usr/src/usr.bin/window/wwclreol.c

#ifndef lint
static  char *sccsid = "@(#)wwclreol.c  3.9 83/09/15";
#endif

#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 nblank, ncleared;

        /*
         * 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.
         */
        {
                register union ww_char *s;
                register char *smap, *win;
                register char *touched;

                smap = &wwsmap[row][col];
                s = &wwns[row][col];
                touched = &wwtouched[row];
                win = &w->ww_win[row][col];
                ncleared = nblank = 0;

                for (i = w->ww_i.r - col; --i >= 0;) {
                        if (*smap++ != w->ww_index) {
                                if (s++->c_w == ' ')
                                        nblank++;
                                win++;
                                continue;
                        }
                        ncleared++;
                        *touched = 1;
                        if (*win == 0) {
                                nblank++;
                                s++->c_w = ' ';
                                win++;
                        } else
                                s++->c_w = ' ' | *win++ << WWC_MSHIFT;
                }
        }

        /*
         * Can/Should we use clear eol?
         */
        if (!cleared && tt.tt_clreol != 0
            && ncleared > wwncol - col - nblank
            && nblank > (wwncol - col) / 2) {
                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 = ' ';
        }
}