json_example_test.go 1.4 KB

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  1. // Copyright 2017 The go-ethereum Authors
  2. // This file is part of the go-ethereum library.
  3. //
  4. // The go-ethereum library is free software: you can redistribute it and/or modify
  5. // it under the terms of the GNU Lesser General Public License as published by
  6. // the Free Software Foundation, either version 3 of the License, or
  7. // (at your option) any later version.
  8. //
  9. // The go-ethereum library is distributed in the hope that it will be useful,
  10. // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12. // GNU Lesser General Public License for more details.
  13. //
  14. // You should have received a copy of the GNU Lesser General Public License
  15. // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
  16. package hexutil_test
  17. import (
  18. "encoding/json"
  19. "fmt"
  20. "github.com/ethereum/go-ethereum/common/hexutil"
  21. )
  22. type MyType [5]byte
  23. func (v *MyType) UnmarshalText(input []byte) error {
  24. return hexutil.UnmarshalFixedText("MyType", input, v[:])
  25. }
  26. func (v MyType) String() string {
  27. return hexutil.Bytes(v[:]).String()
  28. }
  29. func ExampleUnmarshalFixedText() {
  30. var v1, v2 MyType
  31. fmt.Println("v1 error:", json.Unmarshal([]byte(`"0x01"`), &v1))
  32. fmt.Println("v2 error:", json.Unmarshal([]byte(`"0x0101010101"`), &v2))
  33. fmt.Println("v2:", v2)
  34. // Output:
  35. // v1 error: hex string has length 2, want 10 for MyType
  36. // v2 error: <nil>
  37. // v2: 0x0101010101
  38. }