From c705953d77ff1a69a0ec4101b9faf8e73c77e2cc Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Sun, 30 Jun 2019 19:44:15 -0700
Subject: [PATCH] Add usage reporting to LinearFilter (#1750)

---
 wpilibc/src/main/native/cpp/LinearFilter.cpp              | 8 +++++++-
 .../src/main/java/edu/wpi/first/wpilibj/LinearFilter.java | 8 ++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/wpilibc/src/main/native/cpp/LinearFilter.cpp b/wpilibc/src/main/native/cpp/LinearFilter.cpp
index 28cd7c1750..3438ba0196 100644
--- a/wpilibc/src/main/native/cpp/LinearFilter.cpp
+++ b/wpilibc/src/main/native/cpp/LinearFilter.cpp
@@ -10,6 +10,8 @@
 #include <cassert>
 #include <cmath>
 
+#include <hal/HAL.h>
+
 using namespace frc;
 
 LinearFilter::LinearFilter(wpi::ArrayRef<double> ffGains,
@@ -17,7 +19,11 @@ LinearFilter::LinearFilter(wpi::ArrayRef<double> ffGains,
     : m_inputs(ffGains.size()),
       m_outputs(fbGains.size()),
       m_inputGains(ffGains),
-      m_outputGains(fbGains) {}
+      m_outputGains(fbGains) {
+  static int instances = 0;
+  instances++;
+  HAL_Report(HALUsageReporting::kResourceType_LinearFilter, instances);
+}
 
 LinearFilter LinearFilter::SinglePoleIIR(double timeConstant, double period) {
   double gain = std::exp(-period / timeConstant);
diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/LinearFilter.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/LinearFilter.java
index c95baf798b..fbdcd61789 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/LinearFilter.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/LinearFilter.java
@@ -9,6 +9,9 @@ package edu.wpi.first.wpilibj;
 
 import java.util.Arrays;
 
+import edu.wpi.first.hal.FRCNetComm.tResourceType;
+import edu.wpi.first.hal.HAL;
+
 /**
  * This class implements a linear, digital filter. All types of FIR and IIR filters are supported.
  * Static factory methods are provided to create commonly used types of filters.
@@ -52,6 +55,8 @@ public class LinearFilter {
   private final double[] m_inputGains;
   private final double[] m_outputGains;
 
+  private static int instances;
+
   /**
    * Create a linear FIR or IIR filter.
    *
@@ -63,6 +68,9 @@ public class LinearFilter {
     m_outputs = new CircularBuffer(fbGains.length);
     m_inputGains = Arrays.copyOf(ffGains, ffGains.length);
     m_outputGains = Arrays.copyOf(fbGains, fbGains.length);
+
+    instances++;
+    HAL.report(tResourceType.kResourceType_LinearFilter, instances);
   }
 
   /**