/*      $OpenBSD: db_input.c,v 1.19 2020/10/15 03:14:00 deraadt Exp $   */
/*      $NetBSD: db_input.c,v 1.7 1996/02/05 01:57:02 christos Exp $    */

/*
 * Mach Operating System
 * Copyright (c) 1993,1992,1991,1990 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  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 Mellon
 * the rights to redistribute these changes.
 *
 *      Author: David B. Golub, Carnegie Mellon University
 *      Date:   7/90
 */

#include <sys/param.h>
#include <sys/systm.h>

#include <machine/db_machdep.h>

#include <ddb/db_var.h>
#include <ddb/db_output.h>
#include <ddb/db_sym.h>
#include <ddb/db_extern.h>

#include <dev/cons.h>

/*
 * Character input and editing.
 */

void db_putstring(char *, int);
void db_putnchars(int, int);
void db_delete(int, int);
void db_delete_line(void);
int db_inputchar(int);

/*
 * 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 */
#if DB_HISTORY_SIZE != 0
char    db_history[DB_HISTORY_SIZE];    /* start of history buffer */
int     db_history_size = DB_HISTORY_SIZE;/* size of history buffer */
char *  db_history_curr = db_history;   /* start of current line */
char *  db_history_last = db_history;   /* start of last line */
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'

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

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
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;
}

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 DB_HISTORY_SIZE != 0
#define INC_DB_CURR() \
        do { \
                db_history_curr++; \
                if (db_history_curr > \
                        db_history + db_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 + \
                        db_history_size - 1; \
        } while (0)
#endif

/* returns `1' at end-of-line */
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('w'):
                /* erase word back */
                while (db_lc > db_lbuf_start && db_lc[-1] != BLANK)
                        db_delete(1, DEL_BWD);
                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 + 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 DB_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 + db_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 + db_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 DB_HISTORY_SIZE != 0
                /*
                 * Check whether current line is the same
                 * as previous saved line.  If it is, don`t
                 * save it.
                 */
                if (db_history_curr == db_history_prev) {
                        char *pp, *pc;

                        /*
                         * Is it the same?
                         */
                        for (pp = db_history_prev, pc = db_lbuf_start;
                            pc != db_le && *pp; ) {
                                if (*pp != *pc)
                                        break;
                                if (++pp == db_history + db_history_size)
                                        pp = db_history;
                                pc++;
                        }
                        if (!*pp && pc == db_le) {
                                /*
                                 * Repeated previous line. Don`t save.
                                 */
                                db_history_curr = db_history_last;
                                *db_le++ = c;
                                return 1;
                        }
                }
                if (db_le != db_lbuf_start) {
                        char *p;
                        db_history_prev = db_history_last;
                        for (p = db_lbuf_start; p != db_le; p++) {
                                *db_history_last++ = *p;
                                if (db_history_last ==
                                    db_history + db_history_size)
                                        db_history_last = db_history;
                        }
                        *db_history_last++ = '\0';
                        if (db_history_last == db_history + db_history_size)
                                db_history_last = db_history;
                }
                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 - 1;
        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);
}