/* $NetBSD: arithmetic.c,v 1.5 2018/04/21 23:01:29 kre Exp $ */
/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2007
* Herbert Xu <herbert@gondor.apana.org.au>. 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, who obtained it from dash, modified both times...
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: arithmetic.c,v 1.5 2018/04/21 23:01:29 kre Exp $");
#endif /* not lint */
#include <limits.h>
#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "shell.h"
#include "arithmetic.h"
#include "arith_tokens.h"
#include "expand.h"
#include "error.h"
#include "memalloc.h"
#include "output.h"
#include "options.h"
#include "var.h"
#include "show.h"
#include "syntax.h"
#if ARITH_BOR + ARITH_ASS_GAP != ARITH_BORASS || \
ARITH_ASS + ARITH_ASS_GAP != ARITH_EQ
#error Arithmetic tokens are out of order.
#endif
static const char *arith_startbuf;
const char *arith_buf;
union a_token_val a_t_val;
static int last_token;
int arith_lno, arith_var_lno;
#define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec
static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = {
ARITH_PRECEDENCE(ARITH_MUL, 0),
ARITH_PRECEDENCE(ARITH_DIV, 0),
ARITH_PRECEDENCE(ARITH_REM, 0),
ARITH_PRECEDENCE(ARITH_ADD, 1),
ARITH_PRECEDENCE(ARITH_SUB, 1),
ARITH_PRECEDENCE(ARITH_LSHIFT, 2),
ARITH_PRECEDENCE(ARITH_RSHIFT, 2),
ARITH_PRECEDENCE(ARITH_LT, 3),
ARITH_PRECEDENCE(ARITH_LE, 3),
ARITH_PRECEDENCE(ARITH_GT, 3),
ARITH_PRECEDENCE(ARITH_GE, 3),
ARITH_PRECEDENCE(ARITH_EQ, 4),
ARITH_PRECEDENCE(ARITH_NE, 4),
ARITH_PRECEDENCE(ARITH_BAND, 5),
ARITH_PRECEDENCE(ARITH_BXOR, 6),
ARITH_PRECEDENCE(ARITH_BOR, 7),
};
#define ARITH_MAX_PREC 8
int expcmd(int, char **);
static void __dead
arith_err(const char *s)
{
error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
/* NOTREACHED */
}
static intmax_t
arith_lookupvarint(char *varname)
{
const char *str;
char *p;
intmax_t result;
const int oln = line_number;
VTRACE(DBG_ARITH, ("Arith var lookup(\"%s\") with lno=%d\n", varname,
arith_var_lno));
line_number = arith_var_lno;
str = lookupvar(varname);
line_number = oln;
if (uflag && str == NULL)
arith_err("variable not set");
if (str == NULL || *str == '\0')
str = "0";
errno = 0;
result = strtoimax(str, &p, 0);
if (errno != 0 || *p != '\0') {
if (errno == 0) {
while (*p != '\0' && is_space(*p))
p++;
if (*p == '\0')
return result;
}
arith_err("variable contains non-numeric value");
}
return result;
}
static inline int
arith_prec(int op)
{
return prec[op - ARITH_BINOP_MIN];
}
static inline int
higher_prec(int op1, int op2)
{
return arith_prec(op1) < arith_prec(op2);
}
static intmax_t
do_binop(int op, intmax_t a, intmax_t b)
{
VTRACE(DBG_ARITH, ("Arith do binop %d (%jd, %jd)\n", op, a, b));
switch (op) {
default:
arith_err("token error");
case ARITH_REM:
case ARITH_DIV:
if (b == 0)
arith_err("division by zero");
if (a == INTMAX_MIN && b == -1)
arith_err("divide error");
return op == ARITH_REM ? a % b : a / b;
case ARITH_MUL:
return (uintmax_t)a * (uintmax_t)b;
case ARITH_ADD:
return (uintmax_t)a + (uintmax_t)b;
case ARITH_SUB:
return (uintmax_t)a - (uintmax_t)b;
case ARITH_LSHIFT:
return (uintmax_t)a << (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
case ARITH_RSHIFT:
return a >> (b & (sizeof(uintmax_t) * CHAR_BIT - 1));
case ARITH_LT:
return a < b;
case ARITH_LE:
return a <= b;
case ARITH_GT:
return a > b;
case ARITH_GE:
return a >= b;
case ARITH_EQ:
return a == b;
case ARITH_NE:
return a != b;
case ARITH_BAND:
return a & b;
case ARITH_BXOR:
return a ^ b;
case ARITH_BOR:
return a | b;
}
}
static intmax_t assignment(int, int);
static intmax_t comma_list(int, int);
static intmax_t
primary(int token, union a_token_val *val, int op, int noeval)
{
intmax_t result;
char sresult[DIGITS(result) + 1];
VTRACE(DBG_ARITH, ("Arith primary: token %d op %d%s\n",
token, op, noeval ? " noeval" : ""));
switch (token) {
case ARITH_LPAREN:
result = comma_list(op, noeval);
if (last_token != ARITH_RPAREN)
arith_err("expecting ')'");
last_token = arith_token();
return result;
case ARITH_NUM:
last_token = op;
return val->val;
case ARITH_VAR:
result = noeval ? val->val : arith_lookupvarint(val->name);
if (op == ARITH_INCR || op == ARITH_DECR) {
last_token = arith_token();
if (noeval)
return val->val;
snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR,
result + (op == ARITH_INCR ? 1 : -1));
setvar(val->name, sresult, 0);
} else
last_token = op;
return result;
case ARITH_ADD:
*val = a_t_val;
return primary(op, val, arith_token(), noeval);
case ARITH_SUB:
*val = a_t_val;
return -primary(op, val, arith_token(), noeval);
case ARITH_NOT:
*val = a_t_val;
return !primary(op, val, arith_token(), noeval);
case ARITH_BNOT:
*val = a_t_val;
return ~primary(op, val, arith_token(), noeval);
case ARITH_INCR:
case ARITH_DECR:
if (op != ARITH_VAR)
arith_err("incr/decr require var name");
last_token = arith_token();
if (noeval)
return val->val;
result = arith_lookupvarint(a_t_val.name);
snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR,
result += (token == ARITH_INCR ? 1 : -1));
setvar(a_t_val.name, sresult, 0);
return result;
default:
arith_err("expecting primary");
}
return 0; /* never reached */
}
static intmax_t
binop2(intmax_t a, int op, int precedence, int noeval)
{
union a_token_val val;
intmax_t b;
int op2;
int token;
VTRACE(DBG_ARITH, ("Arith: binop2 %jd op %d (P:%d)%s\n",
a, op, precedence, noeval ? " noeval" : ""));
for (;;) {
token = arith_token();
val = a_t_val;
b = primary(token, &val, arith_token(), noeval);
op2 = last_token;
if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX &&
higher_prec(op2, op)) {
b = binop2(b, op2, arith_prec(op), noeval);
op2 = last_token;
}
a = noeval ? b : do_binop(op, a, b);
if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX ||
arith_prec(op2) >= precedence)
return a;
op = op2;
}
}
static intmax_t
binop(int token, union a_token_val *val, int op, int noeval)
{
intmax_t a = primary(token, val, op, noeval);
op = last_token;
if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX)
return a;
return binop2(a, op, ARITH_MAX_PREC, noeval);
}
static intmax_t
and(int token, union a_token_val *val, int op, int noeval)
{
intmax_t a = binop(token, val, op, noeval);
intmax_t b;
op = last_token;
if (op != ARITH_AND)
return a;
VTRACE(DBG_ARITH, ("Arith: AND %jd%s\n", a, noeval ? " noeval" : ""));
token = arith_token();
*val = a_t_val;
b = and(token, val, arith_token(), noeval | !a);
return a && b;
}
static intmax_t
or(int token, union a_token_val *val, int op, int noeval)
{
intmax_t a = and(token, val, op, noeval);
intmax_t b;
op = last_token;
if (op != ARITH_OR)
return a;
VTRACE(DBG_ARITH, ("Arith: OR %jd%s\n", a, noeval ? " noeval" : ""));
token = arith_token();
*val = a_t_val;
b = or(token, val, arith_token(), noeval | !!a);
return a || b;
}
static intmax_t
cond(int token, union a_token_val *val, int op, int noeval)
{
intmax_t a = or(token, val, op, noeval);
intmax_t b;
intmax_t c;
if (last_token != ARITH_QMARK)
return a;
VTRACE(DBG_ARITH, ("Arith: ?: %jd%s\n", a, noeval ? " noeval" : ""));
b = assignment(arith_token(), noeval | !a);
if (last_token != ARITH_COLON)
arith_err("expecting ':'");
token = arith_token();
*val = a_t_val;
c = cond(token, val, arith_token(), noeval | !!a);
return a ? b : c;
}
static intmax_t
assignment(int var, int noeval)
{
union a_token_val val = a_t_val;
int op = arith_token();
intmax_t result;
char sresult[DIGITS(result) + 1];
if (var != ARITH_VAR)
return cond(var, &val, op, noeval);
if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX))
return cond(var, &val, op, noeval);
VTRACE(DBG_ARITH, ("Arith: %s ASSIGN %d%s\n", val.name, op,
noeval ? " noeval" : ""));
result = assignment(arith_token(), noeval);
if (noeval)
return result;
if (op != ARITH_ASS)
result = do_binop(op - ARITH_ASS_GAP,
arith_lookupvarint(val.name), result);
snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result);
setvar(val.name, sresult, 0);
return result;
}
static intmax_t
comma_list(int token, int noeval)
{
intmax_t result = assignment(token, noeval);
while (last_token == ARITH_COMMA) {
VTRACE(DBG_ARITH, ("Arith: comma discarding %jd%s\n", result,
noeval ? " noeval" : ""));
result = assignment(arith_token(), noeval);
}
return result;
}
intmax_t
arith(const char *s, int lno)
{
struct stackmark smark;
intmax_t result;
const char *p;
int nls = 0;
setstackmark(&smark);
arith_lno = lno;
CTRACE(DBG_ARITH, ("Arith(\"%s\", %d) @%d\n", s, lno, arith_lno));
/* check if it is possible we might reference LINENO */
p = s;
while ((p = strchr(p, 'L')) != NULL) {
if (p[1] == 'I' && p[2] == 'N') {
/* if it is possible, we need to correct airth_lno */
p = s;
while ((p = strchr(p, '\n')) != NULL)
nls++, p++;
VTRACE(DBG_ARITH, ("Arith found %d newlines\n", nls));
arith_lno -= nls;
break;
}
p++;
}
arith_buf = arith_startbuf = s;
result = comma_list(arith_token(), 0);
if (last_token)
arith_err("expecting end of expression");
popstackmark(&smark);
CTRACE(DBG_ARITH, ("Arith result=%jd\n", result));
return result;
}
/*
* The let(1)/exp(1) builtin.
*/
int
expcmd(int argc, char **argv)
{
const char *p;
char *concat;
char **ap;
intmax_t i;
if (argc > 1) {
p = argv[1];
if (argc > 2) {
/*
* Concatenate arguments.
*/
STARTSTACKSTR(concat);
ap = argv + 2;
for (;;) {
while (*p)
STPUTC(*p++, concat);
if ((p = *ap++) == NULL)
break;
STPUTC(' ', concat);
}
STPUTC('\0', concat);
p = grabstackstr(concat);
}
} else
p = "";
i = arith(p, line_number);
out1fmt(ARITH_FORMAT_STR "\n", i);
return !i;
}