diff --git a/evmap-internal.h b/evmap-internal.h
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+/*
+ * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
+ *
+ * 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 _EVMAP_H_
+#define _EVMAP_H_
+
+/** @file evmap-internal.h
+ *
+ * An event_map is a utility structure to map each fd or signal to zero or
+ * more events.  Functions to manipulate event_maps should only be used from
+ * inside libevent.  They generally need to hold the lock on the corresponding
+ * event_base.
+ **/
+
+struct event_base;
+struct event;
+
+/** Initialize an event_map for use.
+ */
+void evmap_io_initmap(struct event_io_map* ctx);
+void evmap_signal_initmap(struct event_signal_map* ctx);
+
+/** Remove all entries from an event_map.
+
+	@param ctx the map to clear.
+ */
+void evmap_io_clear(struct event_io_map* ctx);
+void evmap_signal_clear(struct event_signal_map* ctx);
+
+/** Add an IO event (some combination of EV_READ or EV_WRITE) to an
+    event_base's list of events on a given file descriptor, and tell the
+    underlying eventops about the fd if its state has changed.
+
+    Requires that ev is not already added.
+
+    @param base the event_base to operate on.
+    @param fd the file descriptor corresponding to ev.
+    @param ev the event to add.
+*/
+int evmap_io_add(struct event_base *base, evutil_socket_t fd, struct event *ev);
+/** Remove an IO event (some combination of EV_READ or EV_WRITE) to an
+    event_base's list of events on a given file descriptor, and tell the
+    underlying eventops about the fd if its state has changed.
+
+    @param base the event_base to operate on.
+    @param fd the file descriptor corresponding to ev.
+    @param ev the event to remove.
+ */
+int evmap_io_del(struct event_base *base, evutil_socket_t fd, struct event *ev);
+/** Active the set of events waiting on an event_base for a given fd.
+
+    @param base the event_base to operate on.
+    @param fd the file descriptor that has become active.
+    @param events a bitmask of EV_READ|EV_WRITE|EV_ET.
+*/
+void evmap_io_active(struct event_base *base, evutil_socket_t fd, short events);
+
+
+/* These functions behave in the same way as evmap_io_*, except they work on
+ * signals rather than fds.  signals use a linear map everywhere; fds use
+ * either a linear map or a hashtable. */
+int evmap_signal_add(struct event_base *base, int signum, struct event *ev);
+int evmap_signal_del(struct event_base *base, int signum, struct event *ev);
+void evmap_signal_active(struct event_base *base, evutil_socket_t signum, int ncalls);
+
+void *evmap_io_get_fdinfo(struct event_io_map *ctx, evutil_socket_t fd);
+
+void evmap_check_integrity(struct event_base *base);
+
+#endif /* _EVMAP_H_ */