--- a/src/ucx/cx/iterator.h Sun Nov 20 12:43:44 2022 +0100
+++ b/src/ucx/cx/iterator.h Sat Nov 26 17:07:08 2022 +0100
@@ -40,26 +40,53 @@
#include "common.h"
/**
- * Internal iterator struct - use CxIterator.
+ * The base of mutating and non-mutating iterators.
*/
-struct cx_iterator_s {
+struct cx_iterator_base_s {
/**
* True iff the iterator points to valid data.
*/
__attribute__ ((__nonnull__))
- bool (*valid)(struct cx_iterator_s const *);
+ bool (*valid)(void const *);
/**
* Returns a pointer to the current element.
*/
__attribute__ ((__nonnull__))
- void *(*current)(struct cx_iterator_s const *);
+ void *(*current)(void const *);
/**
* Advances the iterator.
*/
__attribute__ ((__nonnull__))
- void (*next)(struct cx_iterator_s *);
+ void (*next)(void *);
+
+ /**
+ * Flag current element for removal, if possible.
+ */
+ __attribute__ ((__nonnull__))
+ bool (*flag_removal)(void *);
+
+ /**
+ * Indicates whether this iterator is muting.
+ */
+ bool mutating;
+
+ /**
+ * Internal flag for removing the current element when advancing.
+ */
+ bool remove;
+};
+
+/**
+ * Internal iterator struct - use CxMutIterator.
+ */
+struct cx_mut_iterator_s {
+
+ /**
+ * The base properties of this iterator.
+ */
+ struct cx_iterator_base_s base;
/**
* Handle for the current element, if required.
@@ -79,7 +106,7 @@
/**
* A pointer to the key.
*/
- void *key;
+ void const *key;
/**
* A pointer to the value.
*/
@@ -97,13 +124,70 @@
* Otherwise, this field is usually uninitialized.
*/
size_t index;
+};
+
+/**
+ * Mutating iterator value type.
+ *
+ * An iterator points to a certain element in an (possibly unbounded) chain of elements.
+ * Iterators that are based on collections (which have a defined "first" element), are supposed
+ * to be "position-aware", which means that they keep track of the current index within the collection.
+ *
+ * @note Objects that are pointed to by an iterator are mutable through that iterator. However, if the
+ * iterator is based on a collection and the underlying collection is mutated by other means than this iterator
+ * (e.g. elements added or removed), the iterator becomes invalid (regardless of what cxIteratorValid() returns)
+ * and MUST be re-obtained from the collection.
+ *
+ * @see CxIterator
+ */
+typedef struct cx_mut_iterator_s CxMutIterator;
+
+/**
+ * Internal iterator struct - use CxIterator.
+ */
+struct cx_iterator_s {
+
+ /**
+ * The base properties of this iterator.
+ */
+ struct cx_iterator_base_s base;
/**
- * Users may set this to true, if the current element shall be removed from the underlying collection
- * when the iterator advances.
- * Has no effect on iterators that are not based on a collection.
+ * Handle for the current element, if required.
+ */
+ void *elem_handle;
+
+ /**
+ * Handle for the source collection, if any.
+ */
+ void const *src_handle;
+
+ /**
+ * Field for storing a key-value pair.
+ * May be used by iterators that iterate over k/v-collections.
*/
- bool remove;
+ struct {
+ /**
+ * A pointer to the key.
+ */
+ void const *key;
+ /**
+ * A pointer to the value.
+ */
+ void *value;
+ } kv_data;
+
+ /**
+ * Field for storing a slot number.
+ * May be used by iterators that iterate over multi-bucket collections.
+ */
+ size_t slot;
+
+ /**
+ * If the iterator is position-aware, contains the index of the element in the underlying collection.
+ * Otherwise, this field is usually uninitialized.
+ */
+ size_t index;
};
/**
@@ -112,10 +196,11 @@
* Iterators that are based on collections (which have a defined "first" element), are supposed
* to be "position-aware", which means that they keep track of the current index within the collection.
*
- * @note Objects that are pointed to by an iterator are mutable through that iterator. However, if the
- * iterator is based on a collection and the underlying collection is mutated (elements added or removed),
- * the iterator becomes invalid (regardless of what cxIteratorValid() returns) and MUST be re-obtained
- * from the collection.
+ * @note Objects that are pointed to by an iterator are always mutable through that iterator. However,
+ * this iterator cannot mutate the collection itself (add or remove elements) and any mutation of the
+ * collection by other means make this iterator invalid (regardless of what cxIteratorValid() returns).
+ *
+ * @see CxMutIterator
*/
typedef struct cx_iterator_s CxIterator;
@@ -124,36 +209,35 @@
*
* This is especially false for past-the-end iterators.
*
- * @param iter a pointer to the iterator
+ * @param iter the iterator
* @return true iff the iterator points to valid data
*/
-__attribute__ ((__nonnull__))
-static inline bool cxIteratorValid(CxIterator const *iter) {
- return iter->valid(iter);
-}
+#define cxIteratorValid(iter) (iter).base.valid(&(iter))
/**
* Returns a pointer to the current element.
*
* The behavior is undefined if this iterator is invalid.
*
- * @param iter a pointer to the iterator
+ * @param iter the iterator
* @return a pointer to the current element
*/
-__attribute__ ((__nonnull__))
-static inline void *cxIteratorCurrent(CxIterator const *iter) {
- return iter->current(iter);
-}
+#define cxIteratorCurrent(iter) (iter).base.current(&iter)
/**
* Advances the iterator to the next element.
*
- * @param iter a pointer to the iterator
+ * @param iter the iterator
*/
-__attribute__ ((__nonnull__))
-static inline void cxIteratorNext(CxIterator *iter) {
- iter->next(iter);
-}
+#define cxIteratorNext(iter) (iter).base.next(&iter)
+
+/**
+ * Flags the current element for removal.
+ *
+ * @param iter the iterator
+ * @return false if this iterator cannot remove the element
+ */
+#define cxIteratorFlagRemoval(iter) (iter).base.flag_removal(&iter)
/**
* Loops over an iterator.
@@ -162,6 +246,6 @@
* @param iter the iterator
*/
#define cx_foreach(type, elem, iter) \
-for (type elem; cxIteratorValid(&iter) && (elem = (type)cxIteratorCurrent(&iter)) != NULL ; cxIteratorNext(&iter)) // NOLINT(bugprone-macro-parentheses)
+for (type elem; cxIteratorValid(iter) && (elem = (type)cxIteratorCurrent(iter)) != NULL ; cxIteratorNext(iter))
-#endif /* UCX_ITERATOR_H */
+#endif // UCX_ITERATOR_H