refactor: optimize object and array handling by preallocating storage

Author: stirante

.gitignore

@@ -12,4 +12,5 @@ docs/
 *.jsonte
 /.idea
 /gen
-data.json
+data.json
+*.out

jsonte/json_processor.go

@@ -547,7 +547,7 @@ func (v *TemplateVisitor) visit(obj types.JsonType, path string) (types.JsonType
 }
 
 func (v *TemplateVisitor) visitObject(obj *types.JsonObject, path string) (types.JsonType, error) {
-	var result = types.NewJsonObject()
+	var result = types.NewJsonObjectWithCapacity(obj.Size())
 	for _, key := range obj.Keys() {
 		err := checkDeadline(v.deadline)
 		if err != nil {
@@ -687,7 +687,7 @@ func PutValue(result *types.JsonObject, key string, r types.JsonType, path strin
 }
 
 func (v *TemplateVisitor) visitArray(arr *types.JsonArray, path string) (types.JsonType, error) {
-	var result = make([]types.JsonType, 0)
+	var result = make([]types.JsonType, 0, len(arr.Value))
 	for i, value := range arr.Value {
 		err := checkDeadline(v.deadline)
 		if err != nil {
@@ -705,7 +705,7 @@ func (v *TemplateVisitor) visitArray(arr *types.JsonArray, path string) (types.J
 // Special visitor for cases when the array element is an object, that generates multiple values
 func (v *TemplateVisitor) visitArrayElement(array []types.JsonType, element types.JsonType, path string) ([]types.JsonType, error) {
 	if obj, ok := element.(*types.JsonObject); ok {
-		filteredKeys := make([]string, 0)
+		filteredKeys := make([]string, 0, obj.Size())
 		for _, key := range obj.Keys() {
 			if key != "$assert" && key != "$comment" {
 				filteredKeys = append(filteredKeys, key)

jsonte/types/object.go

@@ -398,6 +398,12 @@ func NewJsonObject() *JsonObject {
 	return &JsonObject{&navigableMap, nil, nil, nil, nil}
 }
 
+// NewJsonObjectWithCapacity creates a JsonObject preallocating internal storage.
+func NewJsonObjectWithCapacity(capacity int) *JsonObject {
+	navigableMap := utils.NewNavigableMapWithCapacity[string, JsonType](capacity)
+	return &JsonObject{&navigableMap, nil, nil, nil, nil}
+}
+
 func IsReservedKey(k string) bool {
 	return strings.EqualFold(k, "$comment") || strings.EqualFold(k, "$assert")
 }

jsonte/utils/navigable_map.go

@@ -11,10 +11,18 @@ type NavigableMap[K comparable, V any] struct {
 
 // NewNavigableMap creates a new NavigableMap.
 func NewNavigableMap[K comparable, V any]() NavigableMap[K, V] {
+	return NewNavigableMapWithCapacity[K, V](0)
+}
+
+// NewNavigableMapWithCapacity creates a new NavigableMap with preallocated storage.
+func NewNavigableMapWithCapacity[K comparable, V any](capacity int) NavigableMap[K, V] {
+	if capacity < 0 {
+		capacity = 0
+	}
 	return NavigableMap[K, V]{
-		data:  map[K]V{},
-		keys:  []K{},
-		index: map[K]int{},
+		data:  make(map[K]V, capacity),
+		keys:  make([]K, 0, capacity),
+		index: make(map[K]int, capacity),
 	}
 }