New cover scheme

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

#ifndef lint
static  char *sccsid = "@(#)wwdelchar.c 3.7 83/11/23";
#endif

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

wwdelchar(w, row, col)
register struct ww *w;
{
       register i;
       int nvis;

       /*
        * First, shift the line.
        */
       {
               register union ww_char *p, *q;

               p = &w->ww_buf[row][col];
               q = p + 1;
               for (i = w->ww_b.r - col; --i > 0;)
                       *p++ = *q++;
               p->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 changed, and fix wwns.
        */
       {
               register union ww_char *buf;
               register char *win;
               register union ww_char *ns;
               register char *smap;
               char *touched;

               nvis = 0;
               smap = &wwsmap[row][col];
               for (i = w->ww_i.r - col; i > 0 && *smap++ != w->ww_index; i--)
                       col++;
               if (i <= 0)
                       return;
               buf = &w->ww_buf[row][col];
               win = &w->ww_win[row][col];
               ns = &wwns[row][col];
               smap = &wwsmap[row][col];
               touched = &wwtouched[row];
               for (; --i >= 0;)
                       if (*smap++ != w->ww_index) {
                               ns++;
                               buf++;
                               win++;
                       } else if (*win) {
                               ns++->c_w = buf++->c_w ^ *win++ << WWC_MSHIFT;
                               *touched = 1;
                       } else {
                               *ns++ = *buf++;
                               win++;
                               nvis++;
                               *touched = 1;
                       }
       }

       /*
        * Can/Should we use delete character?
        */
       if (tt.tt_delchar != 0 && nvis > (wwncol - col) / 2) {
               register union ww_char *p, *q;

               (*tt.tt_move)(row, col);
               (*tt.tt_delchar)();

               p = &wwos[row][col];
               q = p + 1;
               for (i = wwncol - col; --i > 0;)
                       *p++ = *q++;
               p->c_w = ' ';
       }
}