diff --git a/minheap-internal.h b/minheap-internal.h
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+++ b/minheap-internal.h
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+/*
+ * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
+ *
+ * Copyright (c) 2006 Maxim Yegorushkin <maxim.yegorushkin@gmail.com>
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+#ifndef _MIN_HEAP_H_
+#define _MIN_HEAP_H_
+
+#include "event2/event-config.h"
+#include "event2/event.h"
+#include "event2/event_struct.h"
+#include "event2/util.h"
+#include "util-internal.h"
+#include "mm-internal.h"
+
+typedef struct min_heap
+{
+	struct event** p;
+	unsigned n, a;
+} min_heap_t;
+
+static inline void	     min_heap_ctor(min_heap_t* s);
+static inline void	     min_heap_dtor(min_heap_t* s);
+static inline void	     min_heap_elem_init(struct event* e);
+static inline int	     min_heap_elt_is_top(const struct event *e);
+static inline int	     min_heap_elem_greater(struct event *a, struct event *b);
+static inline int	     min_heap_empty(min_heap_t* s);
+static inline unsigned	     min_heap_size(min_heap_t* s);
+static inline struct event*  min_heap_top(min_heap_t* s);
+static inline int	     min_heap_reserve(min_heap_t* s, unsigned n);
+static inline int	     min_heap_push(min_heap_t* s, struct event* e);
+static inline struct event*  min_heap_pop(min_heap_t* s);
+static inline int	     min_heap_erase(min_heap_t* s, struct event* e);
+static inline void	     min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e);
+static inline void	     min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e);
+
+int min_heap_elem_greater(struct event *a, struct event *b)
+{
+	return evutil_timercmp(&a->ev_timeout, &b->ev_timeout, >);
+}
+
+void min_heap_ctor(min_heap_t* s) { s->p = 0; s->n = 0; s->a = 0; }
+void min_heap_dtor(min_heap_t* s) { if (s->p) mm_free(s->p); }
+void min_heap_elem_init(struct event* e) { e->ev_timeout_pos.min_heap_idx = -1; }
+int min_heap_empty(min_heap_t* s) { return 0u == s->n; }
+unsigned min_heap_size(min_heap_t* s) { return s->n; }
+struct event* min_heap_top(min_heap_t* s) { return s->n ? *s->p : 0; }
+
+int min_heap_push(min_heap_t* s, struct event* e)
+{
+	if (min_heap_reserve(s, s->n + 1))
+		return -1;
+	min_heap_shift_up_(s, s->n++, e);
+	return 0;
+}
+
+struct event* min_heap_pop(min_heap_t* s)
+{
+	if (s->n)
+	{
+		struct event* e = *s->p;
+		min_heap_shift_down_(s, 0u, s->p[--s->n]);
+		e->ev_timeout_pos.min_heap_idx = -1;
+		return e;
+	}
+	return 0;
+}
+
+int min_heap_elt_is_top(const struct event *e)
+{
+	return e->ev_timeout_pos.min_heap_idx == 0;
+}
+
+int min_heap_erase(min_heap_t* s, struct event* e)
+{
+	if (-1 != e->ev_timeout_pos.min_heap_idx)
+	{
+		struct event *last = s->p[--s->n];
+		unsigned parent = (e->ev_timeout_pos.min_heap_idx - 1) / 2;
+		/* we replace e with the last element in the heap.  We might need to
+		   shift it upward if it is less than its parent, or downward if it is
+		   greater than one or both its children. Since the children are known
+		   to be less than the parent, it can't need to shift both up and
+		   down. */
+		if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], last))
+			min_heap_shift_up_(s, e->ev_timeout_pos.min_heap_idx, last);
+		else
+			min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, last);
+		e->ev_timeout_pos.min_heap_idx = -1;
+		return 0;
+	}
+	return -1;
+}
+
+int min_heap_reserve(min_heap_t* s, unsigned n)
+{
+	if (s->a < n)
+	{
+		struct event** p;
+		unsigned a = s->a ? s->a * 2 : 8;
+		if (a < n)
+			a = n;
+		if (!(p = (struct event**)mm_realloc(s->p, a * sizeof *p)))
+			return -1;
+		s->p = p;
+		s->a = a;
+	}
+	return 0;
+}
+
+void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e)
+{
+    unsigned parent = (hole_index - 1) / 2;
+    while (hole_index && min_heap_elem_greater(s->p[parent], e))
+    {
+	(s->p[hole_index] = s->p[parent])->ev_timeout_pos.min_heap_idx = hole_index;
+	hole_index = parent;
+	parent = (hole_index - 1) / 2;
+    }
+    (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
+}
+
+void min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e)
+{
+    unsigned min_child = 2 * (hole_index + 1);
+    while (min_child <= s->n)
+	{
+	min_child -= min_child == s->n || min_heap_elem_greater(s->p[min_child], s->p[min_child - 1]);
+	if (!(min_heap_elem_greater(e, s->p[min_child])))
+	    break;
+	(s->p[hole_index] = s->p[min_child])->ev_timeout_pos.min_heap_idx = hole_index;
+	hole_index = min_child;
+	min_child = 2 * (hole_index + 1);
+	}
+    (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
+}
+
+#endif /* _MIN_HEAP_H_ */