common: improve documentation comments (#16701)

XDCx/order_processor.go

@@ -525,7 +525,7 @@ func DoSettleBalance(coinbase common.Address, takerOrder, makerOrder *tradingsta
 	matchingFee = new(big.Int).Add(matchingFee, common.RelayerFee)
 	matchingFee = new(big.Int).Add(matchingFee, common.RelayerFee)
 
-	if common.EmptyHash(takerExOwner.Hash()) || common.EmptyHash(makerExOwner.Hash()) {
+	if takerExOwner.Hash().IsZero() || makerExOwner.Hash().IsZero() {
 		return fmt.Errorf("empty echange owner: taker: %v , maker : %v", takerExOwner, makerExOwner)
 	}
 	mapBalances := map[common.Address]map[common.Address]*big.Int{}

XDCx/tradingstate/dump.go

@@ -56,7 +56,7 @@ func (t *TradingStateDB) DumpAskTrie(orderBook common.Hash) (map[*big.Int]DumpOr
 	it := trie.NewIterator(exhangeObject.getAsksTrie(t.db).NodeIterator(nil))
 	for it.Next() {
 		priceHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			continue
 		}
 		price := new(big.Int).SetBytes(priceHash.Bytes())
@@ -99,7 +99,7 @@ func (t *TradingStateDB) DumpBidTrie(orderBook common.Hash) (map[*big.Int]DumpOr
 	it := trie.NewIterator(exhangeObject.getBidsTrie(t.db).NodeIterator(nil))
 	for it.Next() {
 		priceHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			continue
 		}
 		price := new(big.Int).SetBytes(priceHash.Bytes())
@@ -142,7 +142,7 @@ func (t *TradingStateDB) GetBids(orderBook common.Hash) (map[*big.Int]*big.Int,
 	it := trie.NewIterator(exhangeObject.getBidsTrie(t.db).NodeIterator(nil))
 	for it.Next() {
 		priceHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			continue
 		}
 		price := new(big.Int).SetBytes(priceHash.Bytes())
@@ -185,7 +185,7 @@ func (t *TradingStateDB) GetAsks(orderBook common.Hash) (map[*big.Int]*big.Int,
 	it := trie.NewIterator(exhangeObject.getAsksTrie(t.db).NodeIterator(nil))
 	for it.Next() {
 		priceHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			continue
 		}
 		price := new(big.Int).SetBytes(priceHash.Bytes())
@@ -224,7 +224,7 @@ func (s *stateOrderList) DumpOrderList(db Database) DumpOrderList {
 	orderListIt := trie.NewIterator(s.getTrie(db).NodeIterator(nil))
 	for orderListIt.Next() {
 		keyHash := common.BytesToHash(orderListIt.Key)
-		if common.EmptyHash(keyHash) {
+		if keyHash.IsZero() {
 			continue
 		}
 		if _, exist := s.cachedStorage[keyHash]; exist {
@@ -235,7 +235,7 @@ func (s *stateOrderList) DumpOrderList(db Database) DumpOrderList {
 		}
 	}
 	for key, value := range s.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			mapResult.Orders[new(big.Int).SetBytes(key.Bytes())] = new(big.Int).SetBytes(value.Bytes())
 		}
 	}
@@ -277,7 +277,7 @@ func (s *stateLendingBook) DumpOrderList(db Database) DumpOrderList {
 	orderListIt := trie.NewIterator(s.getTrie(db).NodeIterator(nil))
 	for orderListIt.Next() {
 		keyHash := common.BytesToHash(orderListIt.Key)
-		if common.EmptyHash(keyHash) {
+		if keyHash.IsZero() {
 			continue
 		}
 		if _, exist := s.cachedStorage[keyHash]; exist {
@@ -288,7 +288,7 @@ func (s *stateLendingBook) DumpOrderList(db Database) DumpOrderList {
 		}
 	}
 	for key, value := range s.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			mapResult.Orders[new(big.Int).SetBytes(key.Bytes())] = new(big.Int).SetBytes(value.Bytes())
 		}
 	}
@@ -311,7 +311,7 @@ func (l *liquidationPriceState) DumpLendingBook(db Database) (DumpLendingBook, e
 	it := trie.NewIterator(l.getTrie(db).NodeIterator(nil))
 	for it.Next() {
 		lendingBook := common.BytesToHash(it.Key)
-		if common.EmptyHash(lendingBook) {
+		if lendingBook.IsZero() {
 			continue
 		}
 		if _, exist := l.stateLendingBooks[lendingBook]; exist {
@@ -326,7 +326,7 @@ func (l *liquidationPriceState) DumpLendingBook(db Database) (DumpLendingBook, e
 		}
 	}
 	for lendingBook, stateLendingBook := range l.stateLendingBooks {
-		if !common.EmptyHash(lendingBook) {
+		if !lendingBook.IsZero() {
 			result.LendingBooks[lendingBook] = stateLendingBook.DumpOrderList(db)
 		}
 	}
@@ -342,7 +342,7 @@ func (t *TradingStateDB) DumpLiquidationPriceTrie(orderBook common.Hash) (map[*b
 	it := trie.NewIterator(exhangeObject.getLiquidationPriceTrie(t.db).NodeIterator(nil))
 	for it.Next() {
 		priceHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			continue
 		}
 		price := new(big.Int).SetBytes(priceHash.Bytes())

XDCx/tradingstate/state_lendingbook.go

@@ -118,7 +118,7 @@ func (s *stateLendingBook) getAllTradeIds(db Database) []common.Hash {
 		return tradeIds
 	}
 	for id, value := range s.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			tradeIds = append(tradeIds, id)
 		}
 	}

XDCx/tradingstate/state_orderbook.go

@@ -85,16 +85,16 @@ func (te *tradingExchanges) empty() bool {
 	if te.data.TotalQuantity != nil && te.data.TotalQuantity.Sign() > 0 {
 		return false
 	}
-	if !common.EmptyHash(te.data.AskRoot) {
+	if !te.data.AskRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(te.data.BidRoot) {
+	if !te.data.BidRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(te.data.OrderRoot) {
+	if !te.data.OrderRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(te.data.LiquidationPriceRoot) {
+	if !te.data.LiquidationPriceRoot.IsZero() {
 		return false
 	}
 	return true

XDCx/tradingstate/statedb.go

@@ -358,7 +358,7 @@ func (t *TradingStateDB) GetBestAskPrice(orderBook common.Hash) (*big.Int, *big.
 	stateObject := t.getStateExchangeObject(orderBook)
 	if stateObject != nil {
 		priceHash := stateObject.getBestPriceAsksTrie(t.db)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			return Zero, Zero
 		}
 		orderList := stateObject.getStateOrderListAskObject(t.db, priceHash)
@@ -375,7 +375,7 @@ func (t *TradingStateDB) GetBestBidPrice(orderBook common.Hash) (*big.Int, *big.
 	stateObject := t.getStateExchangeObject(orderBook)
 	if stateObject != nil {
 		priceHash := stateObject.getBestBidsTrie(t.db)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			return Zero, Zero
 		}
 		orderList := stateObject.getStateBidOrderListObject(t.db, priceHash)

XDCxlending/lendingstate/dump.go

@@ -48,7 +48,7 @@ func (ls *LendingStateDB) DumpInvestingTrie(orderBook common.Hash) (map[*big.Int
 	it := trie.NewIterator(exhangeObject.getInvestingTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		interestHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(interestHash) {
+		if interestHash.IsZero() {
 			continue
 		}
 		interest := new(big.Int).SetBytes(interestHash.Bytes())
@@ -91,7 +91,7 @@ func (ls *LendingStateDB) DumpBorrowingTrie(orderBook common.Hash) (map[*big.Int
 	it := trie.NewIterator(exhangeObject.getBorrowingTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		interestHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(interestHash) {
+		if interestHash.IsZero() {
 			continue
 		}
 		interest := new(big.Int).SetBytes(interestHash.Bytes())
@@ -134,7 +134,7 @@ func (ls *LendingStateDB) GetInvestings(orderBook common.Hash) (map[*big.Int]*bi
 	it := trie.NewIterator(exhangeObject.getInvestingTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		interestHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(interestHash) {
+		if interestHash.IsZero() {
 			continue
 		}
 		interest := new(big.Int).SetBytes(interestHash.Bytes())
@@ -177,7 +177,7 @@ func (ls *LendingStateDB) GetBorrowings(orderBook common.Hash) (map[*big.Int]*bi
 	it := trie.NewIterator(exhangeObject.getBorrowingTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		interestHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(interestHash) {
+		if interestHash.IsZero() {
 			continue
 		}
 		interest := new(big.Int).SetBytes(interestHash.Bytes())
@@ -216,7 +216,7 @@ func (il *itemListState) DumpItemList(db Database) DumpOrderList {
 	orderListIt := trie.NewIterator(il.getTrie(db).NodeIterator(nil))
 	for orderListIt.Next() {
 		keyHash := common.BytesToHash(orderListIt.Key)
-		if common.EmptyHash(keyHash) {
+		if keyHash.IsZero() {
 			continue
 		}
 		if _, exist := il.cachedStorage[keyHash]; exist {
@@ -227,7 +227,7 @@ func (il *itemListState) DumpItemList(db Database) DumpOrderList {
 		}
 	}
 	for key, value := range il.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			mapResult.Orders[new(big.Int).SetBytes(key.Bytes())] = new(big.Int).SetBytes(value.Bytes())
 		}
 	}
@@ -265,7 +265,7 @@ func (lts *liquidationTimeState) DumpItemList(db Database) DumpOrderList {
 	orderListIt := trie.NewIterator(lts.getTrie(db).NodeIterator(nil))
 	for orderListIt.Next() {
 		keyHash := common.BytesToHash(orderListIt.Key)
-		if common.EmptyHash(keyHash) {
+		if keyHash.IsZero() {
 			continue
 		}
 		if _, exist := lts.cachedStorage[keyHash]; exist {
@@ -276,7 +276,7 @@ func (lts *liquidationTimeState) DumpItemList(db Database) DumpOrderList {
 		}
 	}
 	for key, value := range lts.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			mapResult.Orders[new(big.Int).SetBytes(key.Bytes())] = new(big.Int).SetBytes(value.Bytes())
 		}
 	}
@@ -303,7 +303,7 @@ func (ls *LendingStateDB) DumpLiquidationTimeTrie(orderBook common.Hash) (map[*b
 	it := trie.NewIterator(exhangeObject.getLiquidationTimeTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		unixTimeHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(unixTimeHash) {
+		if unixTimeHash.IsZero() {
 			continue
 		}
 		unixTime := new(big.Int).SetBytes(unixTimeHash.Bytes())
@@ -346,7 +346,7 @@ func (ls *LendingStateDB) DumpLendingOrderTrie(orderBook common.Hash) (map[*big.
 	it := trie.NewIterator(exhangeObject.getLendingItemTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		orderIdHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(orderIdHash) {
+		if orderIdHash.IsZero() {
 			continue
 		}
 		orderId := new(big.Int).SetBytes(orderIdHash.Bytes())
@@ -386,7 +386,7 @@ func (ls *LendingStateDB) DumpLendingTradeTrie(orderBook common.Hash) (map[*big.
 	it := trie.NewIterator(exhangeObject.getLendingTradeTrie(ls.db).NodeIterator(nil))
 	for it.Next() {
 		tradeIdHash := common.BytesToHash(it.Key)
-		if common.EmptyHash(tradeIdHash) {
+		if tradeIdHash.IsZero() {
 			continue
 		}
 		tradeId := new(big.Int).SetBytes(tradeIdHash.Bytes())

XDCxlending/lendingstate/state_lendingbook.go

@@ -70,19 +70,19 @@ func (s *lendingExchangeState) empty() bool {
 	if s.data.TradeNonce != 0 {
 		return false
 	}
-	if !common.EmptyHash(s.data.InvestingRoot) {
+	if !s.data.InvestingRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(s.data.BorrowingRoot) {
+	if !s.data.BorrowingRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(s.data.LendingItemRoot) {
+	if !s.data.LendingItemRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(s.data.LendingTradeRoot) {
+	if !s.data.LendingTradeRoot.IsZero() {
 		return false
 	}
-	if !common.EmptyHash(s.data.LiquidationTimeRoot) {
+	if !s.data.LiquidationTimeRoot.IsZero() {
 		return false
 	}
 	return true

XDCxlending/lendingstate/state_liquidationtime.go

@@ -116,7 +116,7 @@ func (lt *liquidationTimeState) getAllTradeIds(db Database) []common.Hash {
 		return tradeIds
 	}
 	for id, value := range lt.cachedStorage {
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			tradeIds = append(tradeIds, id)
 		}
 	}

XDCxlending/lendingstate/statedb.go

@@ -343,7 +343,7 @@ func (ls *LendingStateDB) GetBestInvestingRate(orderBook common.Hash) (*big.Int,
 	stateObject := ls.getLendingExchange(orderBook)
 	if stateObject != nil {
 		investingHash := stateObject.getBestInvestingInterest(ls.db)
-		if common.EmptyHash(investingHash) {
+		if investingHash.IsZero() {
 			return Zero, Zero
 		}
 		orderList := stateObject.getInvestingOrderList(ls.db, investingHash)
@@ -360,7 +360,7 @@ func (ls *LendingStateDB) GetBestBorrowRate(orderBook common.Hash) (*big.Int, *b
 	stateObject := ls.getLendingExchange(orderBook)
 	if stateObject != nil {
 		priceHash := stateObject.getBestBorrowingInterest(ls.db)
-		if common.EmptyHash(priceHash) {
+		if priceHash.IsZero() {
 			return Zero, Zero
 		}
 		orderList := stateObject.getBorrowingOrderList(ls.db, priceHash)

XDCxlending/order_processor.go

@@ -581,7 +581,7 @@ func DoSettleBalance(coinbase common.Address, takerOrder, makerOrder *lendingsta
 	// masternodes only charge borrower relayer fee
 	matchingFee = new(big.Int).Add(matchingFee, common.RelayerLendingFee)
 
-	if common.EmptyHash(takerExOwner.Hash()) || common.EmptyHash(makerExOwner.Hash()) {
+	if takerExOwner.Hash().IsZero() || makerExOwner.Hash().IsZero() {
 		return fmt.Errorf("empty echange owner: taker: %v , maker : %v", takerExOwner, makerExOwner)
 	}
 	mapBalances := map[common.Address]map[common.Address]*big.Int{}

common/bytes.go

@@ -19,15 +19,20 @@ package common
 
 import "encoding/hex"
 
+// ToHex returns the hex representation of b, prefixed with '0x'.
+// For empty slices, the return value is "0x0".
+//
+// Deprecated: use hexutil.Encode instead.
 func ToHex(b []byte) string {
 	hex := Bytes2Hex(b)
-	// Prefer output of "0x0" instead of "0x"
 	if len(hex) == 0 {
 		hex = "0"
 	}
 	return "0x" + hex
 }
 
+// FromHex returns the bytes represented by the hexadecimal string s.
+// s may be prefixed with "0x".
 func FromHex(s string) []byte {
 	if len(s) > 1 {
 		if s[0:2] == "0x" || s[0:2] == "0X" {
@@ -43,9 +48,7 @@ func FromHex(s string) []byte {
 	return Hex2Bytes(s)
 }
 
-// Copy bytes
+// CopyBytes returns an exact copy of the provided bytes.
-//
-// Returns an exact copy of the provided bytes
 func CopyBytes(b []byte) (copiedBytes []byte) {
 	if b == nil {
 		return nil
@@ -55,17 +58,23 @@ func CopyBytes(b []byte) (copiedBytes []byte) {
 
 	return
 }
+
+// hasXDCPrefix validates str begins with 'xdc' or 'XDC'.
 func hasXDCPrefix(str string) bool {
 	return len(str) >= 3 && (str[0] == 'x' || str[0] == 'X') && (str[1] == 'd' || str[1] == 'D') && (str[2] == 'c' || str[2] == 'C')
 }
+
+// hasHexPrefix validates str begins with '0x' or '0X'.
 func hasHexPrefix(str string) bool {
 	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
 }
 
+// isHexCharacter returns bool of c being a valid hexadecimal.
 func isHexCharacter(c byte) bool {
 	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
 }
 
+// isHex validates whether each byte is valid hexadecimal string.
 func isHex(str string) bool {
 	if len(str)%2 != 0 {
 		return false
@@ -78,16 +87,18 @@ func isHex(str string) bool {
 	return true
 }
 
+// Bytes2Hex returns the hexadecimal encoding of d.
 func Bytes2Hex(d []byte) string {
 	return hex.EncodeToString(d)
 }
 
+// Hex2Bytes returns the bytes represented by the hexadecimal string str.
 func Hex2Bytes(str string) []byte {
 	h, _ := hex.DecodeString(str)
-
 	return h
 }
 
+// Hex2BytesFixed returns bytes of a specified fixed length flen.
 func Hex2BytesFixed(str string, flen int) []byte {
 	h, _ := hex.DecodeString(str)
 	if len(h) == flen {
@@ -103,6 +114,7 @@ func Hex2BytesFixed(str string, flen int) []byte {
 	}
 }
 
+// RightPadBytes zero-pads slice to the right up to length l.
 func RightPadBytes(slice []byte, l int) []byte {
 	if l <= len(slice) {
 		return slice
@@ -114,6 +126,7 @@ func RightPadBytes(slice []byte, l int) []byte {
 	return padded
 }
 
+// LeftPadBytes zero-pads slice to the left up to length l.
 func LeftPadBytes(slice []byte, l int) []byte {
 	if l <= len(slice) {
 		return slice

common/math/big.go

@@ -78,7 +78,7 @@ func ParseBig256(s string) (*big.Int, bool) {
 	return bigint, ok
 }
 
-// MustParseBig parses s as a 256 bit big integer and panics if the string is invalid.
+// MustParseBig256 parses s as a 256 bit big integer and panics if the string is invalid.
 func MustParseBig256(s string) *big.Int {
 	v, ok := ParseBig256(s)
 	if !ok {
@@ -186,9 +186,8 @@ func U256(x *big.Int) *big.Int {
 func S256(x *big.Int) *big.Int {
 	if x.Cmp(tt255) < 0 {
 		return x
-	} else {
-		return new(big.Int).Sub(x, tt256)
 	}
+	return new(big.Int).Sub(x, tt256)
 }
 
 // Exp implements exponentiation by squaring.

common/number/int.go

@@ -34,13 +34,12 @@ func limitUnsigned256(x *Number) *Number {
 func limitSigned256(x *Number) *Number {
 	if x.num.Cmp(tt255) < 0 {
 		return x
-	} else {
+	}
 	x.num.Sub(x.num, tt256)
 	return x
-	}
 }
 
-// Number function
+// Initialiser is a Number function
 type Initialiser func(n int64) *Number
 
 // A Number represents a generic integer with a bounding function limiter. Limit is called after each operations
@@ -58,58 +57,58 @@ func NewInitialiser(limiter func(*Number) *Number) Initialiser {
 	}
 }
 
-// Return a Number with a UNSIGNED limiter up to 256 bits
+// Uint256 returns a Number with a UNSIGNED limiter up to 256 bits
 func Uint256(n int64) *Number {
 	return &Number{big.NewInt(n), limitUnsigned256}
 }
 
-// Return a Number with a SIGNED limiter up to 256 bits
+// Int256 returns Number with a SIGNED limiter up to 256 bits
 func Int256(n int64) *Number {
 	return &Number{big.NewInt(n), limitSigned256}
 }
 
-// Returns a Number with a SIGNED unlimited size
+// Big returns a Number with a SIGNED unlimited size
 func Big(n int64) *Number {
 	return &Number{big.NewInt(n), func(x *Number) *Number { return x }}
 }
 
-// Sets i to sum of x+y
+// Add sets i to sum of x+y
 func (i *Number) Add(x, y *Number) *Number {
 	i.num.Add(x.num, y.num)
 	return i.limit(i)
 }
 
-// Sets i to difference of x-y
+// Sub sets i to difference of x-y
 func (i *Number) Sub(x, y *Number) *Number {
 	i.num.Sub(x.num, y.num)
 	return i.limit(i)
 }
 
-// Sets i to product of x*y
+// Mul sets i to product of x*y
 func (i *Number) Mul(x, y *Number) *Number {
 	i.num.Mul(x.num, y.num)
 	return i.limit(i)
 }
 
-// Sets i to the quotient prodject of x/y
+// Div sets i to the quotient prodject of x/y
 func (i *Number) Div(x, y *Number) *Number {
 	i.num.Div(x.num, y.num)
 	return i.limit(i)
 }
 
-// Sets i to x % y
+// Mod sets i to x % y
 func (i *Number) Mod(x, y *Number) *Number {
 	i.num.Mod(x.num, y.num)
 	return i.limit(i)
 }
 
-// Sets i to x << s
+// Lsh sets i to x << s
 func (i *Number) Lsh(x *Number, s uint) *Number {
 	i.num.Lsh(x.num, s)
 	return i.limit(i)
 }
 
-// Sets i to x^y
+// Pow sets i to x^y
 func (i *Number) Pow(x, y *Number) *Number {
 	i.num.Exp(x.num, y.num, big.NewInt(0))
 	return i.limit(i)
@@ -117,13 +116,13 @@ func (i *Number) Pow(x, y *Number) *Number {
 
 // Setters
 
-// Set x to i
+// Set sets x to i
 func (i *Number) Set(x *Number) *Number {
 	i.num.Set(x.num)
 	return i.limit(i)
 }
 
-// Set x bytes to i
+// SetBytes sets x bytes to i
 func (i *Number) SetBytes(x []byte) *Number {
 	i.num.SetBytes(x)
 	return i.limit(i)
@@ -140,12 +139,12 @@ func (i *Number) Cmp(x *Number) int {
 
 // Getters
 
-// Returns the string representation of i
+// String returns the string representation of i
 func (i *Number) String() string {
 	return i.num.String()
 }
 
-// Returns the byte representation of i
+// Bytes returns the byte representation of i
 func (i *Number) Bytes() []byte {
 	return i.num.Bytes()
 }
@@ -160,17 +159,17 @@ func (i *Number) Int64() int64 {
 	return i.num.Int64()
 }
 
-// Returns the signed version of i
+// Int256 returns the signed version of i
 func (i *Number) Int256() *Number {
 	return Int(0).Set(i)
 }
 
-// Returns the unsigned version of i
+// Uint256 returns the unsigned version of i
 func (i *Number) Uint256() *Number {
 	return Uint(0).Set(i)
 }
 
-// Returns the index of the first bit that's set to 1
+// FirstBitSet returns the index of the first bit that's set to 1
 func (i *Number) FirstBitSet() int {
 	for j := 0; j < i.num.BitLen(); j++ {
 		if i.num.Bit(j) > 0 {

common/path.go

@@ -30,6 +30,7 @@ func MakeName(name, version string) string {
 	return fmt.Sprintf("%s/v%s/%s/%s", name, version, runtime.GOOS, runtime.Version())
 }
 
+// FileExist checks if a file exists at filePath.
 func FileExist(filePath string) bool {
 	_, err := os.Stat(filePath)
 	if err != nil && os.IsNotExist(err) {
@@ -39,9 +40,10 @@ func FileExist(filePath string) bool {
 	return true
 }
 
-func AbsolutePath(Datadir string, filename string) string {
+// AbsolutePath returns datadir + filename, or filename if it is absolute.
+func AbsolutePath(datadir string, filename string) string {
 	if filepath.IsAbs(filename) {
 		return filename
 	}
-	return filepath.Join(Datadir, filename)
+	return filepath.Join(datadir, filename)
 }

common/types.go

@@ -106,7 +106,7 @@ func (h Hash) Cmp(other Hash) int {
 // IsZero returns if a Hash is empty
 func (h Hash) IsZero() bool { return h == Hash{} }
 
-// Get the string representation of the underlying hash
+// Str get the string representation of the underlying hash
 func (h Hash) Str() string { return string(h[:]) }
 
 // Bytes gets the byte representation of the underlying hash.
@@ -161,14 +161,6 @@ func (h *Hash) SetBytes(b []byte) {
 	copy(h[HashLength-len(b):], b)
 }
 
-// Set string `s` to h. If s is larger than len(h) s will be cropped (from left) to fit.
-func (h *Hash) SetString(s string) { h.SetBytes([]byte(s)) }
-
-// Sets h to other
-func (h *Hash) Set(other Hash) {
-	copy(h[:], other[:])
-}
-
 // Generate implements testing/quick.Generator.
 func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
 	m := rand.Intn(len(h))
@@ -178,10 +170,6 @@ func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
 	return reflect.ValueOf(h)
 }
 
-func EmptyHash(h Hash) bool {
-	return h == Hash{}
-}
-
 // UnprefixedHash allows marshaling a Hash without 0x prefix.
 type UnprefixedHash Hash
 
@@ -200,6 +188,8 @@ func (h UnprefixedHash) MarshalText() ([]byte, error) {
 // Address represents the 20 byte address of an Ethereum account.
 type Address [AddressLength]byte
 
+// BytesToAddress returns Address with value b.
+// If b is larger than len(h), b will be cropped from the left.
 func BytesToAddress(b []byte) Address {
 	var a Address
 	a.SetBytes(b)
@@ -231,10 +221,16 @@ func IsHexAddress(s string) bool {
 // IsZero returns if a address is empty
 func (a Address) IsZero() bool { return a == Address{} }
 
-// Get the string representation of the underlying address
+// Str gets the string representation of the underlying address
 func (a Address) Str() string { return string(a[:]) }
+
+// Bytes gets the string representation of the underlying address.
 func (a Address) Bytes() []byte { return a[:] }
+
+// Big converts an address to a big integer.
 func (a Address) Big() *big.Int { return new(big.Int).SetBytes(a[:]) }
+
+// Hash converts an address to a hash by left-padding it with zeros.
 func (a Address) Hash() Hash { return BytesToHash(a[:]) }
 
 // Hex returns an EIP55-compliant hex string representation of the address.
@@ -259,7 +255,7 @@ func (a Address) Hex() string {
 	return "xdc" + string(result)
 }
 
-// String implements the stringer interface and is used also by the logger.
+// String implements fmt.Stringer.
 func (a Address) String() string {
 	return a.Hex()
 }
@@ -270,7 +266,8 @@ func (a Address) Format(s fmt.State, c rune) {
 	fmt.Fprintf(s, "%"+string(c), a[:])
 }
 
-// Sets the address to the value of b. If b is larger than len(a) it will panic
+// SetBytes sets the address to the value of b.
+// If b is larger than len(a) it will panic.
 func (a *Address) SetBytes(b []byte) {
 	if len(b) > len(a) {
 		b = b[len(b)-AddressLength:]
@@ -278,14 +275,6 @@ func (a *Address) SetBytes(b []byte) {
 	copy(a[AddressLength-len(b):], b)
 }
 
-// Set string `s` to a. If s is larger than len(a) it will panic
-func (a *Address) SetString(s string) { a.SetBytes([]byte(s)) }
-
-// Sets a to other
-func (a *Address) Set(other Address) {
-	copy(a[:], other[:])
-}
-
 // MarshalText returns the hex representation of a.
 func (a Address) MarshalText() ([]byte, error) {
 	// Handle '0x' or 'xdc' prefix here.
@@ -306,7 +295,7 @@ func (a *Address) UnmarshalJSON(input []byte) error {
 	return hexutil.UnmarshalFixedJSON(addressT, input, a[:])
 }
 
-// UnprefixedHash allows marshaling an Address without 0x prefix.
+// UnprefixedAddress allows marshaling an Address without 0x prefix.
 type UnprefixedAddress Address
 
 // UnmarshalText decodes the address from hex. The 0x prefix is optional.
@@ -319,7 +308,7 @@ func (a UnprefixedAddress) MarshalText() ([]byte, error) {
 	return []byte(hex.EncodeToString(a[:])), nil
 }
 
-// Extract validators from byte array.
+// RemoveItemFromArray extracts validators from byte array.
 func RemoveItemFromArray(array []Address, items []Address) []Address {
 	// Create newArray to stop append change array value
 	newArray := make([]Address, len(array))
@@ -340,7 +329,7 @@ func RemoveItemFromArray(array []Address, items []Address) []Address {
 	return newArray
 }
 
-// Extract validators from byte array.
+// ExtractAddressToBytes extracts validators from byte array.
 func ExtractAddressToBytes(penalties []Address) []byte {
 	data := []byte{}
 	for _, signer := range penalties {

common/types_template.go

@@ -1,64 +0,0 @@
-// Copyright 2015 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build none
-//sed -e 's/_N_/Hash/g' -e 's/_S_/32/g' -e '1d' types_template.go | gofmt -w hash.go
-
-package common
-
-import "math/big"
-
-type _N_ [_S_]byte
-
-func BytesTo_N_(b []byte) _N_ {
-	var h _N_
-	h.SetBytes(b)
-	return h
-}
-func StringTo_N_(s string) _N_ { return BytesTo_N_([]byte(s)) }
-func BigTo_N_(b *big.Int) _N_  { return BytesTo_N_(b.Bytes()) }
-func HexTo_N_(s string) _N_    { return BytesTo_N_(FromHex(s)) }
-
-// Don't use the default 'String' method in case we want to overwrite
-
-// Get the string representation of the underlying hash
-func (h _N_) Str() string   { return string(h[:]) }
-func (h _N_) Bytes() []byte { return h[:] }
-func (h _N_) Big() *big.Int { return new(big.Int).SetBytes(h[:]) }
-func (h _N_) Hex() string   { return "0x" + Bytes2Hex(h[:]) }
-
-// Sets the hash to the value of b. If b is larger than len(h) it will panic
-func (h *_N_) SetBytes(b []byte) {
-	// Use the right most bytes
-	if len(b) > len(h) {
-		b = b[len(b)-_S_:]
-	}
-
-	// Reverse the loop
-	for i := len(b) - 1; i >= 0; i-- {
-		h[_S_-len(b)+i] = b[i]
-	}
-}
-
-// Set string `s` to h. If s is larger than len(h) it will panic
-func (h *_N_) SetString(s string) { h.SetBytes([]byte(s)) }
-
-// Sets h to other
-func (h *_N_) Set(other _N_) {
-	for i, v := range other {
-		h[i] = v
-	}
-}

core/blockchain.go

@@ -957,7 +957,7 @@ func (bc *BlockChain) saveData() {
 					author, _ := bc.Engine().Author(recent.Header())
 					if tradingService != nil {
 						tradingRoot, _ := tradingService.GetTradingStateRoot(recent, author)
-						if !common.EmptyHash(tradingRoot) && tradingTriedb != nil {
+						if !tradingRoot.IsZero() && tradingTriedb != nil {
 							if err := tradingTriedb.Commit(tradingRoot, true); err != nil {
 								log.Error("Failed to commit trading state recent state trie", "err", err)
 							}
@@ -965,7 +965,7 @@ func (bc *BlockChain) saveData() {
 					}
 					if lendingService != nil {
 						lendingRoot, _ := lendingService.GetLendingStateRoot(recent, author)
-						if !common.EmptyHash(lendingRoot) && lendingTriedb != nil {
+						if !lendingRoot.IsZero() && lendingTriedb != nil {
 							if err := lendingTriedb.Commit(lendingRoot, true); err != nil {
 								log.Error("Failed to commit lending state recent state trie", "err", err)
 							}

core/state/state_test.go

@@ -100,7 +100,7 @@ func (s *StateSuite) TestNull(c *checker.C) {
 	s.state.SetState(address, common.Hash{}, value)
 	s.state.Commit(false)
 	value = s.state.GetState(address, common.Hash{})
-	if !common.EmptyHash(value) {
+	if !value.IsZero() {
 		c.Errorf("expected empty hash. got %x", value)
 	}
 }

core/state/trc21_reader.go

@@ -51,7 +51,7 @@ func GetTRC21FeeCapacityFromState(statedb *StateDB) map[common.Address]*big.Int
 	for i := uint64(0); i < tokenCount; i++ {
 		key := GetLocDynamicArrAtElement(slotTokensHash, i, 1)
 		value := statedb.GetState(common.TRC21IssuerSMC, key)
-		if !common.EmptyHash(value) {
+		if !value.IsZero() {
 			token := common.BytesToAddress(value.Bytes())
 			balanceKey := GetLocMappingAtKey(token.Hash(), slotTokensState)
 			balanceHash := statedb.GetState(common.TRC21IssuerSMC, common.BigToHash(balanceKey))
@@ -68,14 +68,14 @@ func PayFeeWithTRC21TxFail(statedb *StateDB, from common.Address, token common.A
 	slotBalanceTrc21 := SlotTRC21Token["balances"]
 	balanceKey := GetLocMappingAtKey(from.Hash(), slotBalanceTrc21)
 	balanceHash := statedb.GetState(token, common.BigToHash(balanceKey))
-	if !common.EmptyHash(balanceHash) {
+	if !balanceHash.IsZero() {
 		balance := balanceHash.Big()
 		feeUsed := big.NewInt(0)
 		if balance.Cmp(feeUsed) <= 0 {
 			return
 		}
 		issuerTokenKey := GetLocSimpleVariable(SlotTRC21Token["issuer"])
-		if common.EmptyHash(issuerTokenKey) {
+		if issuerTokenKey.IsZero() {
 			return
 		}
 		issuerAddr := common.BytesToAddress(statedb.GetState(token, issuerTokenKey).Bytes())
@@ -106,7 +106,7 @@ func ValidateTRC21Tx(statedb *StateDB, from common.Address, token common.Address
 	balanceKey := GetLocMappingAtKey(from.Hash(), slotBalanceTrc21)
 	balanceHash := statedb.GetState(token, common.BigToHash(balanceKey))
 
-	if !common.EmptyHash(balanceHash) {
+	if !balanceHash.IsZero() {
 		balance := balanceHash.Big()
 		minFeeTokenKey := GetLocSimpleVariable(SlotTRC21Token["minFee"])
 		minFeeHash := statedb.GetState(token, minFeeTokenKey)
@@ -129,7 +129,7 @@ func ValidateTRC21Tx(statedb *StateDB, from common.Address, token common.Address
 	} else {
 		// we both accept tx with balance = 0 and fee = 0
 		minFeeTokenKey := GetLocSimpleVariable(SlotTRC21Token["minFee"])
-		if !common.EmptyHash(minFeeTokenKey) {
+		if !minFeeTokenKey.IsZero() {
 			return true
 		}
 	}

core/txpool/order_pool.go

@@ -492,7 +492,7 @@ func (pool *OrderPool) validateOrder(tx *types.OrderTransaction) error {
 	var signer = types.OrderTxSigner{}
 
 	if !tx.IsCancelledOrder() {
-		if !common.EmptyHash(tx.OrderHash()) {
+		if !tx.OrderHash().IsZero() {
 			if signer.Hash(tx) != tx.OrderHash() {
 				return ErrInvalidOrderHash
 			}

eth/downloader/downloader.go

@@ -682,7 +682,7 @@ func (d *Downloader) findAncestor(p *peerConnection, height uint64) (uint64, err
 		}
 	}
 	// If the head fetch already found an ancestor, return
-	if !common.EmptyHash(hash) {
+	if !hash.IsZero() {
 		if int64(number) <= floor {
 			p.log.Warn("Ancestor below allowance", "number", number, "hash", hash, "allowance", floor)
 			return 0, errInvalidAncestor