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ordered_map.go
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ordered_map.go
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package ds
import "sync"
// OrderedMap is a map with a deterministic iteration order
// this datastructure is thread-safe
type OrderedMap[T comparable, V any] struct {
len int
keys map[T]int
values []V
mtx sync.RWMutex
}
// NewOrderedMap returns a new OrderedMap
func NewOrderedMap[T comparable, V any]() *OrderedMap[T, V] {
return &OrderedMap[T, V]{
keys: make(map[T]int),
}
}
// Put adds a key-value pair to the map
func (m *OrderedMap[T, V]) Put(key T, val V) {
m.mtx.Lock()
defer m.mtx.Unlock()
i, ok := m.keys[key]
if ok {
m.values[i] = val
return
}
m.keys[key] = m.len
if len(m.values) == m.len {
m.values = append(m.values, val)
} else {
m.values[m.len] = val
}
m.len++
}
// Get returns the value for a given key
func (m *OrderedMap[T, V]) Get(key T) (V, bool) {
m.mtx.RLock()
defer m.mtx.RUnlock()
i, ok := m.keys[key]
if !ok {
var v V
return v, false
}
return m.values[i], true
}
// Has returns true if the map contains the given key
func (m *OrderedMap[T, V]) Has(key T) bool {
m.mtx.RLock()
defer m.mtx.RUnlock()
_, ok := m.keys[key]
return ok
}
// Delete removes a key-value pair from the map
func (m *OrderedMap[T, V]) Delete(key T) {
m.mtx.Lock()
defer m.mtx.Unlock()
i, ok := m.keys[key]
if !ok {
return
}
delete(m.keys, key)
m.values = append(m.values[:i], m.values[i+1:]...)
m.len--
for k, v := range m.keys {
if v > i {
m.keys[k] = v - 1
}
}
}
// Values returns all values in the map
func (m *OrderedMap[T, V]) Values() []V {
m.mtx.RLock()
defer m.mtx.RUnlock()
return append([]V{}, m.values[0:m.len]...)
}
// Keys returns all keys in the map
func (m *OrderedMap[T, V]) Keys() []T {
m.mtx.RLock()
defer m.mtx.RUnlock()
keys := make([]T, len(m.keys))
for k, v := range m.keys {
keys[v] = k
}
return keys
}
// Len returns a number of the map
func (m *OrderedMap[T, V]) Len() int {
m.mtx.RLock()
defer m.mtx.RUnlock()
return m.len
}