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C/C++ Users Group Library 1996 July
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C-C++ Users Group Library July 1996.iso
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vol_400
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424_02
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ED-157
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scroll_down.c
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C/C++ Source or Header
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1993-09-10
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2KB
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/*
* Copyright (C) 1992 by Rush Record (rhr@clio.rice.edu)
*
* This file is part of ED.
*
* ED is free software; you can redistribute it and/or modify it under the terms
* of the GNU General Public License as published by the Free Software Foundation.
*
* ED is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with ED
* (see the file COPYING). If not, write to the Free Software Foundation, 675
* Mass Ave, Cambridge, MA 02139, USA.
*/
#include "opsys.h"
#include "rec.h"
#include "window.h"
#include "ed_dec.h"
/******************************************************************************\
|Routine: scroll_down
|Callby: bigger_win change_case fix_botrec fix_display remove_win smaller_win
|Purpose: Scrolls the current window down if possible. Returns the number
| of lines actually scrolled.
|Arguments:
| nscroll is the number of lines to try to scroll.
\******************************************************************************/
Int scroll_down(nscroll)
register Int nscroll;
{
register Int i,j;
register rec_ptr r;
if(!nscroll)
return(0);
for(r = TOPREC,i = nscroll;r->prev != BASE && i > 0;i--,r = r->prev)
TOPREC = TOPREC->prev;
if((i = nscroll - i) > 0) /* actual number scrollable */
{
if(i > BOTROW - TOPROW)
ref_window(CURWINDOW);
else
{
move(TOPROW,1);
ins_line(i);
paint(TOPROW,TOPROW + i - 1,FIRSTCOL);
}
for(BOTREC = TOPREC,j = TOPROW;j < BOTROW;j++)
{
if(BOTREC == BASE)
{
BOTREC = 0;
break;
}
else
BOTREC = BOTREC->next;
}
}
return(i);
}