Export reverse byte order function (#10040)

* Reverse byte order

* Update BUILD.bazel

* Go imports

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

encoding/bytesutil/bytes.go

@@ -383,3 +383,14 @@ func IsHex(b []byte) bool {
 	}
 	return hexRegex.Match(b)
 }
+
+// ReverseByteOrder Switch the endianness of a byte slice by reversing its order.
+// this function does not modify the actual input bytes.
+func ReverseByteOrder(input []byte) []byte {
+	b := make([]byte, len(input))
+	copy(b, input)
+	for i := 0; i < len(b)/2; i++ {
+		b[i], b[len(b)-i-1] = b[len(b)-i-1], b[i]
+	}
+	return b
+}

encoding/bytesutil/bytes_test.go

@@ -1,6 +1,7 @@
 package bytesutil_test
 
 import (
+	"bytes"
 	"reflect"
 	"testing"
 
@@ -495,5 +496,14 @@ func TestBytesInvalidInputs(t *testing.T) {
 
 	intRes := bytesutil.ToLowInt64([]byte{})
 	assert.Equal(t, intRes, int64(0))
-
+}
+
+func TestReverseByteOrder(t *testing.T) {
+	input := []byte{0, 1, 2, 3, 4, 5}
+	expectedResult := []byte{5, 4, 3, 2, 1, 0}
+	output := bytesutil.ReverseByteOrder(input)
+
+	// check that the input is not modified and the output is reversed
+	assert.Equal(t, bytes.Equal(input, []byte{0, 1, 2, 3, 4, 5}), true)
+	assert.Equal(t, bytes.Equal(expectedResult, output), true)
 }