From ad45a3c069fa2b68c8dd1cec3b0e65b78537f89d Mon Sep 17 00:00:00 2001
From: Martin HS <martin@swende.se>
Date: Thu, 21 Mar 2024 13:50:13 +0100
Subject: [PATCH] all: use min/max/clear from go1.21 (#29307)

---
 accounts/keystore/keystore.go       | 4 +---
 core/vm/analysis_test.go            | 4 +---
 crypto/crypto.go                    | 4 +---
 crypto/secp256k1/scalar_mult_cgo.go | 8 ++------
 ctxc/peer.go                        | 8 --------
 metrics/sample_test.go              | 7 -------
 p2p/discover/common.go              | 7 -------
 p2p/discover/v5wire/crypto.go       | 4 +---
 rlp/decode.go                       | 4 +---
 9 files changed, 7 insertions(+), 43 deletions(-)

diff --git a/accounts/keystore/keystore.go b/accounts/keystore/keystore.go
index 20c74d1285..8bd6cdb9e3 100644
--- a/accounts/keystore/keystore.go
+++ b/accounts/keystore/keystore.go
@@ -495,7 +495,5 @@ func (ks *KeyStore) ImportPreSaleKey(keyJSON []byte, passphrase string) (account
 // zeroKey zeroes a private key in memory.
 func zeroKey(k *ecdsa.PrivateKey) {
 	b := k.D.Bits()
-	for i := range b {
-		b[i] = 0
-	}
+	clear(b)
 }
diff --git a/core/vm/analysis_test.go b/core/vm/analysis_test.go
index 6c112115dc..ed04619082 100644
--- a/core/vm/analysis_test.go
+++ b/core/vm/analysis_test.go
@@ -93,9 +93,7 @@ func BenchmarkJumpdestOpAnalysis(bench *testing.B) {
 		bits := make(bitvec, len(code)/8+1+4)
 		b.ResetTimer()
 		for i := 0; i < b.N; i++ {
-			for j := range bits {
-				bits[j] = 0
-			}
+			clear(bits)
 			codeBitmapInternal(code, bits)
 		}
 	}
diff --git a/crypto/crypto.go b/crypto/crypto.go
index 9110592179..c3c1501e91 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -288,7 +288,5 @@ func PubkeyToAddress(p ecdsa.PublicKey) common.Address {
 }
 
 func zeroBytes(bytes []byte) {
-	for i := range bytes {
-		bytes[i] = 0
-	}
+	clear(bytes)
 }
diff --git a/crypto/secp256k1/scalar_mult_cgo.go b/crypto/secp256k1/scalar_mult_cgo.go
index 8afa9d023b..bdf8eeede7 100644
--- a/crypto/secp256k1/scalar_mult_cgo.go
+++ b/crypto/secp256k1/scalar_mult_cgo.go
@@ -44,12 +44,8 @@ func (BitCurve *BitCurve) ScalarMult(Bx, By *big.Int, scalar []byte) (*big.Int,
 	// Unpack the result and clear temporaries.
 	x := new(big.Int).SetBytes(point[:32])
 	y := new(big.Int).SetBytes(point[32:])
-	for i := range point {
-		point[i] = 0
-	}
-	for i := range padded {
-		scalar[i] = 0
-	}
+	clear(point)
+	clear(scalar)
 	if res != 1 {
 		return nil, nil
 	}
diff --git a/ctxc/peer.go b/ctxc/peer.go
index 1660c0d326..d3fac1f5b6 100644
--- a/ctxc/peer.go
+++ b/ctxc/peer.go
@@ -60,14 +60,6 @@ const (
 	maxQueuedBlockAnns = 4
 )
 
-// max is a helper function which returns the larger of the two given integers.
-func max(a, b int) int {
-	if a > b {
-		return a
-	}
-	return b
-}
-
 // PeerInfo represents a short summary of the Cortex sub-protocol metadata known
 // about a connected peer.
 type PeerInfo struct {
diff --git a/metrics/sample_test.go b/metrics/sample_test.go
index 7967357055..9835ec1c30 100644
--- a/metrics/sample_test.go
+++ b/metrics/sample_test.go
@@ -87,13 +87,6 @@ func BenchmarkUniformSample1028(b *testing.B) {
 	benchmarkSample(b, NewUniformSample(1028))
 }
 
-func min(a, b int) int {
-	if a < b {
-		return a
-	}
-	return b
-}
-
 func TestExpDecaySample(t *testing.T) {
 	for _, tc := range []struct {
 		reservoirSize int
diff --git a/p2p/discover/common.go b/p2p/discover/common.go
index abf9a2cf7f..1b4661d9f9 100644
--- a/p2p/discover/common.go
+++ b/p2p/discover/common.go
@@ -92,10 +92,3 @@ type ReadPacket struct {
 	Data []byte
 	Addr *net.UDPAddr
 }
-
-func min(x, y int) int {
-	if x > y {
-		return y
-	}
-	return x
-}
diff --git a/p2p/discover/v5wire/crypto.go b/p2p/discover/v5wire/crypto.go
index bb9a06ea96..55d164cda3 100644
--- a/p2p/discover/v5wire/crypto.go
+++ b/p2p/discover/v5wire/crypto.go
@@ -129,9 +129,7 @@ func deriveKeys(hash hashFn, priv *ecdsa.PrivateKey, pub *ecdsa.PublicKey, n1, n
 	sec := session{writeKey: make([]byte, aesKeySize), readKey: make([]byte, aesKeySize)}
 	kdf.Read(sec.writeKey)
 	kdf.Read(sec.readKey)
-	for i := range eph {
-		eph[i] = 0
-	}
+	clear(eph)
 	return &sec
 }
 
diff --git a/rlp/decode.go b/rlp/decode.go
index 1b1640c4f4..57d4c221bd 100644
--- a/rlp/decode.go
+++ b/rlp/decode.go
@@ -1105,9 +1105,7 @@ func (s *Stream) readUint(size byte) (uint64, error) {
 		return uint64(b), err
 	default:
 		buffer := s.uintbuf[:8]
-		for i := range buffer {
-			buffer[i] = 0
-		}
+		clear(buffer)
 		start := int(8 - size)
 		if err := s.readFull(buffer[start:]); err != nil {
 			return 0, err