neo-go/pkg/vm/state.go
2020-07-29 10:14:08 +03:00

84 lines
1.7 KiB
Go

package vm
import (
"strings"
"github.com/pkg/errors"
)
// State of the VM.
type State uint8
// Available States.
const (
// NoneState represents NONE VM state.
NoneState State = 0
// HaltState represents HALT VM state.
HaltState State = 1 << iota
// FaultState represents FAULT VM state.
FaultState
// BreakState represents BREAK VM state.
BreakState
)
// HasFlag checks for State flag presence.
func (s State) HasFlag(f State) bool {
return s&f != 0
}
// String implements the stringer interface.
func (s State) String() string {
if s == NoneState {
return "NONE"
}
ss := make([]string, 0, 3)
if s.HasFlag(HaltState) {
ss = append(ss, "HALT")
}
if s.HasFlag(FaultState) {
ss = append(ss, "FAULT")
}
if s.HasFlag(BreakState) {
ss = append(ss, "BREAK")
}
return strings.Join(ss, ", ")
}
// StateFromString converts string into the VM State.
func StateFromString(s string) (st State, err error) {
if s = strings.TrimSpace(s); s == "NONE" {
return NoneState, nil
}
ss := strings.Split(s, ",")
for _, state := range ss {
switch state = strings.TrimSpace(state); state {
case "HALT":
st |= HaltState
case "FAULT":
st |= FaultState
case "BREAK":
st |= BreakState
default:
return 0, errors.New("unknown state")
}
}
return
}
// MarshalJSON implements the json.Marshaler interface.
func (s State) MarshalJSON() (data []byte, err error) {
return []byte(`"` + s.String() + `"`), nil
}
// UnmarshalJSON implements the json.Marshaler interface.
func (s *State) UnmarshalJSON(data []byte) (err error) {
l := len(data)
if l < 2 || data[0] != '"' || data[l-1] != '"' {
return errors.New("wrong format")
}
*s, err = StateFromString(string(data[1 : l-1]))
return
}