feat: refactor and standardize conversions to Big numeric types (#97)

Introduced traits `ToBig` and `FromBig` for consistent and extensible conversions between various numeric types. Replaced existing ad-hoc conversion functions with implementations of these traits. Updated dependent code to use the new standardized methods, improving clarity and maintainability.

src/constants.rs

@@ -26,4 +26,5 @@ pub enum Rounding {
 }
 
 /// Represents the maximum amount contained in a uint256
-pub const MAX_UINT256: BigInt = to_big_int(U256::MAX);
+pub const MAX_UINT256: BigInt =
+    BigInt::from_bits(BigUint::from_le_slice(&U256::MAX.to_le_bytes::<32>()).unwrap());

src/entities/fractions/currency_amount.rs

@@ -80,8 +80,9 @@ impl<T: BaseCurrency> CurrencyAmount<T> {
     /// Convert the currency amount to a string with exact precision
     #[inline]
     pub fn to_exact(&self) -> String {
-        to_big_decimal(self.quotient())
-            .div(to_big_decimal(self.decimal_scale))
+        self.quotient()
+            .to_big_decimal()
+            .div(self.decimal_scale.to_big_decimal())
             .to_string()
     }
 

src/entities/fractions/fraction.rs

@@ -114,7 +114,7 @@ pub trait FractionBase<M: Clone>: Sized {
     /// Converts the fraction to a [`BigDecimal`]
     #[inline]
     fn to_decimal(&self) -> BigDecimal {
-        to_big_decimal(self.numerator()) / to_big_decimal(self.denominator())
+        self.numerator().to_big_decimal() / self.denominator().to_big_decimal()
     }
 
     /// Converts the fraction to a string with a specified number of significant digits and rounding

src/utils/types.rs

@@ -1,24 +1,181 @@
 use crate::prelude::{BigDecimal, BigInt, BigUint};
-use alloy_primitives::U256;
+use alloy_primitives::{Signed, Uint};
 use fastnum::decimal::{Context, Sign};
 
-#[inline]
-#[must_use]
-pub const fn to_big_decimal(value: BigInt) -> BigDecimal {
-    match value.is_negative() {
-        false => BigDecimal::from_parts(value.to_bits(), 0, Sign::Plus, Context::default()),
-        true => BigDecimal::from_parts(value.to_bits(), 0, Sign::Minus, Context::default()),
+pub trait ToBig: Sized {
+    fn to_big_uint(self) -> BigUint;
+
+    #[inline]
+    fn to_big_int(self) -> BigInt {
+        self.to_big_uint().to_big_int()
+    }
+
+    #[inline]
+    fn to_big_decimal(self) -> BigDecimal {
+        let x = self.to_big_int();
+        BigDecimal::from_parts(
+            x.to_bits(),
+            0,
+            match x.is_negative() {
+                false => Sign::Plus,
+                true => Sign::Minus,
+            },
+            Context::default(),
+        )
     }
 }
 
-#[inline]
-#[must_use]
-pub const fn to_big_uint(x: U256) -> BigUint {
-    BigUint::from_le_slice(x.as_le_slice()).unwrap()
+impl ToBig for BigInt {
+    #[inline]
+    fn to_big_uint(self) -> BigUint {
+        self.to_bits()
+    }
+
+    #[inline]
+    fn to_big_int(self) -> BigInt {
+        self
+    }
 }
 
-#[inline]
-#[must_use]
-pub const fn to_big_int(x: U256) -> BigInt {
-    BigInt::from_bits(to_big_uint(x))
+impl ToBig for BigUint {
+    #[inline]
+    fn to_big_uint(self) -> BigUint {
+        self
+    }
+
+    #[inline]
+    fn to_big_int(self) -> BigInt {
+        BigInt::from_bits(self)
+    }
+
+    #[inline]
+    fn to_big_decimal(self) -> BigDecimal {
+        BigDecimal::from_parts(self, 0, Sign::Plus, Context::default())
+    }
+}
+
+impl<const BITS: usize, const LIMBS: usize> ToBig for Uint<BITS, LIMBS> {
+    #[inline]
+    fn to_big_uint(self) -> BigUint {
+        BigUint::from_le_slice(&self.as_le_bytes()).unwrap()
+    }
+}
+
+impl<const BITS: usize, const LIMBS: usize> ToBig for Signed<BITS, LIMBS> {
+    #[inline]
+    fn to_big_uint(self) -> BigUint {
+        self.into_raw().to_big_uint()
+    }
+
+    #[inline]
+    fn to_big_int(self) -> BigInt {
+        BigInt::from_le_slice(&self.into_raw().as_le_bytes()).unwrap()
+    }
+}
+
+pub trait FromBig: Sized {
+    fn from_big_uint(x: BigUint) -> Self;
+
+    #[inline]
+    #[must_use]
+    fn from_big_int(x: BigInt) -> Self {
+        Self::from_big_uint(x.to_bits())
+    }
+}
+
+impl<const BITS: usize, const LIMBS: usize> FromBig for Uint<BITS, LIMBS> {
+    #[inline]
+    fn from_big_uint(x: BigUint) -> Self {
+        Self::from_limbs_slice(&x.digits()[..LIMBS])
+    }
+}
+
+impl<const BITS: usize, const LIMBS: usize> FromBig for Signed<BITS, LIMBS> {
+    #[inline]
+    fn from_big_uint(x: BigUint) -> Self {
+        Self::from_raw(Uint::from_big_uint(x))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use alloy_primitives::{I256, U256};
+
+    #[test]
+    fn test_uint_to_big() {
+        let x = U256::from_limbs([1, 2, 3, 4]);
+        let y = BigUint::from(1_u64)
+            + (BigUint::from(2_u64) << 64)
+            + (BigUint::from(3_u64) << 128)
+            + (BigUint::from(4_u64) << 192);
+        assert_eq!(x.to_big_uint(), y);
+        assert_eq!(x.to_big_int(), y.to_big_int());
+        assert_eq!(x.to_big_decimal(), y.to_big_decimal());
+
+        let x = -x;
+        let z = (BigUint::from(1_u64) << 256) - y;
+        assert_eq!(x.to_big_uint(), z);
+        assert_eq!(x.to_big_int(), z.to_big_int());
+        assert_eq!(x.to_big_decimal(), z.to_big_decimal());
+    }
+
+    #[test]
+    fn test_signed_to_big() {
+        let x = I256::from_raw(U256::from_limbs([1, 2, 3, 4]));
+        let y: BigInt = BigInt::from(1)
+            + (BigInt::from(2) << 64)
+            + (BigInt::from(3) << 128)
+            + (BigInt::from(4) << 192);
+        assert_eq!(x.to_big_uint(), y.to_big_uint());
+        assert_eq!(x.to_big_int(), y);
+        assert_eq!(x.to_big_decimal(), y.to_big_decimal());
+
+        let x = -x;
+        let z: BigInt = (BigInt::from(1) << 256) - y;
+        assert_eq!(x.to_big_uint(), z.to_big_uint());
+        assert_eq!(x.to_big_int(), -y);
+        assert_eq!(x.to_big_decimal(), (-y).to_big_decimal());
+    }
+
+    #[test]
+    fn test_uint_from_big() {
+        let x = U256::from_limbs([1, 2, 3, 4]);
+        assert_eq!(U256::from_big_uint(x.to_big_uint()), x);
+        assert_eq!(U256::from_big_int(x.to_big_int()), x);
+
+        let x = -x;
+        assert_eq!(U256::from_big_uint(x.to_big_uint()), x);
+        assert_eq!(U256::from_big_int(x.to_big_int()), x);
+
+        assert_eq!(
+            U256::from_big_uint(BigInt::from(-1).to_big_uint()),
+            U256::MAX
+        );
+        assert_eq!(U256::from_big_int(BigInt::from(-1)), U256::MAX);
+
+        assert_eq!(
+            U256::from_big_uint(I256::MIN.to_big_uint()),
+            I256::MIN.into_raw()
+        );
+        assert_eq!(
+            U256::from_big_int(I256::MIN.to_big_int()),
+            I256::MIN.into_raw()
+        );
+    }
+
+    #[test]
+    fn test_signed_from_big() {
+        let x = I256::from_raw(U256::from_limbs([1, 2, 3, 4]));
+        assert_eq!(I256::from_big_uint(x.to_big_uint()), x);
+        assert_eq!(I256::from_big_int(x.to_big_int()), x);
+
+        let x = -x;
+        assert_eq!(I256::from_big_uint(x.to_big_uint()), x);
+        assert_eq!(I256::from_big_int(x.to_big_int()), x);
+        assert_eq!(
+            x.to_big_uint() + (-x.to_big_int()).to_big_uint(),
+            BigUint::from(1_u64) << 256
+        );
+    }
 }