neo-go/pkg/util/uint256.go
Evgeniy Stratonikov 8c31831626 util: reduce allocations in util.Uint256DecodeStringLE
It is used a lot in clients (including our benchmark).
`Uint160` is already optimized.

```
name                     old time/op    new time/op    delta
Uint256DecodeStringLE-8     150ns ±15%     112ns ± 3%  -25.23%  (p=0.000 n=10+10)

name                     old alloc/op   new alloc/op   delta
Uint256DecodeStringLE-8     96.0B ± 0%     64.0B ± 0%  -33.33%  (p=0.000 n=10+10)

name                     old allocs/op  new allocs/op  delta
Uint256DecodeStringLE-8      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
```

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>
2021-08-17 16:53:39 +03:00

129 lines
3.4 KiB
Go

package util
import (
"bytes"
"encoding/hex"
"encoding/json"
"fmt"
"strings"
"github.com/nspcc-dev/neo-go/pkg/io"
"github.com/nspcc-dev/neo-go/pkg/util/slice"
)
// Uint256Size is the size of Uint256 in bytes.
const Uint256Size = 32
// Uint256 is a 32 byte long unsigned integer.
type Uint256 [Uint256Size]uint8
// Uint256DecodeStringLE attempts to decode the given string (in LE representation) into an Uint256.
func Uint256DecodeStringLE(s string) (u Uint256, err error) {
if len(s) != Uint256Size*2 {
return u, fmt.Errorf("expected string size of %d got %d", Uint256Size*2, len(s))
}
b, err := hex.DecodeString(s)
if err != nil {
return u, err
}
slice.Reverse(b)
return Uint256DecodeBytesBE(b)
}
// Uint256DecodeStringBE attempts to decode the given string (in BE representation)
// into an Uint256.
func Uint256DecodeStringBE(s string) (u Uint256, err error) {
if len(s) != Uint256Size*2 {
return u, fmt.Errorf("expected string size of %d got %d", Uint256Size*2, len(s))
}
b, err := hex.DecodeString(s)
if err != nil {
return u, err
}
return Uint256DecodeBytesBE(b)
}
// Uint256DecodeBytesBE attempts to decode the given string (in BE representation) into an Uint256.
func Uint256DecodeBytesBE(b []byte) (u Uint256, err error) {
if len(b) != Uint256Size {
return u, fmt.Errorf("expected []byte of size %d got %d", Uint256Size, len(b))
}
copy(u[:], b)
return u, nil
}
// Uint256DecodeBytesLE attempts to decode the given string (in LE representation) into an Uint256.
func Uint256DecodeBytesLE(b []byte) (u Uint256, err error) {
b = slice.CopyReverse(b)
return Uint256DecodeBytesBE(b)
}
// BytesBE returns a byte slice representation of u.
func (u Uint256) BytesBE() []byte {
return u[:]
}
// Reverse reverses the Uint256 object.
func (u Uint256) Reverse() Uint256 {
res, _ := Uint256DecodeBytesLE(u.BytesBE())
return res
}
// BytesLE return a little-endian byte representation of u.
func (u Uint256) BytesLE() []byte {
return slice.CopyReverse(u.BytesBE())
}
// Equals returns true if both Uint256 values are the same.
func (u Uint256) Equals(other Uint256) bool {
return u == other
}
// String implements the stringer interface.
func (u Uint256) String() string {
return u.StringBE()
}
// StringBE produces string representation of Uint256 with BE byte order.
func (u Uint256) StringBE() string {
return hex.EncodeToString(u.BytesBE())
}
// StringLE produces string representation of Uint256 with LE byte order.
func (u Uint256) StringLE() string {
return hex.EncodeToString(u.BytesLE())
}
// UnmarshalJSON implements the json unmarshaller interface.
func (u *Uint256) UnmarshalJSON(data []byte) (err error) {
var js string
if err = json.Unmarshal(data, &js); err != nil {
return err
}
js = strings.TrimPrefix(js, "0x")
*u, err = Uint256DecodeStringLE(js)
return err
}
// MarshalJSON implements the json marshaller interface.
func (u Uint256) MarshalJSON() ([]byte, error) {
return []byte(`"0x` + u.StringLE() + `"`), nil
}
// CompareTo compares two Uint256 with each other. Possible output: 1, -1, 0
// 1 implies u > other.
// -1 implies u < other.
// 0 implies u = other.
func (u Uint256) CompareTo(other Uint256) int { return bytes.Compare(u[:], other[:]) }
// EncodeBinary implements io.Serializable interface.
func (u *Uint256) EncodeBinary(w *io.BinWriter) {
w.WriteBytes(u[:])
}
// DecodeBinary implements io.Serializable interface.
func (u *Uint256) DecodeBinary(r *io.BinReader) {
r.ReadBytes(u[:])
}