Templatize percentile_filter.h and move it to base/analytics.

BUG=None

Review-Url: https://codereview.webrtc.org/2529063002
Cr-Commit-Position: refs/heads/master@{#15334}

webrtc/BUILD.gn

@@ -370,6 +370,7 @@ if (rtc_include_tests) {
     sources = [
       "api/fakemetricsobserver.cc",
       "base/analytics/exp_filter_unittest.cc",
+      "base/analytics/percentile_filter_unittest.cc",
       "base/array_view_unittest.cc",
       "base/atomicops_unittest.cc",
       "base/autodetectproxy_unittest.cc",

webrtc/base/BUILD.gn

@@ -340,6 +340,10 @@ rtc_static_library("rtc_analytics") {
   sources = [
     "analytics/exp_filter.cc",
     "analytics/exp_filter.h",
+    "analytics/percentile_filter.h",
+  ]
+  deps = [
+    ":rtc_base_approved",
   ]
 }
 

webrtc/base/analytics/percentile_filter.h

@@ -8,15 +8,51 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/modules/video_coding/percentile_filter.h"
+#ifndef WEBRTC_BASE_ANALYTICS_PERCENTILE_FILTER_H_
+#define WEBRTC_BASE_ANALYTICS_PERCENTILE_FILTER_H_
+
+#include <stdint.h>
 
 #include <iterator>
+#include <set>
 
 #include "webrtc/base/checks.h"
 
 namespace webrtc {
 
-PercentileFilter::PercentileFilter(float percentile)
+// Class to efficiently get the percentile value from a group of observations.
+// The percentile is the value below which a given percentage of the
+// observations fall.
+template <typename T>
+class PercentileFilter {
+ public:
+  // Construct filter. |percentile| should be between 0 and 1.
+  explicit PercentileFilter(float percentile);
+
+  // Insert one observation. The complexity of this operation is logarithmic in
+  // the size of the container.
+  void Insert(const T& value);
+
+  // Remove one observation. The complexity of this operation is logarithmic in
+  // the size of the container.
+  void Erase(const T& value);
+
+  // Get the percentile value. The complexity of this operation is constant.
+  T GetPercentileValue() const;
+
+ private:
+  // Update iterator and index to point at target percentile value.
+  void UpdatePercentileIterator();
+
+  const float percentile_;
+  std::multiset<T> set_;
+  // Maintain iterator and index of current target percentile value.
+  typename std::multiset<T>::iterator percentile_it_;
+  int64_t percentile_index_;
+};
+
+template <typename T>
+PercentileFilter<T>::PercentileFilter(float percentile)
     : percentile_(percentile),
       percentile_it_(set_.begin()),
       percentile_index_(0) {
@@ -24,7 +60,8 @@ PercentileFilter::PercentileFilter(float percentile)
   RTC_CHECK_LE(percentile, 1.0f);
 }
 
-void PercentileFilter::Insert(const int64_t& value) {
+template <typename T>
+void PercentileFilter<T>::Insert(const T& value) {
   // Insert element at the upper bound.
   set_.insert(value);
   if (set_.size() == 1u) {
@@ -38,13 +75,15 @@ void PercentileFilter::Insert(const int64_t& value) {
   UpdatePercentileIterator();
 }
 
-void PercentileFilter::Erase(const int64_t& value) {
+template <typename T>
-  std::multiset<int64_t>::const_iterator it = set_.lower_bound(value);
+void PercentileFilter<T>::Erase(const T& value) {
+  typename std::multiset<T>::const_iterator it = set_.lower_bound(value);
   // Ignore erase operation if the element is not present in the current set.
   if (it == set_.end() || *it != value)
     return;
   if (it == percentile_it_) {
-    // If same iterator, update to the following element. Index is not affected.
+    // If same iterator, update to the following element. Index is not
+    // affected.
     percentile_it_ = set_.erase(it);
   } else {
     set_.erase(it);
@@ -55,7 +94,8 @@ void PercentileFilter::Erase(const int64_t& value) {
   UpdatePercentileIterator();
 }
 
-void PercentileFilter::UpdatePercentileIterator() {
+template <typename T>
+void PercentileFilter<T>::UpdatePercentileIterator() {
   if (set_.empty())
     return;
   const int64_t index = static_cast<int64_t>(percentile_ * (set_.size() - 1));
@@ -63,8 +103,11 @@ void PercentileFilter::UpdatePercentileIterator() {
   percentile_index_ = index;
 }
 
-int64_t PercentileFilter::GetPercentileValue() const {
+template <typename T>
+T PercentileFilter<T>::GetPercentileValue() const {
   return set_.empty() ? 0 : *percentile_it_;
 }
 
 }  // namespace webrtc
+
+#endif  // WEBRTC_BASE_ANALYTICS_PERCENTILE_FILTER_H_

webrtc/base/analytics/percentile_filter_unittest.cc

@@ -9,9 +9,10 @@
  */
 
 #include <algorithm>
+#include <climits>
 
+#include "webrtc/base/analytics/percentile_filter.h"
 #include "webrtc/base/constructormagic.h"
-#include "webrtc/modules/video_coding/percentile_filter.h"
 #include "webrtc/test/gtest.h"
 
 namespace webrtc {
@@ -24,7 +25,7 @@ class PercentileFilterTest : public ::testing::TestWithParam<float> {
   }
 
  protected:
-  PercentileFilter filter_;
+  PercentileFilter<int64_t> filter_;
 
  private:
   RTC_DISALLOW_COPY_AND_ASSIGN(PercentileFilterTest);
@@ -35,7 +36,7 @@ INSTANTIATE_TEST_CASE_P(PercentileFilterTests,
                         ::testing::Values(0.0f, 0.1f, 0.5f, 0.9f, 1.0f));
 
 TEST(PercentileFilterTest, MinFilter) {
-  PercentileFilter filter(0.0f);
+  PercentileFilter<int64_t> filter(0.0f);
   filter.Insert(4);
   EXPECT_EQ(4, filter.GetPercentileValue());
   filter.Insert(3);
@@ -43,13 +44,43 @@ TEST(PercentileFilterTest, MinFilter) {
 }
 
 TEST(PercentileFilterTest, MaxFilter) {
-  PercentileFilter filter(1.0f);
+  PercentileFilter<int64_t> filter(1.0f);
   filter.Insert(3);
   EXPECT_EQ(3, filter.GetPercentileValue());
   filter.Insert(4);
   EXPECT_EQ(4, filter.GetPercentileValue());
 }
 
+TEST(PercentileFilterTest, MedianFilterDouble) {
+  PercentileFilter<double> filter(0.5f);
+  filter.Insert(2.71828);
+  filter.Insert(3.14159);
+  filter.Insert(1.41421);
+  EXPECT_EQ(2.71828, filter.GetPercentileValue());
+}
+
+TEST(PercentileFilterTest, MedianFilterInt) {
+  PercentileFilter<int> filter(0.5f);
+  filter.Insert(INT_MIN);
+  filter.Insert(1);
+  filter.Insert(2);
+  EXPECT_EQ(1, filter.GetPercentileValue());
+  filter.Insert(INT_MAX);
+  filter.Erase(INT_MIN);
+  EXPECT_EQ(2, filter.GetPercentileValue());
+}
+
+TEST(PercentileFilterTest, MedianFilterUnsigned) {
+  PercentileFilter<unsigned> filter(0.5f);
+  filter.Insert(UINT_MAX);
+  filter.Insert(2u);
+  filter.Insert(1u);
+  EXPECT_EQ(2u, filter.GetPercentileValue());
+  filter.Insert(0u);
+  filter.Erase(UINT_MAX);
+  EXPECT_EQ(1u, filter.GetPercentileValue());
+}
+
 TEST_P(PercentileFilterTest, EmptyFilter) {
   EXPECT_EQ(0, filter_.GetPercentileValue());
   filter_.Insert(3);

webrtc/modules/BUILD.gn

@@ -503,7 +503,6 @@ if (rtc_include_tests) {
       "video_coding/jitter_buffer_unittest.cc",
       "video_coding/jitter_estimator_tests.cc",
       "video_coding/nack_module_unittest.cc",
-      "video_coding/percentile_filter_unittest.cc",
       "video_coding/protection_bitrate_calculator_unittest.cc",
       "video_coding/receiver_unittest.cc",
       "video_coding/rtp_frame_reference_finder_unittest.cc",

webrtc/modules/video_coding/BUILD.gn

@@ -55,8 +55,6 @@ rtc_static_library("video_coding") {
     "packet.h",
     "packet_buffer.cc",
     "packet_buffer.h",
-    "percentile_filter.cc",
-    "percentile_filter.h",
     "protection_bitrate_calculator.cc",
     "protection_bitrate_calculator.h",
     "receiver.cc",

webrtc/modules/video_coding/codec_timer.h

@@ -13,8 +13,8 @@
 
 #include <queue>
 
+#include "webrtc/base/analytics/percentile_filter.h"
 #include "webrtc/modules/include/module_common_types.h"
-#include "webrtc/modules/video_coding/percentile_filter.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
@@ -43,7 +43,7 @@ class VCMCodecTimer {
   std::queue<Sample> history_;
   // |filter_| contains the same values as |history_|, but in a data structure
   // that allows efficient retrieval of the percentile value.
-  PercentileFilter filter_;
+  PercentileFilter<int64_t> filter_;
 };
 
 }  // namespace webrtc

webrtc/modules/video_coding/percentile_filter.h

@@ -1,50 +0,0 @@
-/*
- *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#ifndef WEBRTC_MODULES_VIDEO_CODING_PERCENTILE_FILTER_H_
-#define WEBRTC_MODULES_VIDEO_CODING_PERCENTILE_FILTER_H_
-
-#include <stdint.h>
-
-#include <set>
-
-namespace webrtc {
-
-// Class to efficiently get the percentile value from a group of observations.
-// The percentile is the value below which a given percentage of the
-// observations fall.
-class PercentileFilter {
- public:
-  // Construct filter. |percentile| should be between 0 and 1.
-  explicit PercentileFilter(float percentile);
-
-  // Insert one observation. The complexity of this operation is logarithmic in
-  // the size of the container.
-  void Insert(const int64_t& value);
-  // Remove one observation. The complexity of this operation is logarithmic in
-  // the size of the container.
-  void Erase(const int64_t& value);
-  // Get the percentile value. The complexity of this operation is constant.
-  int64_t GetPercentileValue() const;
-
- private:
-  // Update iterator and index to point at target percentile value.
-  void UpdatePercentileIterator();
-
-  const float percentile_;
-  std::multiset<int64_t> set_;
-  // Maintain iterator and index of current target percentile value.
-  std::multiset<int64_t>::iterator percentile_it_;
-  int64_t percentile_index_;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_VIDEO_CODING_PERCENTILE_FILTER_H_