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馃悶 Fix LibBytes.uint8At stale byte #1550

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馃悶 Fix LibBytes.uint8At stale byte #1550

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16 changes: 7 additions & 9 deletions src/utils/LibBytes.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -129,21 +129,19 @@ library LibBytes {
assembly {
for { let packed := sload($.slot) } 1 {} {
if iszero(eq(or(packed, 0xff), packed)) {
if iszero(lt(i, and(packed, 0xff))) { break }
if iszero(gt(i, 0x1e)) {
result := byte(i, packed)
break
}
if iszero(gt(i, and(0xff, packed))) {
mstore(0x00, $.slot)
let j := sub(i, 0x1f)
result := byte(and(j, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, j))))
}
break
}
if iszero(gt(i, shr(8, packed))) {
mstore(0x00, $.slot)
result := byte(and(i, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, i))))
let j := sub(i, 0x1f)
result := byte(and(j, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, j))))
break
}
if iszero(gt(shr(8, packed), i)) { break }
mstore(0x00, $.slot)
result := byte(and(i, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, i))))
break
}
}
Expand Down
16 changes: 7 additions & 9 deletions src/utils/g/LibBytes.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -133,21 +133,19 @@ library LibBytes {
assembly {
for { let packed := sload($.slot) } 1 {} {
if iszero(eq(or(packed, 0xff), packed)) {
if iszero(lt(i, and(packed, 0xff))) { break }
if iszero(gt(i, 0x1e)) {
result := byte(i, packed)
break
}
if iszero(gt(i, and(0xff, packed))) {
mstore(0x00, $.slot)
let j := sub(i, 0x1f)
result := byte(and(j, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, j))))
}
break
}
if iszero(gt(i, shr(8, packed))) {
mstore(0x00, $.slot)
result := byte(and(i, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, i))))
let j := sub(i, 0x1f)
result := byte(and(j, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, j))))
break
}
if iszero(gt(shr(8, packed), i)) { break }
mstore(0x00, $.slot)
result := byte(and(i, 0x1f), sload(add(keccak256(0x00, 0x20), shr(5, i))))
break
}
}
Expand Down
59 changes: 59 additions & 0 deletions test/LibBytes.t.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,22 @@ pragma solidity ^0.8.4;
import "./utils/SoladyTest.sol";
import {LibBytes} from "../src/utils/LibBytes.sol";

contract BytesStore {
LibBytes.BytesStorage internal value;

function set(bytes calldata newValue) external {
LibBytes.setCalldata(value, newValue);
}

function length() external view returns (uint256) {
return LibBytes.length(value);
}

function at_(uint256 index) external view returns (uint8) {
return LibBytes.uint8At(value, index);
}
}

contract LibBytesTest is SoladyTest {
function testLoad(bytes memory a) public {
if (a.length < 32) a = abi.encodePacked(a, new bytes(32));
Expand Down Expand Up @@ -414,4 +430,47 @@ contract LibBytesTest is SoladyTest {
require(keccak256(expectedChildren[i]) == keccak256(children[i]));
}
}

function testUint8AtStaleByteAfterShrink() public {
BytesStore store = new BytesStore();
bytes memory previous = new bytes(32);
previous[31] = 0xbb;

store.set(previous);
store.set(new bytes(31));

assertEq(store.length(), 31);
assertEq(store.at_(31), 0);
}

function testUint8AtPaddingAfterShortValue() public {
BytesStore store = _storeWithDirtyPadding(5);
assertEq(store.length(), 5);
assertEq(store.at_(4), 0x11);
assertEq(store.at_(5), 0);
assertEq(store.at_(30), 0);
}

function testUint8AtPaddingAfterSpilledValue() public {
BytesStore store = _storeWithDirtyPadding(40);
assertEq(store.length(), 40);
assertEq(store.at_(39), 0x11);
assertEq(store.at_(40), 0);
}

function _storeWithDirtyPadding(uint256 n) internal returns (BytesStore store) {
store = new BytesStore();

bytes memory value = new bytes(n);
for (uint256 i; i < n; ++i) {
value[i] = 0x11;
}

bytes memory data = abi.encodeWithSelector(BytesStore.set.selector, value);
for (uint256 i = 4 + 32 + 32 + n; i < data.length; ++i) {
data[i] = 0xaa;
}
(bool success,) = address(store).call(data);
require(success);
}
}
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