util: Add a DAG datastructure.

I keep writing this for various schedulers.

Acked-by: Timothy Arceri <[email protected]>

1 files changed, 65 insertions, 0 deletions

diff --git a/src/util/dag.h b/src/util/dag.h
new file mode 100644
index 00000000000..bb46b483972
--- /dev/null
+++ b/src/util/dag.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright © 2019 Broadcom
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef DAG_H
+#define DAG_H
+
+#include <stdint.h>
+#include "util/list.h"
+#include "util/u_dynarray.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct dag_edge {
+   struct dag_node *child;
+   /* User-defined data associated with the edge. */
+   void *data;
+};
+
+struct dag_node {
+   /* Position in the DAG heads list (or a self-link) */
+   struct list_head link;
+   /* Array struct edge to the children. */
+   struct util_dynarray edges;
+   uint32_t parent_count;
+};
+
+struct dag {
+   struct list_head heads;
+};
+
+struct dag *dag_create(void *mem_ctx);
+void dag_init_node(struct dag *dag, struct dag_node *node);
+void dag_add_edge(struct dag_node *parent, struct dag_node *child, void *data);
+void dag_remove_edge(struct dag *dag, struct dag_edge *edge);
+void dag_traverse_bottom_up(struct dag *dag, void (*cb)(struct dag_node *node,
+                                                        void *data), void *data);
+void dag_prune_head(struct dag *dag, struct dag_node *node);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif