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Finally implement a simple commandline history in DDB.

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Emacs-style line editing has already been there (did anybody ever
notice this? :), so i `only' had to add ^P and ^N.  The approach is
fairly minimalistic, with the advantage of keeping the bloat as small
as 864 bytes of .text and 16 bytes of .bss, plus 10*120 bytes
malloc'ed history buffer at the first use.
This commit is contained in:
Joerg Wunsch 1996-08-10 13:38:44 +00:00
parent e0d275f1a6
commit b463077353
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=17495
1 changed files with 71 additions and 2 deletions
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73
sys/ddb/db_input.c
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@ -23,7 +23,7 @@
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $Id: db_input.c,v 1.12 1995/12/10 19:07:59 bde Exp $
* $Id: db_input.c,v 1.13 1996/05/08 04:28:34 gpalmer Exp $
*/
/*
@ -32,6 +32,7 @@
*/
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <machine/cons.h>
@ -53,6 +54,13 @@ static char * db_lbuf_end; /* end of input line buffer */
static char * db_lc; /* current character */
static char * db_le; /* one past last character */
/*
* Simple input line history support.
*/
static char * db_lhistory;
static int db_lhistlsize, db_lhistidx, db_lhistcur;
#define DB_LHIST_NLINES 10
#define CTRL(c) ((c) & 0x1f)
#define isspace(c) ((c) == ' ' || (c) == '\t')
#define BLANK ' '
@ -171,11 +179,46 @@ db_inputchar(c)
break;
case CTRL('r'):
db_putstring("^R\n", 3);
redraw:
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 CTRL('p'):
/* Make previous history line the active one. */
if (db_lhistcur >= 0) {
bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
db_lbuf_start, db_lhistlsize);
db_lhistcur--;
goto hist_redraw;
}
break;
case CTRL('n'):
/* Make next history line the active one. */
if (db_lhistcur < db_lhistidx - 1) {
db_lhistcur += 2;
bcopy(db_lhistory + db_lhistcur * db_lhistlsize,
db_lbuf_start, db_lhistlsize);
} else {
/*
* ^N through tail of history, reset the
* buffer to zero length.
*/
*db_lbuf_start = '\0';
db_lhistcur = db_lhistidx;
}
hist_redraw:
db_putnchars(BACKUP, db_le - db_lbuf_start);
db_putnchars(BLANK, db_le - db_lbuf_start);
db_putnchars(BACKUP, db_le - db_lbuf_start);
db_le = index(db_lbuf_start, '\0');
if (db_le[-1] == '\r' || db_le[-1] == '\n')
*--db_le = '\0';
db_lc = db_le;
goto redraw;
case '\n':
case '\r':
*db_le++ = c;
@ -211,6 +254,20 @@ db_readline(lstart, lsize)
char * lstart;
int lsize;
{
if (db_lhistory && lsize != db_lhistlsize) {
/* Should not happen, but to be sane, throw history away. */
FREE(db_lhistory, M_TEMP);
db_lhistory = 0;
}
if (db_lhistory == 0) {
/* Initialize input line history. */
db_lhistlsize = lsize;
db_lhistidx = -1;
MALLOC(db_lhistory, char *, lsize * DB_LHIST_NLINES,
M_TEMP, M_NOWAIT);
}
db_lhistcur = db_lhistidx;
db_force_whitespace(); /* synch output position */
db_lbuf_start = lstart;
@ -222,8 +279,20 @@ db_readline(lstart, lsize)
continue;
db_printf("\n"); /* synch output position */
*db_le = 0;
if (db_le - db_lbuf_start > 1) {
/* Maintain input line history for non-empty lines. */
if (++db_lhistidx == DB_LHIST_NLINES) {
/* Rotate history. */
ovbcopy(db_lhistory + db_lhistlsize, db_lhistory,
db_lhistlsize * (DB_LHIST_NLINES - 1));
db_lhistidx--;
}
bcopy(lstart, db_lhistory + (db_lhistidx * db_lhistlsize),
db_lhistlsize);
}
return (db_le - db_lbuf_start);
}