github.com/ledgerwatch/erigon-lib@v1.0.0/common/hexutility/bytes.go (about)

     1  /*
     2     Copyright 2023 The Erigon contributors
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package hexutility
    18  
    19  import (
    20  	"encoding/hex"
    21  	"encoding/json"
    22  	"reflect"
    23  )
    24  
    25  var bytesT = reflect.TypeOf(Bytes(nil))
    26  
    27  // Bytes marshals/unmarshals as a JSON string with 0x prefix.
    28  // The empty slice marshals as "0x".
    29  type Bytes []byte
    30  
    31  const hexPrefix = `0x`
    32  
    33  // MarshalText implements encoding.TextMarshaler
    34  func (b Bytes) MarshalText() ([]byte, error) {
    35  	result := make([]byte, len(b)*2+2)
    36  	copy(result, hexPrefix)
    37  	hex.Encode(result[2:], b)
    38  	return result, nil
    39  }
    40  
    41  // UnmarshalJSON implements json.Unmarshaler.
    42  func (b *Bytes) UnmarshalJSON(input []byte) error {
    43  	if !isString(input) {
    44  		return &json.UnmarshalTypeError{Value: "non-string", Type: bytesT}
    45  	}
    46  	return wrapTypeError(b.UnmarshalText(input[1:len(input)-1]), bytesT)
    47  }
    48  
    49  // UnmarshalText implements encoding.TextUnmarshaler.
    50  func (b *Bytes) UnmarshalText(input []byte) error {
    51  	raw, err := checkText(input, true)
    52  	if err != nil {
    53  		return err
    54  	}
    55  	dec := make([]byte, len(raw)/2)
    56  	_, err = hex.Decode(dec, raw)
    57  	if err == nil {
    58  		*b = dec
    59  	}
    60  	return err
    61  }
    62  
    63  // String returns the hex encoding of b.
    64  func (b Bytes) String() string {
    65  	return Encode(b)
    66  }