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use snarkvm_fields::PrimeField;
use snarkvm_r1cs::ConstraintSystem;
use crate::{
bits::Boolean,
errors::UnsignedIntegerError,
integers::uint::*,
traits::{
alloc::AllocGadget,
integers::{Integer, Pow},
select::CondSelectGadget,
},
};
macro_rules! pow_int_impl {
($($gadget:ident),*) => ($(
impl<F: PrimeField> Pow<F> for $gadget {
type ErrorType = UnsignedIntegerError;
fn pow<CS: ConstraintSystem<F>>(
&self,
mut cs: CS,
other: &Self,
) -> Result<Self, Self::ErrorType> {
let is_constant = Boolean::constant(Self::result_is_constant(&self, &other));
let constant_result = Self::constant(1 as <$gadget as Integer>::IntegerType);
let allocated_result = Self::alloc(
&mut cs.ns(|| format!("allocated_1u{}", <$gadget as Integer>::SIZE)),
|| Ok(1 as <$gadget as Integer>::IntegerType),
)?;
let mut result = Self::conditionally_select(
&mut cs.ns(|| "constant_or_allocated"),
&is_constant,
&constant_result,
&allocated_result,
)?;
for (i, bit) in other.bits.iter().rev().enumerate() {
result = result.mul(cs.ns(|| format!("square_{}", i)), &result).unwrap();
let mul_by_self = result
.mul(cs.ns(|| format!("multiply_by_self_{}", i)), &self)
.unwrap();
result = Self::conditionally_select(
&mut cs.ns(|| format!("mul_by_self_or_result_{}", i)),
&bit,
&mul_by_self,
&result,
)?;
}
Ok(result)
}
}
)*)
}
pow_int_impl!(UInt8, UInt16, UInt32, UInt64);