mirror of
https://gitlab.com/pulsechaincom/erigon-pulse.git
synced 2024-12-23 12:07:17 +00:00
231e468e19
git-subtree-dir: erigon-lib git-subtree-mainline:3c8cbda809git-subtree-split:93d9c9d9fe
80 lines
2.0 KiB
Go
80 lines
2.0 KiB
Go
/*
|
|
Copyright 2021 Erigon contributors
|
|
|
|
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 hexutility
|
|
|
|
import (
|
|
"encoding/hex"
|
|
"fmt"
|
|
)
|
|
|
|
const (
|
|
badNibble = ^uint64(0)
|
|
)
|
|
|
|
// UnmarshalFixedText decodes the input as a string with 0x prefix. The length of out
|
|
// determines the required input length. This function is commonly used to implement the
|
|
// UnmarshalText method for fixed-size types.
|
|
func UnmarshalFixedText(typeName string, input, out []byte) error {
|
|
raw, err := checkText(input, true)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if len(raw)/2 != len(out) {
|
|
return fmt.Errorf("hex string has length %d, want %d for %s", len(raw), len(out)*2, typeName)
|
|
}
|
|
// Pre-verify syntax before modifying out.
|
|
for _, b := range raw {
|
|
if decodeNibble(b) == badNibble {
|
|
return ErrSyntax
|
|
}
|
|
}
|
|
_, err = hex.Decode(out, raw)
|
|
return err
|
|
}
|
|
|
|
func checkText(input []byte, wantPrefix bool) ([]byte, error) {
|
|
if len(input) == 0 {
|
|
return nil, nil // empty strings are allowed
|
|
}
|
|
if bytesHave0xPrefix(input) {
|
|
input = input[2:]
|
|
} else if wantPrefix {
|
|
return nil, ErrMissingPrefix
|
|
}
|
|
if len(input)%2 != 0 {
|
|
return nil, ErrOddLength
|
|
}
|
|
return input, nil
|
|
}
|
|
|
|
func bytesHave0xPrefix(input []byte) bool {
|
|
return len(input) >= 2 && input[0] == '0' && (input[1] == 'x' || input[1] == 'X')
|
|
}
|
|
|
|
func decodeNibble(in byte) uint64 {
|
|
switch {
|
|
case in >= '0' && in <= '9':
|
|
return uint64(in - '0')
|
|
case in >= 'A' && in <= 'F':
|
|
return uint64(in - 'A' + 10)
|
|
case in >= 'a' && in <= 'f':
|
|
return uint64(in - 'a' + 10)
|
|
default:
|
|
return badNibble
|
|
}
|
|
}
|