db_input.c revision 90528 
1/*
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19 *  School of Computer Science
20 *  Carnegie Mellon University
21 *  Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 *
26 * $FreeBSD: head/sys/ddb/db_input.c 90528 2002-02-11 14:14:42Z yar $
27 */
28
29/*
30 *	Author: David B. Golub, Carnegie Mellon University
31 *	Date:	7/90
32 */
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/cons.h>
37
38#include <ddb/ddb.h>
39#include <ddb/db_output.h>
40
41/*
42 * Character input and editing.
43 */
44
45/*
46 * We don't track output position while editing input,
47 * since input always ends with a new-line.  We just
48 * reset the line position at the end.
49 */
50static char *	db_lbuf_start;	/* start of input line buffer */
51static char *	db_lbuf_end;	/* end of input line buffer */
52static char *	db_lc;		/* current character */
53static char *	db_le;		/* one past last character */
54
55/*
56 * Simple input line history support.
57 */
58static char	db_lhistory[2048];
59static int	db_lhistlsize, db_lhistidx, db_lhistcur;
60static int	db_lhist_nlines;
61
62#define	CTRL(c)		((c) & 0x1f)
63#define	BLANK		' '
64#define	BACKUP		'\b'
65
66static int	cnmaygetc __P((void));
67static void	db_delete __P((int n, int bwd));
68static int	db_inputchar __P((int c));
69static void	db_putnchars __P((int c, int count));
70static void	db_putstring __P((char *s, int count));
71
72void
73db_putstring(s, count)
74	char	*s;
75	int	count;
76{
77	while (--count >= 0)
78	    cnputc(*s++);
79}
80
81void
82db_putnchars(c, count)
83	int	c;
84	int	count;
85{
86	while (--count >= 0)
87	    cnputc(c);
88}
89
90/*
91 * Delete N characters, forward or backward
92 */
93#define	DEL_FWD		0
94#define	DEL_BWD		1
95void
96db_delete(n, bwd)
97	int	n;
98	int	bwd;
99{
100	register char *p;
101
102	if (bwd) {
103	    db_lc -= n;
104	    db_putnchars(BACKUP, n);
105	}
106	for (p = db_lc; p < db_le-n; p++) {
107	    *p = *(p+n);
108	    cnputc(*p);
109	}
110	db_putnchars(BLANK, n);
111	db_putnchars(BACKUP, db_le - db_lc);
112	db_le -= n;
113}
114
115/* returns TRUE at end-of-line */
116int
117db_inputchar(c)
118	int	c;
119{
120	static int escstate;
121
122	if (escstate == 1) {
123		/* ESC seen, look for [ or O */
124		if (c == '[' || c == 'O')
125			escstate++;
126		else
127			escstate = 0; /* re-init state machine */
128		return (0);
129	} else if (escstate == 2) {
130		escstate = 0;
131		/*
132		 * If a valid cursor key has been found, translate
133		 * into an emacs-style control key, and fall through.
134		 * Otherwise, drop off.
135		 */
136		switch (c) {
137		case 'A':	/* up */
138			c = CTRL('p');
139			break;
140		case 'B':	/* down */
141			c = CTRL('n');
142			break;
143		case 'C':	/* right */
144			c = CTRL('f');
145			break;
146		case 'D':	/* left */
147			c = CTRL('b');
148			break;
149		default:
150			return (0);
151		}
152	}
153
154	switch (c) {
155	    case CTRL('['):
156		escstate = 1;
157		break;
158	    case CTRL('b'):
159		/* back up one character */
160		if (db_lc > db_lbuf_start) {
161		    cnputc(BACKUP);
162		    db_lc--;
163		}
164		break;
165	    case CTRL('f'):
166		/* forward one character */
167		if (db_lc < db_le) {
168		    cnputc(*db_lc);
169		    db_lc++;
170		}
171		break;
172	    case CTRL('a'):
173		/* beginning of line */
174		while (db_lc > db_lbuf_start) {
175		    cnputc(BACKUP);
176		    db_lc--;
177		}
178		break;
179	    case CTRL('e'):
180		/* end of line */
181		while (db_lc < db_le) {
182		    cnputc(*db_lc);
183		    db_lc++;
184		}
185		break;
186	    case CTRL('h'):
187	    case 0177:
188		/* erase previous character */
189		if (db_lc > db_lbuf_start)
190		    db_delete(1, DEL_BWD);
191		break;
192	    case CTRL('u'):
193		/* delete to beginning of line */
194		if (db_lc > db_lbuf_start)
195		    db_delete(db_lc - db_lbuf_start, DEL_BWD);
196		break;
197	    case CTRL('d'):
198		/* erase next character */
199		if (db_lc < db_le)
200		    db_delete(1, DEL_FWD);
201		break;
202	    case CTRL('k'):
203		/* delete to end of line */
204		if (db_lc < db_le)
205		    db_delete(db_le - db_lc, DEL_FWD);
206		break;
207	    case CTRL('t'):
208		/* twiddle last 2 characters */
209		if (db_lc >= db_lbuf_start + 2) {
210		    c = db_lc[-2];
211		    db_lc[-2] = db_lc[-1];
212		    db_lc[-1] = c;
213		    cnputc(BACKUP);
214		    cnputc(BACKUP);
215		    cnputc(db_lc[-2]);
216		    cnputc(db_lc[-1]);
217		}
218		break;
219	    case CTRL('r'):
220		db_putstring("^R\n", 3);
221	    redraw:
222		if (db_le > db_lbuf_start) {
223		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
224		    db_putnchars(BACKUP, db_le - db_lc);
225		}
226		break;
227	    case CTRL('p'):
228		/* Make previous history line the active one. */
229		if (db_lhistcur >= 0) {
230		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
231			  db_lbuf_start, db_lhistlsize);
232		    db_lhistcur--;
233		    goto hist_redraw;
234		}
235		break;
236	    case CTRL('n'):
237		/* Make next history line the active one. */
238		if (db_lhistcur < db_lhistidx - 1) {
239		    db_lhistcur += 2;
240		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
241			  db_lbuf_start, db_lhistlsize);
242		} else {
243		    /*
244		     * ^N through tail of history, reset the
245		     * buffer to zero length.
246		     */
247		    *db_lbuf_start = '\0';
248		    db_lhistcur = db_lhistidx;
249		}
250
251	    hist_redraw:
252		db_putnchars(BACKUP, db_le - db_lbuf_start);
253		db_putnchars(BLANK, db_le - db_lbuf_start);
254		db_putnchars(BACKUP, db_le - db_lbuf_start);
255		db_le = index(db_lbuf_start, '\0');
256		if (db_le[-1] == '\r' || db_le[-1] == '\n')
257		    *--db_le = '\0';
258		db_lc = db_le;
259		goto redraw;
260
261	    case -1:
262		/*
263		 * eek! the console returned eof.
264		 * probably that means we HAVE no console.. we should try bail
265		 * XXX
266		 */
267		c = '\r';
268	    case '\n':
269	    case '\r':
270		*db_le++ = c;
271		return (1);
272	    default:
273		if (db_le == db_lbuf_end) {
274		    cnputc('\007');
275		}
276		else if (c >= ' ' && c <= '~') {
277		    register char *p;
278
279		    for (p = db_le; p > db_lc; p--)
280			*p = *(p-1);
281		    *db_lc++ = c;
282		    db_le++;
283		    cnputc(c);
284		    db_putstring(db_lc, db_le - db_lc);
285		    db_putnchars(BACKUP, db_le - db_lc);
286		}
287		break;
288	}
289	return (0);
290}
291
292int
293cnmaygetc()
294{
295	return (-1);
296}
297
298int
299db_readline(lstart, lsize)
300	char *	lstart;
301	int	lsize;
302{
303	if (lsize != db_lhistlsize) {
304		/*
305		 * (Re)initialize input line history.  Throw away any
306		 * existing history.
307		 */
308		db_lhist_nlines = sizeof(db_lhistory) / lsize;
309		db_lhistlsize = lsize;
310		db_lhistidx = -1;
311	}
312	db_lhistcur = db_lhistidx;
313
314	db_force_whitespace();	/* synch output position */
315
316	db_lbuf_start = lstart;
317	db_lbuf_end   = lstart + lsize;
318	db_lc = lstart;
319	db_le = lstart;
320
321	while (!db_inputchar(cngetc()))
322	    continue;
323
324	db_printf("\n");	/* synch output position */
325	*db_le = 0;
326
327	if (db_le - db_lbuf_start > 1) {
328	    /* Maintain input line history for non-empty lines. */
329	    if (++db_lhistidx == db_lhist_nlines) {
330		/* Rotate history. */
331		ovbcopy(db_lhistory + db_lhistlsize, db_lhistory,
332			db_lhistlsize * (db_lhist_nlines - 1));
333		db_lhistidx--;
334	    }
335	    bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
336		  db_lhistlsize);
337	}
338
339	return (db_le - db_lbuf_start);
340}
341
342void
343db_check_interrupt()
344{
345	register int	c;
346
347	c = cnmaygetc();
348	switch (c) {
349	    case -1:		/* no character */
350		return;
351
352	    case CTRL('c'):
353		db_error((char *)0);
354		/*NOTREACHED*/
355
356	    case CTRL('s'):
357		do {
358		    c = cnmaygetc();
359		    if (c == CTRL('c'))
360			db_error((char *)0);
361		} while (c != CTRL('q'));
362		break;
363
364	    default:
365		/* drop on floor */
366		break;
367	}
368}
369