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Audit fix/missing signextend #319

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merged 2 commits into from
Apr 11, 2023
Merged

Audit fix/missing signextend #319

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70fc338
feat: use Solidity instead of Assembly
clemlak Apr 5, 2023
6ac4340
test: update addSignedDelta test
clemlak Apr 5, 2023
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16 changes: 5 additions & 11 deletions contracts/libraries/AssemblyLib.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -65,9 +65,7 @@ library AssemblyLib {
}

/**
* @dev Adds a signed `delta` to an unsigned `input` by using the sign-agnostic 256-bit type used in yul.
* Checks for overflow manually and reverts with `InvalidLiquidity()`, because this function is used to
* change liquidity in a position or pool.
* @dev Adds a signed `delta` to an unsigned `input`.
* @custom:example
* ```
* uint128 output = addSignedDelta(uint128(15), -int128(5));
Expand All @@ -78,14 +76,10 @@ library AssemblyLib {
uint128 input,
int128 delta
) internal pure returns (uint128 output) {
bytes memory revertData =
abi.encodeWithSelector(InvalidLiquidity.selector);
assembly {
output := add(input, delta)
// Reverts on overflow.
if gt(output, 0xffffffffffffffffffffffffffffffff) {
revert(add(32, revertData), mload(revertData))
} // 0x1fff9681
if (delta > 0) {
output = input + uint128(delta);
} else {
output = input - uint128(-delta);
}
}

Expand Down
26 changes: 20 additions & 6 deletions test/TestAssemblyLib.t.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -25,15 +25,29 @@ contract TestAssemblyLib is Test {
}
}

/*
FIXME: These tests are not working yet.
function testFuzz_addSignedDelta(uint128 input, int128 delta) public {
// If delta is positive but the sum of input and delta is greater than
// the maximum value of uint128, we revert.
if (delta >= 0 && (uint256(input) + uint256(uint128(delta))) > type(uint128).max) {
vm.expectRevert();
}

// If delta is negative but its absolute value is greater than input,
// we revert.
if (
delta == -170141183460469231731687303715884105728
|| delta < 0 && uint128(-delta) > input
) {
vm.expectRevert();
}

uint128 output = AssemblyLib.addSignedDelta(input, delta);

assertEq(
AssemblyLib.addSignedDelta(input, delta),
delta < 0 ? uint128(-delta) : uint128(delta)
output,
delta < 0 ? input - uint128(-delta) : input + uint128(delta)
);
}
*/

function testFuzz_separate(uint8 a, uint8 b) public {
vm.assume(a <= 15);
Expand Down Expand Up @@ -90,7 +104,7 @@ contract TestAssemblyLib is Test {
vm.expectRevert(DataTooLong.selector);
AssemblyLib.toBytes8(input);
}

function test_pack() public {
bytes1 output = AssemblyLib.pack(bytes1(0x01), bytes1(0x02));
assertEq(output, bytes1(0x12));
Expand Down