On Wed, 17 Jun 2026 19:08:57 GMT, Ferenc Rakoczi <[email protected]> wrote:
>> Yes, the definition of Java class `IntegerPolynomial` does limit the
>> possible subclasses. However, as I mentioned in my earlier comment, that
>> list includes `IntegerPolynomialModBinP`
>>
>>
>> public abstract sealed class IntegerPolynomial implements IntegerFieldModuloP
>> permits IntegerPolynomial1305, IntegerPolynomial25519,
>> IntegerPolynomial448, IntegerPolynomialP256,
>> MontgomeryIntegerPolynomialP256, IntegerPolynomialP384,
>> IntegerPolynomialP521, IntegerPolynomialModBinP, P256OrderField,
>> P384OrderField, P521OrderField, Curve25519OrderField,
>> Curve448OrderField {
>>
>>
>> This specific subclass employs a limb count specified by a caller in the
>> constructor
>>
>>
>> public sealed class IntegerPolynomialModBinP extends IntegerPolynomial {
>> ...
>> public IntegerPolynomialModBinP(int bitsPerLimb,
>> int numLimbs,
>> int power,
>> BigInteger subtrahend) {
>> super(bitsPerLimb, numLimbs, 1,
>> BigInteger.valueOf(2).pow(power).subtract(subtrahend));
>>
>>
>> So, for this class it looks as if a user could specify numLimbs == 0 when
>> creating an `IntegerPolynomialModBinP` and that same count will be passed on
>> up to `IntegerPolynomial`.
>>
>> Now, that doesn't guarantee that any subsequent call to
>> `IntegerPolynomial::mult` will end up being passed a zero length array but
>> I'd like to be reassured why this won't happen.
>
> 0 as number of limbs doesn't make sense as no number can be represented that
> way. I think the IntegerPolynomialModBinP class was created for testing
> purposes mainly and only the two inner classes should subclass it, i.e. the
> constructor should rather be private and in that case the 0 number of limbs
> would not be a concern. @ascarpino, do you remember what this class was made
> for and whether it is obsolete now?
Perhaps the `Curve25519OrderField` and `Curve448OrderField` can be refactored
away from `IntegerPolynomialModBinP`, but I would not suggest that for this PR.
I'm ok with changing the constructor to be private, but it's not accessible
from the public API, so it's not a necessary change.
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PR Review Comment: https://git.openjdk.org/jdk/pull/30941#discussion_r3432048761
