/*      $NetBSD: arith_token.c,v 1.8 2026/03/22 19:18:50 kre Exp $      */

/*-
 * Copyright (c) 2002
 *      Herbert Xu.
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * From FreeBSD, from dash
 */

#include <sys/cdefs.h>

#ifndef lint
__RCSID("$NetBSD: arith_token.c,v 1.8 2026/03/22 19:18:50 kre Exp $");
#endif /* not lint */

#include <inttypes.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>

#include "shell.h"
#include "arith_tokens.h"
#include "expand.h"
#include "error.h"
#include "memalloc.h"
#include "parser.h"
#include "syntax.h"
#include "show.h"

#if ARITH_BOR + ARITH_ASS_GAP != ARITH_BORASS || \
        ARITH_ASS + ARITH_ASS_GAP != ARITH_EQ
#error Arithmetic tokens are out of order.
#endif

/*
 * Scan next arithmetic token, return its type,
 * leave its value (when applicable) in (global) a_t_val.
 *
 * Input text is in (global) arith_buf which is updated to
 * refer to the next char after the token returned, except
 * on error (ARITH_BAD returned) where arith_buf is not altered.
 */
int
arith_token(void)
{
        int token;
        const char *buf = arith_buf;
        char *end;
        const char *p;

        for (;;) {
                token = *buf;

                if (is_digit(token)) {
                        /*
                         * Numbers all start with a digit, and nothing
                         * else does, the number ends wherever
                         * strtoimax() stops...
                         */
                        a_t_val.val = strtoimax(buf, &end, 0);
                        if (is_in_name(*end)) {
                                token = *end;
                                while (is_in_name(*++end))
                                        continue;
                                error("arithmetic: unexpected '%c' "
                                      "(out of range) in numeric constant: "
                                      "%.*s", token, (int)(end - buf), buf);
                        }
                        arith_buf = end;
                        VTRACE(DBG_ARITH, ("Arith token ARITH_NUM=%jd\n",
                            a_t_val.val));
                        return ARITH_NUM;

                } else if (is_name(token)) {
                        /*
                         * Variable names all start with an alpha (or '_')
                         * and nothing else does.  They continue for the
                         * longest unbroken sequence of alphanumerics ( + _ )
                         */
                        arith_var_lno = arith_lno;
                        p = buf;
                        while (buf++, is_in_name(*buf))
                                ;
                        a_t_val.name = stalloc(buf - p + 1);
                        memcpy(a_t_val.name, p, buf - p);
                        a_t_val.name[buf - p] = '\0';
                        arith_buf = buf;
                        VTRACE(DBG_ARITH, ("Arith token ARITH_VAR=\"%s\"\n",
                            a_t_val.name));
                        return ARITH_VAR;

                } else switch (token) {
                        /*
                         * everything else must be some kind of
                         * operator, white space, or an error.
                         */
                case '\n':
                        arith_lno++;
                        VTRACE(DBG_ARITH, ("Arith: newline\n"));
                        /* FALLTHROUGH */
                case ' ':
                case '\t':
                        buf++;
                        continue;

                default:
                        error("arithmetic: unexpected '%c' (%#x) in expression",
                            token, token);
                        /* NOTREACHED */

                case '=':
                        token = ARITH_ASS;
 checkeq:
                        buf++;
 checkeqcur:
                        if (*buf != '=')
                                goto out;
                        token += ARITH_ASS_GAP;
                        break;

                case '>':
                        switch (*++buf) {
                        case '=':
                                token = ARITH_GE;
                                break;
                        case '>':
                                token = ARITH_RSHIFT;
                                goto checkeq;
                        default:
                                token = ARITH_GT;
                                goto out;
                        }
                        break;

                case '<':
                        switch (*++buf) {
                        case '=':
                                token = ARITH_LE;
                                break;
                        case '<':
                                token = ARITH_LSHIFT;
                                goto checkeq;
                        default:
                                token = ARITH_LT;
                                goto out;
                        }
                        break;

                case '|':
                        if (*++buf != '|') {
                                token = ARITH_BOR;
                                goto checkeqcur;
                        }
                        token = ARITH_OR;
                        break;

                case '&':
                        if (*++buf != '&') {
                                token = ARITH_BAND;
                                goto checkeqcur;
                        }
                        token = ARITH_AND;
                        break;

                case '!':
                        if (*++buf != '=') {
                                token = ARITH_NOT;
                                goto out;
                        }
                        token = ARITH_NE;
                        break;

                case 0:
                        goto out;

                case '(':
                        token = ARITH_LPAREN;
                        break;
                case ')':
                        token = ARITH_RPAREN;
                        break;

                case '*':
                        token = ARITH_MUL;
                        goto checkeq;
                case '/':
                        token = ARITH_DIV;
                        goto checkeq;
                case '%':
                        token = ARITH_REM;
                        goto checkeq;

                case '+':
                        if (buf[1] == '+') {
                                buf++;
                                token = ARITH_INCR;
                                break;
                        }
                        token = ARITH_ADD;
                        goto checkeq;
                case '-':
                        if (buf[1] == '-') {
                                buf++;
                                token = ARITH_DECR;
                                break;
                        }
                        token = ARITH_SUB;
                        goto checkeq;
                case '~':
                        token = ARITH_BNOT;
                        break;
                case '^':
                        token = ARITH_BXOR;
                        goto checkeq;

                case '?':
                        token = ARITH_QMARK;
                        break;
                case ':':
                        token = ARITH_COLON;
                        break;
                case ',':
                        token = ARITH_COMMA;
                        break;
                }
                break;
        }
        buf++;
 out:
        arith_buf = buf;
        VTRACE(DBG_ARITH, ("Arith token: %d\n", token));
        return token;
}