pcm/Normalizer: expose the class, convert functions to methods

src/filter/plugins/NormalizeFilterPlugin.cxx

@@ -12,20 +12,15 @@
 #include <string.h>
 
 class NormalizeFilter final : public Filter {
-	Compressor *const compressor;
+	PcmNormalizer normalizer;
 
 	PcmBuffer buffer;
 
 public:
 	explicit NormalizeFilter(const AudioFormat &audio_format)
-		:Filter(audio_format), compressor(Compressor_new()) {
+		:Filter(audio_format) {
 	}
 
-	~NormalizeFilter() override {
-		Compressor_delete(compressor);
-	}
-
-
 	NormalizeFilter(const NormalizeFilter &) = delete;
 	NormalizeFilter &operator=(const NormalizeFilter &) = delete;
 
@@ -59,7 +54,7 @@ NormalizeFilter::FilterPCM(std::span<const std::byte> src)
 	auto *dest = (int16_t *)buffer.Get(src.size());
 	memcpy(dest, src.data(), src.size());
 
-	Compressor_Process_int16(compressor, dest, src.size() / 2);
+	normalizer.ProcessS16(dest, src.size() / 2);
 	return { (const std::byte *)dest, src.size() };
 }
 

src/pcm/Normalizer.cxx

@@ -4,68 +4,17 @@
 
 #include "Normalizer.hxx"
 
-struct Compressor {
-	///! Target level (on a scale of 0-32767)
-	static constexpr int target = 16384;
-
-	//! The maximum amount to amplify by
-	static constexpr int maxgain = 32;
-
-	//! How much inertia ramping has
-	static constexpr int smooth = 8;
-
-        //! History of the peak values
-        int *const peaks;
-
-        //! History of the gain values
-        int *const gain;
-
-        //! History of clip amounts
-        int *const clipped;
-
-        unsigned int pos = 0;
-        const unsigned int bufsz;
-
-	Compressor(unsigned history) noexcept
-		:peaks(new int[history]{}),
-		 gain(new int[history]{}),
-		 clipped(new int[history]{}),
-		 bufsz(history)
-	{
-	}
-
-	~Compressor() noexcept {
-		delete[] peaks;
-		delete[] gain;
-		delete[] clipped;
-	}
-};
-
-struct Compressor *
-Compressor_new(unsigned int history) noexcept
-{
-	return new Compressor(history);
-}
-
 void
-Compressor_delete(struct Compressor *obj) noexcept
-{
-	delete obj;
-}
-
-void
-Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
-			 unsigned int count) noexcept
+PcmNormalizer::ProcessS16(int16_t *audio, unsigned int count) noexcept
 {
 	int16_t *ap;
 	unsigned int i;
-        int *peaks = obj->peaks;
-        int curGain = obj->gain[obj->pos];
+        int curGain = gain[pos];
         int newGain;
         int peakVal = 1;
         int peakPos = 0;
-        int slot = (obj->pos + 1) % obj->bufsz;
-        int *clipped = obj->clipped + slot;
+        int slot = (pos + 1) % bufsz;
+        int *clipped_ = clipped + slot;
         unsigned int ramp = count;
         int delta;
 
@@ -84,7 +33,7 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
 	peaks[slot] = peakVal;
 
 
-	for (i = 0; i < obj->bufsz; i++)
+	for (i = 0; i < bufsz; i++)
 	{
 		if (peaks[i] > peakVal)
 		{
@@ -94,15 +43,14 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
 	}
 
 	//! Determine target gain
-	newGain = (1 << 10)*obj->target/peakVal;
+	newGain = (1 << 10)*target/peakVal;
 
         //! Adjust the gain with inertia from the previous gain value
-        newGain = (curGain*((1 << obj->smooth) - 1) + newGain)
-                >> obj->smooth;
+        newGain = (curGain*((1 << smooth) - 1) + newGain) >> smooth;
 
         //! Make sure it's no more than the maximum gain value
-        if (newGain > (obj->maxgain << 10))
-                newGain = obj->maxgain << 10;
+        if (newGain > (maxgain << 10))
+                newGain = maxgain << 10;
 
         //! Make sure it's no less than 1:1
 	if (newGain < (1 << 10))
@@ -117,7 +65,7 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
         }
 
         //! Record the new gain
-        obj->gain[slot] = newGain;
+        gain[slot] = newGain;
 
         if (!ramp)
                 ramp = 1;
@@ -126,7 +74,7 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
 	delta = (newGain - curGain) / (int)ramp;
 
 	ap = audio;
-        *clipped = 0;
+        *clipped_ = 0;
 	for (i = 0; i < count; i++)
 	{
 		int sample;
@@ -135,11 +83,11 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
 		sample = *ap*curGain >> 10;
 		if (sample < -32768)
 		{
-			*clipped += -32768 - sample;
+			*clipped_ += -32768 - sample;
 			sample = -32768;
 		} else if (sample > 32767)
 		{
-			*clipped += sample - 32767;
+			*clipped_ += sample - 32767;
 			sample = 32767;
 		}
 		*ap++ = sample;
@@ -151,6 +99,6 @@ Compressor_Process_int16(struct Compressor *obj, int16_t *audio,
                         curGain = newGain;
 	}
 
-        obj->pos = slot;
+        pos = slot;
 }
 

src/pcm/Normalizer.hxx

@@ -6,19 +6,46 @@
 
 #include <cstdint>
 
-struct Compressor;
+class PcmNormalizer {
+	///! Target level (on a scale of 0-32767)
+	static constexpr int target = 16384;
 
-//! Create a new compressor (use history value of 0 for default)
-struct Compressor *
-Compressor_new(unsigned int history = 400) noexcept;
+	//! The maximum amount to amplify by
+	static constexpr int maxgain = 32;
 
-//! Delete a compressor
-void
-Compressor_delete(struct Compressor *) noexcept;
+	//! How much inertia ramping has
+	static constexpr int smooth = 8;
+
+        //! History of the peak values
+        int *const peaks;
+
+        //! History of the gain values
+        int *const gain;
+
+        //! History of clip amounts
+        int *const clipped;
+
+        unsigned int pos = 0;
+        const unsigned int bufsz;
+
+public:
+	PcmNormalizer(unsigned history=400) noexcept
+		:peaks(new int[history]{}),
+		 gain(new int[history]{}),
+		 clipped(new int[history]{}),
+		 bufsz(history)
+	{
+	}
+
+	~PcmNormalizer() noexcept {
+		delete[] peaks;
+		delete[] gain;
+		delete[] clipped;
+	}
 
 	//! Process 16-bit signed data
-void
-Compressor_Process_int16(struct Compressor *, int16_t *data, unsigned int count) noexcept;
+	void ProcessS16(int16_t *data, unsigned int count) noexcept;
+};
 
 //! TODO: Compressor_Process_int32, Compressor_Process_float, others as needed
 

test/run_normalize.cxx

@@ -22,7 +22,6 @@
 
 int main(int argc, char **argv)
 try {
-	struct Compressor *compressor;
 	static char buffer[4096];
 	ssize_t nbytes;
 
@@ -35,16 +34,14 @@ try {
 	if (argc > 1)
 		audio_format = ParseAudioFormat(argv[1], false);
 
-	compressor = Compressor_new();
+	PcmNormalizer normalizer;
 
 	while ((nbytes = read(0, buffer, sizeof(buffer))) > 0) {
-		Compressor_Process_int16(compressor,
-					 (int16_t *)buffer, nbytes / 2);
+		normalizer.ProcessS16((int16_t *)buffer, nbytes / 2);
 
 		[[maybe_unused]] ssize_t ignored = write(1, buffer, nbytes);
 	}
 
-	Compressor_delete(compressor);
 	return EXIT_SUCCESS;
 } catch (...) {
 	PrintException(std::current_exception());