/* $OpenBSD: wwupdate.c,v 1.5 2003/06/03 02:56:23 millert Exp $ */ /* $NetBSD: wwupdate.c,v 1.3 1995/09/28 10:36:00 tls Exp $ */ /* * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Edward Wang at The University of California, Berkeley. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static char sccsid[] = "@(#)wwupdate.c 8.1 (Berkeley) 6/6/93"; #else static char rcsid[] = "$OpenBSD: wwupdate.c,v 1.5 2003/06/03 02:56:23 millert Exp $"; #endif #endif /* not lint */ #include "ww.h" #include "tt.h" wwupdate1(top, bot) { int i; int j; char *touched; struct ww_update *upd; char check_clreos = 0; int scan_top, scan_bot; wwnupdate++; { char *t1 = wwtouched + top, *t2 = wwtouched + bot; int n; while (!*t1++) if (t1 == t2) return; while (!*--t2) ; scan_top = top = t1 - wwtouched - 1; scan_bot = bot = t2 - wwtouched + 1; if (scan_bot - scan_top > 1 && (tt.tt_clreos != 0 || tt.tt_clear != 0)) { int st = tt.tt_clreos != 0 ? scan_top : 0; /* * t1 is one past the first touched row, * t2 is on the last touched row. */ for (t1--, n = 1; t1 < t2;) if (*t1++) n++; /* * If we can't clreos then we try for clearing * the whole screen. */ if (check_clreos = n * 10 > (wwnrow - st) * 9) { scan_top = st; scan_bot = wwnrow; } } } if (tt.tt_clreol == 0 && !check_clreos) goto simple; for (i = scan_top, touched = &wwtouched[i], upd = &wwupd[i]; i < scan_bot; i++, touched++, upd++) { int gain = 0; int best_gain = 0; int best_col; union ww_char *ns, *os; if (wwinterrupt()) return; if (!check_clreos && !*touched) continue; wwnupdscan++; 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, more or less: * 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_col = j; best_gain = gain; } } upd->best_gain = best_gain; upd->best_col = best_col; upd->gain = gain; } if (check_clreos) { struct ww_update *u; int gain = 0; int best_gain = 0; int best_row; int simple_gain = 0; char didit = 0; /* * gain is the advantage of clearing all the lines. * best_gain is the advantage of clearing to eos * at best_row and u->best_col. * simple_gain is the advantage of using only clreol. * We use g > best_gain because u->best_col can be * undefined when u->best_gain is 0 so we can't use it. */ for (j = scan_bot - 1, u = wwupd + j; j >= top; j--, u--) { int g = gain + u->best_gain; if (g > best_gain) { best_gain = g; best_row = j; } gain += u->gain; if (tt.tt_clreol != 0 && u->best_gain > 4) simple_gain += u->best_gain - 4; } if (tt.tt_clreos == 0) { if (gain > simple_gain && gain > 4) { xxclear(); i = top = scan_top; bot = scan_bot; j = 0; didit = 1; } } else if (best_gain > simple_gain && best_gain > 4) { i = best_row; xxclreos(i, j = wwupd[i].best_col); bot = scan_bot; didit = 1; } if (didit) { wwnupdclreos++; wwnupdclreosline += wwnrow - i; u = wwupd + i; while (i < scan_bot) { union ww_char *os = &wwos[i][j]; for (j = wwncol - j; --j >= 0;) os++->c_w = ' '; wwtouched[i++] |= WWU_TOUCHED; u++->best_gain = 0; j = 0; } } else wwnupdclreosmiss++; } simple: for (i = top, touched = &wwtouched[i], upd = &wwupd[i]; i < bot; i++, touched++, upd++) { union ww_char *os, *ns; char didit; if (!*touched) continue; *touched = 0; wwnupdline++; didit = 0; if (tt.tt_clreol != 0 && upd->best_gain > 4) { wwnupdclreol++; xxclreol(i, j = upd->best_col); for (os = &wwos[i][j], j = wwncol - j; --j >= 0;) os++->c_w = ' '; didit = 1; } ns = wwns[i]; os = wwos[i]; for (j = 0; j < wwncol;) { char *p, *q; char m; int c; int 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; c = j - 1; os[-1] = ns[-1]; *p++ = ns[-1].c_c; n = 5; q = p; while (j < wwncol && ns->c_m == 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++; } n = q - buf; if (!wwwrap || i != wwnrow - 1 || c + n != wwncol) xxwrite(i, c, buf, n, m); else if (tt.tt_inschar || tt.tt_insspace) { if (n > 1) { q[-2] = q[-1]; n--; } else c--; xxwrite(i, c, buf, n, m); c += n - 1; if (tt.tt_inschar) xxinschar(i, c, ns[-2].c_c, ns[-2].c_m); else { xxinsspace(i, c); xxwrite(i, c, &ns[-2].c_c, 1, ns[-2].c_m); } } else { if (--n) xxwrite(i, c, buf, n, m); os[-1] = lastc; *touched = WWU_TOUCHED; } didit = 1; } if (!didit) wwnupdmiss++; } }