utils.go

// Copyright 2020 dfuse Platform Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package bin

import (
	"math/big"
	"reflect"
)

func isZero(rv reflect.Value) (b bool) {
	return rv.Kind() == 0
}

func twosComplement(v []byte) []byte {
	buf := make([]byte, len(v))
	for i, b := range v {
		buf[i] = b ^ byte(0xff)
	}
	one := big.NewInt(1)
	value := (&big.Int{}).SetBytes(buf)
	return value.Add(value, one).Bytes()
}