added stack, added smapHEADmaster

1 files changed, 104 insertions, 0 deletions

diff --git a/container/smap.go b/container/smap.go
new file mode 100644
index 0000000..688ec40
--- /dev/null
+++ b/container/smap.go
@@ -0,0 +1,104 @@
+package container
+
+import (
+	"slices"
+	"sync"
+)
+
+// M is ordered and concurent safe map implementation.
+type M[K comparable, V any] struct {
+	m  map[K]V
+	k  []K
+	mu sync.RWMutex
+}
+
+// Make returns new instance with `capacity` initial capacity.
+func Make[K comparable, V any](capacity int) M[K, V] {
+	return M[K, V]{
+		m: make(map[K]V, capacity),
+		k: make([]K, 0, capacity),
+	}
+}
+
+// Get value `V` by key `k K`. Returns zero value if the key is absent.
+func (m *M[K, V]) Get(k K) V {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	return m.m[k]
+}
+
+// Get2 value `v V` by key `k K` and a presence flag `ok bool`. Returns
+// `(value, true)` if the key exists, and `(zero value, false)` if the key is
+// absent.
+func (m *M[K, V]) Get2(k K) (v V, ok bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	v, ok = m.m[k]
+
+	return v, ok
+}
+
+// Has returns true if key `k K` exists in map.
+func (m *M[K, V]) Has(k K) bool {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	_, ok := m.m[k]
+
+	return ok
+}
+
+// Set value `v V` to key `k K`.
+func (m *M[K, V]) Set(k K, v V) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, exists := m.m[k]; !exists {
+		m.k = append(m.k, k)
+	}
+
+	m.m[k] = v
+}
+
+// Delete key `k K` from map.
+func (m *M[K, V]) Delete(k K) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if _, ok := m.m[k]; !ok {
+		return
+	}
+
+	idx := slices.Index(m.k, k)
+	m.k = slices.Delete(m.k, idx, idx+1)
+
+	delete(m.m, k)
+}
+
+// Keys is iterator over keys.
+func (m *M[K, V]) Keys(yield func(K) bool) {
+	for _, k := range m.k {
+		if !yield(k) {
+			break
+		}
+	}
+}
+
+// Values is iterator over values.
+func (m *M[K, V]) Values(yield func(V) bool) {
+	for _, k := range m.k {
+		if !yield(m.m[k]) {
+			break
+		}
+	}
+}
+
+// Entries is iterator over key:value pairs.
+func (m *M[K, V]) Entries(yield func(K, V) bool) {
+	for _, k := range m.k {
+		if !yield(k, m.m[k]) {
+			break
+		}
+	}
+}