/* $NetBSD: db_input.c,v 1.28 2020/10/30 06:57:08 skrll Exp $ */
/*
* 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 "AS IS"
* 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
[email protected]
* 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.
*
* Author: David B. Golub, Carnegie Mellon University
* Date: 7/90
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_input.c,v 1.28 2020/10/30 06:57:08 skrll Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddbparam.h"
#endif
#include <sys/param.h>
#include <sys/proc.h>
#include <ddb/ddb.h>
#include <dev/cons.h>
#ifndef DDB_HISTORY_SIZE
#define DDB_HISTORY_SIZE 0
#endif /* DDB_HISTORY_SIZE */
/*
* 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.
*/
static char *db_lbuf_start; /* start of input line buffer */
static char *db_lbuf_end; /* end of input line buffer */
static char *db_lc; /* current character */
static char *db_le; /* one past last character */
#if DDB_HISTORY_SIZE != 0
static char db_history[DDB_HISTORY_SIZE]; /* start of history buffer */
static char *db_history_curr = db_history; /* start of current line */
static char *db_history_last = db_history; /* start of last line */
static char *db_history_prev = (char *) 0; /* start of previous line */
#endif
#define CTRL(c) ((c) & 0x1f)
#define isspace(c) ((c) == ' ' || (c) == '\t')
#define BLANK ' '
#define BACKUP '\b'
static int cnmaygetc(void);
static void db_putstring(const char *, int);
static void db_putnchars(int, int);
static void db_delete(int, int);
static void db_delete_line(void);
static int db_inputchar(int);
static void
db_putstring(const char *s, int count)
{
while (--count >= 0)
cnputc(*s++);
}
static void
db_putnchars(int c, int count)
{
while (--count >= 0)
cnputc(c);
}
/*
* Delete N characters, forward or backward
*/
#define DEL_FWD 0
#define DEL_BWD 1
static void
db_delete(int n, int bwd)
{
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;
}
static void
db_delete_line(void)
{
db_delete(db_le - db_lc, DEL_FWD);
db_delete(db_lc - db_lbuf_start, DEL_BWD);
db_le = db_lc = db_lbuf_start;
}
#if DDB_HISTORY_SIZE != 0
#define INC_DB_CURR() do { \
++db_history_curr; \
if (db_history_curr > db_history + DDB_HISTORY_SIZE - 1) \
db_history_curr = db_history; \
} while (0)
#define DEC_DB_CURR() do { \
--db_history_curr; \
if (db_history_curr < db_history) \
db_history_curr = db_history + DDB_HISTORY_SIZE - 1; \
} while (0)
static inline void
db_hist_put(int c)
{
KASSERT(&db_history[0] <= db_history_last);
KASSERT(db_history_last <= &db_history[DDB_HISTORY_SIZE-1]);
*db_history_last++ = c;
if (db_history_last > &db_history[DDB_HISTORY_SIZE-1])
db_history_last = db_history;
}
#endif
/* returns true at end-of-line */
static int
db_inputchar(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('u'):
/* delete line */
db_delete_line();
break;
case CTRL('t'):
/* twiddle last 2 characters */
if (db_lc >= db_lbuf_start + 1) {
if (db_lc < db_le) {
c = db_lc[-1];
db_lc[-1] = db_lc[0];
db_lc[0] = c;
cnputc(BACKUP);
cnputc(db_lc[-1]);
cnputc(db_lc[0]);
db_lc++;
} else 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;
#if DDB_HISTORY_SIZE != 0
case CTRL('p'):
DEC_DB_CURR();
while (db_history_curr != db_history_last) {
DEC_DB_CURR();
if (*db_history_curr == '\0')
break;
}
db_delete_line();
if (db_history_curr == db_history_last) {
INC_DB_CURR();
db_le = db_lc = db_lbuf_start;
} else {
char *p;
INC_DB_CURR();
for (p = db_history_curr, db_le = db_lbuf_start;
*p; ) {
*db_le++ = *p++;
if (p >= db_history + DDB_HISTORY_SIZE) {
p = db_history;
}
}
db_lc = db_le;
}
db_putstring(db_lbuf_start, db_le - db_lbuf_start);
break;
case CTRL('n'):
while (db_history_curr != db_history_last) {
if (*db_history_curr == '\0')
break;
INC_DB_CURR();
}
if (db_history_curr != db_history_last) {
INC_DB_CURR();
db_delete_line();
if (db_history_curr != db_history_last) {
char *p;
for (p = db_history_curr,
db_le = db_lbuf_start; *p;) {
*db_le++ = *p++;
if (p >= db_history + DDB_HISTORY_SIZE) {
p = db_history;
}
}
db_lc = db_le;
}
db_putstring(db_lbuf_start, db_le - db_lbuf_start);
}
break;
#endif
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':
#if DDB_HISTORY_SIZE != 0
/* Check if it same than previous line */
if (db_history_curr == db_history_prev) {
char *pp, *pc;
/* Is it unmodified */
for (pp = db_history_prev, pc = db_lbuf_start;
pc != db_le && *pp; pp++, pc++) {
if (*pp != *pc)
break;
if (++pp >= db_history + DDB_HISTORY_SIZE) {
pp = db_history;
}
if (++pc >= db_history + DDB_HISTORY_SIZE) {
pc = db_history;
}
}
if (!*pp && pc == db_le) {
/* Repeted previous line, not saved */
db_history_curr = db_history_last;
*db_le++ = c;
return (true);
}
}
if (db_le != db_lbuf_start) {
char *p;
db_history_prev = db_history_last;
for (p = db_lbuf_start; p != db_le; ) {
db_hist_put(*p++);
}
db_hist_put(0);
}
db_history_curr = db_history_last;
#endif
*db_le++ = c;
return (1);
default:
if (db_le == db_lbuf_end) {
cnputc('\007');
}
else if (c >= ' ' && c <= '~') {
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(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(void)
{
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);
/*NOTREACHED*/
}
} while (c != CTRL('q'));
break;
default:
/* drop on floor */
break;
}
}
static int
cnmaygetc(void)
{
return (-1);
}
