From 16993cdb081b831420c7e86d981afd11726197d1 Mon Sep 17 00:00:00 2001
From: Daniel Wang <99078276+dantaik@users.noreply.github.com>
Date: Wed, 22 Feb 2023 11:42:23 +0800
Subject: [PATCH] feat(protocol): partially randomize prover reward (#13184)
Co-authored-by: dave | d1onys1us <13951458+d1onys1us@users.noreply.github.com>
Co-authored-by: David <david@taiko.xyz>
---
packages/protocol/contracts/L1/TaikoData.sol | 1 +
packages/protocol/contracts/L1/TaikoL1.sol | 6 ++
.../protocol/contracts/L1/libs/LibProving.sol | 5 +-
.../protocol/contracts/L1/libs/LibUtils.sol | 2 +-
.../contracts/L1/libs/LibVerifying.sol | 90 +++++++++++++++----
packages/protocol/contracts/L2/TaikoL2.sol | 2 +-
.../contracts/libs/LibReceiptDecoder.sol | 4 +-
.../contracts/libs/LibSharedConfig.sol | 1 +
.../protocol/contracts/libs/LibTxDecoder.sol | 8 +-
.../protocol/contracts/libs/LibTxUtils.sol | 2 +-
.../contracts/test/L1/TestTaikoL1.sol | 1 +
.../test/L1/TestTaikoL1EnableTokenomics.sol | 1 +
.../contracts/test/L1/TestTaikoL2.sol | 1 +
.../L1/TestTaikoL2EnablePublicInputsCheck.sol | 1 +
.../contracts/test/libs/TestLibProving.sol | 5 +-
.../test/thirdparty/TestLibRLPReader.sol | 2 +-
.../contracts/thirdparty/LibBytesUtils.sol | 4 +-
.../contracts/thirdparty/LibMerkleTrie.sol | 8 +-
.../contracts/thirdparty/LibRLPReader.sol | 4 +-
.../contracts/thirdparty/LibRLPWriter.sol | 10 +--
20 files changed, 113 insertions(+), 45 deletions(-)
diff --git a/packages/protocol/contracts/L1/TaikoData.sol b/packages/protocol/contracts/L1/TaikoData.sol
index 41886b9bcea..8843adfaada 100644
--- a/packages/protocol/contracts/L1/TaikoData.sol
+++ b/packages/protocol/contracts/L1/TaikoData.sol
@@ -38,6 +38,7 @@ library TaikoData {
uint64 proofTimeCap;
uint64 bootstrapDiscountHalvingPeriod;
uint64 initialUncleDelay;
+ uint64 proverRewardRandomizedPercentage;
bool enableTokenomics;
bool enablePublicInputsCheck;
bool enableProofValidation;
diff --git a/packages/protocol/contracts/L1/TaikoL1.sol b/packages/protocol/contracts/L1/TaikoL1.sol
index 2e199096adb..63593e53758 100644
--- a/packages/protocol/contracts/L1/TaikoL1.sol
+++ b/packages/protocol/contracts/L1/TaikoL1.sol
@@ -287,6 +287,12 @@ contract TaikoL1 is
return LibUtils.getUncleProofDelay(state, getConfig(), blockId);
}
+ function getProverRewardBips(
+ uint256 numProvers
+ ) public view returns (uint256[] memory) {
+ return LibVerifying.getProverRewardBips(getConfig(), numProvers);
+ }
+
function getConfig() public pure virtual returns (TaikoData.Config memory) {
return LibSharedConfig.getConfig();
}
diff --git a/packages/protocol/contracts/L1/libs/LibProving.sol b/packages/protocol/contracts/L1/libs/LibProving.sol
index 3614fa5c75d..1f99af5003a 100644
--- a/packages/protocol/contracts/L1/libs/LibProving.sol
+++ b/packages/protocol/contracts/L1/libs/LibProving.sol
@@ -284,7 +284,7 @@ library LibProving {
bytes32 blockHash = evidence.header.hashBlockHeader();
if (!skipZKPVerification) {
- for (uint256 i = 0; i < config.zkProofsPerBlock; ++i) {
+ for (uint256 i; i < config.zkProofsPerBlock; ++i) {
bytes32 instance = keccak256(
abi.encode(
blockHash,
@@ -292,6 +292,7 @@ library LibProving {
evidence.meta.txListHash
)
);
+
if (
!proofVerifier.verifyZKP({
verifierId: string(
@@ -357,7 +358,7 @@ library LibProving {
})
) revert L1_TOO_LATE();
- for (uint256 i = 0; i < fc.provers.length; ++i) {
+ for (uint256 i; i < fc.provers.length; ++i) {
if (fc.provers[i] == prover) revert L1_DUP_PROVERS();
}
diff --git a/packages/protocol/contracts/L1/libs/LibUtils.sol b/packages/protocol/contracts/L1/libs/LibUtils.sol
index a5d8749093d..58073f30e9f 100644
--- a/packages/protocol/contracts/L1/libs/LibUtils.sol
+++ b/packages/protocol/contracts/L1/libs/LibUtils.sol
@@ -98,7 +98,7 @@ library LibUtils {
) internal view returns (uint256 newFeeBase, uint256 tRelBp) {
if (tAvg == 0) {
newFeeBase = state.feeBase;
- tRelBp = 0;
+ // tRelBp = 0;
} else {
uint256 _tAvg = tAvg > config.proofTimeCap
? config.proofTimeCap
diff --git a/packages/protocol/contracts/L1/libs/LibVerifying.sol b/packages/protocol/contracts/L1/libs/LibVerifying.sol
index 8b18be76b55..13b4d884335 100644
--- a/packages/protocol/contracts/L1/libs/LibVerifying.sol
+++ b/packages/protocol/contracts/L1/libs/LibVerifying.sol
@@ -62,7 +62,7 @@ library LibVerifying {
bytes32 latestL2Hash = state.l2Hashes[
latestL2Height % config.blockHashHistory
];
- uint64 processed = 0;
+ uint64 processed;
for (
uint256 i = state.latestVerifiedId + 1;
@@ -144,6 +144,63 @@ library LibVerifying {
reward = (reward * (10000 - config.rewardBurnBips)) / 10000;
}
+ /**
+ * A function that calculates the weight for each prover based on the number
+ * of provers and a random seed. The weight is a number between 0 and 100.
+ * The sum of the weights will be 100. The weight is calculated in bips,
+ * so the weight of 1 will be 0.01%.
+ *
+ * @param config The config of the Taiko protocol (stores the randomized percentage)
+ * @param numProvers The number of provers
+ * @return bips The weight of each prover in bips
+ */
+ function getProverRewardBips(
+ TaikoData.Config memory config,
+ uint256 numProvers
+ ) public view returns (uint256[] memory bips) {
+ bips = new uint256[](numProvers);
+
+ uint256 randomized = config.proverRewardRandomizedPercentage;
+ if (randomized > 100) {
+ randomized = 100;
+ }
+
+ uint256 sum;
+ uint256 i;
+
+ // Calculate the randomized weight
+ if (randomized > 0) {
+ unchecked {
+ uint256 seed = block.prevrandao;
+ for (i = 0; i < numProvers; ++i) {
+ // Get an uint16, note that smart provers may
+ // choose the right timing to maximize their rewards
+ // which helps blocks to be verified sooner.
+ bips[i] = uint16(seed * (1 + i));
+ sum += bips[i];
+ }
+ for (i = 0; i < numProvers; ++i) {
+ bips[i] = (bips[i] * 100 * randomized) / sum;
+ }
+ }
+ }
+
+ // Add the fixed weight. If there are 5 provers, then their
+ // weight will be:
+ // 1<<4=16, 1<<3=8, 1<<2=4, 1<<1=2, 1<<0=1
+ if (randomized != 100) {
+ unchecked {
+ sum = (1 << numProvers) - 1;
+ uint256 fix = 100 - randomized;
+ uint256 weight = 1 << (numProvers - 1);
+ for (i = 0; i < numProvers; ++i) {
+ bips[i] += (weight * 100 * fix) / sum;
+ weight >>= 1;
+ }
+ }
+ }
+ }
+
function _refundProposerDeposit(
TaikoData.ProposedBlock storage target,
uint256 tRelBp,
@@ -162,30 +219,27 @@ library LibVerifying {
uint256 reward,
TkoToken tkoToken
) private {
- uint256 start;
+ uint256 offset;
uint256 count = fc.provers.length;
if (config.enableOracleProver) {
- start = 1;
+ offset = 1;
count -= 1;
}
- uint256 sum = (1 << count) - 1;
- uint256 weight = 1 << (count - 1);
- for (uint i = 0; i < count; ++i) {
- uint256 proverReward = (reward * weight) / sum;
- if (proverReward == 0) {
- break;
- }
+ uint256[] memory bips = getProverRewardBips(config, count);
- if (tkoToken.balanceOf(fc.provers[start + i]) == 0) {
- // Reduce reward to 1 wei as a penalty if the prover
- // has 0 TKO balance. This allows the next prover reward
- // to be fully paid.
- proverReward = uint256(1);
+ for (uint256 i; i < count; ++i) {
+ uint256 proverReward = (reward * bips[i]) / 10000;
+ if (proverReward != 0) {
+ if (tkoToken.balanceOf(fc.provers[offset + i]) == 0) {
+ // Reduce reward to 1 wei as a penalty if the prover
+ // has 0 TKO balance. This allows the next prover reward
+ // to be fully paid.
+ proverReward = uint256(1);
+ }
+ tkoToken.mint(fc.provers[offset + i], proverReward);
}
- tkoToken.mint(fc.provers[start + i], proverReward);
- weight = weight >> 1;
}
}
@@ -245,7 +299,7 @@ library LibVerifying {
function _cleanUp(TaikoData.ForkChoice storage fc) private {
fc.blockHash = 0;
fc.provenAt = 0;
- for (uint i = 0; i < fc.provers.length; ++i) {
+ for (uint256 i; i < fc.provers.length; ++i) {
fc.provers[i] = address(0);
}
delete fc.provers;
diff --git a/packages/protocol/contracts/L2/TaikoL2.sol b/packages/protocol/contracts/L2/TaikoL2.sol
index 4a61c1d33ca..20841415adf 100644
--- a/packages/protocol/contracts/L2/TaikoL2.sol
+++ b/packages/protocol/contracts/L2/TaikoL2.sol
@@ -64,7 +64,7 @@ contract TaikoL2 is AddressResolver, ReentrancyGuard, IHeaderSync {
bytes32[255] memory ancestors;
uint256 number = block.number;
- for (uint256 i = 0; i < 255 && number >= i + 2; ++i) {
+ for (uint256 i; i < 255 && number >= i + 2; ++i) {
ancestors[i] = blockhash(number - i - 2);
}
diff --git a/packages/protocol/contracts/libs/LibReceiptDecoder.sol b/packages/protocol/contracts/libs/LibReceiptDecoder.sol
index d14e9197379..87174c9d54e 100644
--- a/packages/protocol/contracts/libs/LibReceiptDecoder.sol
+++ b/packages/protocol/contracts/libs/LibReceiptDecoder.sol
@@ -60,7 +60,7 @@ library LibReceiptDecoder {
) internal pure returns (Log[] memory) {
Log[] memory logs = new Log[](logsRlp.length);
- for (uint256 i = 0; i < logsRlp.length; ++i) {
+ for (uint256 i; i < logsRlp.length; ++i) {
LibRLPReader.RLPItem[] memory rlpItems = LibRLPReader.readList(
logsRlp[i]
);
@@ -77,7 +77,7 @@ library LibReceiptDecoder {
) internal pure returns (bytes32[] memory) {
bytes32[] memory topics = new bytes32[](topicsRlp.length);
- for (uint256 i = 0; i < topicsRlp.length; ++i) {
+ for (uint256 i; i < topicsRlp.length; ++i) {
topics[i] = LibRLPReader.readBytes32(topicsRlp[i]);
}
diff --git a/packages/protocol/contracts/libs/LibSharedConfig.sol b/packages/protocol/contracts/libs/LibSharedConfig.sol
index bfde1b6d260..9770762f539 100644
--- a/packages/protocol/contracts/libs/LibSharedConfig.sol
+++ b/packages/protocol/contracts/libs/LibSharedConfig.sol
@@ -41,6 +41,7 @@ library LibSharedConfig {
proofTimeCap: 60 minutes,
bootstrapDiscountHalvingPeriod: 180 days,
initialUncleDelay: 60 minutes,
+ proverRewardRandomizedPercentage: 0,
enableTokenomics: false,
enablePublicInputsCheck: true,
enableProofValidation: false,
diff --git a/packages/protocol/contracts/libs/LibTxDecoder.sol b/packages/protocol/contracts/libs/LibTxDecoder.sol
index edbd1973146..c92e0160d86 100644
--- a/packages/protocol/contracts/libs/LibTxDecoder.sol
+++ b/packages/protocol/contracts/libs/LibTxDecoder.sol
@@ -82,7 +82,7 @@ library LibTxDecoder {
LibRLPReader.RLPItem[] memory txs = LibRLPReader.readList(encoded);
Tx[] memory _txList = new Tx[](txs.length);
- for (uint256 i = 0; i < txs.length; ++i) {
+ for (uint256 i; i < txs.length; ++i) {
_txList[i] = decodeTx(chainId, LibRLPReader.readBytes(txs[i]));
}
@@ -211,7 +211,7 @@ library LibTxDecoder {
LibRLPReader.RLPItem[] memory accessListRLP
) internal pure returns (AccessItem[] memory accessList) {
accessList = new AccessItem[](accessListRLP.length);
- for (uint256 i = 0; i < accessListRLP.length; ++i) {
+ for (uint256 i; i < accessListRLP.length; ++i) {
LibRLPReader.RLPItem[] memory items = LibRLPReader.readList(
accessListRLP[i]
);
@@ -220,7 +220,7 @@ library LibTxDecoder {
items[1]
);
bytes32[] memory slots = new bytes32[](slotListRLP.length);
- for (uint256 j = 0; j < slotListRLP.length; ++j) {
+ for (uint256 j; j < slotListRLP.length; ++j) {
slots[j] = LibRLPReader.readBytes32(slotListRLP[j]);
}
accessList[i] = AccessItem(addr, slots);
@@ -231,7 +231,7 @@ library LibTxDecoder {
TxList memory txList
) internal pure returns (uint256 sum) {
Tx[] memory items = txList.items;
- for (uint256 i = 0; i < items.length; ++i) {
+ for (uint256 i; i < items.length; ++i) {
sum += items[i].gasLimit;
}
}
diff --git a/packages/protocol/contracts/libs/LibTxUtils.sol b/packages/protocol/contracts/libs/LibTxUtils.sol
index c7ef36419a2..d316a763bfb 100644
--- a/packages/protocol/contracts/libs/LibTxUtils.sol
+++ b/packages/protocol/contracts/libs/LibTxUtils.sol
@@ -55,7 +55,7 @@ library LibTxUtils {
transaction.txType == 0 ? txRLPItems.length : txRLPItems.length - 3
);
- for (uint256 i = 0; i < list.length; ++i) {
+ for (uint256 i; i < list.length; ++i) {
// For Non-legacy transactions, accessList is always the
// fourth to last item.
if (transaction.txType != 0 && i == list.length - 1) {
diff --git a/packages/protocol/contracts/test/L1/TestTaikoL1.sol b/packages/protocol/contracts/test/L1/TestTaikoL1.sol
index a4bde07d5e5..06024663730 100644
--- a/packages/protocol/contracts/test/L1/TestTaikoL1.sol
+++ b/packages/protocol/contracts/test/L1/TestTaikoL1.sol
@@ -47,6 +47,7 @@ contract TestTaikoL1 is TaikoL1, IProofVerifier {
config.proofTimeCap = 4 seconds;
config.bootstrapDiscountHalvingPeriod = 180 days;
config.initialUncleDelay = 1 seconds;
+ config.proverRewardRandomizedPercentage = 0;
config.enableTokenomics = false;
config.enablePublicInputsCheck = false;
config.enableOracleProver = false;
diff --git a/packages/protocol/contracts/test/L1/TestTaikoL1EnableTokenomics.sol b/packages/protocol/contracts/test/L1/TestTaikoL1EnableTokenomics.sol
index 68f634b48c9..8191bfca592 100644
--- a/packages/protocol/contracts/test/L1/TestTaikoL1EnableTokenomics.sol
+++ b/packages/protocol/contracts/test/L1/TestTaikoL1EnableTokenomics.sol
@@ -47,6 +47,7 @@ contract TestTaikoL1EnableTokenomics is TaikoL1, IProofVerifier {
config.proofTimeCap = 5 seconds;
config.bootstrapDiscountHalvingPeriod = 1 seconds;
config.initialUncleDelay = 1 seconds;
+ config.proverRewardRandomizedPercentage = 0;
config.enableTokenomics = true;
config.enablePublicInputsCheck = false;
config.enableProofValidation = false;
diff --git a/packages/protocol/contracts/test/L1/TestTaikoL2.sol b/packages/protocol/contracts/test/L1/TestTaikoL2.sol
index ae786c018e1..648cea4b244 100644
--- a/packages/protocol/contracts/test/L1/TestTaikoL2.sol
+++ b/packages/protocol/contracts/test/L1/TestTaikoL2.sol
@@ -48,6 +48,7 @@ contract TestTaikoL2 is TaikoL2 {
config.proofTimeCap = 60 minutes;
config.bootstrapDiscountHalvingPeriod = 180 days;
config.initialUncleDelay = 1 minutes;
+ config.proverRewardRandomizedPercentage = 0;
config.enableTokenomics = true;
config.enablePublicInputsCheck = false;
config.enableProofValidation = false;
diff --git a/packages/protocol/contracts/test/L1/TestTaikoL2EnablePublicInputsCheck.sol b/packages/protocol/contracts/test/L1/TestTaikoL2EnablePublicInputsCheck.sol
index 7f479f97bbc..052e9bd38a6 100644
--- a/packages/protocol/contracts/test/L1/TestTaikoL2EnablePublicInputsCheck.sol
+++ b/packages/protocol/contracts/test/L1/TestTaikoL2EnablePublicInputsCheck.sol
@@ -48,6 +48,7 @@ contract TestTaikoL2EnablePublicInputsCheck is TaikoL2 {
config.proofTimeCap = 60 minutes;
config.bootstrapDiscountHalvingPeriod = 180 days;
config.initialUncleDelay = 1 minutes;
+ config.proverRewardRandomizedPercentage = 0;
config.enableTokenomics = true;
config.enablePublicInputsCheck = true;
config.enableProofValidation = true;
diff --git a/packages/protocol/contracts/test/libs/TestLibProving.sol b/packages/protocol/contracts/test/libs/TestLibProving.sol
index 24e5f87279d..7062c672722 100644
--- a/packages/protocol/contracts/test/libs/TestLibProving.sol
+++ b/packages/protocol/contracts/test/libs/TestLibProving.sol
@@ -290,7 +290,7 @@ library TestLibProving {
bytes32 blockHash = evidence.header.hashBlockHeader();
if (!skipZKPVerification) {
- for (uint256 i = 0; i < config.zkProofsPerBlock; ++i) {
+ for (uint256 i; i < config.zkProofsPerBlock; ++i) {
bytes32 instance = keccak256(
abi.encode(
blockHash,
@@ -298,6 +298,7 @@ library TestLibProving {
evidence.meta.txListHash
)
);
+
if (
!proofVerifier.verifyZKP({
verifierId: string(
@@ -363,7 +364,7 @@ library TestLibProving {
})
) revert L1_TOO_LATE();
- for (uint256 i = 0; i < fc.provers.length; ++i) {
+ for (uint256 i; i < fc.provers.length; ++i) {
if (fc.provers[i] == prover) revert L1_DUP_PROVERS();
}
diff --git a/packages/protocol/contracts/test/thirdparty/TestLibRLPReader.sol b/packages/protocol/contracts/test/thirdparty/TestLibRLPReader.sol
index 9b665fba2f7..7de89cae7c3 100644
--- a/packages/protocol/contracts/test/thirdparty/TestLibRLPReader.sol
+++ b/packages/protocol/contracts/test/thirdparty/TestLibRLPReader.sol
@@ -11,7 +11,7 @@ contract TestLibRLPReader {
function readList(bytes memory _in) public pure returns (bytes[] memory) {
LibRLPReader.RLPItem[] memory decoded = LibRLPReader.readList(_in);
bytes[] memory out = new bytes[](decoded.length);
- for (uint256 i = 0; i < out.length; ++i) {
+ for (uint256 i; i < out.length; ++i) {
out[i] = LibRLPReader.readRawBytes(decoded[i]);
}
return out;
diff --git a/packages/protocol/contracts/thirdparty/LibBytesUtils.sol b/packages/protocol/contracts/thirdparty/LibBytesUtils.sol
index 69f27184251..54e082a9cdc 100644
--- a/packages/protocol/contracts/thirdparty/LibBytesUtils.sol
+++ b/packages/protocol/contracts/thirdparty/LibBytesUtils.sol
@@ -142,7 +142,7 @@ library LibBytesUtils {
) internal pure returns (bytes memory) {
bytes memory nibbles = new bytes(_bytes.length * 2);
- for (uint256 i = 0; i < _bytes.length; ++i) {
+ for (uint256 i; i < _bytes.length; ++i) {
nibbles[i * 2] = _bytes[i] >> 4;
nibbles[i * 2 + 1] = bytes1(uint8(_bytes[i]) % 16);
}
@@ -155,7 +155,7 @@ library LibBytesUtils {
) internal pure returns (bytes memory) {
bytes memory ret = new bytes(_bytes.length / 2);
- for (uint256 i = 0; i < ret.length; ++i) {
+ for (uint256 i; i < ret.length; ++i) {
ret[i] = (_bytes[i * 2] << 4) | (_bytes[i * 2 + 1]);
}
diff --git a/packages/protocol/contracts/thirdparty/LibMerkleTrie.sol b/packages/protocol/contracts/thirdparty/LibMerkleTrie.sol
index 5c5446858d3..5f893543262 100644
--- a/packages/protocol/contracts/thirdparty/LibMerkleTrie.sol
+++ b/packages/protocol/contracts/thirdparty/LibMerkleTrie.sol
@@ -158,7 +158,7 @@ library LibMerkleTrie {
bool _isFinalNode
)
{
- uint256 pathLength = 0;
+ uint256 pathLength;
bytes memory key = LibBytesUtils.toNibbles(_key);
bytes32 currentNodeID = _root;
@@ -167,7 +167,7 @@ library LibMerkleTrie {
TrieNode memory currentNode;
// Proof is top-down, so we start at the first element (root).
- for (uint256 i = 0; i < _proof.length; ++i) {
+ for (uint256 i; i < _proof.length; ++i) {
currentNode = _proof[i];
currentKeyIndex += currentKeyIncrement;
@@ -286,7 +286,7 @@ library LibMerkleTrie {
LibRLPReader.RLPItem[] memory nodes = LibRLPReader.readList(_proof);
TrieNode[] memory proof = new TrieNode[](nodes.length);
- for (uint256 i = 0; i < nodes.length; ++i) {
+ for (uint256 i; i < nodes.length; ++i) {
bytes memory encoded = LibRLPReader.readBytes(nodes[i]);
proof[i] = TrieNode({
encoded: encoded,
@@ -354,7 +354,7 @@ library LibMerkleTrie {
bytes memory _a,
bytes memory _b
) private pure returns (uint256 _shared) {
- uint256 i = 0;
+ uint256 i;
while (_a.length > i && _b.length > i && _a[i] == _b[i]) {
++i;
}
diff --git a/packages/protocol/contracts/thirdparty/LibRLPReader.sol b/packages/protocol/contracts/thirdparty/LibRLPReader.sol
index 3df840372c8..09c51a04006 100644
--- a/packages/protocol/contracts/thirdparty/LibRLPReader.sol
+++ b/packages/protocol/contracts/thirdparty/LibRLPReader.sol
@@ -93,7 +93,7 @@ library LibRLPReader {
// simply set a reasonable maximum list length and decrease the size before we finish.
RLPItem[] memory out = new RLPItem[](MAX_LIST_LENGTH);
- uint256 itemCount = 0;
+ uint256 itemCount;
uint256 offset = listOffset;
while (offset < _in.length) {
require(
@@ -424,7 +424,7 @@ library LibRLPReader {
}
// Copy over as many complete words as we can.
- for (uint256 i = 0; i < _length / 32; ++i) {
+ for (uint256 i; i < _length / 32; ++i) {
assembly {
mstore(dest, mload(src))
}
diff --git a/packages/protocol/contracts/thirdparty/LibRLPWriter.sol b/packages/protocol/contracts/thirdparty/LibRLPWriter.sol
index ae256de5e78..58934a53c16 100644
--- a/packages/protocol/contracts/thirdparty/LibRLPWriter.sol
+++ b/packages/protocol/contracts/thirdparty/LibRLPWriter.sol
@@ -172,7 +172,7 @@ library LibRLPWriter {
function _toBinary(uint256 _x) private pure returns (bytes memory) {
bytes memory b = abi.encodePacked(_x);
- uint256 i = 0;
+ uint256 i;
for (; i < 32; ++i) {
if (b[i] != 0) {
break;
@@ -180,7 +180,7 @@ library LibRLPWriter {
}
bytes memory res = new bytes(32 - i);
- for (uint256 j = 0; j < res.length; ++j) {
+ for (uint256 j; j < res.length; ++j) {
res[j] = b[i++];
}
@@ -198,10 +198,10 @@ library LibRLPWriter {
) private pure returns (bytes memory) {
bytes memory b = abi.encodePacked(_x);
- uint256 i = 0;
+ uint256 i;
bytes memory res = new bytes(32);
- for (uint256 j = 0; j < res.length; ++j) {
+ for (uint256 j; j < res.length; ++j) {
res[j] = b[i++];
}
@@ -253,7 +253,7 @@ library LibRLPWriter {
}
uint256 len;
- uint256 i = 0;
+ uint256 i;
for (; i < _list.length; ++i) {
len += _list[i].length;
}