From a3b822d7f2e49343a62705c0b3247dc0febd54ee Mon Sep 17 00:00:00 2001
From: cuiweixie <cuiweixie@gmail.com>
Date: Tue, 12 Aug 2025 10:32:19 +0800
Subject: [PATCH] internal/era: refactor to use slices.Reverse

---
 internal/era/accumulator.go | 11 ++---------
 internal/era/era.go         |  4 +++-
 internal/era/era_test.go    |  4 +++-
 internal/era/iterator.go    |  4 +++-
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/internal/era/accumulator.go b/internal/era/accumulator.go
index 83a761f1fd..fc6a3774a9 100644
--- a/internal/era/accumulator.go
+++ b/internal/era/accumulator.go
@@ -20,6 +20,7 @@ import (
 	"errors"
 	"fmt"
 	"math/big"
+	"slices"
 
 	"github.com/ethereum/go-ethereum/common"
 	ssz "github.com/ferranbt/fastssz"
@@ -78,14 +79,6 @@ func (h *headerRecord) HashTreeRootWith(hh ssz.HashWalker) (err error) {
 // bigToBytes32 converts a big.Int into a little-endian 32-byte array.
 func bigToBytes32(n *big.Int) (b [32]byte) {
 	n.FillBytes(b[:])
-	reverseOrder(b[:])
+	slices.Reverse(b[:])
 	return
 }
-
-// reverseOrder reverses the byte order of a slice.
-func reverseOrder(b []byte) []byte {
-	for i := 0; i < 16; i++ {
-		b[i], b[32-i-1] = b[32-i-1], b[i]
-	}
-	return b
-}
diff --git a/internal/era/era.go b/internal/era/era.go
index 118c67abfd..7d10c7cf99 100644
--- a/internal/era/era.go
+++ b/internal/era/era.go
@@ -23,6 +23,7 @@ import (
 	"math/big"
 	"os"
 	"path"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -244,7 +245,8 @@ func (e *Era) InitialTD() (*big.Int, error) {
 	if err != nil {
 		return nil, err
 	}
-	td := new(big.Int).SetBytes(reverseOrder(rawTd))
+	slices.Reverse(rawTd)
+	td := new(big.Int).SetBytes(rawTd)
 	return td.Sub(td, header.Difficulty), nil
 }
 
diff --git a/internal/era/era_test.go b/internal/era/era_test.go
index 31fa0076a6..8587f03e9c 100644
--- a/internal/era/era_test.go
+++ b/internal/era/era_test.go
@@ -22,6 +22,7 @@ import (
 	"io"
 	"math/big"
 	"os"
+	"slices"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -136,7 +137,8 @@ func TestEra1Builder(t *testing.T) {
 		if err != nil {
 			t.Fatalf("error reading td: %v", err)
 		}
-		td := new(big.Int).SetBytes(reverseOrder(rawTd))
+		slices.Reverse(rawTd)
+		td := new(big.Int).SetBytes(rawTd)
 		if td.Cmp(chain.tds[i]) != 0 {
 			t.Fatalf("mismatched tds: want %s, got %s", chain.tds[i], td)
 		}
diff --git a/internal/era/iterator.go b/internal/era/iterator.go
index 3c4f82d850..4ea93b17d9 100644
--- a/internal/era/iterator.go
+++ b/internal/era/iterator.go
@@ -20,6 +20,7 @@ import (
 	"errors"
 	"io"
 	"math/big"
+	"slices"
 
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -107,7 +108,8 @@ func (it *Iterator) TotalDifficulty() (*big.Int, error) {
 	if err != nil {
 		return nil, err
 	}
-	return new(big.Int).SetBytes(reverseOrder(td)), nil
+	slices.Reverse(td)
+	return new(big.Int).SetBytes(td), nil
 }
 
 // RawIterator reads an RLP-encode Era1 entries.