db_input.c revision 1.7 
1/*	$NetBSD: db_input.c,v 1.7 1996/02/05 01:57:02 christos Exp $	*/
2
3/*
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 *
28 *	Author: David B. Golub, Carnegie Mellon University
29 *	Date:	7/90
30 */
31
32#include <sys/param.h>
33#include <sys/proc.h>
34
35#include <machine/db_machdep.h>
36
37#include <ddb/db_output.h>
38#include <ddb/db_command.h>
39#include <ddb/db_sym.h>
40#include <ddb/db_extern.h>
41
42#include <dev/cons.h>
43
44/*
45 * Character input and editing.
46 */
47
48/*
49 * We don't track output position while editing input,
50 * since input always ends with a new-line.  We just
51 * reset the line position at the end.
52 */
53char *	db_lbuf_start;	/* start of input line buffer */
54char *	db_lbuf_end;	/* end of input line buffer */
55char *	db_lc;		/* current character */
56char *	db_le;		/* one past last character */
57
58#define	CTRL(c)		((c) & 0x1f)
59#define	isspace(c)	((c) == ' ' || (c) == '\t')
60#define	BLANK		' '
61#define	BACKUP		'\b'
62
63static int cnmaygetc __P((void));
64
65void
66db_putstring(s, count)
67	char	*s;
68	int	count;
69{
70	while (--count >= 0)
71	    cnputc(*s++);
72}
73
74void
75db_putnchars(c, count)
76	int	c;
77	int	count;
78{
79	while (--count >= 0)
80	    cnputc(c);
81}
82
83/*
84 * Delete N characters, forward or backward
85 */
86#define	DEL_FWD		0
87#define	DEL_BWD		1
88void
89db_delete(n, bwd)
90	int	n;
91	int	bwd;
92{
93	register char *p;
94
95	if (bwd) {
96	    db_lc -= n;
97	    db_putnchars(BACKUP, n);
98	}
99	for (p = db_lc; p < db_le-n; p++) {
100	    *p = *(p+n);
101	    cnputc(*p);
102	}
103	db_putnchars(BLANK, n);
104	db_putnchars(BACKUP, db_le - db_lc);
105	db_le -= n;
106}
107
108/* returns TRUE at end-of-line */
109int
110db_inputchar(c)
111	int	c;
112{
113	switch (c) {
114	    case CTRL('b'):
115		/* back up one character */
116		if (db_lc > db_lbuf_start) {
117		    cnputc(BACKUP);
118		    db_lc--;
119		}
120		break;
121	    case CTRL('f'):
122		/* forward one character */
123		if (db_lc < db_le) {
124		    cnputc(*db_lc);
125		    db_lc++;
126		}
127		break;
128	    case CTRL('a'):
129		/* beginning of line */
130		while (db_lc > db_lbuf_start) {
131		    cnputc(BACKUP);
132		    db_lc--;
133		}
134		break;
135	    case CTRL('e'):
136		/* end of line */
137		while (db_lc < db_le) {
138		    cnputc(*db_lc);
139		    db_lc++;
140		}
141		break;
142	    case CTRL('h'):
143	    case 0177:
144		/* erase previous character */
145		if (db_lc > db_lbuf_start)
146		    db_delete(1, DEL_BWD);
147		break;
148	    case CTRL('d'):
149		/* erase next character */
150		if (db_lc < db_le)
151		    db_delete(1, DEL_FWD);
152		break;
153	    case CTRL('k'):
154		/* delete to end of line */
155		if (db_lc < db_le)
156		    db_delete(db_le - db_lc, DEL_FWD);
157		break;
158	    case CTRL('t'):
159		/* twiddle last 2 characters */
160		if (db_lc >= db_lbuf_start + 2) {
161		    c = db_lc[-2];
162		    db_lc[-2] = db_lc[-1];
163		    db_lc[-1] = c;
164		    cnputc(BACKUP);
165		    cnputc(BACKUP);
166		    cnputc(db_lc[-2]);
167		    cnputc(db_lc[-1]);
168		}
169		break;
170	    case CTRL('r'):
171		db_putstring("^R\n", 3);
172		if (db_le > db_lbuf_start) {
173		    db_putstring(db_lbuf_start, db_le - db_lbuf_start);
174		    db_putnchars(BACKUP, db_le - db_lc);
175		}
176		break;
177	    case '\n':
178	    case '\r':
179		*db_le++ = c;
180		return (1);
181	    default:
182		if (db_le == db_lbuf_end) {
183		    cnputc('\007');
184		}
185		else if (c >= ' ' && c <= '~') {
186		    register char *p;
187
188		    for (p = db_le; p > db_lc; p--)
189			*p = *(p-1);
190		    *db_lc++ = c;
191		    db_le++;
192		    cnputc(c);
193		    db_putstring(db_lc, db_le - db_lc);
194		    db_putnchars(BACKUP, db_le - db_lc);
195		}
196		break;
197	}
198	return (0);
199}
200
201int
202db_readline(lstart, lsize)
203	char *	lstart;
204	int	lsize;
205{
206	db_force_whitespace();	/* synch output position */
207
208	db_lbuf_start = lstart;
209	db_lbuf_end   = lstart + lsize;
210	db_lc = lstart;
211	db_le = lstart;
212
213	while (!db_inputchar(cngetc()))
214	    continue;
215
216	db_putchar('\n');	/* synch output position */
217
218	*db_le = 0;
219	return (db_le - db_lbuf_start);
220}
221
222void
223db_check_interrupt()
224{
225	register int	c;
226
227	c = cnmaygetc();
228	switch (c) {
229	    case -1:		/* no character */
230		return;
231
232	    case CTRL('c'):
233		db_error((char *)0);
234		/*NOTREACHED*/
235
236	    case CTRL('s'):
237		do {
238		    c = cnmaygetc();
239		    if (c == CTRL('c')) {
240			db_error((char *)0);
241			/*NOTREACHED*/
242		    }
243		} while (c != CTRL('q'));
244		break;
245
246	    default:
247		/* drop on floor */
248		break;
249	}
250}
251
252static int
253cnmaygetc ()
254{
255	return (-1);
256}
257