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bytes.go
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bytes.go
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// Package common contains various helper functions.
package common
import (
"encoding/hex"
"errors"
"github.com/entropyio/go-entropy/common/hexutil"
)
// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
if has0xPrefix(s) {
s = s[2:]
}
if len(s)%2 == 1 {
s = "0" + s
}
return Hex2Bytes(s)
}
// CopyBytes returns an exact copy of the provided bytes.
func CopyBytes(b []byte) (copiedBytes []byte) {
if b == nil {
return nil
}
copiedBytes = make([]byte, len(b))
copy(copiedBytes, b)
return
}
// has0xPrefix validates str begins with '0x' or '0X'.
func has0xPrefix(str string) bool {
return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}
// isHexCharacter returns bool of c being a valid hexadecimal.
func isHexCharacter(c byte) bool {
return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}
// isHex validates whether each byte is valid hexadecimal string.
func isHex(str string) bool {
if len(str)%2 != 0 {
return false
}
for _, c := range []byte(str) {
if !isHexCharacter(c) {
return false
}
}
return true
}
// Bytes2Hex returns the hexadecimal encoding of d.
func Bytes2Hex(d []byte) string {
return hex.EncodeToString(d)
}
// Hex2Bytes returns the bytes represented by the hexadecimal string str.
func Hex2Bytes(str string) []byte {
h, _ := hex.DecodeString(str)
return h
}
// Hex2BytesFixed returns bytes of a specified fixed length flen.
func Hex2BytesFixed(str string, flen int) []byte {
h, _ := hex.DecodeString(str)
if len(h) == flen {
return h
}
if len(h) > flen {
return h[len(h)-flen:]
}
hh := make([]byte, flen)
copy(hh[flen-len(h):flen], h)
return hh
}
// ParseHexOrString tries to hexdecode b, but if the prefix is missing, it instead just returns the raw bytes
func ParseHexOrString(str string) ([]byte, error) {
b, err := hexutil.Decode(str)
if errors.Is(err, hexutil.ErrMissingPrefix) {
return []byte(str), nil
}
return b, err
}
// RightPadBytes zero-pads slice to the right up to length l.
func RightPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded, slice)
return padded
}
// LeftPadBytes zero-pads slice to the left up to length l.
func LeftPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
}
padded := make([]byte, l)
copy(padded[l-len(slice):], slice)
return padded
}
// TrimLeftZeroes returns a subslice of s without leading zeroes
func TrimLeftZeroes(s []byte) []byte {
idx := 0
for ; idx < len(s); idx++ {
if s[idx] != 0 {
break
}
}
return s[idx:]
}
// TrimRightZeroes returns a subslice of s without trailing zeroes
func TrimRightZeroes(s []byte) []byte {
idx := len(s)
for ; idx > 0; idx-- {
if s[idx-1] != 0 {
break
}
}
return s[:idx]
}