db_input.c revision 17495 
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 *	$Id: db_input.c,v 1.13 1996/05/08 04:28:34 gpalmer Exp $
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/malloc.h>
36#include <sys/systm.h>
37
38#include <machine/cons.h>
39
40#include <ddb/ddb.h>
41#include <ddb/db_output.h>
42
43/*
44 * Character input and editing.
45 */
46
47/*
48 * We don't track output position while editing input,
49 * since input always ends with a new-line.  We just
50 * reset the line position at the end.
51 */
52static char *	db_lbuf_start;	/* start of input line buffer */
53static char *	db_lbuf_end;	/* end of input line buffer */
54static char *	db_lc;		/* current character */
55static char *	db_le;		/* one past last character */
56
57/*
58 * Simple input line history support.
59 */
60static char *	db_lhistory;
61static int	db_lhistlsize, db_lhistidx, db_lhistcur;
62#define DB_LHIST_NLINES 10
63
64#define	CTRL(c)		((c) & 0x1f)
65#define	isspace(c)	((c) == ' ' || (c) == '\t')
66#define	BLANK		' '
67#define	BACKUP		'\b'
68
69static int	cnmaygetc __P((void));
70static void	db_delete __P((int n, int bwd));
71static int	db_inputchar __P((int c));
72static void	db_putnchars __P((int c, int count));
73static void	db_putstring __P((char *s, int count));
74
75void
76db_putstring(s, count)
77	char	*s;
78	int	count;
79{
80	while (--count >= 0)
81	    cnputc(*s++);
82}
83
84void
85db_putnchars(c, count)
86	int	c;
87	int	count;
88{
89	while (--count >= 0)
90	    cnputc(c);
91}
92
93/*
94 * Delete N characters, forward or backward
95 */
96#define	DEL_FWD		0
97#define	DEL_BWD		1
98void
99db_delete(n, bwd)
100	int	n;
101	int	bwd;
102{
103	register char *p;
104
105	if (bwd) {
106	    db_lc -= n;
107	    db_putnchars(BACKUP, n);
108	}
109	for (p = db_lc; p < db_le-n; p++) {
110	    *p = *(p+n);
111	    cnputc(*p);
112	}
113	db_putnchars(BLANK, n);
114	db_putnchars(BACKUP, db_le - db_lc);
115	db_le -= n;
116}
117
118/* returns TRUE at end-of-line */
119int
120db_inputchar(c)
121	int	c;
122{
123	switch (c) {
124	    case CTRL('b'):
125		/* back up one character */
126		if (db_lc > db_lbuf_start) {
127		    cnputc(BACKUP);
128		    db_lc--;
129		}
130		break;
131	    case CTRL('f'):
132		/* forward one character */
133		if (db_lc < db_le) {
134		    cnputc(*db_lc);
135		    db_lc++;
136		}
137		break;
138	    case CTRL('a'):
139		/* beginning of line */
140		while (db_lc > db_lbuf_start) {
141		    cnputc(BACKUP);
142		    db_lc--;
143		}
144		break;
145	    case CTRL('e'):
146		/* end of line */
147		while (db_lc < db_le) {
148		    cnputc(*db_lc);
149		    db_lc++;
150		}
151		break;
152	    case CTRL('h'):
153	    case 0177:
154		/* erase previous character */
155		if (db_lc > db_lbuf_start)
156		    db_delete(1, DEL_BWD);
157		break;
158	    case CTRL('d'):
159		/* erase next character */
160		if (db_lc < db_le)
161		    db_delete(1, DEL_FWD);
162		break;
163	    case CTRL('k'):
164		/* delete to end of line */
165		if (db_lc < db_le)
166		    db_delete(db_le - db_lc, DEL_FWD);
167		break;
168	    case CTRL('t'):
169		/* twiddle last 2 characters */
170		if (db_lc >= db_lbuf_start + 2) {
171		    c = db_lc[-2];
172		    db_lc[-2] = db_lc[-1];
173		    db_lc[-1] = c;
174		    cnputc(BACKUP);
175		    cnputc(BACKUP);
176		    cnputc(db_lc[-2]);
177		    cnputc(db_lc[-1]);
178		}
179		break;
180	    case CTRL('r'):
181		db_putstring("^R\n", 3);
182	    redraw:
183		if (db_le > db_lbuf_start) {
184		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
185		    db_putnchars(BACKUP, db_le - db_lc);
186		}
187		break;
188	    case CTRL('p'):
189		/* Make previous history line the active one. */
190		if (db_lhistcur >= 0) {
191		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
192			  db_lbuf_start, db_lhistlsize);
193		    db_lhistcur--;
194		    goto hist_redraw;
195		}
196		break;
197	    case CTRL('n'):
198		/* Make next history line the active one. */
199		if (db_lhistcur < db_lhistidx - 1) {
200		    db_lhistcur += 2;
201		    bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
202			  db_lbuf_start, db_lhistlsize);
203		} else {
204		    /*
205		     * ^N through tail of history, reset the
206		     * buffer to zero length.
207		     */
208		    *db_lbuf_start = '\0';
209		    db_lhistcur = db_lhistidx;
210		}
211
212	    hist_redraw:
213		db_putnchars(BACKUP, db_le - db_lbuf_start);
214		db_putnchars(BLANK, db_le - db_lbuf_start);
215		db_putnchars(BACKUP, db_le - db_lbuf_start);
216		db_le = index(db_lbuf_start, '\0');
217		if (db_le[-1] == '\r' || db_le[-1] == '\n')
218		    *--db_le = '\0';
219		db_lc = db_le;
220		goto redraw;
221
222	    case '\n':
223	    case '\r':
224		*db_le++ = c;
225		return (1);
226	    default:
227		if (db_le == db_lbuf_end) {
228		    cnputc('\007');
229		}
230		else if (c >= ' ' && c <= '~') {
231		    register char *p;
232
233		    for (p = db_le; p > db_lc; p--)
234			*p = *(p-1);
235		    *db_lc++ = c;
236		    db_le++;
237		    cnputc(c);
238		    db_putstring(db_lc, db_le - db_lc);
239		    db_putnchars(BACKUP, db_le - db_lc);
240		}
241		break;
242	}
243	return (0);
244}
245
246int
247cnmaygetc()
248{
249	return (-1);
250}
251
252int
253db_readline(lstart, lsize)
254	char *	lstart;
255	int	lsize;
256{
257	if (db_lhistory && lsize != db_lhistlsize) {
258		/* Should not happen, but to be sane, throw history away. */
259		FREE(db_lhistory, M_TEMP);
260		db_lhistory = 0;
261	}
262	if (db_lhistory == 0) {
263		/* Initialize input line history. */
264		db_lhistlsize = lsize;
265		db_lhistidx = -1;
266		MALLOC(db_lhistory, char *, lsize * DB_LHIST_NLINES,
267		       M_TEMP, M_NOWAIT);
268	}
269	db_lhistcur = db_lhistidx;
270
271	db_force_whitespace();	/* synch output position */
272
273	db_lbuf_start = lstart;
274	db_lbuf_end   = lstart + lsize;
275	db_lc = lstart;
276	db_le = lstart;
277
278	while (!db_inputchar(cngetc()))
279	    continue;
280
281	db_printf("\n");	/* synch output position */
282	*db_le = 0;
283
284	if (db_le - db_lbuf_start > 1) {
285	    /* Maintain input line history for non-empty lines. */
286	    if (++db_lhistidx == DB_LHIST_NLINES) {
287		/* Rotate history. */
288		ovbcopy(db_lhistory + db_lhistlsize, db_lhistory,
289			db_lhistlsize * (DB_LHIST_NLINES - 1));
290		db_lhistidx--;
291	    }
292	    bcopy(lstart, db_lhistory + (db_lhistidx * db_lhistlsize),
293		  db_lhistlsize);
294	}
295
296	return (db_le - db_lbuf_start);
297}
298
299void
300db_check_interrupt()
301{
302	register int	c;
303
304	c = cnmaygetc();
305	switch (c) {
306	    case -1:		/* no character */
307		return;
308
309	    case CTRL('c'):
310		db_error((char *)0);
311		/*NOTREACHED*/
312
313	    case CTRL('s'):
314		do {
315		    c = cnmaygetc();
316		    if (c == CTRL('c'))
317			db_error((char *)0);
318		} while (c != CTRL('q'));
319		break;
320
321	    default:
322		/* drop on floor */
323		break;
324	}
325}
326
327/* called from kdb_trap in db_interface.c */
328void
329cnpollc (flag)
330	int flag;
331{
332}
333