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Trailing-Edge - PDP-10 Archives - bb-r775d-bm_tops20_ks_upd_4 - sources/wfloclin.bli
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 %TITLE 'WFLOCLIN - find a specified line by number'
MODULE WFLOCLIN (				! Find a specified line by number
		IDENT = '3-001'			! File: WFLOCLIN.BLI Edit: CJG3001
		) =
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:
!
!	Find a specified line, given its number.
!
! ENVIRONMENT:	Runs at any access mode - AST reentrant
!
! AUTHOR: Bob Kushlis, CREATION DATE: October 16, 1978
!
! MODIFIED BY:
!
! 1-001	- Original.  DJS 23-Feb-1981.  This module was created by
!	extracting routine WFLOCLIN from module EDTWF.
! 1-002	- Regularize headers.  JBS 19-Mar-1981
! 1-003	- Use the ASSERT macro.  JBS 01-Jun-1981
! 3-001 - Modify ASSERT macro to include error code. CJG 30-Jan-1984
!--

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

REQUIRE 'EDTSRC:TRAROUNAM';

FORWARD ROUTINE
    EDT$$LOC_LN;

!
! INCLUDE FILES:
!

REQUIRE 'EDTSRC:EDTREQ';

!
! MACROS:
!
!	NONE
!
! EQUATED SYMBOLS:
!
!	NONE
!
! OWN STORAGE:
!
!	NONE
!
! EXTERNAL REFERENCES:
!
!	In the routine
%SBTTL 'EDT$$LOC_LN  - find a specified line by number'

GLOBAL ROUTINE EDT$$LOC_LN (			! Find a specified line, given its number
	LINE_NUM				! Number of line to find
    ) =

!++
! FUNCTIONAL DESCRIPTION:
!
!	This procedure searches for a specified line number.  If the line number
!	is found, the buffer is left postioned there, if not, the buffer is positioned
!	to the first line with a number larger than the line to be located.  The value
!	returned is 1 if the actual line was located and 0 otherwise.
!
! FORMAL PARAMETERS:
!
!  LINE_NUM 		the address of the line number to be located.
!
! IMPLICIT INPUTS:
!
!	WK_LN
!
! IMPLICIT OUTPUTS:
!
!	WK_LN
!
! ROUTINE VALUE
!
!	1 = the line was found
!	0 = the line was not found, positioned right after where it should have been
!
! SIDE EFFECTS:
!
!	NONE
!
!--

    BEGIN

    EXTERNAL ROUTINE
	EDT$$CMP_LNO,
	EDT$$RD_PRVLN,
	EDT$$RD_NXTLN;

    EXTERNAL
	WK_LN : REF LIN_BLOCK;		! Pointer to current line

    MAP
	LINE_NUM : REF LN_BLOCK;

    LOCAL
	RELAT1,
	RELAT2;

    RELAT1 = 2;					! make sure no match first time

    DO
	BEGIN
	RELAT2 = EDT$$CMP_LNO (WK_LN [LIN_NUM], .LINE_NUM);
!+
! If the relationship between the current line and the target line has gone from
! -1 to 1, or vice versa, without touching 0 in between, then the target line is
! not in the buffer.
!-

	IF (.RELAT1 EQL .RELAT2) THEN EXITLOOP;

	SELECTONE .RELAT2 OF
	    SET

	    [-1] : 				! Move forward to find the line

		IF ( NOT EDT$$RD_NXTLN ()) THEN RETURN (0);	! Return if at end of buffer

	    [0] : 				! We are on the line, return success
		RETURN (1);

	    [1] : 				! Move backward to find the line

		IF ( NOT EDT$$RD_PRVLN ()) THEN RETURN (0);	! Return if at beginning of buffer

	    [OTHERWISE] :
		ASSERT (12, 0);
	    TES;

	RELAT1 = -.RELAT2;			! Remember previous relation
	END
    UNTIL 0;

!+
! Make sure we are positioned on the line just larger than the (missing) target line.
!-

    IF (.RELAT2 EQL -1) THEN EDT$$RD_NXTLN ();

    RETURN (0);
    END;


END
ELUDOM