freebsd-dev/bin/sh/arith_yacc.c

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/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <limits.h>
#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include "arith.h"
#include "arith_yacc.h"
#include "expand.h"
#include "shell.h"
#include "error.h"
#include "memalloc.h"
#include "output.h"
#include "options.h"
#include "var.h"
#if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ
#error Arithmetic tokens are out of order.
#endif
static const char *arith_startbuf;
const char *arith_buf;
union yystype yylval;
static int last_token;
#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 letcmd(int, char **);
static __dead2 void yyerror(const char *s)
{
error("arithmetic expression: %s: \"%s\"", s, arith_startbuf);
/* NOTREACHED */
}
static arith_t arith_lookupvarint(char *varname)
{
const char *str;
char *p;
arith_t result;
str = lookupvar(varname);
if (uflag && str == NULL)
yyerror("variable not set");
if (str == NULL || *str == '\0')
str = "0";
errno = 0;
result = strtoarith_t(str, &p, 0);
if (errno != 0 || *p != '\0')
yyerror("variable conversion error");
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 arith_t do_binop(int op, arith_t a, arith_t b)
{
switch (op) {
default:
case ARITH_REM:
case ARITH_DIV:
if (!b)
yyerror("division by zero");
if (a == ARITH_MIN && b == -1)
yyerror("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 arith_t assignment(int var, int noeval);
static arith_t primary(int token, union yystype *val, int op, int noeval)
{
arith_t result;
again:
switch (token) {
case ARITH_LPAREN:
result = assignment(op, noeval);
if (last_token != ARITH_RPAREN)
yyerror("expecting ')'");
last_token = yylex();
return result;
case ARITH_NUM:
last_token = op;
return val->val;
case ARITH_VAR:
last_token = op;
return noeval ? val->val : arith_lookupvarint(val->name);
case ARITH_ADD:
token = op;
*val = yylval;
op = yylex();
goto again;
case ARITH_SUB:
*val = yylval;
return -primary(op, val, yylex(), noeval);
case ARITH_NOT:
*val = yylval;
return !primary(op, val, yylex(), noeval);
case ARITH_BNOT:
*val = yylval;
return ~primary(op, val, yylex(), noeval);
default:
yyerror("expecting primary");
}
}
static arith_t binop2(arith_t a, int op, int precedence, int noeval)
{
for (;;) {
union yystype val;
arith_t b;
int op2;
int token;
token = yylex();
val = yylval;
b = primary(token, &val, yylex(), 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 arith_t binop(int token, union yystype *val, int op, int noeval)
{
arith_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 arith_t and(int token, union yystype *val, int op, int noeval)
{
arith_t a = binop(token, val, op, noeval);
arith_t b;
op = last_token;
if (op != ARITH_AND)
return a;
token = yylex();
*val = yylval;
b = and(token, val, yylex(), noeval | !a);
return a && b;
}
static arith_t or(int token, union yystype *val, int op, int noeval)
{
arith_t a = and(token, val, op, noeval);
arith_t b;
op = last_token;
if (op != ARITH_OR)
return a;
token = yylex();
*val = yylval;
b = or(token, val, yylex(), noeval | !!a);
return a || b;
}
static arith_t cond(int token, union yystype *val, int op, int noeval)
{
arith_t a = or(token, val, op, noeval);
arith_t b;
arith_t c;
if (last_token != ARITH_QMARK)
return a;
b = assignment(yylex(), noeval | !a);
if (last_token != ARITH_COLON)
yyerror("expecting ':'");
token = yylex();
*val = yylval;
c = cond(token, val, yylex(), noeval | !!a);
return a ? b : c;
}
static arith_t assignment(int var, int noeval)
{
union yystype val = yylval;
int op = yylex();
arith_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);
result = assignment(yylex(), noeval);
if (noeval)
return result;
if (op != ARITH_ASS)
result = do_binop(op - 11, arith_lookupvarint(val.name), result);
snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result);
setvar(val.name, sresult, 0);
return result;
}
arith_t arith(const char *s)
{
struct stackmark smark;
arith_t result;
setstackmark(&smark);
arith_buf = arith_startbuf = s;
result = assignment(yylex(), 0);
if (last_token)
yyerror("expecting EOF");
popstackmark(&smark);
return result;
}
/*
* The exp(1) builtin.
*/
int
letcmd(int argc, char **argv)
{
const char *p;
char *concat;
char **ap;
arith_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);
out1fmt(ARITH_FORMAT_STR "\n", i);
return !i;
}