neoneo-go/_pkg.dev/vm/stack/map.go

167 lines
3.4 KiB
Go
Raw Normal View History

package stack
import (
"errors"
"fmt"
"sort"
"github.com/CityOfZion/neo-go/pkg/crypto/hash"
)
// Map represents a map of key, value pair on the stack.
// Both key and value are stack Items.
type Map struct {
*abstractItem
val map[Item]Item
}
// NewMap returns a Map stack Item given
// a map whose keys and values are stack Items.
func NewMap(val map[Item]Item) (*Map, error) {
return &Map{
abstractItem: &abstractItem{},
val: val,
}, nil
}
// Map will overwrite the default implementation
// to allow go to cast this item as an Map.
func (m *Map) Map() (*Map, error) {
return m, nil
}
// Boolean overrides the default Boolean method
// to convert an Map into a Boolean StackItem
func (m *Map) Boolean() (*Boolean, error) {
return NewBoolean(true), nil
}
// ContainsKey returns a boolean whose value is true
// iff the underlying map value contains the Item i
// as a key.
func (m *Map) ContainsKey(key Item) (*Boolean, error) {
for k := range m.Value() {
if ok, err := CompareHash(k, key); err != nil {
return nil, err
} else if ok.Value() {
return ok, nil
}
}
return NewBoolean(false), nil
}
// Value returns the underlying map's value
func (m *Map) Value() map[Item]Item {
return m.val
}
// Remove removes the Item i from the
// underlying map's value.
func (m *Map) Remove(key Item) error {
var d Item
for k := range m.Value() {
if ok, err := CompareHash(k, key); err != nil {
return err
} else if ok.Value() {
d = k
}
}
if d != nil {
delete(m.Value(), d)
}
return nil
}
// Add inserts a new key, value pair of Items into
// the underlying map's value.
func (m *Map) Add(key Item, value Item) error {
for k := range m.Value() {
if ok, err := CompareHash(k, key); err != nil {
return err
} else if ok.Value() {
return errors.New("try to insert duplicate key! ")
}
}
m.Value()[key] = value
return nil
}
// ValueOfKey tries to get the value of the key Item
// from the map's underlying value.
func (m *Map) ValueOfKey(key Item) (Item, error) {
for k, v := range m.Value() {
if ok, err := CompareHash(k, key); err != nil {
return nil, err
} else if ok.Value() {
return v, nil
}
}
return nil, nil
}
// Clear empties the the underlying map's value.
func (m *Map) Clear() {
m.val = map[Item]Item{}
}
// CompareHash compare the the Hashes of two items.
// If they are equal it returns a true boolean. Otherwise
// it returns false boolean. Item whose hashes are equal are
// to be considered equal.
func CompareHash(i1 Item, i2 Item) (*Boolean, error) {
hash1, err := i1.Hash()
if err != nil {
return nil, err
}
hash2, err := i2.Hash()
if err != nil {
return nil, err
}
if hash1 == hash2 {
return NewBoolean(true), nil
}
return NewBoolean(false), nil
}
// Hash overrides the default abstract hash method.
func (m *Map) Hash() (string, error) {
var hashSlice sort.StringSlice = []string{}
var data = fmt.Sprintf("%T ", m)
for k, v := range m.Value() {
hk, err := k.Hash()
if err != nil {
return "", err
}
hv, err := v.Hash()
if err != nil {
return "", err
}
hashSlice = append(hashSlice, hk)
hashSlice = append(hashSlice, hv)
}
hashSlice.Sort()
for _, h := range hashSlice {
data += h
}
return KeyGenerator([]byte(data))
}
// KeyGenerator hashes a byte slice to obtain a unique identifier.
func KeyGenerator(data []byte) (string, error) {
h, err := hash.Sha256([]byte(data))
if err != nil {
return "", err
}
return h.String(), nil
}