FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_input.c
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 /*
27 * Author: David B. Golub, Carnegie Mellon University
28 * Date: 7/90
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD: src/sys/ddb/db_input.c,v 1.39 2008/03/07 13:13:17 rwatson Exp $");
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 */
50 static char * db_lbuf_start; /* start of input line buffer */
51 static char * db_lbuf_end; /* end of input line buffer */
52 static char * db_lc; /* current character */
53 static char * db_le; /* one past last character */
54
55 /*
56 * Simple input line history support.
57 */
58 static char db_lhistory[2048];
59 static int db_lhistlsize, db_lhistidx, db_lhistcur;
60 static int db_lhist_nlines;
61
62 #define CTRL(c) ((c) & 0x1f)
63 #define BLANK ' '
64 #define BACKUP '\b'
65
66 static int cnmaygetc(void);
67 static void db_delete(int n, int bwd);
68 static int db_inputchar(int c);
69 static void db_putnchars(int c, int count);
70 static void db_putstring(char *s, int count);
71
72 static void
73 db_putstring(s, count)
74 char *s;
75 int count;
76 {
77 while (--count >= 0)
78 cnputc(*s++);
79 }
80
81 static void
82 db_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
95 static void
96 db_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 */
116 static int
117 db_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('d'):
193 /* erase next character */
194 if (db_lc < db_le)
195 db_delete(1, DEL_FWD);
196 break;
197 case CTRL('u'):
198 /* kill entire line: */
199 /* at first, delete to beginning of line */
200 if (db_lc > db_lbuf_start)
201 db_delete(db_lc - db_lbuf_start, DEL_BWD);
202 /* FALLTHROUGH */
203 case CTRL('k'):
204 /* delete to end of line */
205 if (db_lc < db_le)
206 db_delete(db_le - db_lc, DEL_FWD);
207 break;
208 case CTRL('t'):
209 /* twiddle last 2 characters */
210 if (db_lc >= db_lbuf_start + 2) {
211 c = db_lc[-2];
212 db_lc[-2] = db_lc[-1];
213 db_lc[-1] = c;
214 cnputc(BACKUP);
215 cnputc(BACKUP);
216 cnputc(db_lc[-2]);
217 cnputc(db_lc[-1]);
218 }
219 break;
220 case CTRL('r'):
221 db_putstring("^R\n", 3);
222 redraw:
223 if (db_le > db_lbuf_start) {
224 db_putstring(db_lbuf_start, db_le - db_lbuf_start);
225 db_putnchars(BACKUP, db_le - db_lc);
226 }
227 break;
228 case CTRL('p'):
229 /* Make previous history line the active one. */
230 if (db_lhistcur >= 0) {
231 bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
232 db_lbuf_start, db_lhistlsize);
233 db_lhistcur--;
234 goto hist_redraw;
235 }
236 break;
237 case CTRL('n'):
238 /* Make next history line the active one. */
239 if (db_lhistcur < db_lhistidx - 1) {
240 db_lhistcur += 2;
241 bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
242 db_lbuf_start, db_lhistlsize);
243 } else {
244 /*
245 * ^N through tail of history, reset the
246 * buffer to zero length.
247 */
248 *db_lbuf_start = '\0';
249 db_lhistcur = db_lhistidx;
250 }
251
252 hist_redraw:
253 db_putnchars(BACKUP, db_lc - db_lbuf_start);
254 db_putnchars(BLANK, db_le - db_lbuf_start);
255 db_putnchars(BACKUP, db_le - db_lbuf_start);
256 db_le = index(db_lbuf_start, '\0');
257 if (db_le[-1] == '\r' || db_le[-1] == '\n')
258 *--db_le = '\0';
259 db_lc = db_le;
260 goto redraw;
261
262 case -1:
263 /*
264 * eek! the console returned eof.
265 * probably that means we HAVE no console.. we should try bail
266 * XXX
267 */
268 c = '\r';
269 case '\n':
270 /* FALLTHROUGH */
271 case '\r':
272 *db_le++ = c;
273 return (1);
274 default:
275 if (db_le == db_lbuf_end) {
276 cnputc('\007');
277 }
278 else if (c >= ' ' && c <= '~') {
279 register char *p;
280
281 for (p = db_le; p > db_lc; p--)
282 *p = *(p-1);
283 *db_lc++ = c;
284 db_le++;
285 cnputc(c);
286 db_putstring(db_lc, db_le - db_lc);
287 db_putnchars(BACKUP, db_le - db_lc);
288 }
289 break;
290 }
291 return (0);
292 }
293
294 static int
295 cnmaygetc()
296 {
297 return (-1);
298 }
299
300 int
301 db_readline(lstart, lsize)
302 char * lstart;
303 int lsize;
304 {
305
306 if (lsize < 2)
307 return (0);
308 if (lsize != db_lhistlsize) {
309 /*
310 * (Re)initialize input line history. Throw away any
311 * existing history.
312 */
313 db_lhist_nlines = sizeof(db_lhistory) / lsize;
314 db_lhistlsize = lsize;
315 db_lhistidx = -1;
316 }
317 db_lhistcur = db_lhistidx;
318
319 db_force_whitespace(); /* synch output position */
320
321 db_lbuf_start = lstart;
322 db_lbuf_end = lstart + lsize - 2; /* Will append NL and NUL. */
323 db_lc = lstart;
324 db_le = lstart;
325
326 while (!db_inputchar(cngetc()))
327 continue;
328
329 db_capture_write(lstart, db_le - db_lbuf_start);
330 db_printf("\n"); /* synch output position */
331 *db_le = 0;
332
333 if (db_le - db_lbuf_start > 1) {
334 /* Maintain input line history for non-empty lines. */
335 if (++db_lhistidx == db_lhist_nlines) {
336 /* Rotate history. */
337 bcopy(db_lhistory + db_lhistlsize, db_lhistory,
338 db_lhistlsize * (db_lhist_nlines - 1));
339 db_lhistidx--;
340 }
341 bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
342 db_lhistlsize);
343 }
344
345 return (db_le - db_lbuf_start);
346 }
347
348 void
349 db_check_interrupt()
350 {
351 register int c;
352
353 c = cnmaygetc();
354 switch (c) {
355 case -1: /* no character */
356 return;
357
358 case CTRL('c'):
359 db_error((char *)0);
360 /*NOTREACHED*/
361
362 case CTRL('s'):
363 do {
364 c = cnmaygetc();
365 if (c == CTRL('c'))
366 db_error((char *)0);
367 } while (c != CTRL('q'));
368 break;
369
370 default:
371 /* drop on floor */
372 break;
373 }
374 }
375
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