From e5024097af329d8f49249fa7e18108c2e4168d3d Mon Sep 17 00:00:00 2001
From: Andrei Vlad Birgaoanu <andreivladbrg@gmail.com>
Date: Tue, 7 Jan 2025 23:54:47 +0200
Subject: [PATCH] refactor: use unchecked and casting in
 calculateStreamedPercentage

docs: last polishes
---
 src/LockupNFTDescriptor.sol   | 5 ++++-
 src/SablierLockup.sol         | 8 ++++----
 src/libraries/VestingMath.sol | 4 ++--
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/LockupNFTDescriptor.sol b/src/LockupNFTDescriptor.sol
index 0f5e35edf..d0885901e 100644
--- a/src/LockupNFTDescriptor.sol
+++ b/src/LockupNFTDescriptor.sol
@@ -198,7 +198,10 @@ contract LockupNFTDescriptor is ILockupNFTDescriptor {
         pure
         returns (uint256)
     {
-        return streamedAmount * 10_000 / depositedAmount;
+        // This cannot overflow because both inputs are uint128s, and zero deposit amounts are not allowed in Sablier.
+        unchecked {
+            return uint256(streamedAmount) * 10_000 / depositedAmount;
+        }
     }
 
     /// @notice Generates a pseudo-random HSL color by hashing together the `chainid`, the `sablier` address,
diff --git a/src/SablierLockup.sol b/src/SablierLockup.sol
index bd8300504..47389397b 100644
--- a/src/SablierLockup.sol
+++ b/src/SablierLockup.sol
@@ -297,7 +297,7 @@ contract SablierLockup is ISablierLockup, SablierLockupBase {
 
     /// @inheritdoc SablierLockupBase
     function _calculateStreamedAmount(uint256 streamId) internal view override returns (uint128) {
-        // Load the stream's parameters in memory.
+        // Load in memory the parameters used in {VestingMath}.
         uint40 blockTimestamp = uint40(block.timestamp);
         uint128 depositedAmount = _streams[streamId].amounts.deposited;
         Lockup.Model lockupModel = _streams[streamId].lockupModel;
@@ -305,7 +305,7 @@ contract SablierLockup is ISablierLockup, SablierLockupBase {
         Lockup.Timestamps memory timestamps =
             Lockup.Timestamps({ start: _streams[streamId].startTime, end: _streams[streamId].endTime });
 
-        // Calculate streamed amount for the Lockup Dynamic model.
+        // Calculate the streamed amount for the Lockup Dynamic model.
         if (lockupModel == Lockup.Model.LOCKUP_DYNAMIC) {
             streamedAmount = VestingMath.calculateLockupDynamicStreamedAmount({
                 depositedAmount: depositedAmount,
@@ -315,7 +315,7 @@ contract SablierLockup is ISablierLockup, SablierLockupBase {
                 withdrawnAmount: _streams[streamId].amounts.withdrawn
             });
         }
-        // Calculate streamed amount for the Lockup Linear model.
+        // Calculate the streamed amount for the Lockup Linear model.
         else if (lockupModel == Lockup.Model.LOCKUP_LINEAR) {
             streamedAmount = VestingMath.calculateLockupLinearStreamedAmount({
                 depositedAmount: depositedAmount,
@@ -326,7 +326,7 @@ contract SablierLockup is ISablierLockup, SablierLockupBase {
                 withdrawnAmount: _streams[streamId].amounts.withdrawn
             });
         }
-        // Calculate streamed amount for the Lockup Tranched model.
+        // Calculate the streamed amount for the Lockup Tranched model.
         else if (lockupModel == Lockup.Model.LOCKUP_TRANCHED) {
             streamedAmount = VestingMath.calculateLockupTranchedStreamedAmount({
                 depositedAmount: depositedAmount,
diff --git a/src/libraries/VestingMath.sol b/src/libraries/VestingMath.sol
index be75ac47b..43a591095 100644
--- a/src/libraries/VestingMath.sol
+++ b/src/libraries/VestingMath.sol
@@ -115,9 +115,9 @@ library VestingMath {
     /// @dev Lockup linear model uses the following distribution function:
     ///
     /// $$
-    ///        ( x * sa + s,  cliffTime > blockTimestamp
+    ///        ( x * sa + s,  cliff time > block timestamp
     /// f(x) = (
-    ///        ( x * sa + s + c, cliffTime <= blockTimestamp
+    ///        ( x * sa + s + c, cliff time <= block timestamp
     /// $$
     ///
     /// Where: