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authorGuido van Rossum <guido@python.org>1991-12-31 13:14:13 (GMT)
committerGuido van Rossum <guido@python.org>1991-12-31 13:14:13 (GMT)
commitafbb8db8e6647de7aaf20078c2259efbbfc086d0 (patch)
tree76da98c69f26d80e77f1af26ec4614475379a6b0 /Objects/longobject.c
parent768a3f0ab8c1abdf14372cbdf3c83cc93b28ac4e (diff)
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Fixed bug in long masking ops.
Diffstat (limited to 'Objects/longobject.c')
-rw-r--r--Objects/longobject.c59
1 files changed, 31 insertions, 28 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 37f2f35..b21738d 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -1145,6 +1145,9 @@ long_lshift(a, b)
return (object *) long_znormalize(z);
}
+#define MAX(x, y) ((x) < (y) ? (y) : (x))
+#define MIN(x, y) ((x) > (y) ? (y) : (x))
+
/* Logical or the absolute values of two long integers.
The second value is first xor'ed with 'mask'. */
@@ -1155,22 +1158,23 @@ x_or(a, b, mask)
int mask;
{
int size_a = ZABS(a->ob_size), size_b = ZABS(b->ob_size);
+ int size_max = MAX(size_a, size_b);
+ int size_min = MIN(size_a, size_b);
longobject *z;
int i;
- /* Ensure a is the larger of the two: */
- if (size_a < size_b) {
- { longobject *temp = a; a = b; b = temp; }
- { int size_temp = size_a; size_a = size_b; size_b = size_temp; }
- }
- z = alloclongobject(size_a);
+ z = alloclongobject(size_max);
if (z == NULL)
return NULL;
- for (i = 0; i < size_b; ++i) {
+ for (i = 0; i < size_min; ++i) {
z->ob_digit[i] = a->ob_digit[i] | (b->ob_digit[i] ^ mask);
}
+ /* At most one of the following two loops executes */
for (; i < size_a; ++i) {
- z->ob_digit[i] = a->ob_digit[i] | mask;
+ z->ob_digit[i] = a->ob_digit[i] | (0 ^ mask);
+ }
+ for (; i < size_b; ++i) {
+ z->ob_digit[i] = 0 | (b->ob_digit[i] ^ mask);
}
return long_znormalize(z);
}
@@ -1185,22 +1189,23 @@ x_and(a, b, mask)
int mask;
{
int size_a = ZABS(a->ob_size), size_b = ZABS(b->ob_size);
+ int size_max = MAX(size_a, size_b);
+ int size_min = MIN(size_a, size_b);
longobject *z;
int i;
- /* Ensure a is the larger of the two: */
- if (size_a < size_b) {
- { longobject *temp = a; a = b; b = temp; }
- { int size_temp = size_a; size_a = size_b; size_b = size_temp; }
- }
- z = alloclongobject(size_a);
+ z = alloclongobject(size_max);
if (z == NULL)
return NULL;
- for (i = 0; i < size_b; ++i) {
+ for (i = 0; i < size_min; ++i) {
z->ob_digit[i] = a->ob_digit[i] & (b->ob_digit[i] ^ mask);
}
+ /* At most one of the following two loops executes */
for (; i < size_a; ++i) {
- z->ob_digit[i] = a->ob_digit[i] & mask;
+ z->ob_digit[i] = a->ob_digit[i] & (0 ^ mask);
+ }
+ for (; i < size_b; ++i) {
+ z->ob_digit[i] = 0 & (b->ob_digit[i] ^ mask);
}
return long_znormalize(z);
}
@@ -1208,36 +1213,34 @@ x_and(a, b, mask)
/* Logical xor the absolute values of two long integers.
The second value is first xor'ed with 'mask'. */
-static longobject *x_and PROTO((longobject *, longobject *, int));
+static longobject *x_xor PROTO((longobject *, longobject *, int));
static longobject *
x_xor(a, b, mask)
longobject *a, *b;
int mask;
{
int size_a = ZABS(a->ob_size), size_b = ZABS(b->ob_size);
+ int size_max = MAX(size_a, size_b);
+ int size_min = MIN(size_a, size_b);
longobject *z;
int i;
- /* Ensure a is the larger of the two: */
- if (size_a < size_b) {
- { longobject *temp = a; a = b; b = temp; }
- { int size_temp = size_a; size_a = size_b; size_b = size_temp; }
- }
- z = alloclongobject(size_a);
+ z = alloclongobject(size_max);
if (z == NULL)
return NULL;
- for (i = 0; i < size_b; ++i) {
+ for (i = 0; i < size_min; ++i) {
z->ob_digit[i] = a->ob_digit[i] ^ (b->ob_digit[i] ^ mask);
}
+ /* At most one of the following two loops executes */
for (; i < size_a; ++i) {
- z->ob_digit[i] = a->ob_digit[i] ^ mask;
+ z->ob_digit[i] = a->ob_digit[i] ^ (0 ^ mask);
+ }
+ for (; i < size_b; ++i) {
+ z->ob_digit[i] = 0 ^ (b->ob_digit[i] ^ mask);
}
return long_znormalize(z);
}
-#define MAX(x, y) ((x) < (y) ? (y) : (x))
-#define MIN(x, y) ((x) > (y) ? (y) : (x))
-
static object *
long_and(a, w)
longobject *a;