minor chore

NethermindEth · Jan 17, 2025 · 70bef42 · 70bef42
1 parent 3929edc
commit 70bef42
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Showing 2 changed files with 24 additions and 13 deletions.
diff --git a/core/trie/bitarray.go b/core/trie/bitarray.go
@@ -532,7 +532,7 @@ func (b *BitArray) setFelt(f *felt.Felt) {
 }
 
 func (b *BitArray) setBytes32(data []byte) {
-	_ = data[31]
+	_ = data[31] // bound check hint, see https://golang.org/issue/14808
 	b.words[3] = binary.BigEndian.Uint64(data[0:8])
 	b.words[2] = binary.BigEndian.Uint64(data[8:16])
 	b.words[1] = binary.BigEndian.Uint64(data[16:24])
@@ -543,7 +543,6 @@ func (b *BitArray) setBytes32(data []byte) {
 // It rounds up to the nearest byte.
 func (b *BitArray) byteCount() uint {
 	const bits8 = 8
-	// Cast to uint16 to avoid overflow
 	return (uint(b.len) + (bits8 - 1)) / uint(bits8)
 }
 
@@ -590,6 +589,20 @@ func (b *BitArray) clear() *BitArray {
 
 // Truncates the bit array to the specified length, ensuring that any unused bits are all zeros.
 //
+// Example:
+//
+//	b := &BitArray{
+//	    len: 5,
+//	    words: [4]uint64{
+//	        0xFFFFFFFFFFFFFFFF,  // Before: all bits are 1
+//	        0x0, 0x0, 0x0,
+//	    },
+//	}
+//	b.truncateToLength()
+//	// After: only first 5 bits remain
+//	// words[0] = 0x000000000000001F
+//	// words[1..3] = 0x0
+//
 //nolint:mnd
 func (b *BitArray) truncateToLength() {
 	switch {

diff --git a/core/trie/bitarray_test.go b/core/trie/bitarray_test.go
@@ -3,7 +3,6 @@ package trie
 import (
 	"bytes"
 	"encoding/binary"
-	"math"
 	"math/bits"
 	"testing"
 
@@ -12,8 +11,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-var maxBits = [4]uint64{math.MaxUint64, math.MaxUint64, math.MaxUint64, math.MaxUint64}
-
 const (
 	ones63 = 0x7FFFFFFFFFFFFFFF // 63 bits of 1
 )
@@ -26,12 +23,12 @@ func TestBytes(t *testing.T) {
 	}{
 		{
 			name: "length == 0",
-			ba:   BitArray{len: 0, words: maxBits},
+			ba:   BitArray{len: 0, words: [4]uint64{0, 0, 0, 0}},
 			want: [32]byte{},
 		},
 		{
 			name: "length < 64",
-			ba:   BitArray{len: 38, words: maxBits},
+			ba:   BitArray{len: 38, words: [4]uint64{0x3FFFFFFFFF, 0, 0, 0}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[24:32], 0x3FFFFFFFFF)
@@ -40,7 +37,7 @@ func TestBytes(t *testing.T) {
 		},
 		{
 			name: "64 <= length < 128",
-			ba:   BitArray{len: 100, words: maxBits},
+			ba:   BitArray{len: 100, words: [4]uint64{maxUint64, 0xFFFFFFFFF, 0, 0}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[16:24], 0xFFFFFFFFF)
@@ -50,7 +47,7 @@ func TestBytes(t *testing.T) {
 		},
 		{
 			name: "128 <= length < 192",
-			ba:   BitArray{len: 130, words: maxBits},
+			ba:   BitArray{len: 130, words: [4]uint64{maxUint64, maxUint64, 0x3, 0}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[8:16], 0x3)
@@ -61,7 +58,7 @@ func TestBytes(t *testing.T) {
 		},
 		{
 			name: "192 <= length < 255",
-			ba:   BitArray{len: 201, words: maxBits},
+			ba:   BitArray{len: 201, words: [4]uint64{maxUint64, maxUint64, maxUint64, 0x1FF}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[0:8], 0x1FF)
@@ -73,7 +70,7 @@ func TestBytes(t *testing.T) {
 		},
 		{
 			name: "length == 254",
-			ba:   BitArray{len: 254, words: maxBits},
+			ba:   BitArray{len: 254, words: [4]uint64{maxUint64, maxUint64, maxUint64, 0x3FFFFFFFFFFFFFFF}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[0:8], 0x3FFFFFFFFFFFFFFF)
@@ -85,7 +82,7 @@ func TestBytes(t *testing.T) {
 		},
 		{
 			name: "length == 255",
-			ba:   BitArray{len: 255, words: maxBits},
+			ba:   BitArray{len: 255, words: [4]uint64{maxUint64, maxUint64, maxUint64, ones63}},
 			want: func() [32]byte {
 				var b [32]byte
 				binary.BigEndian.PutUint64(b[0:8], ones63)
@@ -1118,7 +1115,8 @@ func TestWriteAndUnmarshalBinary(t *testing.T) {
 			}
 
 			var gotBitArray BitArray
-			gotBitArray.UnmarshalBinary(got)
+			err = gotBitArray.UnmarshalBinary(got)
+			require.NoError(t, err)
 			if !gotBitArray.Equal(&tt.ba) {
 				t.Errorf("UnmarshalBinary() = %v, want %v", gotBitArray, tt.ba)
 			}