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  * $FreeBSD: src/sys/ddb/db_input.c,v 1.28.2.1 2002/03/08 16:37:10 yar 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/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(char *s, int count)
  74 {
  75         while (--count >= 0)
  76             cnputc(*s++);
  77 }
  78
  79 static void
  80 db_putnchars(int c, int count)
  81 {
  82         while (--count >= 0)
  83             cnputc(c);
  84 }
  85
  86 /*
  87  * Delete N characters, forward or backward
  88  */
  89 #define DEL_FWD         0
  90 #define DEL_BWD         1
  91 static void
  92 db_delete(int n, int bwd)
  93 {
  94         char *p;
  95
  96         if (bwd) {
  97             db_lc -= n;
  98             db_putnchars(BACKUP, n);
  99         }
 100         for (p = db_lc; p < db_le-n; p++) {
 101             *p = *(p+n);
 102             cnputc(*p);
 103         }
 104         db_putnchars(BLANK, n);
 105         db_putnchars(BACKUP, db_le - db_lc);
 106         db_le -= n;
 107 }
 108
 109 /* returns TRUE at end-of-line */
 110 static int
 111 db_inputchar(int c)
 112 {
 113         static int escstate;
 114
 115         if (escstate == 1) {
 116                 /* ESC seen, look for [ or O */
 117                 if (c == '[' || c == 'O')
 118                         escstate++;
 119                 else
 120                         escstate = 0; /* re-init state machine */
 121                 return (0);
 122         } else if (escstate == 2) {
 123                 escstate = 0;
 124                 /*
 125                  * If a valid cursor key has been found, translate
 126                  * into an emacs-style control key, and fall through.
 127                  * Otherwise, drop off.
 128                  */
 129                 switch (c) {
 130                 case 'A':       /* up */
 131                         c = CTRL('p');
 132                         break;
 133                 case 'B':       /* down */
 134                         c = CTRL('n');
 135                         break;
 136                 case 'C':       /* right */
 137                         c = CTRL('f');
 138                         break;
 139                 case 'D':       /* left */
 140                         c = CTRL('b');
 141                         break;
 142                 default:
 143                         return (0);
 144                 }
 145         }
 146
 147         switch (c) {
 148             case CTRL('['):
 149                 escstate = 1;
 150                 break;
 151             case CTRL('b'):
 152                 /* back up one character */
 153                 if (db_lc > db_lbuf_start) {
 154                     cnputc(BACKUP);
 155                     db_lc--;
 156                 }
 157                 break;
 158             case CTRL('f'):
 159                 /* forward one character */
 160                 if (db_lc < db_le) {
 161                     cnputc(*db_lc);
 162                     db_lc++;
 163                 }
 164                 break;
 165             case CTRL('a'):
 166                 /* beginning of line */
 167                 while (db_lc > db_lbuf_start) {
 168                     cnputc(BACKUP);
 169                     db_lc--;
 170                 }
 171                 break;
 172             case CTRL('e'):
 173                 /* end of line */
 174                 while (db_lc < db_le) {
 175                     cnputc(*db_lc);
 176                     db_lc++;
 177                 }
 178                 break;
 179             case CTRL('h'):
 180             case 0177:
 181                 /* erase previous character */
 182                 if (db_lc > db_lbuf_start)
 183                     db_delete(1, DEL_BWD);
 184                 break;
 185             case CTRL('d'):
 186                 /* erase next character */
 187                 if (db_lc < db_le)
 188                     db_delete(1, DEL_FWD);
 189                 break;
 190             case CTRL('u'):
 191                 /* kill entire line: */
 192                 /* at first, delete to beginning of line */
 193                 if (db_lc > db_lbuf_start)
 194                     db_delete(db_lc - db_lbuf_start, DEL_BWD);
 195                 /* FALLTHROUGH */
 196             case CTRL('k'):
 197                 /* delete to end of line */
 198                 if (db_lc < db_le)
 199                     db_delete(db_le - db_lc, DEL_FWD);
 200                 break;
 201             case CTRL('t'):
 202                 /* twiddle last 2 characters */
 203                 if (db_lc >= db_lbuf_start + 2) {
 204                     c = db_lc[-2];
 205                     db_lc[-2] = db_lc[-1];
 206                     db_lc[-1] = c;
 207                     cnputc(BACKUP);
 208                     cnputc(BACKUP);
 209                     cnputc(db_lc[-2]);
 210                     cnputc(db_lc[-1]);
 211                 }
 212                 break;
 213             case CTRL('r'):
 214                 db_putstring("^R\n", 3);
 215             redraw:
 216                 if (db_le > db_lbuf_start) {
 217                     db_putstring(db_lbuf_start, db_le - db_lbuf_start);
 218                     db_putnchars(BACKUP, db_le - db_lc);
 219                 }
 220                 break;
 221             case CTRL('p'):
 222                 /* Make previous history line the active one. */
 223                 if (db_lhistcur >= 0) {
 224                     bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
 225                           db_lbuf_start, db_lhistlsize);
 226                     db_lhistcur--;
 227                     goto hist_redraw;
 228                 }
 229                 break;
 230             case CTRL('n'):
 231                 /* Make next history line the active one. */
 232                 if (db_lhistcur < db_lhistidx - 1) {
 233                     db_lhistcur += 2;
 234                     bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
 235                           db_lbuf_start, db_lhistlsize);
 236                 } else {
 237                     /*
 238                      * ^N through tail of history, reset the
 239                      * buffer to zero length.
 240                      */
 241                     *db_lbuf_start = '\0';
 242                     db_lhistcur = db_lhistidx;
 243                 }
 244
 245             hist_redraw:
 246                 db_putnchars(BACKUP, db_le - db_lbuf_start);
 247                 db_putnchars(BLANK, db_le - db_lbuf_start);
 248                 db_putnchars(BACKUP, db_le - db_lbuf_start);
 249                 db_le = index(db_lbuf_start, '\0');
 250                 if (db_le[-1] == '\r' || db_le[-1] == '\n')
 251                     *--db_le = '\0';
 252                 db_lc = db_le;
 253                 goto redraw;
 254
 255             case -1:
 256                 /*
 257                  * eek! the console returned eof.
 258                  * probably that means we HAVE no console.. we should try bail
 259                  * XXX
 260                  */
 261                 return (0);
 262             case '\n':
 263             case '\r':
 264                 *db_le++ = c;
 265                 return (1);
 266             default:
 267                 if (db_le == db_lbuf_end) {
 268                     cnputc('\007');
 269                 }
 270                 else if (c >= ' ' && c <= '~') {
 271                     char *p;
 272
 273                     for (p = db_le; p > db_lc; p--)
 274                         *p = *(p-1);
 275                     *db_lc++ = c;
 276                     db_le++;
 277                     cnputc(c);
 278                     db_putstring(db_lc, db_le - db_lc);
 279                     db_putnchars(BACKUP, db_le - db_lc);
 280                 }
 281                 break;
 282         }
 283         return (0);
 284 }
 285
 286 static int
 287 cnmaygetc(void)
 288 {
 289         return (-1);
 290 }
 291
 292 int
 293 db_readline(char *lstart, int lsize)
 294 {
 295         if (lsize != db_lhistlsize) {
 296                 /*
 297                  * (Re)initialize input line history.  Throw away any
 298                  * existing history.
 299                  */
 300                 db_lhist_nlines = sizeof(db_lhistory) / lsize;
 301                 db_lhistlsize = lsize;
 302                 db_lhistidx = -1;
 303         }
 304         db_lhistcur = db_lhistidx;
 305
 306         db_force_whitespace();  /* synch output position */
 307
 308         db_lbuf_start = lstart;
 309         db_lbuf_end   = lstart + lsize;
 310         db_lc = lstart;
 311         db_le = lstart;
 312
 313         while (!db_inputchar(cngetc()))
 314             continue;
 315
 316         db_printf("\n");        /* synch output position */
 317         *db_le = 0;
 318
 319         if (db_le - db_lbuf_start > 1) {
 320             /* Maintain input line history for non-empty lines. */
 321             if (++db_lhistidx == db_lhist_nlines) {
 322                 /* Rotate history. */
 323                 bcopy(db_lhistory + db_lhistlsize, db_lhistory,
 324                       db_lhistlsize * (db_lhist_nlines - 1));
 325                 db_lhistidx--;
 326             }
 327             bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
 328                   db_lhistlsize);
 329         }
 330
 331         return (db_le - db_lbuf_start);
 332 }
 333
 334 void
 335 db_check_interrupt(void)
 336 {
 337         int     c;
 338
 339         c = cnmaygetc();
 340         switch (c) {
 341             case -1:            /* no character */
 342                 return;
 343
 344             case CTRL('c'):
 345                 db_error(NULL);
 346                 /*NOTREACHED*/
 347
 348             case CTRL('s'):
 349                 do {
 350                     c = cnmaygetc();
 351                     if (c == CTRL('c'))
 352                         db_error(NULL);
 353                 } while (c != CTRL('q'));
 354                 break;
 355
 356             default:
 357                 /* drop on floor */
 358                 break;
 359         }
 360 }