Merge pull request #35 from DaniPopes/bitmath

Author: 0xKitsune

src/bit_math.rs

@@ -1,125 +1,26 @@
-use std::ops::ShrAssign;
-
+use crate::error::UniswapV3MathError;
 use alloy::primitives::U256;
 
-use crate::{
-    error::UniswapV3MathError, U128_MAX, U16_MAX, U256_1, U256_15, U256_3, U32_MAX, U64_MAX, U8_MAX,
-};
-
-pub fn most_significant_bit(mut x: U256) -> Result<u8, UniswapV3MathError> {
-    let mut r = 0;
-
+pub fn most_significant_bit(x: U256) -> Result<u8, UniswapV3MathError> {
     if x.is_zero() {
         return Err(UniswapV3MathError::ZeroValue);
     }
-
-    if x >= U256::from_limbs([0, 0, 1, 0]) {
-        x.shr_assign(128);
-        r += 128;
-    }
-
-    if x >= U256::from_limbs([0, 1, 0, 0]) {
-        x.shr_assign(64);
-        r += 64;
-    }
-
-    if x >= U256::from_limbs([4294967296, 0, 0, 0]) {
-        x.shr_assign(32);
-        r += 32;
-    }
-
-    if x >= U256::from_limbs([65536, 0, 0, 0]) {
-        x.shr_assign(16);
-        r += 16;
-    }
-
-    if x >= U256::from_limbs([256, 0, 0, 0]) {
-        x.shr_assign(8);
-        r += 8;
-    }
-
-    if x >= U256::from_limbs([16, 0, 0, 0]) {
-        x.shr_assign(4);
-        r += 4;
-    }
-    if x >= U256::from_limbs([4, 0, 0, 0]) {
-        x.shr_assign(2);
-        r += 2;
-    }
-
-    if x >= U256::from_limbs([2, 0, 0, 0]) {
-        r += 1;
-    }
-
-    Ok(r)
+    Ok(255 - x.leading_zeros() as u8)
 }
 
-pub fn least_significant_bit(mut x: U256) -> Result<u8, UniswapV3MathError> {
+pub fn least_significant_bit(x: U256) -> Result<u8, UniswapV3MathError> {
     if x.is_zero() {
         return Err(UniswapV3MathError::ZeroValue);
     }
-
-    let mut r = 255;
-
-    if x & U128_MAX > U256::ZERO {
-        r -= 128;
-    } else {
-        x >>= 128;
-    }
-
-    if x & U64_MAX > U256::ZERO {
-        r -= 64;
-    } else {
-        x >>= 64;
-    }
-
-    if x & U32_MAX > U256::ZERO {
-        r -= 32;
-    } else {
-        x >>= 32;
-    }
-
-    if x & U16_MAX > U256::ZERO {
-        r -= 16;
-    } else {
-        x >>= 16;
-    }
-
-    if x & U8_MAX > U256::ZERO {
-        r -= 8;
-    } else {
-        x >>= 8;
-    }
-
-    if x & U256_15 > U256::ZERO {
-        r -= 4;
-    } else {
-        x >>= 4;
-    }
-
-    if x & U256_3 > U256::ZERO {
-        r -= 2;
-    } else {
-        x >>= 2;
-    }
-
-    if x & U256_1 > U256::ZERO {
-        r -= 1;
-    }
-
-    Ok(r)
+    Ok(x.trailing_zeros() as u8)
 }
 
 #[cfg(test)]
 mod test {
-
-    use std::str::FromStr;
-
-    use alloy::primitives::U256;
-
-    use crate::{bit_math::least_significant_bit, U256_1};
-
     use super::most_significant_bit;
+    use crate::{bit_math::least_significant_bit, U256_1};
+    use alloy::primitives::U256;
+    use std::str::FromStr;
 
     #[test]
     fn test_most_significant_bit() {

src/lib.rs

@@ -41,8 +41,3 @@ const U256_262144: U256 = U256::from_limbs([262144, 0, 0, 0]);
 const U256_524288: U256 = U256::from_limbs([524288, 0, 0, 0]);
 
 const U256_MAX_TICK: U256 = U256::from_limbs([887272, 0, 0, 0]);
-const U128_MAX: U256 = U256::from_limbs([u64::MAX, u64::MAX, 0, 0]);
-const U64_MAX: U256 = U256::from_limbs([u64::MAX, 0, 0, 0]);
-const U32_MAX: U256 = U256::from_limbs([u32::MAX as u64, 0, 0, 0]);
-const U16_MAX: U256 = U256::from_limbs([u16::MAX as u64, 0, 0, 0]);
-const U8_MAX: U256 = U256::from_limbs([u8::MAX as u64, 0, 0, 0]);

src/tick_math.rs

@@ -229,7 +229,6 @@ pub fn get_tick_at_sqrt_ratio(sqrt_price_x_96: U256) -> Result<i32, UniswapV3Mat
 #[cfg(test)]
 mod test {
     use super::*;
-    use alloy::primitives::U256;
     use std::{ops::Sub, str::FromStr};
 
     #[test]