249 lines
4.8 KiB
C
249 lines
4.8 KiB
C
/*
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* Author: David B. Golub, Carnegie Mellon University
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* Date: 7/90
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* $Id: db_input.c,v 1.3 1993/12/18 04:46:33 mycroft Exp $
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*/
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <ddb/db_output.h>
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/*
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* Character input and editing.
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*/
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/*
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* We don't track output position while editing input,
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* since input always ends with a new-line. We just
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* reset the line position at the end.
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*/
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char * db_lbuf_start; /* start of input line buffer */
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char * db_lbuf_end; /* end of input line buffer */
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char * db_lc; /* current character */
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char * db_le; /* one past last character */
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#define CTRL(c) ((c) & 0x1f)
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#define isspace(c) ((c) == ' ' || (c) == '\t')
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#define BLANK ' '
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#define BACKUP '\b'
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void
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db_putstring(s, count)
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char *s;
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int count;
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{
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while (--count >= 0)
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cnputc(*s++);
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}
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void
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db_putnchars(c, count)
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int c;
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int count;
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{
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while (--count >= 0)
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cnputc(c);
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}
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/*
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* Delete N characters, forward or backward
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*/
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#define DEL_FWD 0
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#define DEL_BWD 1
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void
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db_delete(n, bwd)
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int n;
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int bwd;
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{
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register char *p;
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if (bwd) {
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db_lc -= n;
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db_putnchars(BACKUP, n);
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}
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for (p = db_lc; p < db_le-n; p++) {
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*p = *(p+n);
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cnputc(*p);
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}
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db_putnchars(BLANK, n);
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db_putnchars(BACKUP, db_le - db_lc);
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db_le -= n;
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}
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/* returns TRUE at end-of-line */
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int
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db_inputchar(c)
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int c;
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{
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switch (c) {
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case CTRL('b'):
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/* back up one character */
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if (db_lc > db_lbuf_start) {
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cnputc(BACKUP);
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db_lc--;
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}
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break;
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case CTRL('f'):
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/* forward one character */
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if (db_lc < db_le) {
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cnputc(*db_lc);
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db_lc++;
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}
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break;
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case CTRL('a'):
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/* beginning of line */
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while (db_lc > db_lbuf_start) {
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cnputc(BACKUP);
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db_lc--;
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}
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break;
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case CTRL('e'):
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/* end of line */
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while (db_lc < db_le) {
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cnputc(*db_lc);
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db_lc++;
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}
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break;
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case CTRL('h'):
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case 0177:
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/* erase previous character */
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if (db_lc > db_lbuf_start)
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db_delete(1, DEL_BWD);
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break;
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case CTRL('d'):
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/* erase next character */
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if (db_lc < db_le)
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db_delete(1, DEL_FWD);
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break;
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case CTRL('k'):
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/* delete to end of line */
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if (db_lc < db_le)
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db_delete(db_le - db_lc, DEL_FWD);
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break;
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case CTRL('t'):
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/* twiddle last 2 characters */
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if (db_lc >= db_lbuf_start + 2) {
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c = db_lc[-2];
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db_lc[-2] = db_lc[-1];
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db_lc[-1] = c;
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cnputc(BACKUP);
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cnputc(BACKUP);
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cnputc(db_lc[-2]);
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cnputc(db_lc[-1]);
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}
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break;
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case CTRL('r'):
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db_putstring("^R\n", 3);
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if (db_le > db_lbuf_start) {
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db_putstring(db_lbuf_start, db_le - db_lbuf_start);
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db_putnchars(BACKUP, db_le - db_lc);
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}
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break;
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case '\n':
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case '\r':
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*db_le++ = c;
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return (1);
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default:
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if (db_le == db_lbuf_end) {
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cnputc('\007');
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}
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else if (c >= ' ' && c <= '~') {
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register char *p;
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for (p = db_le; p > db_lc; p--)
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*p = *(p-1);
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*db_lc++ = c;
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db_le++;
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cnputc(c);
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db_putstring(db_lc, db_le - db_lc);
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db_putnchars(BACKUP, db_le - db_lc);
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}
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break;
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}
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return (0);
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}
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int
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db_readline(lstart, lsize)
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char * lstart;
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int lsize;
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{
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db_force_whitespace(); /* synch output position */
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db_lbuf_start = lstart;
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db_lbuf_end = lstart + lsize;
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db_lc = lstart;
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db_le = lstart;
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while (!db_inputchar(cngetc()))
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continue;
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db_putchar('\n'); /* synch output position */
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*db_le = 0;
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return (db_le - db_lbuf_start);
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}
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void
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db_check_interrupt()
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{
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register int c;
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c = cnmaygetc();
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switch (c) {
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case -1: /* no character */
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return;
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case CTRL('c'):
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db_error((char *)0);
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/*NOTREACHED*/
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case CTRL('s'):
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do {
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c = cnmaygetc();
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if (c == CTRL('c'))
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db_error((char *)0);
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} while (c != CTRL('q'));
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break;
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default:
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/* drop on floor */
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break;
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}
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}
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cnmaygetc ()
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{
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return (-1);
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}
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/* called from kdb_trap in db_interface.c */
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cnpollc (flag)
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{
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}
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