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Fix off-by-one error in long_repr. 

Implement long_pow.
This commit is contained in:
Guido van Rossum 1991-05-28 21:58:16 +00:00
parent 70d934601f
commit c7ec9c98e2
1 changed files with 50 additions and 5 deletions
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55
Objects/longobject.c
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@ -278,6 +278,7 @@ long_format(a, base)
assert(p > q);
do {
} while ((*q++ = *p++) != '\0');
q--;
resizestring((object **)&str, (int) (q - GETSTRINGVALUE(str)));
}
return str;
@ -844,16 +845,60 @@ long_divmod(v, w)
}
static object *
long_pow(v, w)
longobject *v;
register object *w;
long_pow(a, w)
longobject *a;
object *w;
{
register longobject *b;
longobject *z;
int size_b, i;
if (!is_longobject(w)) {
err_badarg();
return NULL;
}
err_setstr(SystemError, "long power not implemented");
return NULL;
b = (longobject *)w;
size_b = b->ob_size;
if (size_b < 0) {
err_setstr(RuntimeError, "long integer to the negative power");
return NULL;
}
z = (longobject *)newlongobject(1L);
INCREF(a);
for (i = 0; i < size_b; ++i) {
digit bi = b->ob_digit[i];
int j;
for (j = 0; j < SHIFT; ++j) {
longobject *temp;
if (bi & 1) {
temp = (longobject *)long_mul(z, (object *)a);
DECREF(z);
z = temp;
if (z == NULL)
break;
}
bi >>= 1;
if (bi == 0 && i+1 == size_b)
break;
temp = (longobject *)long_mul(a, (object *)a);
DECREF(a);
a = temp;
if (a == NULL) {
DECREF(z);
z = NULL;
break;
}
}
if (a == NULL)
break;
}
XDECREF(a);
return (object *)z;
}
static object *