fromPrimitive

Creates a new big integer from a primitive type. This function may not run in constant time.

Function parameters

Parameters

T:type
init_value:T

An unsigned big integer with a fixed maximum size (`max_bits`), suitable for cryptographic operations.

Functions

Uint: An unsigned big integer with a fixed maximum size (`max_bits`), suitable for cryptographic operations.
Modulus: A modulus, defining a finite field.

Error sets in this namespace

Error Sets

OverflowError: Value is too large for the destination.
InvalidModulusError: Invalid modulus.
NullExponentError: Exponentiation with a null exponent.
FieldElementError: Invalid field element for the given modulus.
RepresentationError: Invalid representation (Montgomery vs non-Montgomery domain.)
Error: The set of all possible errors `std.crypto.ff` functions can return.

Source

Implementation

pub fn fromPrimitive(comptime T: type, init_value: T) OverflowError!Self {
    var x = init_value;
    var out: Self = .{
        .limbs_buffer = undefined,
        .limbs_len = max_limbs_count,
    };
    for (&out.limbs_buffer) |*limb| {
        limb.* = if (@bitSizeOf(T) > t_bits) @as(TLimb, @truncate(x)) else x;
        x = math.shr(T, x, t_bits);
    }
    if (x != 0) {
        return error.Overflow;
    }
    return out;
}