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