sns: BaseFilter::status()

no real reason to expose internal state, just report filter readiness

code/espurna/filters/BaseFilter.h

@@ -11,16 +11,16 @@ class BaseFilter {
 public:
     virtual ~BaseFilter() = default;
 
-    // Reset internal value to default and also erases internal storage
+    // Reset internal state to default
     virtual void reset() {
     }
 
-    // Defaults to 0 aka no backing storage
-    virtual size_t capacity() const {
-        return 0;
+    // Defaults to false aka filter is not initialized
+    virtual bool status() const {
+        return false;
     }
 
-    // Resize the backing storage (when it is available)
+    // Resize the backing storage (when it is available) and reset internal state
     virtual void resize(size_t) {
     }
 

code/espurna/filters/LastFilter.h

@@ -13,8 +13,8 @@ public:
         _value = value;
     }
 
-    size_t capacity() const override {
-        return 1;
+    bool status() const override {
+        return true;
     }
 
     void reset() override {

code/espurna/filters/MaxFilter.h

@@ -15,8 +15,8 @@ public:
         _value = std::max(value, _value);
     }
 
-    size_t capacity() const override {
-        return 1;
+    bool status() const override {
+        return true;
     }
 
     void resize(size_t) override {

code/espurna/filters/MedianFilter.h

@@ -61,8 +61,8 @@ public:
         return out;
     }
 
-    size_t capacity() const override {
-        return _capacity;
+    bool status() const override {
+        return _values.capacity() > 0;
     }
 
     void resize(size_t capacity) override {
@@ -72,14 +72,12 @@ public:
 
 private:
     void _reset() {
-        auto previous = _values.size()
-            ? _values.back()
-            : 0.0;
-        _values.clear();
-        _values.push_back(previous);
-
+        if (_values.size()) {
+            _values.erase(_values.begin(), _values.end() - 1);
+        } else {
+            _values.clear();
+        }
     }
 
     std::vector<double> _values;
-    size_t _capacity = 0;
 };

code/espurna/filters/MovingAverageFilter.h

@@ -17,8 +17,8 @@ public:
         }
     }
 
-    size_t capacity() const override {
-        return _values.capacity();
+    bool status() const override {
+        return _values.capacity() > 0;
     }
 
     double value() const override {

code/espurna/filters/SumFilter.h

@@ -13,8 +13,8 @@ public:
         _value += value;
     }
 
-    size_t capacity() const override {
-        return 1;
+    bool status() const override {
+        return true;
     }
 
     void resize(size_t) override {

code/test/unit/src/filters/filters.cpp

@@ -19,12 +19,12 @@ namespace {
 void test_last() {
     auto filter = LastFilter();
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     filter.resize(123);
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     filter.update(123.4);
@@ -43,12 +43,12 @@ void test_last() {
 void test_max() {
     auto filter = MaxFilter();
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     filter.resize(567);
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     filter.update(5.0);
@@ -78,12 +78,12 @@ void test_max() {
 
 void test_median() {
     auto filter = MedianFilter();
-    TEST_ASSERT_EQUAL(0, filter.capacity());
+    TEST_ASSERT(!filter.status());
 
     const double one[] {4., 3., 5., 6., 2., 2., 3., 4., 7., 9.};
     filter.resize(std::size(one));
 
-    TEST_ASSERT_EQUAL(std::size(samples), filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     for (const auto& sample : one) {
@@ -95,6 +95,7 @@ void test_median() {
     const double two[] {6., 6.1, 6.2, 6.3, 6.4, 6.5, 2.5, 4.5, 2.6, 2.5, 2.4};
     filter.resize(std::size(two));
 
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(9, filter.value());
 
     for (const auto& sample : two) {
@@ -106,6 +107,7 @@ void test_median() {
     const double three[] {2.4, 2.4};
     filter.resize(std::size(three));
 
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(2.4, filter.value());
 
     for (const auto& sample : three) {
@@ -118,13 +120,13 @@ void test_median() {
 void test_moving_average() {
     auto filter = MovingAverageFilter();
 
-    TEST_ASSERT_EQUAL(0, filter.capacity());
+    TEST_ASSERT(!filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     const double samples[] {22., 22.3, 22.1, 22.1, 22.1, 22.0, 22.5, 22.1};
     filter.resize(std::size(samples));
 
-    TEST_ASSERT_EQUAL(std::size(samples), filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     for (const auto& sample : samples) {
@@ -137,13 +139,13 @@ void test_moving_average() {
 void test_sum() {
     auto filter = SumFilter();
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     const double samples[] {20., 20.1, 13., 10., 5., 14., 29., 32.};
     filter.resize(std::size(samples));
 
-    TEST_ASSERT_EQUAL(1, filter.capacity());
+    TEST_ASSERT(filter.status());
     TEST_ASSERT_EQUAL_DOUBLE(0.0, filter.value());
 
     for (const auto& sample : samples) {