refresh.c

早期freebsd实现

					lx = win->begx + win->maxx - 1;
					return (OK);
				} 
			if (wx < win->maxx || wy < win->maxy - 1 || 
			    !(win->flags & __SCROLLWIN)) {
				if (!curwin) {
					csp->attr = nsp->attr;
					putchar(csp->ch = nsp->ch);
					csp++;
				} else 
					putchar(nsp->ch);
			}
#ifdef DEBUG
			__CTRACE("makech: putchar(%c)\n", nsp->ch & 0177);
#endif
			if (UC && (nsp->attr & __STANDOUT)) {
				putchar('\b');
				tputs(UC, 0, __cputchar);
			}
			nsp++;
#ifdef DEBUG
		__CTRACE("makech: 2: wx = %d, lx = %d\n", wx, lx);
#endif
		}
		if (lx == wx + win->begx)	/* If no change. */
			break;
		lx = wx + win->begx;
		if (lx >= COLS && AM)
			lx = COLS - 1;
		else if (wx >= win->maxx) {
			domvcur(ly, lx, ly, win->maxx + win->begx - 1);
			lx = win->maxx + win->begx - 1;
		}

#ifdef DEBUG
		__CTRACE("makech: 3: wx = %d, lx = %d\n", wx, lx);
#endif
	}
	return (OK);
}

/*
 * domvcur --
 *	Do a mvcur, leaving standout mode if necessary.
 */
static void
domvcur(oy, ox, ny, nx)
	int oy, ox, ny, nx;
{
	if (curscr->flags & __WSTANDOUT && !MS) {
		tputs(SE, 0, __cputchar);
		curscr->flags &= ~__WSTANDOUT;
	}

	__mvcur(oy, ox, ny, nx, 1);
}

/*
 * Quickch() attempts to detect a pattern in the change of the window
 * in order to optimize the change, e.g., scroll n lines as opposed to 
 * repainting the screen line by line.
 */

static void
quickch(win)
	WINDOW *win;
{
#define THRESH		(int) win->maxy / 4

	register __LINE *clp, *tmp1, *tmp2;
	register int bsize, curs, curw, starts, startw, i, j;
	int n, target, cur_period, bot, top, sc_region;
	__LDATA buf[1024];
	u_int blank_hash;

	/* 
	 * Find how many lines from the top of the screen are unchanged.
	 */
	for (top = 0; top < win->maxy; top++) 
		if (win->lines[top]->flags & __FORCEPAINT ||
		    win->lines[top]->hash != curscr->lines[top]->hash 
		    || memcmp(win->lines[top]->line, 
		    curscr->lines[top]->line, 
		    win->maxx * __LDATASIZE) != 0)
			break;
		else
			win->lines[top]->flags &= ~__ISDIRTY;
       /*
	* Find how many lines from bottom of screen are unchanged. 
	*/
	for (bot = win->maxy - 1; bot >= 0; bot--)
		if (win->lines[bot]->flags & __FORCEPAINT ||
		    win->lines[bot]->hash != curscr->lines[bot]->hash 
		    || memcmp(win->lines[bot]->line, 
		    curscr->lines[bot]->line, 
		    win->maxx * __LDATASIZE) != 0)
			break;
		else
			win->lines[bot]->flags &= ~__ISDIRTY;

#ifdef NO_JERKINESS
	/*
	 * If we have a bottom unchanged region return.  Scrolling the
	 * bottom region up and then back down causes a screen jitter.
	 * This will increase the number of characters sent to the screen
	 * but it looks better.
	 */
	if (bot < win->maxy - 1)
		return;
#endif /* NO_JERKINESS */

	/*
	 * Search for the largest block of text not changed.
	 * Invariants of the loop:
	 * - Startw is the index of the beginning of the examined block in win.
         * - Starts is the index of the beginning of the examined block in 
	 *    curscr.
	 * - Curs is the index of one past the end of the exmined block in win.
	 * - Curw is the index of one past the end of the exmined block in 
	 *   curscr.
	 * - bsize is the current size of the examined block.
         */
	for (bsize = bot - top; bsize >= THRESH; bsize--) {
		for (startw = top; startw <= bot - bsize; startw++)
			for (starts = top; starts <= bot - bsize; 
			     starts++) {
				for (curw = startw, curs = starts;
				     curs < starts + bsize; curw++, curs++)
					if (win->lines[curw]->flags &
					    __FORCEPAINT ||
					    (win->lines[curw]->hash !=
					    curscr->lines[curs]->hash ||
				            memcmp(win->lines[curw]->line, 
					    curscr->lines[curs]->line, 
					    win->maxx * __LDATASIZE) != 0))
						break;
				if (curs == starts + bsize)
					goto done;
			}
	}
 done:
	/* Did not find anything */
	if (bsize < THRESH)	
		return;

#ifdef DEBUG
	__CTRACE("quickch:bsize=%d,starts=%d,startw=%d,curw=%d,curs=%d,top=%d,bot=%d\n", 
		bsize, starts, startw, curw, curs, top, bot);
#endif

	/* 
	 * Make sure that there is no overlap between the bottom and top 
	 * regions and the middle scrolled block.
	 */
	if (bot < curs)
		bot = curs - 1;
	if (top > starts)
		top = starts;

	n = startw - starts;

#ifdef DEBUG
		__CTRACE("#####################################\n");
		for (i = 0; i < curscr->maxy; i++) {
			__CTRACE("C: %d:", i);
			__CTRACE(" 0x%x \n", curscr->lines[i]->hash);
			for (j = 0; j < curscr->maxx; j++) 
				__CTRACE("%c", 
			           curscr->lines[i]->line[j].ch);
			__CTRACE("\n");
			for (j = 0; j < curscr->maxx; j++) 
				__CTRACE("%x", 
			           curscr->lines[i]->line[j].attr);
			__CTRACE("\n");
			__CTRACE("W: %d:", i);
			__CTRACE(" 0x%x \n", win->lines[i]->hash);
			__CTRACE(" 0x%x ", win->lines[i]->flags);
			for (j = 0; j < win->maxx; j++) 
				__CTRACE("%c", 
			           win->lines[i]->line[j].ch);
			__CTRACE("\n");
			for (j = 0; j < win->maxx; j++) 
				__CTRACE("%x", 
			           win->lines[i]->line[j].attr);
			__CTRACE("\n");
		}
#endif 
	
	/* So we don't have to call __hash() each time */
	for (i = 0; i < win->maxx; i++) {
		buf[i].ch = ' ';
		buf[i].attr = 0;
	}
	blank_hash = __hash((char *) buf, win->maxx * __LDATASIZE);

	/*
	 * Perform the rotation to maintain the consistency of curscr.
	 * This is hairy since we are doing an *in place* rotation.
	 * Invariants of the loop:
	 * - I is the index of the current line.
	 * - Target is the index of the target of line i.
	 * - Tmp1 points to current line (i).
	 * - Tmp2 and points to target line (target);
	 * - Cur_period is the index of the end of the current period. 
	 *   (see below).
	 *
	 * There are 2 major issues here that make this rotation non-trivial:
	 * 1.  Scrolling in a scrolling region bounded by the top
	 *     and bottom regions determined (whose size is sc_region).
	 * 2.  As a result of the use of the mod function, there may be a 
	 *     period introduced, i.e., 2 maps to 4, 4 to 6, n-2 to 0, and
	 *     0 to 2, which then causes all odd lines not to be rotated.
	 *     To remedy this, an index of the end ( = beginning) of the 
	 *     current 'period' is kept, cur_period, and when it is reached, 
	 *     the next period is started from cur_period + 1 which is 
	 *     guaranteed not to have been reached since that would mean that
	 *     all records would have been reached. (think about it...).
	 * 
	 * Lines in the rotation can have 3 attributes which are marked on the
	 * line so that curscr is consistent with the visual screen.
	 * 1.  Not dirty -- lines inside the scrolled block, top region or
	 *                  bottom region.
	 * 2.  Blank lines -- lines in the differential of the scrolling 
	 *		      region adjacent to top and bot regions 
	 *                    depending on scrolling direction.
	 * 3.  Dirty line -- all other lines are marked dirty.
	 */
	sc_region = bot - top + 1;
	i = top;
	tmp1 = curscr->lines[top];
	cur_period = top;
	for (j = top; j <= bot; j++) {
		target = (i - top + n + sc_region) % sc_region + top;
		tmp2 = curscr->lines[target];
		curscr->lines[target] = tmp1;
		/* Mark block as clean and blank out scrolled lines. */
		clp = curscr->lines[target];
#ifdef DEBUG
		__CTRACE("quickch: n=%d startw=%d curw=%d i = %d target=%d ",
			n, startw, curw, i, target);
#endif
		if ((target >= startw && target < curw) || target < top 
		    || target > bot) {
#ifdef DEBUG
			__CTRACE("-- notdirty");
#endif
			win->lines[target]->flags &= ~__ISDIRTY;
		} else if ((n > 0 && target >= top && target < top + n) ||
		           (n < 0 && target <= bot && target > bot + n)) {
			if (clp->hash != blank_hash ||  memcmp(clp->line, 
			    buf, win->maxx * __LDATASIZE) !=0) {
				(void)memcpy(clp->line,  buf,
				    win->maxx * __LDATASIZE);
#ifdef DEBUG
				__CTRACE("-- blanked out: dirty");
#endif
				clp->hash = blank_hash;
				__touchline(win, target, 0, win->maxx - 1, 0);
			} else {
				__touchline(win, target, 0, win->maxx - 1, 0);
#ifdef DEBUG
				__CTRACE(" -- blank line already: dirty");
#endif
			}
		} else {
#ifdef DEBUG
			__CTRACE(" -- dirty");
#endif
			__touchline(win, target, 0, win->maxx - 1, 0);
		}
#ifdef DEBUG
		__CTRACE("\n");
#endif
		if (target == cur_period) {
			i = target + 1;
			tmp1 = curscr->lines[i];
			cur_period = i;
		} else {
			tmp1 = tmp2;
			i = target;
		}
	}
#ifdef DEBUG
		__CTRACE("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$\n");
		for (i = 0; i < curscr->maxy; i++) {
			__CTRACE("C: %d:", i);
			for (j = 0; j < curscr->maxx; j++) 
				__CTRACE("%c", 
			           curscr->lines[i]->line[j].ch);
			__CTRACE("\n");
			__CTRACE("W: %d:", i);
			for (j = 0; j < win->maxx; j++) 
				__CTRACE("%c", 
			           win->lines[i]->line[j].ch);
			__CTRACE("\n");
		}
#endif
	if (n != 0) {
		WINDOW *wp;
		scrolln(win, starts, startw, curs, bot, top);
		/*
		 * Need to repoint any subwindow lines to the rotated
		 * line structured. 
		 */
		for (wp = win->nextp; wp != win; wp = wp->nextp)
			__set_subwin(win, wp);
	}
}

/*
 * Scrolln performs the scroll by n lines, where n is starts - startw.
 */
static void
scrolln(win, starts, startw, curs, bot, top)
	WINDOW *win;
	int starts, startw, curs, bot, top;
{
	int i, oy, ox, n;

	oy = curscr->cury;
	ox = curscr->curx;
	n = starts - startw;

	if (n > 0) {
		__mvcur(oy, ox, top, 0, 1);
		/* Scroll up the block */
		if (DL)
			tputs(__tscroll(DL, n), 0, __cputchar);
		else
			for(i = 0; i < n; i++)
				tputs(dl, 0, __cputchar);

		/* 
		 * Push down the bottom region.
		 */
		__mvcur(top, 0, bot - n + 1, 0, 1);
		if (AL) 
			tputs(__tscroll(AL, n), 0, __cputchar);
		else
			for(i = 0; i < n; i++)
				tputs(al, 0, __cputchar);
		__mvcur(bot - n + 1, 0, oy, ox, 1);
	} else {
		/* Preserve the bottom lines */
		__mvcur(oy, ox, bot + n + 1, 0, 1);	/* n < 0 */
		if (DL)
			tputs(__tscroll(DL, -n), 0, __cputchar);
		else
		       	for(i = n; i < 0; i++)
				tputs(dl, 0, __cputchar);
		__mvcur(bot + n + 1, 0, top, 0, 1);

		/* Scroll the block down */
		if (AL) 
			tputs(__tscroll(AL, -n), 0, __cputchar);
		else
			for(i = n; i < 0; i++)
				tputs(al, 0, __cputchar);
		__mvcur(top, 0, oy, ox, 1);
	}		
}