Add implementation for ordered map

utils/orderedmap.go

@@ -0,0 +1,82 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package utils
+
+// OrderedMap is a map that maintains the order of its key-value pairs.
+type OrderedMap[K comparable, V any] struct {
+	keys   []K     // keys holds the keys in order of their insertion.
+	values map[K]V // values is a map of key-value pairs.
+}
+
+// NewOrderedMap creates a new ordered map and returns a pointer to it.
+func NewOrderedMap[K comparable, V any]() *OrderedMap[K, V] {
+	return &OrderedMap[K, V]{
+		keys:   make([]K, 0),  // Initialize an empty slice for keys.
+		values: make(map[K]V), // Initialize an empty map for key-value pairs.
+	}
+}
+
+// Set adds a new key-value pair to the ordered map. If the key already exists, it updates the value.
+func (om *OrderedMap[K, V]) Set(key K, value V) {
+	// If the key does not exist in the map, append it to the keys slice.
+	if _, exists := om.values[key]; !exists {
+		om.keys = append(om.keys, key)
+	}
+	// Add or update the value for the key in the map.
+	om.values[key] = value
+}
+
+// Get retrieves the value associated with the given key from the ordered map.
+// It returns the value and a boolean indicating whether the key exists in the map.
+func (om *OrderedMap[K, V]) Get(key K) (V, bool) {
+	// Retrieve the value for the key from the map.
+	val, ok := om.values[key]
+	return val, ok
+}
+
+// Delete removes the key-value pair associated with the given key from the ordered map.
+func (om *OrderedMap[K, V]) Delete(key K) {
+	// Iterate over the keys slice to find the key to delete.
+	for i, k := range om.keys {
+		// When the key is found, remove it from the slice.
+		if k == key {
+			om.keys = append(om.keys[:i], om.keys[i+1:]...)
+			break
+		}
+	}
+	// Remove the key-value pair from the map.
+	delete(om.values, key)
+}
+
+// Keys returns all keys of the ordered map in order of their insertion.
+func (om *OrderedMap[K, V]) Keys() []K {
+	return om.keys
+}
+
+// Values returns all values of the ordered map in the order of their corresponding keys' insertion.
+func (om *OrderedMap[K, V]) Values() []V {
+	// Initialize an empty slice to hold the values.
+	vals := make([]V, 0, len(om.values))
+
+	// Iterate over the keys in order and append the corresponding value to the values slice.
+	for _, key := range om.keys {
+		vals = append(vals, om.values[key])
+	}
+	return vals
+}