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Add overflow tests

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This commit is contained in:
Stefan Eßer 2000-07-22 10:59:36 +00:00
parent abb15d867a
commit 915198b41b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=63755
1 changed files with 76 additions and 3 deletions
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79
bin/expr/expr.y
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@ -14,7 +14,9 @@
#include <locale.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <regex.h>
#include <limits.h>
enum valtype {
integer, numeric_string, string
@ -154,7 +156,11 @@ struct val *vp;
return 0;
/* vp->type == numeric_string, make it numeric */
errno = 0;
i = strtoq(vp->u.s, (char**)NULL, 10);
if (errno != 0) {
errx (2, "overflow");
}
free (vp->u.s);
vp->u.i = i;
vp->type = integer;
@ -409,6 +415,20 @@ struct val *a, *b;
return r;
}
int
chk_plus (a, b, r)
quad_t a, b, r;
{
/* sum of two positive numbers must be positive */
if (a > 0 && b > 0 && r <= 0)
return 1;
/* sum of two negative numbers must be negative */
if (a < 0 && b < 0 && r >= 0)
return 1;
/* all other cases are OK */
return 0;
}
struct val *
op_plus (a, b)
struct val *a, *b;
@ -420,11 +440,29 @@ struct val *a, *b;
}
r = make_integer (/*(quad_t)*/(a->u.i + b->u.i));
if (chk_plus (a->u.i, b->u.i, r->u.i)) {
errx (2, "overflow");
}
free_value (a);
free_value (b);
return r;
}
int
chk_minus (a, b, r)
quad_t a, b, r;
{
/* special case subtraction of QUAD_MIN */
if (b == QUAD_MIN) {
if (a >= 0)
return 1;
else
return 0;
}
/* this is allowed for b != QUAD_MIN */
return chk_plus (a, -b, r);
}
struct val *
op_minus (a, b)
struct val *a, *b;
@ -436,11 +474,27 @@ struct val *a, *b;
}
r = make_integer (/*(quad_t)*/(a->u.i - b->u.i));
if (chk_minus (a->u.i, b->u.i, r->u.i)) {
errx (2, "overflow");
}
free_value (a);
free_value (b);
return r;
}
int
chk_times (a, b, r)
quad_t a, b, r;
{
/* special case: first operand is 0, no overflow possible */
if (a == 0)
return 0;
/* cerify that result of division matches second operand */
if (r / a != b)
return 1;
return 0;
}
struct val *
op_times (a, b)
struct val *a, *b;
@ -452,11 +506,26 @@ struct val *a, *b;
}
r = make_integer (/*(quad_t)*/(a->u.i * b->u.i));
if (chk_times (a->u.i, b->u.i, r->u.i)) {
errx (2, "overflow");
}
free_value (a);
free_value (b);
return (r);
}
int
chk_div (a, b, r)
quad_t a, b, r;
{
/* div by zero has been taken care of before */
/* only QUAD_MIN / -1 causes overflow */
if (a == QUAD_MIN && b == -1)
return 1;
/* everything else is OK */
return 0;
}
struct val *
op_div (a, b)
struct val *a, *b;
@ -472,6 +541,9 @@ struct val *a, *b;
}
r = make_integer (/*(quad_t)*/(a->u.i / b->u.i));
if (chk_div (a->u.i, b->u.i, r->u.i)) {
errx (2, "overflow");
}
free_value (a);
free_value (b);
return r;
@ -492,6 +564,7 @@ struct val *a, *b;
}
r = make_integer (/*(quad_t)*/(a->u.i % b->u.i));
/* chk_rem necessary ??? */
free_value (a);
free_value (b);
return r;