Merge pull request #9 from jshiv/fix/change_reverse

Removed copy from reverse function

Author: naveenv92

payload.go

@@ -251,10 +251,9 @@ func (p *Payload) PackLittleEndian() *big.Int {
 
 // Reverse byte array for little endian signals.
 func reverse(data []byte) []byte {
-	reversedArray := make([]byte, len(data))
-	copy(reversedArray, data)
-	for i, j := 0, len(reversedArray)-1; i < j; i, j = i+1, j-1 {
-		reversedArray[i], reversedArray[j] = reversedArray[j], reversedArray[i]
+	reversedArray := make([]byte, 0, len(data))
+	for i := len(data) - 1; i >= 0; i-- {
+		reversedArray = append(reversedArray, data[i])
 	}
 	return reversedArray
 }

payload_test.go

@@ -2,6 +2,7 @@ package can
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 )
 
@@ -66,6 +67,24 @@ func TestSignedBigEndian(t *testing.T) {
 	fmt.Println(payload.SignedBitsBigEndian(signal.start, signal.length))
 }
 
+func TestReverse(t *testing.T) {
+	payloadHexes := []string{
+		"17399b6c89d22805003f", // Even Length
+		"17399b6c89d22805003f17399b6c89d22805003f17399b6c89d22805003f", // Long Even
+		"17399b6c89d2280500", // Odd Length
+		"17399b6c89d228050017399b6c89d228050017399b6c89d2280500", // Long Odd
+	}
+
+	for _, hex := range payloadHexes {
+		p, _ := PayloadFromHex(hex)
+
+		twiceReversed := reverse(reverse(p.Data))
+		if !reflect.DeepEqual(p.Data, twiceReversed) {
+			t.Errorf("Reversed slices are not equal, input: %v, output: %v", p.Data, twiceReversed)
+		}
+	}
+}
+
 func Benchmark4BytesPayload_PackLittleEndian(b *testing.B) {
 	data := []byte{0x40, 0x23, 0x01, 0x12}
 	payload := Payload{Data: data}