prysm-pulse/shared/bytesutil/bytes.go

91 lines
2.3 KiB
Go

// Package bytesutil defines helper methods for converting integers to byte slices.
package bytesutil
import (
"encoding/binary"
)
// Bytes1 returns integer x to bytes in big-endian format, x.to_bytes(1, 'big').
func Bytes1(x uint64) []byte {
bytes := make([]byte, 8)
binary.BigEndian.PutUint64(bytes, x)
return bytes[7:]
}
// Bytes2 returns integer x to bytes in big-endian format, x.to_bytes(2, 'big').
func Bytes2(x uint64) []byte {
bytes := make([]byte, 8)
binary.BigEndian.PutUint64(bytes, x)
return bytes[6:]
}
// Bytes3 returns integer x to bytes in big-endian format, x.to_bytes(3, 'big').
func Bytes3(x uint64) []byte {
bytes := make([]byte, 8)
binary.BigEndian.PutUint64(bytes, x)
return bytes[5:]
}
// Bytes4 returns integer x to bytes in big-endian format, x.to_bytes(4, 'big').
func Bytes4(x uint64) []byte {
bytes := make([]byte, 8)
binary.BigEndian.PutUint64(bytes, x)
return bytes[4:]
}
// Bytes8 returns integer x to bytes in big-endian format, x.to_bytes(8, 'big').
func Bytes8(x uint64) []byte {
bytes := make([]byte, 8)
binary.BigEndian.PutUint64(bytes, x)
return bytes
}
// FromBytes8 returns an integer which is stored in the big-endian format(8, 'big')
// from a byte array.
func FromBytes8(x []byte) uint64 {
return binary.BigEndian.Uint64(x)
}
// LowerThan returns true if byte slice x is lower than byte slice y. (big endian format)
// This is used in spec to compare winning block root hash.
// Mentioned in spec as "ties broken by favoring lower `shard_block_root` values".
func LowerThan(x []byte, y []byte) bool {
for i, b := range x {
if b > y[i] {
return false
}
}
return true
}
// ToBytes32 is a convenience method for converting a byte slice to a fix
// sized 32 byte array. This method will truncate the input if it is larger
// than 32 bytes.
func ToBytes32(x []byte) [32]byte {
var y [32]byte
copy(y[:], x)
return y
}
// ToBytes48 is a convenience method for converting a byte slice to a fix
// sized 48 byte array. This method will truncate the input if it is larger
// than 48 bytes.
func ToBytes48(x []byte) [48]byte {
var y [48]byte
copy(y[:], x)
return y
}
// Xor xors the bytes in x and y and returns the result.
func Xor(x []byte, y []byte) []byte {
n := len(x)
if len(y) < n {
n = len(y)
}
var result []byte
for i := 0; i < n; i++ {
result = append(result, x[i]^y[i])
}
return result
}