386BSD 0.1 development

[unix-history] / usr / src / sys.386bsd / ddb / db_input.c

/* 
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
* 
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
* 
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 
* CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
* 
* Carnegie Mellon requests users of this software to return to
* 
*  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
*  School of Computer Science
*  Carnegie Mellon University
*  Pittsburgh PA 15213-3890
* 
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* HISTORY
* $Log: db_input.c,v $
* Revision 1.1  1992/03/25  21:45:10  pace
* Initial revision
*
* Revision 2.4  91/02/14  14:41:53  mrt
*      Add input line editing.
*      [90/11/11            dbg]
* 
* Revision 2.3  91/02/05  17:06:32  mrt
*      Changed to new Mach copyright
*      [91/01/31  16:18:13  mrt]
* 
* Revision 2.2  90/08/27  21:51:03  dbg
*      Reduce lint.
*      [90/08/07            dbg]
*      Created.
*      [90/07/25            dbg]
* 
*/
/*
*      Author: David B. Golub, Carnegie Mellon University
*      Date:   7/90
*/

#include "param.h"
#include "proc.h"
#include <ddb/db_output.h>

/*
* Character input and editing.
*/

/*
* We don't track output position while editing input,
* since input always ends with a new-line.  We just
* reset the line position at the end.
*/
char *  db_lbuf_start;  /* start of input line buffer */
char *  db_lbuf_end;    /* end of input line buffer */
char *  db_lc;          /* current character */
char *  db_le;          /* one past last character */

#define CTRL(c)         ((c) & 0x1f)
#define isspace(c)      ((c) == ' ' || (c) == '\t')
#define BLANK           ' '
#define BACKUP          '\b'

void
db_putstring(s, count)
       char    *s;
       int     count;
{
       while (--count >= 0)
           cnputc(*s++);
}

void
db_putnchars(c, count)
       int     c;
       int     count;
{
       while (--count >= 0)
           cnputc(c);
}

/*
* Delete N characters, forward or backward
*/
#define DEL_FWD         0
#define DEL_BWD         1
void
db_delete(n, bwd)
       int     n;
       int     bwd;
{
       register char *p;

       if (bwd) {
           db_lc -= n;
           db_putnchars(BACKUP, n);
       }
       for (p = db_lc; p < db_le-n; p++) {
           *p = *(p+n);
           cnputc(*p);
       }
       db_putnchars(BLANK, n);
       db_putnchars(BACKUP, db_le - db_lc);
       db_le -= n;
}

/* returns TRUE at end-of-line */
int
db_inputchar(c)
       int     c;
{
       switch (c) {
           case CTRL('b'):
               /* back up one character */
               if (db_lc > db_lbuf_start) {
                   cnputc(BACKUP);
                   db_lc--;
               }
               break;
           case CTRL('f'):
               /* forward one character */
               if (db_lc < db_le) {
                   cnputc(*db_lc);
                   db_lc++;
               }
               break;
           case CTRL('a'):
               /* beginning of line */
               while (db_lc > db_lbuf_start) {
                   cnputc(BACKUP);
                   db_lc--;
               }
               break;
           case CTRL('e'):
               /* end of line */
               while (db_lc < db_le) {
                   cnputc(*db_lc);
                   db_lc++;
               }
               break;
           case CTRL('h'):
           case 0177:
               /* erase previous character */
               if (db_lc > db_lbuf_start)
                   db_delete(1, DEL_BWD);
               break;
           case CTRL('d'):
               /* erase next character */
               if (db_lc < db_le)
                   db_delete(1, DEL_FWD);
               break;
           case CTRL('k'):
               /* delete to end of line */
               if (db_lc < db_le)
                   db_delete(db_le - db_lc, DEL_FWD);
               break;
           case CTRL('t'):
               /* twiddle last 2 characters */
               if (db_lc >= db_lbuf_start + 2) {
                   c = db_lc[-2];
                   db_lc[-2] = db_lc[-1];
                   db_lc[-1] = c;
                   cnputc(BACKUP);
                   cnputc(BACKUP);
                   cnputc(db_lc[-2]);
                   cnputc(db_lc[-1]);
               }
               break;
           case CTRL('r'):
               db_putstring("^R\n", 3);
               if (db_le > db_lbuf_start) {
                   db_putstring(db_lbuf_start, db_le - db_lbuf_start);
                   db_putnchars(BACKUP, db_le - db_lc);
               }
               break;
           case '\n':
           case '\r':
               *db_le++ = c;
               return (1);
           default:
               if (db_le == db_lbuf_end) {
                   cnputc('\007');
               }
               else if (c >= ' ' && c <= '~') {
                   register char *p;

                   for (p = db_le; p > db_lc; p--)
                       *p = *(p-1);
                   *db_lc++ = c;
                   db_le++;
                   cnputc(c);
                   db_putstring(db_lc, db_le - db_lc);
                   db_putnchars(BACKUP, db_le - db_lc);
               }
               break;
       }
       return (0);
}

int
db_readline(lstart, lsize)
       char *  lstart;
       int     lsize;
{
       db_force_whitespace();  /* synch output position */

       db_lbuf_start = lstart;
       db_lbuf_end   = lstart + lsize;
       db_lc = lstart;
       db_le = lstart;

       while (!db_inputchar(cngetc()))
           continue;

       db_putchar('\n');       /* synch output position */

       *db_le = 0;
       return (db_le - db_lbuf_start);
}

void
db_check_interrupt()
{
       register int    c;

       c = cnmaygetc();
       switch (c) {
           case -1:            /* no character */
               return;

           case CTRL('c'):
               db_error((char *)0);
               /*NOTREACHED*/

           case CTRL('s'):
               do {
                   c = cnmaygetc();
                   if (c == CTRL('c'))
                       db_error((char *)0);
               } while (c != CTRL('q'));
               break;

           default:
               /* drop on floor */
               break;
       }
}

cnmaygetc ()
{
       return (-1);
}

/* called from kdb_trap in db_interface.c */
cnpollc (flag)
{
}