Add get_tokens_owed

src/utils/mod.rs

@@ -1,20 +1,21 @@
+mod bit_math;
 mod compute_pool_address;
-pub use compute_pool_address::compute_pool_address;
-
 mod encode_sqrt_ratio_x96;
-pub use encode_sqrt_ratio_x96::encode_sqrt_ratio_x96;
-
-mod nearest_usable_tick;
-pub use nearest_usable_tick::nearest_usable_tick;
-
 mod full_math;
-pub use full_math::*;
-
 mod liquidity_math;
-pub use liquidity_math::add_delta;
+mod nearest_usable_tick;
+mod position;
+mod price_tick_conversions;
+mod tick_math;
 
-mod bit_math;
+use alloy_primitives::U256;
 pub use bit_math::*;
-
-mod tick_math;
+pub use compute_pool_address::compute_pool_address;
+pub use encode_sqrt_ratio_x96::encode_sqrt_ratio_x96;
+pub use full_math::*;
+pub use liquidity_math::add_delta;
+pub use nearest_usable_tick::nearest_usable_tick;
+pub use position::get_tokens_owed;
 pub use tick_math::*;
+
+pub const Q128: U256 = U256::from_limbs([0, 0, 1, 0]);

src/utils/position.rs

@@ -0,0 +1,30 @@
+use super::Q128;
+use alloy_primitives::U256;
+
+/// Computes the amount of fees owed to a position
+pub fn get_tokens_owed(
+    fee_growth_inside_0_last_x128: U256,
+    fee_growth_inside_1_last_x128: U256,
+    liquidity: u128,
+    fee_growth_inside_0_x128: U256,
+    fee_growth_inside_1_x128: U256,
+) -> (U256, U256) {
+    let liquidity = U256::from(liquidity);
+    let tokens_owed_0 =
+        (fee_growth_inside_0_x128 - fee_growth_inside_0_last_x128) * liquidity / Q128;
+    let tokens_owed_1 =
+        (fee_growth_inside_1_x128 - fee_growth_inside_1_last_x128) * liquidity / Q128;
+    (tokens_owed_0, tokens_owed_1)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_get_tokens_owed() {
+        let (tokens_owed_0, tokens_owed_1) = get_tokens_owed(U256::ZERO, U256::ZERO, 1, Q128, Q128);
+        assert_eq!(tokens_owed_0, U256::from(1));
+        assert_eq!(tokens_owed_1, U256::from(1));
+    }
+}