idtree: new module

[ccan] / ccan / idtree / idtree.h

diff --git a/ccan/idtree/idtree.h b/ccan/idtree/idtree.h
new file mode 100644 (file)
index 0000000..a8f8719
--- /dev/null
+++ b/ccan/idtree/idtree.h
@@ -0,0 +1,53 @@
+#ifndef CCAN_IDTREE_H
+#define CCAN_IDTREE_H
+#include <stdbool.h>
+
+/**
+ * idtree_new - create an idr_context
+ * @mem_ctx: talloc parent to allocate from (may be NULL).
+ *
+ * Allocate an empty id tree.  You can free it with talloc_free().
+ */
+struct idtree *idtree_new(void *mem_ctx);
+
+/**
+ * idtree_add - get lowest available id, and assign a pointer to it.
+ * @idtree: the tree to allocate from
+ * @ptr: the non-NULL pointer to associate with the id
+ * @limit: the maximum id to allocate (ie. INT_MAX means no limit).
+ *
+ * This returns a non-negative id number, or -1 if all are taken.
+ */
+int idtree_add(struct idtree *idtree, const void *ptr, int limit);
+
+/**
+ * idtree_add_above - get lowest available id, starting at a given value.
+ * @idtree: the tree to allocate from
+ * @ptr: the non-NULL pointer to associate with the id
+ * @starting_id: the minimum id value to consider.
+ * @limit: the maximum id to allocate (ie. INT_MAX means no limit).
+ *
+ * This returns a non-negative id number, or -1 if all are taken.
+ */
+int idtree_add_above(struct idtree *idtree, const void *ptr,
+                    int starting_id, int limit);
+
+/**
+ * idtree_lookup - look up a given id
+ * @idtree: the tree to look in
+ * @id: the id to look up
+ *
+ * Returns NULL if the value is not found, otherwise the pointer value
+ * set with the idtree_add()/idtree_add_above().
+ */
+void *idtree_lookup(const struct idtree *idtree, int id);
+
+/**
+ * idtree_remove - remove a given id.
+ * @idtree: the tree to remove from
+ * @id: the id to remove.
+ *
+ * Returns false if the id was not in the tree.
+ */
+bool idtree_remove(struct idtree *idtree, int id);
+#endif /* CCAN_IDTREE_H */