// Copyright 2017 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see . package hexutil_test import ( "encoding/json" "fmt" "github.com/ethereum/go-ethereum/common/hexutil" ) type MyType [5]byte func (v *MyType) UnmarshalText(input []byte) error { return hexutil.UnmarshalFixedText("MyType", input, v[:]) } func (v MyType) String() string { return hexutil.Bytes(v[:]).String() } func ExampleUnmarshalFixedText() { var v1, v2 MyType fmt.Println("v1 error:", json.Unmarshal([]byte(`"0x01"`), &v1)) fmt.Println("v2 error:", json.Unmarshal([]byte(`"0x0101010101"`), &v2)) fmt.Println("v2:", v2) // Output: // v1 error: hex string has length 2, want 10 for MyType // v2 error: // v2: 0x0101010101 }