Add efficient priority queue implementation

1 files changed, 52 insertions, 0 deletions

diff --git a/src/pqueue.h b/src/pqueue.h
new file mode 100644
index 0000000..126c3ea
--- /dev/null
+++ b/src/pqueue.h
@@ -0,0 +1,52 @@
+/*
+  Copyright (c) 2012-2015, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+   \file
+
+   Priority queues
+*/
+
+#pragma once
+
+#include "types.h"
+
+
+struct fastd_pqueue {
+	fastd_pqueue_t **pprev;
+	fastd_pqueue_t *next;
+
+	fastd_pqueue_t *children;
+
+	int64_t value;
+};
+
+
+static inline bool fastd_pqueue_linked(fastd_pqueue_t *elem) {
+	return elem->pprev;
+}
+
+void fastd_pqueue_insert(fastd_pqueue_t **pqueue, fastd_pqueue_t *elem);
+void fastd_pqueue_remove(fastd_pqueue_t *elem);