add header file

diff --git a/distbench/function.h b/distbench/function.h
index c842bef1e5d5a87fbfa422eafac69ec0ca8b8af8..b214a92eed0c630358f611d071e623511cd26d32 100644 (file)
--- a/distbench/function.h
+++ b/distbench/function.h
@@ -1,3 +1,93 @@
-/* Example function that returns something. */
+/**
+ * collectd - src/daemon/distribution.h
+ * Copyright (C) 2019-2020  Google LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *   Svetlana Shmidt <sshmidt at google.com>
+ **/
 
-extern int my_function();
+#ifndef COLLECTD_DISTRIBUTION_H
+#define COLLECTD_DISTRIBUTION_H
+
+#include"collectd.h"
+
+typedef struct bucket_s {
+  uint64_t bucket_counter;
+  double maximum;
+} bucket_t;
+
+struct distribution_s;
+typedef struct distribution_s distribution_t;
+
+typedef struct buckets_array_s {
+  size_t num_buckets;
+  bucket_t *buckets;
+} buckets_array_t;
+
+//constructor functions:
+/**
+ * function creates new distribution with the linear buckets:
+ * [0; size) [size; 2 * size) ... [(num_buckets - 1) * size; infinity)
+ * @param num_buckets - number of buckets. Should be greater than 0
+ * @param size - size of each bucket. Should be greater than 0
+ * @return - pointer to a new distribution or null pointer if parameters are wrong or memory allocation fails
+ */
+distribution_t* distribution_new_linear(size_t num_buckets, double size);
+
+/**
+ * function creates new distribution with the exponential buckets:
+ * [0; factor) [factor; factor * base) ... [factor * base^{num_buckets - 2}; infinity)
+ * @param num_buckets - number of buckets. Should be greater than 0
+ * @param base - base of geometric progression. Should be greater than 1
+ * @param factor - size of the first bucket. Should be greater than 0
+ * @return - pointer to a new distribution or null pointer if parameters are wrong or memory allocation fails
+ */
+distribution_t* distribution_new_exponential(size_t num_buckets, double base, double factor);
+
+/**
+ * function creates new distribution with the custom buckets:
+ * [0; custom_bucket_boundaries[0]) [custom_bucket_boundaries[0]; custom_bucket_boundaries[1]) ...
+ * ... [custom_bucket_boundaries[array_size - 1], infinity)
+ * @param array_size - size of array of bucket boundaries. Number of buckets is array_size + 1
+ * @param custom_buckets_boundaries - array with bucket boundaries. Should be increasing and positive
+ * @return - pointer to a new distribution or null pointer if parameters are wrong or memory allocation fails
+ */
+distribution_t* distribution_new_custom(size_t array_size, double *custom_buckets_boundaries);
+
+/** add new value to a distribution **/
+void distribution_update(distribution_t *dist, double gauge);
+
+/**
+ * @param percent - should be in (0; 100] range
+ * @return - an approximation of percent percentile
+ * (upper bound of such bucket that all less or equal buckets contain more than percent percents of values)
+ * or NAN if parameters are wrong or distribution is empty
+ */
+double distribution_percentile(distribution_t *dist, double percent);
+
+/** @return - average of all values in distribution or NAN if distribution is empty */
+double distribution_average(distribution_t *dist);
+
+/** @return - pointer to the copy of distribution or null if memory allocation fails */
+distribution_t* distribution_clone(distribution_t *dist);
+
+/** destroy the distribution and free memory **/
+void distribution_destroy(distribution_t *d);