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[unix-history] / usr / src / usr.bin / window / wwclreol.c

#ifndef lint
static char sccsid[] = "@(#)wwclreol.c  3.14 %G%";
#endif

/*
* Copyright (c) 1983 Regents of the University of California,
* All rights reserved.  Redistribution permitted subject to
* the terms of the Berkeley Software License Agreement.
*/

#include "ww.h"
#include "tt.h"

/*
* Clear w to the end of line.
* If cleared is true, then the screen line has already been cleared
* previously.
*/
wwclreol1(w, row, col, cleared)
register struct ww *w;
int row, col;
char cleared;
{
       register i;
       int gain;

       /*
        * Clear the buffer right off
        */
       {
               register union ww_char *buf;

               buf = &w->ww_buf[row][col]; 
               for (i = w->ww_b.r - col; --i >= 0;)
                       buf++->c_w = ' ';
       }

       /*
        * If can't see it, just return.
        */
       if (row < w->ww_i.t || row >= w->ww_i.b
           || w->ww_i.r <= 0 || w->ww_i.r <= col)
               return;

       if (col < w->ww_i.l)
               col = w->ww_i.l;

       /*
        * Now find out how much is actually cleared, and fix wwns.
        */
       if (cleared) {
               register union ww_char *s;
               register char *smap, *win;

               i = col;
               smap = &wwsmap[row][i];
               s = &wwns[row][i];
               win = &w->ww_win[row][i];
               for (i = w->ww_i.r - i; --i >= 0;) {
                       if (*smap++ != w->ww_index)
                               continue;
                       s++->c_w = ' ' | *win++ << WWC_MSHIFT;
               }
       } else {
               register union ww_char *s;
               register char *smap, *win;
               int ntouched = 0;

               i = col;
               smap = &wwsmap[row][i];
               s = wwns[row];
               win = w->ww_win[row];
               gain = 0;
               for (; i < w->ww_i.r; i++) {
                       if (*smap++ != w->ww_index) {
                               if (s[i].c_w != ' ')
                                       gain--;
                       } else if (win[i] == 0) {
                               if (s[i].c_w != ' ') {
                                       gain++;
                                       ntouched++;
                                       s[i].c_w = ' ';
                               }
                       } else {
                               short c = ' ' | win[i] << WWC_MSHIFT;
                               if (s[i].c_w == c)
                                       gain--;
                               else {
                                       s[i].c_w = c;
                                       ntouched++;
                               }
                       }
               }
               s += i;
               for (i = wwncol - i; --i >= 0;)
                       if (s++->c_w != ' ')
                               gain--;
               if (ntouched > 0)
                       wwtouched[row] |= WWU_TOUCHED;
       }

       /*
        * Can/Should we use clear eol?
        */
       if (!cleared && tt.tt_clreol != 0 && gain > 4) {
               register union ww_char *s;

               /* clear to the end */
               (*tt.tt_move)(row, col);
               (*tt.tt_clreol)();
               s = &wwos[row][col];
               for (i = wwncol - col; --i >= 0;)
                       s++->c_w = ' ';
       }
}