From 9236f8f3139cd7a661363c50a7322e33f049b5bb Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@etlcpp.com>
Date: Sun, 1 Nov 2026 19:11:27 +0000
Subject: [PATCH] debounce updates

---
 include/etl/debounce_value.h    |  56 ++-----------
 test/test_debounce_value.cpp    | 144 +++++++++++++++++++++++++++++++-
 test/vs2022/etl.vcxproj         |   1 -
 test/vs2022/etl.vcxproj.filters |   9 ++
 4 files changed, 155 insertions(+), 55 deletions(-)

diff --git a/include/etl/debounce_value.h b/include/etl/debounce_value.h
index 515a2388..e8bd82eb 100644
--- a/include/etl/debounce_value.h
+++ b/include/etl/debounce_value.h
@@ -60,8 +60,7 @@ namespace etl
       /// Constructor.
       //*************************************************************************
       debounce_value_base(value_type initial_value)
-        : value(initial_value)
-        , last_value(initial_value)
+        : last_value(initial_value)
         , count(0)
         , state(Unstable)
         , notification(nullptr)
@@ -71,7 +70,7 @@ namespace etl
       //*************************************************************************
       /// Adds a new value.
       /// If the value has changed, the counter is reset and the value is marked as unstable.
-      /// Returns 'true' if the value is stable.
+      /// Returns 'true' if the value has changed.
       //*************************************************************************
       bool add(value_type value, count_type stable_count)
       {
@@ -108,7 +107,7 @@ namespace etl
 
         last_value = value;
 
-        return is_stable();
+        return has_changed();
       }
 
       //*************************************************************************
@@ -133,7 +132,7 @@ namespace etl
       //*************************************************************************
       value_type get() const
       {
-        return value;
+        return last_value;
       }
 
       //*************************************************************************
@@ -163,7 +162,6 @@ namespace etl
         Changed  = 2
       };
 
-      value_type         value;
       value_type         last_value;
       count_type         count;
       notification_type* notification;
@@ -171,51 +169,7 @@ namespace etl
     };
   } // namespace private_debounce_value
 
-  template <typename TValue, typename TCount, typename TTag>
-  class debounce_value;
-
-  //*************************************************************************
-  /// A debounced for a value.
-  /// The debounced will only change its value if the new value has been stable for a given number of calls.
-  /// Compile-time stable count.
-  //*************************************************************************
-  template <typename TValue, typename TCount, TCount Stable_Count>
-  class debounce_value<TValue, TCount, etl::integral_constant<TCount, Stable_Count>> // (2) compile-time specialization
-    : public private_debounce_value::debounce_value_base<TValue, TCount>
-  {
-  public:
-
-    using value_type = typename private_debounce_value::debounce_value_base<TValue, TCount>::value_type;
-    using count_type = typename private_debounce_value::debounce_value_base<TValue, TCount>::count_type;
-
-    //*************************************************************************
-    /// Constructor.
-    //*************************************************************************
-    explicit debounce_value(value_type initial_value)
-      : private_debounce_value::debounce_value_base<TValue, TCount>(initial_value)
-    {
-    }
-
-    //*************************************************************************
-    /// Adds a new value to the debounced.
-    /// If the value has changed, the counter is reset and the debounced is marked as unstable.
-    //*************************************************************************
-    bool add(value_type value)
-    {
-      return private_debounce_value::debounce_value_base<TValue, TCount>::add(value, Stable_Count);
-    }
-  };
-
-  //*************************************************************************
-  /// A debounced for a value.
-  /// The debounced will only change its value if the new value has been stable for a given number of calls.
-  /// Runtime stable count.
-  //*************************************************************************
-  struct debounce_runtime_tag
-  {
-  };
-
-  template <typename TValue, typename TCount = uint16_t, typename TTag = debounce_runtime_tag>
+  template <typename TValue, typename TCount>
   class debounce_value : public private_debounce_value::debounce_value_base<TValue, TCount>
   {
   public:
diff --git a/test/test_debounce_value.cpp b/test/test_debounce_value.cpp
index d13a50b0..f3f87e03 100644
--- a/test/test_debounce_value.cpp
+++ b/test/test_debounce_value.cpp
@@ -30,6 +30,8 @@ SOFTWARE.
 
 #include "etl/debounce_value.h"
 
+#include <vector>
+
 namespace
 {
   uint8_t notification_value = 0;
@@ -46,7 +48,8 @@ namespace
 
   SUITE(test_debounce)
   {
-    TEST(test_debounce_value_runtime)
+    //*************************************************************************
+    TEST(test_debounce_value)
     {
       const uint8_t Initial_Value = 1;
       const uint8_t Stable_Count  = 4;
@@ -81,12 +84,13 @@ namespace
       CHECK_TRUE(value.add(2));
       CHECK_TRUE(value.is_stable());
       CHECK_TRUE(value.has_changed());
+      CHECK_EQUAL(2, value.get());
 
       // Notified.
       CHECK_EQUAL(2, notification_value);
 
       // Still stable.
-      CHECK_TRUE(value.add(2));
+      CHECK_FALSE(value.add(2));
       CHECK_TRUE(value.is_stable());
       CHECK_FALSE(value.has_changed());
 
@@ -112,14 +116,148 @@ namespace
       CHECK_TRUE(value.add(3));
       CHECK_TRUE(value.is_stable());
       CHECK_TRUE(value.has_changed());
+      CHECK_EQUAL(3, value.get());
 
       // Notified.
       CHECK_EQUAL(3, notification_value);
 
       // Stable.
-      CHECK_TRUE(value.add(3));
+      CHECK_FALSE(value.add(3));
       CHECK_TRUE(value.is_stable());
       CHECK_FALSE(value.has_changed());
     }
+
+    //*************************************************************************
+    TEST(test_debounce_value_modify_stable_count)
+    {
+      const uint8_t Initial_Value = 1;
+      const uint8_t Stable_Count = 4;
+
+      etl::debounce_value<uint8_t, uint8_t> value(Initial_Value, Stable_Count);
+
+      value.set_notification(notification);
+
+      notification_value = 0;
+
+      CHECK_FALSE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      //*******************************
+      // Transition from unstable to stable.
+      CHECK_FALSE(value.add(2));
+      CHECK_FALSE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      CHECK_FALSE(value.add(2));
+      CHECK_FALSE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      CHECK_FALSE(value.add(2));
+      CHECK_FALSE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      // Not notified yet.
+      CHECK_EQUAL(0, notification_value);
+
+      // Stable & changed.
+      CHECK_TRUE(value.add(2));
+      CHECK_TRUE(value.is_stable());
+      CHECK_TRUE(value.has_changed());
+      CHECK_EQUAL(2, value.get());
+
+      // Notified.
+      CHECK_EQUAL(2, notification_value);
+
+      // Still stable.
+      CHECK_FALSE(value.add(2));
+      CHECK_TRUE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      //*******************************
+      // Change the stable count.
+      value.set_stable_count(2);
+
+      //*******************************
+      // Transition from unstable to stable.
+      // Unstable.
+      CHECK_FALSE(value.add(3));
+      CHECK_FALSE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+
+      // Not notified yet.
+      CHECK_EQUAL(2, notification_value);
+
+      // Stable & changed.
+      CHECK_TRUE(value.add(3));
+      CHECK_TRUE(value.is_stable());
+      CHECK_TRUE(value.has_changed());
+      CHECK_EQUAL(3, value.get());
+
+      // Notified.
+      CHECK_EQUAL(3, notification_value);
+
+      // Stable.
+      CHECK_FALSE(value.add(3));
+      CHECK_TRUE(value.is_stable());
+      CHECK_FALSE(value.has_changed());
+    }
+
+    //*************************************************************************
+    TEST(test_debounce_value_modify_notification)
+    {
+      const uint8_t Initial_Value = 1;
+      const uint8_t Stable_Count  = 4;
+
+      etl::debounce_value<uint8_t, uint8_t> value(Initial_Value, Stable_Count);
+
+      value.set_notification(notification);
+
+      notification_value = 0;
+
+      //*******************************
+      // Transition from unstable to stable.
+      CHECK_FALSE(value.add(2));
+      CHECK_FALSE(value.add(2));
+      CHECK_FALSE(value.add(2));
+      CHECK_TRUE(value.add(2));
+
+      // Notified.
+      CHECK_EQUAL(2, notification_value);
+
+      value.clear_notification();
+
+      //*******************************
+      // Transition from unstable to stable.
+      // Unstable.
+      CHECK_FALSE(value.add(3));
+      CHECK_FALSE(value.add(3));
+      CHECK_FALSE(value.add(3));
+      CHECK_TRUE(value.add(3));
+
+      // Not notified, so the value remains the same.
+      CHECK_EQUAL(2, notification_value);
+    }
+
+    //*************************************************************************
+    TEST(test_debounce_values_from_an_input)
+    {
+      std::vector<uint8_t> input = { 1, 2, 3, 3, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6 };
+      std::vector<uint8_t> output;
+      std::vector<uint8_t> expected = { 2, 3, 4, 6 };
+
+      const uint8_t Stable_Count = 3;
+      etl::debounce_value<uint8_t, uint8_t> value(0, Stable_Count);
+
+      for (uint8_t v : input)
+      {
+        if (value.add(v))
+        {
+          output.push_back(value.get());
+        }
+      }
+
+      CHECK_EQUAL(expected.size(), output.size());
+      CHECK_ARRAY_EQUAL(expected.data(), output.data(), expected.size());
+    }
   }
 } // namespace
diff --git a/test/vs2022/etl.vcxproj b/test/vs2022/etl.vcxproj
index e0e4fc2d..6ebafcc4 100644
--- a/test/vs2022/etl.vcxproj
+++ b/test/vs2022/etl.vcxproj
@@ -10411,7 +10411,6 @@
     <ClCompile Include="..\test_math_functions.cpp" />
     <ClCompile Include="..\test_message.cpp" />
     <ClCompile Include="..\test_message_broker.cpp" />
-    <ClCompile Include="..\test_notification.cpp" />
     <ClCompile Include="..\test_not_null_pointer.cpp" />
     <ClCompile Include="..\test_not_null_pointer_constexpr.cpp" />
     <ClCompile Include="..\test_not_null_unique_pointer.cpp" />
diff --git a/test/vs2022/etl.vcxproj.filters b/test/vs2022/etl.vcxproj.filters
index 1ac2027d..d53a1889 100644
--- a/test/vs2022/etl.vcxproj.filters
+++ b/test/vs2022/etl.vcxproj.filters
@@ -1566,6 +1566,12 @@
     <ClInclude Include="..\..\include\etl\format.h">
       <Filter>UnitTest++\Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\include\etl\debounce_value.h">
+      <Filter>UnitTest++\Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\..\include\etl\notification.h">
+      <Filter>UnitTest++\Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\test_string_char.cpp">
@@ -3839,6 +3845,9 @@
     <ClCompile Include="..\test_vector_member_function_pointer_external_buffer.cpp">
       <Filter>Tests\Containers</Filter>
     </ClCompile>
+    <ClCompile Include="..\test_debounce_value.cpp">
+      <Filter>Tests\Misc</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\..\library.properties">