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mksh/expr.c
tg a34b05d2e6 Import OpenBSD 3.3 source repository from CTM 3132 the first time 
This opens an OpenBSD-mirabile (aka MirBSD) repository.

### MirBSD is:
# Copyright (c) 1982-2003 by Thorsten "mirabile" Glaser <x86@ePost.de>
# Copyright © 1968-2003  The authors of And contributors to UNIX®, the
#       C Language, BSD/Berkeley Unix; 386BSD, NetBSD 1.1 and OpenBSD.
#
# Anyone who obtained a copy of this work is hereby permitted to freely use,
# distribute, modify, merge, sublicence, give away or sell it as long as the
# authors are given due credit and the following notice is retained:
#
# This work is provided "as is", with no explicit or implicit warranty what-
# soever. Use it only at your own risk. In no event may an author or contri-
# butor be held liable for any damage, directly or indirectly, that origina-
# ted through or is caused by creation or modification of this work.

MirBSD is my private tree. MirBSD does not differ very much from OpenBSD
and intentionally tracks OpenBSD. That's why it _is_ OpenBSD, just not the
official one. It's like with DarrenBSD.

At time of this writing, no advertising for MirBSD must be done,
because the advertising clause has not yet been sorted out.

http://templeofhate.com/tglaser/MirBSD/index.php
2003-03-22 17:35:03 +00:00

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/* $OpenBSD: expr.c,v 1.8 2003/02/28 09:45:09 jmc Exp $ */
/*
* Korn expression evaluation
*/
/*
* todo: better error handling: if in builtin, should be builtin error, etc.
*/
#include "sh.h"
#include <ctype.h>
/* The order of these enums is constrained by the order of opinfo[] */
enum token {
/* some (long) unary operators */
O_PLUSPLUS = 0, O_MINUSMINUS,
/* binary operators */
O_EQ, O_NE,
/* assignments are assumed to be in range O_ASN .. O_BORASN */
O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN,
O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN,
O_LSHIFT, O_RSHIFT,
O_LE, O_GE, O_LT, O_GT,
O_LAND,
O_LOR,
O_TIMES, O_DIV, O_MOD,
O_PLUS, O_MINUS,
O_BAND,
O_BXOR,
O_BOR,
O_TERN,
O_COMMA,
/* things after this aren't used as binary operators */
/* unary that are not also binaries */
O_BNOT, O_LNOT,
/* misc */
OPEN_PAREN, CLOSE_PAREN, CTERN,
/* things that don't appear in the opinfo[] table */
VAR, LIT, END, BAD
};
#define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA)
#define IS_ASSIGNOP(op) ((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN)
enum prec {
P_PRIMARY = 0, /* VAR, LIT, (), ~ ! - + */
P_MULT, /* * / % */
P_ADD, /* + - */
P_SHIFT, /* << >> */
P_RELATION, /* < <= > >= */
P_EQUALITY, /* == != */
P_BAND, /* & */
P_BXOR, /* ^ */
P_BOR, /* | */
P_LAND, /* && */
P_LOR, /* || */
P_TERN, /* ?: */
P_ASSIGN, /* = *= /= %= += -= <<= >>= &= ^= |= */
P_COMMA /* , */
};
#define MAX_PREC P_COMMA
struct opinfo {
char name[4];
int len; /* name length */
enum prec prec; /* precedence: lower is higher */
};
/* Tokens in this table must be ordered so the longest are first
* (eg, += before +). If you change something, change the order
* of enum token too.
*/
static const struct opinfo opinfo[] = {
{ "++", 2, P_PRIMARY }, /* before + */
{ "--", 2, P_PRIMARY }, /* before - */
{ "==", 2, P_EQUALITY }, /* before = */
{ "!=", 2, P_EQUALITY }, /* before ! */
{ "=", 1, P_ASSIGN }, /* keep assigns in a block */
{ "*=", 2, P_ASSIGN },
{ "/=", 2, P_ASSIGN },
{ "%=", 2, P_ASSIGN },
{ "+=", 2, P_ASSIGN },
{ "-=", 2, P_ASSIGN },
{ "<<=", 3, P_ASSIGN },
{ ">>=", 3, P_ASSIGN },
{ "&=", 2, P_ASSIGN },
{ "^=", 2, P_ASSIGN },
{ "|=", 2, P_ASSIGN },
{ "<<", 2, P_SHIFT },
{ ">>", 2, P_SHIFT },
{ "<=", 2, P_RELATION },
{ ">=", 2, P_RELATION },
{ "<", 1, P_RELATION },
{ ">", 1, P_RELATION },
{ "&&", 2, P_LAND },
{ "||", 2, P_LOR },
{ "*", 1, P_MULT },
{ "/", 1, P_MULT },
{ "%", 1, P_MULT },
{ "+", 1, P_ADD },
{ "-", 1, P_ADD },
{ "&", 1, P_BAND },
{ "^", 1, P_BXOR },
{ "|", 1, P_BOR },
{ "?", 1, P_TERN },
{ ",", 1, P_COMMA },
{ "~", 1, P_PRIMARY },
{ "!", 1, P_PRIMARY },
{ "(", 1, P_PRIMARY },
{ ")", 1, P_PRIMARY },
{ ":", 1, P_PRIMARY },
{ "", 0, P_PRIMARY } /* end of table */
};
typedef struct expr_state Expr_state;
struct expr_state {
const char *expression; /* expression being evaluated */
const char *tokp; /* lexical position */
enum token tok; /* token from token() */
int noassign; /* don't do assigns (for ?:,&&,||) */
struct tbl *val; /* value from token() */
struct tbl *evaling; /* variable that is being recursively
* expanded (EXPRINEVAL flag set)
*/
};
enum error_type { ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE,
ET_LVALUE, ET_RDONLY, ET_STR };
static void evalerr ARGS((Expr_state *es, enum error_type type,
const char *str)) GCC_FUNC_ATTR(noreturn);
static struct tbl *evalexpr ARGS((Expr_state *es, enum prec prec));
static void token ARGS((Expr_state *es));
static struct tbl *do_ppmm ARGS((Expr_state *es, enum token op,
struct tbl *vasn, bool_t is_prefix));
static void assign_check ARGS((Expr_state *es, enum token op,
struct tbl *vasn));
static struct tbl *tempvar ARGS((void));
static struct tbl *intvar ARGS((Expr_state *es, struct tbl *vp));
/*
* parse and evalute expression
*/
int
evaluate(expr, rval, error_ok)
const char *expr;
long *rval;
int error_ok;
{
struct tbl v;
int ret;
v.flag = DEFINED|INTEGER;
v.type = 0;
ret = v_evaluate(&v, expr, error_ok);
*rval = v.val.i;
return ret;
}
/*
* parse and evalute expression, storing result in vp.
*/
int
v_evaluate(vp, expr, error_ok)
struct tbl *vp;
const char *expr;
volatile int error_ok;
{
struct tbl *v;
Expr_state curstate;
Expr_state * const es = &curstate;
int i;
/* save state to allow recursive calls */
curstate.expression = curstate.tokp = expr;
curstate.noassign = 0;
curstate.evaling = (struct tbl *) 0;
newenv(E_ERRH);
i = ksh_sigsetjmp(e->jbuf, 0);
if (i) {
/* Clear EXPRINEVAL in of any variables we were playing with */
if (curstate.evaling)
curstate.evaling->flag &= ~EXPRINEVAL;
quitenv();
if (i == LAEXPR) {
if (error_ok == KSH_RETURN_ERROR)
return 0;
errorf(null);
}
unwind(i);
/*NOTREACHED*/
}
token(es);
#if 1 /* ifdef-out to disallow empty expressions to be treated as 0 */
if (es->tok == END) {
es->tok = LIT;
es->val = tempvar();
}
#endif /* 0 */
v = intvar(es, evalexpr(es, MAX_PREC));
if (es->tok != END)
evalerr(es, ET_UNEXPECTED, (char *) 0);
if (vp->flag & INTEGER)
setint_v(vp, v);
else
/* can fail if readony */
setstr(vp, str_val(v), error_ok);
quitenv();
return 1;
}
static void
evalerr(es, type, str)
Expr_state *es;
enum error_type type;
const char *str;
{
char tbuf[2];
const char *s;
switch (type) {
case ET_UNEXPECTED:
switch (es->tok) {
case VAR:
s = es->val->name;
break;
case LIT:
s = str_val(es->val);
break;
case END:
s = "end of expression";
break;
case BAD:
tbuf[0] = *es->tokp;
tbuf[1] = '\0';
s = tbuf;
break;
default:
s = opinfo[(int)es->tok].name;
}
warningf(TRUE, "%s: unexpected `%s'", es->expression, s);
break;
case ET_BADLIT:
warningf(TRUE, "%s: bad number `%s'", es->expression, str);
break;
case ET_RECURSIVE:
warningf(TRUE, "%s: expression recurses on parameter `%s'",
es->expression, str);
break;
case ET_LVALUE:
warningf(TRUE, "%s: %s requires lvalue",
es->expression, str);
break;
case ET_RDONLY:
warningf(TRUE, "%s: %s applied to read only variable",
es->expression, str);
break;
default: /* keep gcc happy */
case ET_STR:
warningf(TRUE, "%s: %s", es->expression, str);
break;
}
unwind(LAEXPR);
}
static struct tbl *
evalexpr(es, prec)
Expr_state *es;
enum prec prec;
{
struct tbl *vl, UNINITIALIZED(*vr), *vasn;
enum token op;
long UNINITIALIZED(res);
if (prec == P_PRIMARY) {
op = es->tok;
if (op == O_BNOT || op == O_LNOT || op == O_MINUS
|| op == O_PLUS)
{
token(es);
vl = intvar(es, evalexpr(es, P_PRIMARY));
if (op == O_BNOT)
vl->val.i = ~vl->val.i;
else if (op == O_LNOT)
vl->val.i = !vl->val.i;
else if (op == O_MINUS)
vl->val.i = -vl->val.i;
/* op == O_PLUS is a no-op */
} else if (op == OPEN_PAREN) {
token(es);
vl = evalexpr(es, MAX_PREC);
if (es->tok != CLOSE_PAREN)
evalerr(es, ET_STR, "missing )");
token(es);
} else if (op == O_PLUSPLUS || op == O_MINUSMINUS) {
token(es);
vl = do_ppmm(es, op, es->val, TRUE);
token(es);
} else if (op == VAR || op == LIT) {
vl = es->val;
token(es);
} else {
evalerr(es, ET_UNEXPECTED, (char *) 0);
/*NOTREACHED*/
}
if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) {
vl = do_ppmm(es, es->tok, vl, FALSE);
token(es);
}
return vl;
}
vl = evalexpr(es, ((int) prec) - 1);
for (op = es->tok; IS_BINOP(op) && opinfo[(int) op].prec == prec;
op = es->tok)
{
token(es);
vasn = vl;
if (op != O_ASN) /* vl may not have a value yet */
vl = intvar(es, vl);
if (IS_ASSIGNOP(op)) {
assign_check(es, op, vasn);
vr = intvar(es, evalexpr(es, P_ASSIGN));
} else if (op != O_TERN && op != O_LAND && op != O_LOR)
vr = intvar(es, evalexpr(es, ((int) prec) - 1));
if ((op == O_DIV || op == O_MOD || op == O_DIVASN
|| op == O_MODASN) && vr->val.i == 0)
{
if (es->noassign)
vr->val.i = 1;
else
evalerr(es, ET_STR, "zero divisor");
}
switch ((int) op) {
case O_TIMES:
case O_TIMESASN:
res = vl->val.i * vr->val.i;
break;
case O_DIV:
case O_DIVASN:
res = vl->val.i / vr->val.i;
break;
case O_MOD:
case O_MODASN:
res = vl->val.i % vr->val.i;
break;
case O_PLUS:
case O_PLUSASN:
res = vl->val.i + vr->val.i;
break;
case O_MINUS:
case O_MINUSASN:
res = vl->val.i - vr->val.i;
break;
case O_LSHIFT:
case O_LSHIFTASN:
res = vl->val.i << vr->val.i;
break;
case O_RSHIFT:
case O_RSHIFTASN:
res = vl->val.i >> vr->val.i;
break;
case O_LT:
res = vl->val.i < vr->val.i;
break;
case O_LE:
res = vl->val.i <= vr->val.i;
break;
case O_GT:
res = vl->val.i > vr->val.i;
break;
case O_GE:
res = vl->val.i >= vr->val.i;
break;
case O_EQ:
res = vl->val.i == vr->val.i;
break;
case O_NE:
res = vl->val.i != vr->val.i;
break;
case O_BAND:
case O_BANDASN:
res = vl->val.i & vr->val.i;
break;
case O_BXOR:
case O_BXORASN:
res = vl->val.i ^ vr->val.i;
break;
case O_BOR:
case O_BORASN:
res = vl->val.i | vr->val.i;
break;
case O_LAND:
if (!vl->val.i)
es->noassign++;
vr = intvar(es, evalexpr(es, ((int) prec) - 1));
res = vl->val.i && vr->val.i;
if (!vl->val.i)
es->noassign--;
break;
case O_LOR:
if (vl->val.i)
es->noassign++;
vr = intvar(es, evalexpr(es, ((int) prec) - 1));
res = vl->val.i || vr->val.i;
if (vl->val.i)
es->noassign--;
break;
case O_TERN:
{
int e = vl->val.i != 0;
if (!e)
es->noassign++;
vl = evalexpr(es, MAX_PREC);
if (!e)
es->noassign--;
if (es->tok != CTERN)
evalerr(es, ET_STR, "missing :");
token(es);
if (e)
es->noassign++;
vr = evalexpr(es, P_TERN);
if (e)
es->noassign--;
vl = e ? vl : vr;
}
break;
case O_ASN:
res = vr->val.i;
break;
case O_COMMA:
res = vr->val.i;
break;
}
if (IS_ASSIGNOP(op)) {
vr->val.i = res;
if (vasn->flag & INTEGER)
setint_v(vasn, vr);
else
setint(vasn, res);
vl = vr;
} else if (op != O_TERN)
vl->val.i = res;
}
return vl;
}
static void
token(es)
Expr_state *es;
{
const char *cp;
int c;
char *tvar;
/* skip white space */
for (cp = es->tokp; (c = *cp), isspace(c); cp++)
;
es->tokp = cp;
if (c == '\0')
es->tok = END;
else if (letter(c)) {
for (; letnum(c); c = *cp)
cp++;
if (c == '[') {
int len;
len = array_ref_len(cp);
if (len == 0)
evalerr(es, ET_STR, "missing ]");
cp += len;
}
#ifdef KSH
else if (c == '(' /*)*/ ) {
/* todo: add math functions (all take single argument):
* abs acos asin atan cos cosh exp int log sin sinh sqrt
* tan tanh
*/
;
}
#endif /* KSH */
if (es->noassign) {
es->val = tempvar();
es->val->flag |= EXPRLVALUE;
} else {
tvar = str_nsave(es->tokp, cp - es->tokp, ATEMP);
es->val = global(tvar);
afree(tvar, ATEMP);
}
es->tok = VAR;
} else if (digit(c)) {
for (; c != '_' && (letnum(c) || c == '#'); c = *cp++)
;
tvar = str_nsave(es->tokp, --cp - es->tokp, ATEMP);
es->val = tempvar();
es->val->flag &= ~INTEGER;
es->val->type = 0;
es->val->val.s = tvar;
if (setint_v(es->val, es->val) == NULL)
evalerr(es, ET_BADLIT, tvar);
afree(tvar, ATEMP);
es->tok = LIT;
} else {
int i, n0;
for (i = 0; (n0 = opinfo[i].name[0]); i++)
if (c == n0
&& strncmp(cp, opinfo[i].name, opinfo[i].len) == 0)
{
es->tok = (enum token) i;
cp += opinfo[i].len;
break;
}
if (!n0)
es->tok = BAD;
}
es->tokp = cp;
}
/* Do a ++ or -- operation */
static struct tbl *
do_ppmm(es, op, vasn, is_prefix)
Expr_state *es;
enum token op;
struct tbl *vasn;
bool_t is_prefix;
{
struct tbl *vl;
int oval;
assign_check(es, op, vasn);
vl = intvar(es, vasn);
oval = op == O_PLUSPLUS ? vl->val.i++ : vl->val.i--;
if (vasn->flag & INTEGER)
setint_v(vasn, vl);
else
setint(vasn, vl->val.i);
if (!is_prefix) /* undo the inc/dec */
vl->val.i = oval;
return vl;
}
static void
assign_check(es, op, vasn)
Expr_state *es;
enum token op;
struct tbl *vasn;
{
if (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE))
evalerr(es, ET_LVALUE, opinfo[(int) op].name);
else if (vasn->flag & RDONLY)
evalerr(es, ET_RDONLY, opinfo[(int) op].name);
}
static struct tbl *
tempvar()
{
register struct tbl *vp;
vp = (struct tbl*) alloc(sizeof(struct tbl), ATEMP);
vp->flag = ISSET|INTEGER;
vp->type = 0;
vp->areap = ATEMP;
vp->val.i = 0;
vp->name[0] = '\0';
return vp;
}
/* cast (string) variable to temporary integer variable */
static struct tbl *
intvar(es, vp)
Expr_state *es;
struct tbl *vp;
{
struct tbl *vq;
/* try to avoid replacing a temp var with another temp var */
if (vp->name[0] == '\0'
&& (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER))
return vp;
vq = tempvar();
if (setint_v(vq, vp) == NULL) {
if (vp->flag & EXPRINEVAL)
evalerr(es, ET_RECURSIVE, vp->name);
es->evaling = vp;
vp->flag |= EXPRINEVAL;
v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR);
vp->flag &= ~EXPRINEVAL;
es->evaling = (struct tbl *) 0;
}
return vq;
}
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