refresh.c

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			}
		}
	}
	/*
         * Pragmatics I: If old trailing whitespace or not enough characters to
         * save to be worth it, then don't save the last same info.
         */
	if ((oe - ols) < MIN_END_KEEP) {
		ols = oe;
		nls = ne;
	}
	/*
         * Pragmatics II: if the terminal isn't smart enough, make the data
         * dumber so the smart update doesn't try anything fancy
         */

	/*
         * fx is the number of characters we need to insert/delete: in the
         * beginning to bring the two same begins together
         */
	fx = (nsb - nfd) - (osb - ofd);
	/*
         * sx is the number of characters we need to insert/delete: in the
         * end to bring the two same last parts together
         */
	sx = (nls - nse) - (ols - ose);

	if (!EL_CAN_INSERT) {
		if (fx > 0) {
			osb = ols;
			ose = ols;
			nsb = nls;
			nse = nls;
		}
		if (sx > 0) {
			ols = oe;
			nls = ne;
		}
		if ((ols - ofd) < (nls - nfd)) {
			ols = oe;
			nls = ne;
		}
	}
	if (!EL_CAN_DELETE) {
		if (fx < 0) {
			osb = ols;
			ose = ols;
			nsb = nls;
			nse = nls;
		}
		if (sx < 0) {
			ols = oe;
			nls = ne;
		}
		if ((ols - ofd) > (nls - nfd)) {
			ols = oe;
			nls = ne;
		}
	}
	/*
         * Pragmatics III: make sure the middle shifted pointers are correct if
         * they don't point to anything (we may have moved ols or nls).
         */
	/* if the change isn't worth it, don't bother */
	/* was: if (osb == ose) */
	if ((ose - osb) < MIN_END_KEEP) {
		osb = ols;
		ose = ols;
		nsb = nls;
		nse = nls;
	}
	/*
         * Now that we are done with pragmatics we recompute fx, sx
         */
	fx = (nsb - nfd) - (osb - ofd);
	sx = (nls - nse) - (ols - ose);

	ELRE_DEBUG(1, (__F, "\n"));
	ELRE_DEBUG(1, (__F, "ofd %d, osb %d, ose %d, ols %d, oe %d\n",
		ofd - old, osb - old, ose - old, ols - old, oe - old));
	ELRE_DEBUG(1, (__F, "nfd %d, nsb %d, nse %d, nls %d, ne %d\n",
		nfd - new, nsb - new, nse - new, nls - new, ne - new));
	ELRE_DEBUG(1, (__F,
		"xxx-xxx:\"00000000001111111111222222222233333333334\"\r\n"));
	ELRE_DEBUG(1, (__F,
		"xxx-xxx:\"01234567890123456789012345678901234567890\"\r\n"));
#ifdef DEBUG_REFRESH
	re_printstr(el, "old- oe", old, oe);
	re_printstr(el, "new- ne", new, ne);
	re_printstr(el, "old-ofd", old, ofd);
	re_printstr(el, "new-nfd", new, nfd);
	re_printstr(el, "ofd-osb", ofd, osb);
	re_printstr(el, "nfd-nsb", nfd, nsb);
	re_printstr(el, "osb-ose", osb, ose);
	re_printstr(el, "nsb-nse", nsb, nse);
	re_printstr(el, "ose-ols", ose, ols);
	re_printstr(el, "nse-nls", nse, nls);
	re_printstr(el, "ols- oe", ols, oe);
	re_printstr(el, "nls- ne", nls, ne);
#endif /* DEBUG_REFRESH */

	/*
         * el_cursor.v to this line i MUST be in this routine so that if we
         * don't have to change the line, we don't move to it. el_cursor.h to
         * first diff char
         */
	term_move_to_line(el, i);

	/*
         * at this point we have something like this:
         *
         * /old                  /ofd    /osb               /ose    /ols     /oe
         * v.....................v       v..................v       v........v
         * eddie> Oh, my fredded gruntle-buggy is to me, as foo var lurgid as
         * eddie> Oh, my fredded quiux buggy is to me, as gruntle-lurgid as
         * ^.....................^     ^..................^       ^........^
         * \new                  \nfd  \nsb               \nse     \nls    \ne
         *
         * fx is the difference in length between the chars between nfd and
         * nsb, and the chars between ofd and osb, and is thus the number of
         * characters to delete if < 0 (new is shorter than old, as above),
         * or insert (new is longer than short).
         *
         * sx is the same for the second differences.
         */

	/*
         * if we have a net insert on the first difference, AND inserting the
         * net amount ((nsb-nfd) - (osb-ofd)) won't push the last useful
         * character (which is ne if nls != ne, otherwise is nse) off the edge
	 * of the screen (el->el_term.t_size.h) else we do the deletes first
	 * so that we keep everything we need to.
         */

	/*
         * if the last same is the same like the end, there is no last same
         * part, otherwise we want to keep the last same part set p to the
         * last useful old character
         */
	p = (ols != oe) ? oe : ose;

	/*
         * if (There is a diffence in the beginning) && (we need to insert
         *   characters) && (the number of characters to insert is less than
         *   the term width)
	 *	We need to do an insert!
	 * else if (we need to delete characters)
	 *	We need to delete characters!
	 * else
	 *	No insert or delete
         */
	if ((nsb != nfd) && fx > 0 &&
	    ((p - old) + fx <= el->el_term.t_size.h)) {
		ELRE_DEBUG(1,
		    (__F, "first diff insert at %d...\r\n", nfd - new));
		/*
		 * Move to the first char to insert, where the first diff is.
		 */
		term_move_to_char(el, nfd - new);
		/*
		 * Check if we have stuff to keep at end
		 */
		if (nsb != ne) {
			ELRE_DEBUG(1, (__F, "with stuff to keep at end\r\n"));
			/*
		         * insert fx chars of new starting at nfd
		         */
			if (fx > 0) {
				ELRE_DEBUG(!EL_CAN_INSERT, (__F,
				"ERROR: cannot insert in early first diff\n"));
				term_insertwrite(el, nfd, fx);
				re_insert(el, old, ofd - old,
				    el->el_term.t_size.h, nfd, fx);
			}
			/*
		         * write (nsb-nfd) - fx chars of new starting at
		         * (nfd + fx)
			 */
			term_overwrite(el, nfd + fx, (nsb - nfd) - fx);
			re__strncopy(ofd + fx, nfd + fx,
			    (size_t) ((nsb - nfd) - fx));
		} else {
			ELRE_DEBUG(1, (__F, "without anything to save\r\n"));
			term_overwrite(el, nfd, (nsb - nfd));
			re__strncopy(ofd, nfd, (size_t) (nsb - nfd));
			/*
		         * Done
		         */
			return;
		}
	} else if (fx < 0) {
		ELRE_DEBUG(1,
		    (__F, "first diff delete at %d...\r\n", ofd - old));
		/*
		 * move to the first char to delete where the first diff is
		 */
		term_move_to_char(el, ofd - old);
		/*
		 * Check if we have stuff to save
		 */
		if (osb != oe) {
			ELRE_DEBUG(1, (__F, "with stuff to save at end\r\n"));
			/*
		         * fx is less than zero *always* here but we check
		         * for code symmetry
		         */
			if (fx < 0) {
				ELRE_DEBUG(!EL_CAN_DELETE, (__F,
				    "ERROR: cannot delete in first diff\n"));
				term_deletechars(el, -fx);
				re_delete(el, old, ofd - old,
				    el->el_term.t_size.h, -fx);
			}
			/*
		         * write (nsb-nfd) chars of new starting at nfd
		         */
			term_overwrite(el, nfd, (nsb - nfd));
			re__strncopy(ofd, nfd, (size_t) (nsb - nfd));

		} else {
			ELRE_DEBUG(1, (__F,
			    "but with nothing left to save\r\n"));
			/*
		         * write (nsb-nfd) chars of new starting at nfd
		         */
			term_overwrite(el, nfd, (nsb - nfd));
			ELRE_DEBUG(1, (__F,
			    "cleareol %d\n", (oe - old) - (ne - new)));
			term_clear_EOL(el, (oe - old) - (ne - new));
			/*
		         * Done
		         */
			return;
		}
	} else
		fx = 0;

	if (sx < 0 && (ose - old) + fx < el->el_term.t_size.h) {
		ELRE_DEBUG(1, (__F,
		    "second diff delete at %d...\r\n", (ose - old) + fx));
		/*
		 * Check if we have stuff to delete
		 */
		/*
		 * fx is the number of characters inserted (+) or deleted (-)
		 */

		term_move_to_char(el, (ose - old) + fx);
		/*
		 * Check if we have stuff to save
		 */
		if (ols != oe) {
			ELRE_DEBUG(1, (__F, "with stuff to save at end\r\n"));
			/*
		         * Again a duplicate test.
		         */
			if (sx < 0) {
				ELRE_DEBUG(!EL_CAN_DELETE, (__F,
				    "ERROR: cannot delete in second diff\n"));
				term_deletechars(el, -sx);
			}
			/*
		         * write (nls-nse) chars of new starting at nse
		         */
			term_overwrite(el, nse, (nls - nse));
		} else {
			ELRE_DEBUG(1, (__F,
			    "but with nothing left to save\r\n"));
			term_overwrite(el, nse, (nls - nse));
			ELRE_DEBUG(1, (__F,
			    "cleareol %d\n", (oe - old) - (ne - new)));
			if ((oe - old) - (ne - new) != 0)
				term_clear_EOL(el, (oe - old) - (ne - new));
		}
	}
	/*
         * if we have a first insert AND WE HAVEN'T ALREADY DONE IT...
         */
	if ((nsb != nfd) && (osb - ofd) <= (nsb - nfd) && (fx == 0)) {
		ELRE_DEBUG(1, (__F, "late first diff insert at %d...\r\n",
		    nfd - new));

		term_move_to_char(el, nfd - new);
		/*
		 * Check if we have stuff to keep at the end
		 */
		if (nsb != ne) {
			ELRE_DEBUG(1, (__F, "with stuff to keep at end\r\n"));
			/*
		         * We have to recalculate fx here because we set it
		         * to zero above as a flag saying that we hadn't done
		         * an early first insert.
		         */
			fx = (nsb - nfd) - (osb - ofd);
			if (fx > 0) {
				/*
				 * insert fx chars of new starting at nfd
				 */
				ELRE_DEBUG(!EL_CAN_INSERT, (__F,
				 "ERROR: cannot insert in late first diff\n"));
				term_insertwrite(el, nfd, fx);
				re_insert(el, old, ofd - old,
				    el->el_term.t_size.h, nfd, fx);
			}
			/*
		         * write (nsb-nfd) - fx chars of new starting at
		         * (nfd + fx)
			 */
			term_overwrite(el, nfd + fx, (nsb - nfd) - fx);
			re__strncopy(ofd + fx, nfd + fx,
			    (size_t) ((nsb - nfd) - fx));
		} else {
			ELRE_DEBUG(1, (__F, "without anything to save\r\n"));
			term_overwrite(el, nfd, (nsb - nfd));
			re__strncopy(ofd, nfd, (size_t) (nsb - nfd));
		}
	}
	/*
         * line is now NEW up to nse
         */
	if (sx >= 0) {
		ELRE_DEBUG(1, (__F,
		    "second diff insert at %d...\r\n", nse - new));
		term_move_to_char(el, nse - new);
		if (ols != oe) {
			ELRE_DEBUG(1, (__F, "with stuff to keep at end\r\n"));
			if (sx > 0) {
				/* insert sx chars of new starting at nse */
				ELRE_DEBUG(!EL_CAN_INSERT, (__F,
				    "ERROR: cannot insert in second diff\n"));
				term_insertwrite(el, nse, sx);
			}
			/*
		         * write (nls-nse) - sx chars of new starting at
			 * (nse + sx)
		         */
			term_overwrite(el, nse + sx, (nls - nse) - sx);
		} else {
			ELRE_DEBUG(1, (__F, "without anything to save\r\n"));
			term_overwrite(el, nse, (nls - nse));

			/*
	                 * No need to do a clear-to-end here because we were
	                 * doing a second insert, so we will have over
	                 * written all of the old string.
		         */
		}
	}
	ELRE_DEBUG(1, (__F, "done.\r\n"));
}


/* re__copy_and_pad():
 *	Copy string and pad with spaces
 */
private void
re__copy_and_pad(char *dst, const char *src, size_t width)
{
	int i;

	for (i = 0; i < width; i++) {
		if (*src == '\0')
			break;
		*dst++ = *src++;
	}

	for (; i < width; i++)
		*dst++ = ' ';

	*dst = '\0';
}


/* re_refresh_cursor():
 *	Move to the new cursor position
 */
protected void
re_refresh_cursor(EditLine *el)
{
	char *cp, c;
	int h, v, th;

	/* first we must find where the cursor is... */
	h = el->el_prompt.p_pos.h;
	v = el->el_prompt.p_pos.v;
	th = el->el_term.t_size.h;	/* optimize for speed */

	/* do input buffer to el->el_line.cursor */
	for (cp = el->el_line.buffer; cp < el->el_line.cursor; cp++) {
		c = *cp;
		h++;		/* all chars at least this long */

		if (c == '\n') {/* handle newline in data part too */
			h = 0;
			v++;
		} else {
			if (c == '\t') {	/* if a tab, to next tab stop */
				while (h & 07) {
					h++;
				}
			} else if (iscntrl((unsigned char) c)) {
						/* if control char */
				h++;
				if (h > th) {	/* if overflow, compensate */
					h = 1;
					v++;
				}
			} else if (!isprint((unsigned char) c)) {
				h += 3;
				if (h > th) {	/* if overflow, compensate */
					h = h - th;
					v++;
				}
			}
		}

		if (h >= th) {	/* check, extra long tabs picked up here also */
			h = 0;
			v++;
		}
	}

	/* now go there */
	term_move_to_line(el, v);
	term_move_to_char(el, h);
	term__flush();
}


/* re_fastputc():
 *	Add a character fast.
 */
private void
re_fastputc(EditLine *el, int c)
{

	term__putc(c);
	el->el_display[el->el_cursor.v][el->el_cursor.h++] = c;
	if (el->el_cursor.h >= el->el_term.t_size.h) {
		/* if we must overflow */
		el->el_cursor.h = 0;

		/*
		 * If we would overflow (input is longer than terminal size),
		 * emulate scroll by dropping first line and shuffling the rest.
		 * We do this via pointer shuffling - it's safe in this case
		 * and we avoid memcpy().
		 */
		if (el->el_cursor.v + 1 >= el->el_term.t_size.v) {
			int i, lins = el->el_term.t_size.v;
			char *firstline = el->el_display[0];
	
			for(i=1; i < lins; i++)
				el->el_display[i-1] = el->el_display[i];

			re__copy_and_pad(firstline, "", 0);
			el->el_display[i-1] = firstline;
		} else {
			el->el_cursor.v++;
			el->el_refresh.r_oldcv++;
		}
		if (EL_HAS_AUTO_MARGINS) {
			if (EL_HAS_MAGIC_MARGINS) {
				term__putc(' ');
				term__putc('\b');
			}
		} else {
			term__putc('\r');
			term__putc('\n');
		}
	}
}


/* re_fastaddc():
 *	we added just one char, handle it fast.
 *	Assumes that screen cursor == real cursor
 */
protected void
re_fastaddc(EditLine *el)
{
	char c;
	int rhdiff;

	c = el->el_line.cursor[-1];

	if (c == '\t' || el->el_line.cursor != el->el_line.lastchar) {
		re_refresh(el);	/* too hard to handle */
		return;
	}
	rhdiff = el->el_term.t_size.h - el->el_cursor.h -
	    el->el_rprompt.p_pos.h;
	if (el->el_rprompt.p_pos.h && rhdiff < 3) {
		re_refresh(el);	/* clear out rprompt if less than 1 char gap */
		return;
	}			/* else (only do at end of line, no TAB) */
	if (iscntrl((unsigned char) c)) {	/* if control char, do caret */
		char mc = (c == '\177') ? '?' : (c | 0100);
		re_fastputc(el, '^');
		re_fastputc(el, mc);
	} else if (isprint((unsigned char) c)) {	/* normal char */
		re_fastputc(el, c);
	} else {
		re_fastputc(el, '\\');
		re_fastputc(el, (int) ((((unsigned int) c >> 6) & 7) + '0'));
		re_fastputc(el, (int) ((((unsigned int) c >> 3) & 7) + '0'));
		re_fastputc(el, (c & 7) + '0');
	}
	term__flush();
}


/* re_clear_display():
 *	clear the screen buffers so that new new prompt starts fresh.
 */
protected void
re_clear_display(EditLine *el)
{
	int i;

	el->el_cursor.v = 0;
	el->el_cursor.h = 0;
	for (i = 0; i < el->el_term.t_size.v; i++)
		el->el_display[i][0] = '\0';
	el->el_refresh.r_oldcv = 0;
}


/* re_clear_lines():
 *	Make sure all lines are *really* blank
 */
protected void
re_clear_lines(EditLine *el)
{

	if (EL_CAN_CEOL) {
		int i;
		term_move_to_char(el, 0);
		for (i = 0; i <= el->el_refresh.r_oldcv; i++) {
			/* for each line on the screen */
			term_move_to_line(el, i);
			term_clear_EOL(el, el->el_term.t_size.h);
		}
		term_move_to_line(el, 0);
	} else {
		term_move_to_line(el, el->el_refresh.r_oldcv);
					/* go to last line */
		term__putc('\r');	/* go to BOL */
		term__putc('\n');	/* go to new line */
	}
}