	CP,					! Character pointer into the current record
	LIN,					! Relative line number (first line = 0)
	COL,					! Column number (first column = 0), unshifted
	CHAR,					! Current character
	CHAR_WID,				! Width of the current character
	LINE_DONE;				! 1 = we are done with this line

    LIN = 0;
    COL = 0;
    CP = CH$PTR (LN_BUF, 0, BYTE_SIZE);
    LINE_DONE = 0;

    DECR I FROM CH$DIFF (.LN_PTR, .CP) - 1 TO 0 DO
	BEGIN

	IF ( NOT .LINE_DONE)
	THEN
	    BEGIN
	    CHAR = CH$RCHAR_A (CP);
	    CHAR_WID = EDT$$FMT_CHWID (.CHAR, .COL);

	    IF ((.COL + .CHAR_WID) LEQ (.TI_WID + .SHF))
	    THEN
!+
! The character fits on this line, count it and go on to the next.
!-
		COL = .COL + .CHAR_WID
	    ELSE
!+
! The character does not fit on this line.
!-

		IF .TRUN
	 	THEN
		    BEGIN
!+
! In TRUNCATE mode, just position to the last column and terminate.
!-
		    COL = .TI_WID + .SHF - 1;
		    LINE_DONE = 1;
		    END
		ELSE
		    BEGIN
!+
! In NOTRUNCATE mode, try fitting it on the next line.  Don't produce too many lines.
!-
		    LIN = .LIN + 1;
		    COL = .SHF + 2;
!+
! We can't use .CHAR_WID in the next statement because the width of a tab may be
! different on the new line since it is in a new position.
!-

		    IF (.LIN GEQ 255) THEN LINE_DONE = 1 ELSE COL = .COL + EDT$$FMT_CHWID (.CHAR, .COL);

		    END;
	    END

        ELSE
	    EXITLOOP;

	END;

!+
! In NOTRUNCATE mode, make sure the current character will fit on this line.  If it will not,
! move the cursor to the beginning of the next line.
!-

    IF (( NOT .TRUN) AND ( NOT .LINE_DONE) AND (CH$PTR_NEQ (.LN_PTR, .LN_END)))
    THEN
	BEGIN
	CHAR = CH$RCHAR_A (CP);
	CHAR_WID = EDT$$FMT_CHWID (.CHAR, .COL);

	IF ((.COL + .CHAR_WID) GTR (.TI_WID + .SHF))
	THEN
	    BEGIN
	    LIN = .LIN + 1;
	    COL = .SHF + 2;
	    END;

	END;

    .LINE = .LIN;
    .COLUMN = MAX (0, MIN (.COL - .SHF, .TI_WID - 1));
    END;					! of routine EDT$$SC_CPUCSPOS

!<BLF/PAGE>

END						! of module SCRCOMCUR

ELUDOM