bug from last time

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

#ifndef lint
static  char *sccsid = "@(#)wwupdate.c  3.12 84/03/03";
#endif

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

wwupdate1(top, bot)
{
       int i;
       register j;
       register union ww_char *ns, *os;
       char *touched;
       char didit;

       wwnupdate++;
       for (i = top, touched = &wwtouched[i]; i < bot && !wwinterrupt();
            i++, touched++) {
               if (!*touched)
                       continue;
               if (*touched & WWU_MAJOR && tt.tt_clreol != 0) {
                       register gain = 0;
                       register best_gain = 0;
                       register best;

                       wwnmajline++;
                       j = wwncol;
                       ns = &wwns[i][j];
                       os = &wwos[i][j];
                       while (--j >= 0) {
                               /*
                                * The cost of clearing is:
                                *      ncol - nblank + X
                                * The cost of straight update is:
                                *      ncol - nsame
                                * We clear if:  nblank - nsame > X
                                * X is the clreol overhead.
                                * So we make gain = nblank - nsame.
                                */
                               if ((--ns)->c_w == (--os)->c_w)
                                       gain--;
                               else
                                       best_gain--;
                               if (ns->c_w == ' ')
                                       gain++;
                               if (gain >= best_gain) {
                                       best = j;
                                       best_gain = gain;
                               }
                       }
                       if (best_gain > 4) {
                               (*tt.tt_move)(i, best);
                               (*tt.tt_clreol)();
                               for (j = wwncol - best, os = &wwos[i][best];
                                    --j >= 0;)
                                       os++->c_w = ' ';
                       } else
                               wwnmajmiss++;
               }
               wwnupdline++;
               didit = 0;
               ns = wwns[i];
               os = wwos[i];
               for (j = 0; j < wwncol;) {
                       register char *p, *q;
                       char m;
                       int c;
                       register n;
                       char buf[512];                  /* > wwncol */
                       union ww_char lastc;

                       for (; j++ < wwncol && ns++->c_w == os++->c_w;)
                               ;
                       if (j > wwncol)
                               break;
                       p = buf;
                       m = ns[-1].c_m & tt.tt_availmodes;
                       c = j - 1;
                       os[-1] = ns[-1];
                       *p++ = ns[-1].c_c;
                       n = 5;
                       q = p;
                       while (j < wwncol && (ns->c_m&tt.tt_availmodes) == m) {
                               *p++ = ns->c_c;
                               if (ns->c_w == os->c_w) {
                                       if (--n <= 0)
                                               break;
                                       os++;
                                       ns++;
                               } else {
                                       n = 5;
                                       q = p;
                                       lastc = *os;
                                       *os++ = *ns++;
                               }
                               j++;
                       }
                       tt.tt_nmodes = m;
                       if (wwwrap
                           && i == wwnrow - 1 && q - buf + c == wwncol) {
                               if (tt.tt_hasinsert) {
                                       if (q - buf != 1) {
                                               (*tt.tt_move)(i, c);
                                               (*tt.tt_write)(buf + 1,
                                                       q - buf - 1);
                                               (*tt.tt_move)(i, c);
                                               tt.tt_ninsert = 1;
                                               (*tt.tt_write)(buf, 1);
                                               tt.tt_ninsert = 0;
                                       } else {
                                               (*tt.tt_move)(i, c - 1);
                                               (*tt.tt_write)(buf, 1);
                                               tt.tt_nmodes = ns[-2].c_m;
                                               (*tt.tt_move)(i, c - 1);
                                               tt.tt_ninsert = 1;
                                               (*tt.tt_write)(&ns[-2].c_c, 1);
                                               tt.tt_ninsert = 0;
                                       }
                               } else {
                                       (*tt.tt_move)(i, c);
                                       os[-1] = lastc;
                                       (*tt.tt_write)(buf, q - buf - 1);
                               }
                       } else {
                               (*tt.tt_move)(i, c);
                               (*tt.tt_write)(buf, q - buf);
                       }
                       didit++;
               }
               if (!didit)
                       wwnupdmiss++;
               *touched = 0;
       }
}