Merge upstream/development

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/pqueue.h b/src/pqueue.h
new file mode 100644
index 000000000..7a1394803
--- /dev/null
+++ b/src/pqueue.h
@@ -0,0 +1,97 @@
+/*
+ *	BORING COPYRIGHT NOTICE:
+ *
+ *	This file is a heavily modified version of the priority queue found
+ *	in the Apache project and the libpqueue library.
+ *
+ *		https://github.com/vy/libpqueue
+ *
+ *	These are the original authors:
+ *
+ *		Copyright 2010 Volkan Yazıcı <volkan.yazici@gmail.com>
+ *		Copyright 2006-2010 The Apache Software Foundation
+ *
+ *  This file is licensed under the Apache 2.0 license, which 
+ *  supposedly makes it compatible with the GPLv2 that libgit2 uses.
+ *
+ *  Check the Apache license at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  So much licensing trouble for a binary heap. Oh well.
+ */
+
+#ifndef INCLUDE_pqueue_h__
+#define INCLUDE_pqueue_h__
+
+/** callback functions to get/set/compare the priority of an element */
+typedef int (*git_pqueue_cmp)(void *a, void *b);
+
+/** the priority queue handle */
+typedef struct {
+    size_t size, avail, step;
+    git_pqueue_cmp cmppri;
+    void **d;
+} git_pqueue;
+
+
+/**
+ * initialize the queue
+ *
+ * @param n the initial estimate of the number of queue items for which memory
+ *          should be preallocated
+ * @param cmppri the callback function to compare two nodes of the queue
+ *
+ * @Return the handle or NULL for insufficent memory
+ */
+int git_pqueue_init(git_pqueue *q, size_t n, git_pqueue_cmp cmppri);
+
+
+/**
+ * free all memory used by the queue
+ * @param q the queue
+ */
+void git_pqueue_free(git_pqueue *q);
+
+/**
+ * clear all the elements in the queue
+ * @param q the queue
+ */
+void git_pqueue_clear(git_pqueue *q);
+
+/**
+ * return the size of the queue.
+ * @param q the queue
+ */
+size_t git_pqueue_size(git_pqueue *q);
+
+
+/**
+ * insert an item into the queue.
+ * @param q the queue
+ * @param d the item
+ * @return 0 on success
+ */
+int git_pqueue_insert(git_pqueue *q, void *d);
+
+
+/**
+ * pop the highest-ranking item from the queue.
+ * @param p the queue
+ * @param d where to copy the entry to
+ * @return NULL on error, otherwise the entry
+ */
+void *git_pqueue_pop(git_pqueue *q);
+
+
+/**
+ * access highest-ranking item without removing it.
+ * @param q the queue
+ * @param d the entry
+ * @return NULL on error, otherwise the entry
+ */
+void *git_pqueue_peek(git_pqueue *q);
+
+#endif /* PQUEUE_H */
+/** @} */
+