--- /dev/null
+/*
+ * Copyright (c) 2008, Titanium Mirror, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * - 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.
+ * - Neither the name of Titanium Mirror, Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * 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
+ * OWNER 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.
+ */
+
+/**
+ * An interface used by averagers.
+ *
+ * @author R. Steve McKown <rsmckown@gmail.com>
+ */
+
+interface Average<val_t> {
+ /* Reset the averager. Any samples submitted since the last average was
+ * signalled, or all samples submitted if average was not signalled, are
+ * discarded.
+ */
+ command void reset();
+
+ /* Submit a value to the averager, to be averaged into the next average. */
+ command void submit(val_t);
+
+ /* Submit a null value to the averager. Each null submitted counts as one
+ * of the expected values for calculating the average. Each null submitted
+ * reduces the divisor for the subsequent average by one.
+ */
+ command void null();
+
+ /* Signalled after the expected number of samples + nulls have been delivered
+ * and their set have been used to calculate a new average.
+ */
+ event void average(val_t);
+}