462 lines
9.9 KiB
C
462 lines
9.9 KiB
C
/*-
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* SPDX-License-Identifier: MIT-CMU
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*
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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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/*
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* Author: David B. Golub, Carnegie Mellon University
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* Date: 7/90
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/cons.h>
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#include <sys/sysctl.h>
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#include <ddb/ddb.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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static char * db_lbuf_start; /* start of input line buffer */
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static char * db_lbuf_end; /* end of input line buffer */
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static char * db_lc; /* current character */
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static char * db_le; /* one past last character */
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/*
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* Raw input buffer, processed only for certain control characters.
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*/
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#define DB_RAW_SIZE 512
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static char db_raw[DB_RAW_SIZE];
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static u_int db_raw_pos;
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static u_int db_raw_cnt;
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static int db_raw_warned;
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static int ddb_prioritize_control_input = 1;
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SYSCTL_INT(_debug_ddb, OID_AUTO, prioritize_control_input, CTLFLAG_RWTUN,
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&ddb_prioritize_control_input, 0,
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"Drop input when the buffer fills in order to keep servicing ^C/^S/^Q");
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/*
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* Simple input line history support.
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*/
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static char db_lhistory[2048];
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static int db_lhistlsize, db_lhistidx, db_lhistcur;
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static int db_lhist_nlines;
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#define CTRL(c) ((c) & 0x1f)
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#define BLANK ' '
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#define BACKUP '\b'
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static void db_delete(int n, int bwd);
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static int db_inputchar(int c);
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static void db_putnchars(int c, int count);
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static void db_putstring(char *s, int count);
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static int db_raw_pop(void);
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static void db_raw_push(int);
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static int db_raw_space(void);
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static void
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db_putstring(char *s, 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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static void
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db_putnchars(int c, 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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static void
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db_delete(int n, int bwd)
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{
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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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static int
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db_inputchar(int c)
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{
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static int escstate;
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if (escstate == 1) {
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/* ESC seen, look for [ or O */
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if (c == '[' || c == 'O')
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escstate++;
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else
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escstate = 0; /* re-init state machine */
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return (0);
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} else if (escstate == 2) {
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escstate = 0;
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/*
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* If a valid cursor key has been found, translate
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* into an emacs-style control key, and fall through.
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* Otherwise, drop off.
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*/
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switch (c) {
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case 'A': /* up */
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c = CTRL('p');
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break;
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case 'B': /* down */
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c = CTRL('n');
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break;
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case 'C': /* right */
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c = CTRL('f');
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break;
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case 'D': /* left */
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c = CTRL('b');
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break;
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default:
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return (0);
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}
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}
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switch (c) {
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case CTRL('['):
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escstate = 1;
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break;
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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('u'):
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case CTRL('c'):
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/* kill entire line: */
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/* at first, delete to beginning of line */
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if (db_lc > db_lbuf_start)
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db_delete(db_lc - db_lbuf_start, DEL_BWD);
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/* FALLTHROUGH */
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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('w'):
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/* erase previous word */
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for (; db_lc > db_lbuf_start;) {
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if (*(db_lc - 1) != ' ')
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break;
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db_delete(1, DEL_BWD);
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}
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for (; db_lc > db_lbuf_start;) {
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if (*(db_lc - 1) == ' ')
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break;
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db_delete(1, DEL_BWD);
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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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redraw:
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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 CTRL('p'):
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/* Make previous history line the active one. */
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if (db_lhistcur >= 0) {
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bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
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db_lbuf_start, db_lhistlsize);
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db_lhistcur--;
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goto hist_redraw;
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}
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break;
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case CTRL('n'):
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/* Make next history line the active one. */
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if (db_lhistcur < db_lhistidx - 1) {
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db_lhistcur += 2;
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bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
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db_lbuf_start, db_lhistlsize);
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} else {
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/*
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* ^N through tail of history, reset the
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* buffer to zero length.
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*/
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*db_lbuf_start = '\0';
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db_lhistcur = db_lhistidx;
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}
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hist_redraw:
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db_putnchars(BACKUP, db_lc - db_lbuf_start);
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db_putnchars(BLANK, db_le - db_lbuf_start);
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db_putnchars(BACKUP, db_le - db_lbuf_start);
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db_le = strchr(db_lbuf_start, '\0');
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if (db_le[-1] == '\r' || db_le[-1] == '\n')
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*--db_le = '\0';
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db_lc = db_le;
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goto redraw;
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case -1:
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/*
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* eek! the console returned eof.
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* probably that means we HAVE no console.. we should try bail
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* XXX
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*/
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c = '\r';
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case '\n':
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/* FALLTHROUGH */
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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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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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/* Get a character from the console, first checking the raw input buffer. */
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int
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db_getc(void)
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{
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int c;
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if (db_raw_cnt == 0) {
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c = cngetc();
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} else {
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c = db_raw_pop();
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if (c == '\r')
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c = '\n';
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}
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return (c);
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}
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/* Whether the raw input buffer has space to accept another character. */
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static int
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db_raw_space(void)
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{
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return (db_raw_cnt < DB_RAW_SIZE);
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}
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/* Un-get a character from the console by buffering it. */
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static void
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db_raw_push(int c)
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{
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if (!db_raw_space())
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db_error(NULL);
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db_raw[(db_raw_pos + db_raw_cnt++) % DB_RAW_SIZE] = c;
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}
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/* Drain a character from the raw input buffer. */
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static int
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db_raw_pop(void)
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{
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if (db_raw_cnt == 0)
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return (-1);
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db_raw_cnt--;
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db_raw_warned = 0;
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return (db_raw[db_raw_pos++ % DB_RAW_SIZE]);
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}
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int
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db_readline(char *lstart, int lsize)
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{
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if (lsize < 2)
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return (0);
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if (lsize != db_lhistlsize) {
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/*
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* (Re)initialize input line history. Throw away any
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* existing history.
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*/
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db_lhist_nlines = sizeof(db_lhistory) / lsize;
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db_lhistlsize = lsize;
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db_lhistidx = -1;
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}
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db_lhistcur = db_lhistidx;
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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 - 2; /* Will append NL and NUL. */
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db_lc = lstart;
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db_le = lstart;
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while (!db_inputchar(db_getc()))
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continue;
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db_capture_write(lstart, db_le - db_lbuf_start);
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db_printf("\n"); /* synch output position */
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*db_le = 0;
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if (db_le - db_lbuf_start > 1) {
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/* Maintain input line history for non-empty lines. */
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if (++db_lhistidx == db_lhist_nlines) {
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/* Rotate history. */
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bcopy(db_lhistory + db_lhistlsize, db_lhistory,
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db_lhistlsize * (db_lhist_nlines - 1));
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db_lhistidx--;
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}
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bcopy(lstart, db_lhistory + db_lhistidx * db_lhistlsize,
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db_lhistlsize);
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}
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return (db_le - db_lbuf_start);
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}
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static void
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db_do_interrupt(const char *reason)
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{
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/* Do a pager quit too because some commands have jmpbuf handling. */
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db_disable_pager();
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db_pager_quit = 1;
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db_error(reason);
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}
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void
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db_check_interrupt(void)
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{
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int c;
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/*
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* Check console input for control characters. Non-control input is
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* buffered. When buffer space is exhausted, either stop responding to
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* control input or drop further non-control input on the floor.
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*/
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for (;;) {
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if (!ddb_prioritize_control_input && !db_raw_space())
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return;
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c = cncheckc();
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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_do_interrupt("^C");
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/*NOTREACHED*/
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case CTRL('s'):
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do {
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c = cncheckc();
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if (c == CTRL('c'))
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db_do_interrupt("^C");
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} while (c != CTRL('q'));
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break;
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default:
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if (db_raw_space()) {
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db_raw_push(c);
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} else if (!db_raw_warned) {
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db_raw_warned = 1;
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db_printf("\n--Exceeded input buffer--\n");
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}
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break;
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}
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}
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}
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