Restore MovingMedian to the simpler single filter and provide ..Stack separately. Seems little point in coalescing memory there, now we have separate ring buffers anyway

src/common/MovingMedian.h

@@ -38,74 +38,96 @@ namespace RubberBand
 {
 
 template <typename T>
-class MovingMedianStack
+class MovingMedian : public SampleFilter<T>
 {
 public:
-    MovingMedianStack(int nfilters, int filterLength, float percentile = 50.f) :
+    MovingMedian(int filterLength, float percentile = 50.f) :
-        m_buffers(nfilters, filterLength),
+        m_buffer(filterLength),
-        m_sortspace(nfilters * filterLength, {}),
+        m_sortspace(filterLength, {})
-        m_length(filterLength)
     {
         setPercentile(percentile);
     }
 
-    ~MovingMedianStack() { 
+    ~MovingMedian() { 
     }
 
-    int getNFilters() const {
+    MovingMedian(const MovingMedian &) =default;
-        return m_buffers.size();
+    MovingMedian &operator=(const MovingMedian &) =default;
-    }
 
     int getSize() const {
-        return m_length;
+        return m_buffer.getSize();
     }
     
     void setPercentile(float p) {
-        m_index = int((m_length * p) / 100.f);
+        int length = getSize();
-        if (m_index >= m_length) m_index = m_length-1;
+        m_index = int((length * p) / 100.f);
+        if (m_index >= length) m_index = length-1;
         if (m_index < 0) m_index = 0;
     }
 
-    void push(int filter, T value) {
+    void push(T value) {
         if (value != value) {
             std::cerr << "WARNING: MovingMedian: NaN encountered" << std::endl;
             value = T();
         }
-        auto &buf = m_buffers[filter];
+        if (m_buffer.getWriteSpace() == 0) {
-        if (buf.getWriteSpace() == 0) {
+            T toDrop = m_buffer.readOne();
-            T toDrop = buf.readOne();
+            dropAndPut(toDrop, value);
-            dropAndPut(filter, toDrop, value);
+            m_buffer.writeOne(value);
-            buf.writeOne(value);
         } else {
-            put(filter, value);
+            put(value);
-            buf.writeOne(value);
+            m_buffer.writeOne(value);
         }
     }
 
-    T get(int filter) const {
+    T get() const {
-        const T *sorted = sortedFor(filter);
+	return m_sortspace[m_index];
-	return sorted[m_index];
     }
 
     void reset() {
-        for (auto &buf : m_buffers) buf.reset();
+        m_buffer.reset();
 	v_zero(m_sortspace.data(), m_sortspace.size());
     }
 
+    // Convenience function that applies a given filter to an array
+    // in-place. Array has length n. Modifies both the filter and the
+    // array.
+    //
+    static void filter(MovingMedian<T> &mm, T *v, int n) {
+        int fn = mm.getSize();
+        int lag = fn / 2;
+        mm.reset();
+        int i = 0;
+        for (; i < lag; ++i) {
+            if (i < n) mm.push(v[i]);
+        }
+        for (; i < n; ++i) {
+            mm.push(v[i]);
+            v[i-lag] = mm.get();
+        }
+        for (; i < lag; ++i) {
+            // just for the unusual case where lag > n
+            mm.push(T());
+            (void)mm.get();
+        }
+        for (; i < n + lag; ++i) {
+            mm.push(T());
+            v[i-lag] = mm.get();
+        }
+    }
+
+    // As above but with a vector argument
+    //
+    static void filter(MovingMedian<T> &mm, std::vector<T> &v) {
+        filter(mm, v.data(), v.size());
+    }
+    
 private:
-    FixedVector<SingleThreadRingBuffer<T>> m_buffers;
+    SingleThreadRingBuffer<T> m_buffer;
-    FixedVector<T> m_sortspace;
+    std::vector<T> m_sortspace;
-    int m_length;
     int m_index;
 
-    const T *sortedFor(int filter) const {
+    void dropAndPut(const T &toDrop, const T &toPut) {
-        return m_sortspace.data() + filter * m_length;
-    }
-    T *sortedFor(int filter) {
-        return m_sortspace.data() + filter * m_length;
-    }
-
-    void dropAndPut(int filter, const T &toDrop, const T &toPut) {
 	// precondition: sorted contains m_length values, one of which is toDrop
 	// postcondition: sorted contains m_length values, one of which is toPut
         // (and one instance of toDrop has been removed)
@@ -114,8 +136,8 @@ private:
         // longer than maybe 16 items). Two binary searches plus a
         // memmove should be faster for longer ones.
         
-        const int n = m_length;
+        const int n = getSize();
-        T *sorted = sortedFor(filter);
+        T *sorted = m_sortspace.data();
         int dropIx;
         if (toDrop <= *sorted) {
             // this is quite a common short-circuit in situations
@@ -175,12 +197,12 @@ private:
 #endif
     }
 
-    void put(int filter, const T &toPut) {
+    void put(const T &toPut) {
 	// precondition: sorted contains fewer than m_length values,
 	// packed at the start
 	// postcondition: sorted contains up to m_length values,
         // packed at the start, one of which is toPut
-        const int n = m_buffers[filter].getReadSpace(); // items in sorted
+        const int n = m_buffer.getReadSpace(); // items in sorted
 
 #ifdef DEBUG_MM
         if (n >= m_length) {
@@ -188,7 +210,7 @@ private:
         }
 #endif
             
-        T *sorted = sortedFor(filter);
+        T *sorted = m_sortspace.data();
         int putIx = std::lower_bound(sorted, sorted + n, toPut) - sorted;
 
 #ifdef DEBUG_MM
@@ -220,81 +242,46 @@ private:
         }
 #endif
     }
-
-    MovingMedianStack(const MovingMedianStack &) =delete;
-    MovingMedianStack &operator=(const MovingMedianStack &) =delete;
 };
 
 template <typename T>
-class MovingMedian : public SampleFilter<T>
+class MovingMedianStack
 {
 public:
-    MovingMedian(int size, float percentile = 50.f) :
+    MovingMedianStack(int nfilters, int size, float percentile = 50.f) :
-        m_mm(1, size, percentile)
+        m_stack(nfilters, { size, percentile })
     {
     }
 
-    ~MovingMedian() {
+    ~MovingMedianStack() {
     }
 
     int getSize() const {
-        return m_mm.getSize();
+        return m_stack[0].getSize();
     }
 
     void setPercentile(float p) {
-        m_mm.setPercentile(p);
+        for (auto &f: m_stack) {
+            f.setPercentile(p);
+        }
     }
 
-    void push(T value) {
+    void push(int filter, T value) {
-        m_mm.push(0, value);
+        m_stack[filter].push(value);
     }
 
-    T get() const {
+    T get(int filter) const {
-        return m_mm.get(0);
+        return m_stack[filter].get();
     }
 
     void reset() {
-        m_mm.reset();
+        for (auto &f: m_stack) {
+            f.reset();
         }
-
-    // Convenience function that applies a given filter to an array
-    // in-place. Array has length n. Modifies both the filter and the
-    // array.
-    //
-    static void filter(MovingMedian<T> &mm, T *v, int n) {
-        int fn = mm.getSize();
-        int lag = fn / 2;
-        mm.reset();
-        int i = 0;
-        for (; i < lag; ++i) {
-            if (i < n) mm.push(v[i]);
-        }
-        for (; i < n; ++i) {
-            mm.push(v[i]);
-            v[i-lag] = mm.get();
-        }
-        for (; i < lag; ++i) {
-            // just for the unusual case where lag > n
-            mm.push(T());
-            (void)mm.get();
-        }
-        for (; i < n + lag; ++i) {
-            mm.push(T());
-            v[i-lag] = mm.get();
-        }
-    }
-
-    // As above but with a vector argument
-    //
-    static void filter(MovingMedian<T> &mm, std::vector<T> &v) {
-        filter(mm, v.data(), v.size());
     }
     
 private:
-    MovingMedianStack<T> m_mm;
+    std::vector<MovingMedian<T>> m_stack;
-
-    MovingMedian(const MovingMedian &) =delete;
-    MovingMedian &operator=(const MovingMedian &) =delete;
 };
 
 }