Save alloc

accounts/abi/argument.go

@@ -182,10 +182,20 @@ func (arguments Arguments) copyTuple(v interface{}, marshalledValues []interface
 // without supplying a struct to unpack into. Instead, this method returns a list containing the
 // values. An atomic argument will be a list with one element.
 func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) {
-	nonIndexedArgs := arguments.NonIndexed()
-	retval := make([]interface{}, 0, len(nonIndexedArgs))
+	size := 0
+	for _, arg := range arguments {
+		if arg.Indexed {
+			continue
+		}
+		size++
+	}
+
+	retval := make([]interface{}, 0, size)
 	virtualArgs := 0
-	for index, arg := range nonIndexedArgs {
+	for index, arg := range arguments {
+		if arg.Indexed {
+			continue
+		}
 		marshalledValue, err := toGoType((index+virtualArgs)*32, arg.Type, data)
 		if err != nil {
 			return nil, err

accounts/abi/unpack_test.go

@@ -31,6 +31,46 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+func BenchmarkUnpack(b *testing.B) {
+	testCases := []struct {
+		def    string
+		packed string
+	}{
+		{
+			def:    `[{"type": "uint32"}]`,
+			packed: "0000000000000000000000000000000000000000000000000000000000000001",
+		},
+		{
+			def: `[{"type": "uint32[]"}]`,
+			packed: "0000000000000000000000000000000000000000000000000000000000000020" +
+				"0000000000000000000000000000000000000000000000000000000000000002" +
+				"0000000000000000000000000000000000000000000000000000000000000001" +
+				"0000000000000000000000000000000000000000000000000000000000000002",
+		},
+	}
+	for i, test := range testCases {
+		b.Run(strconv.Itoa(i), func(b *testing.B) {
+			def := fmt.Sprintf(`[{ "name" : "method", "type": "function", "outputs": %s}]`, test.def)
+			abi, err := JSON(strings.NewReader(def))
+			if err != nil {
+				b.Fatalf("invalid ABI definition %s: %v", def, err)
+			}
+			encb, err := hex.DecodeString(test.packed)
+			if err != nil {
+				b.Fatalf("invalid hex %s: %v", test.packed, err)
+			}
+
+			b.ResetTimer()
+
+			var result any
+			for range b.N {
+				result, _ = abi.Unpack("method", encb)
+			}
+			_ = result
+		})
+	}
+}
+
 // TestUnpack tests the general pack/unpack tests in packing_test.go
 func TestUnpack(t *testing.T) {
 	t.Parallel()