pcm/Dsd{16,32}: convert public function to stateful class

src/pcm/Dsd16.cxx

@@ -18,7 +18,6 @@
  */
 
 #include "Dsd16.hxx"
-#include "Buffer.hxx"
 #include "util/ConstBuffer.hxx"
 
 /**
@@ -51,9 +50,14 @@ Dsd8To16(uint16_t *dest, const uint8_t *src,
 	}
 }
 
+void
+Dsd16Converter::Open(unsigned _channels) noexcept
+{
+	channels = _channels;
+}
+
 ConstBuffer<uint16_t>
-Dsd8To16(PcmBuffer &buffer, unsigned channels,
-	 ConstBuffer<uint8_t> _src) noexcept
+Dsd16Converter::Convert(ConstBuffer<uint8_t> _src) noexcept
 {
 	const size_t in_frames = _src.size / channels;
 	const size_t out_frames = in_frames / 2;

src/pcm/Dsd16.hxx

@@ -20,16 +20,27 @@
 #ifndef MPD_PCM_DSD_16_HXX
 #define MPD_PCM_DSD_16_HXX
 
+#include "Buffer.hxx"
+
 #include <stdint.h>
 
 template<typename T> struct ConstBuffer;
-class PcmBuffer;
 
 /**
  * Convert DSD_U8 to DSD_U16 (native endian, oldest bits in MSB).
  */
-ConstBuffer<uint16_t>
-Dsd8To16(PcmBuffer &buffer, unsigned channels,
-	 ConstBuffer<uint8_t> src) noexcept;
+class Dsd16Converter {
+	unsigned channels;
+
+	PcmBuffer buffer;
+
+public:
+	void Open(unsigned _channels) noexcept;
+
+	void Reset() noexcept {
+	}
+
+	ConstBuffer<uint16_t> Convert(ConstBuffer<uint8_t> src) noexcept;
+};
 
 #endif

src/pcm/Dsd32.cxx

@@ -53,9 +53,14 @@ Dsd8To32(uint32_t *dest, const uint8_t *src,
 	}
 }
 
+void
+Dsd32Converter::Open(unsigned _channels) noexcept
+{
+	channels = _channels;
+}
+
 ConstBuffer<uint32_t>
-Dsd8To32(PcmBuffer &buffer, unsigned channels,
-	 ConstBuffer<uint8_t> _src) noexcept
+Dsd32Converter::Convert(ConstBuffer<uint8_t> _src) noexcept
 {
 	const size_t in_frames = _src.size / channels;
 	const size_t out_frames = in_frames / 4;

src/pcm/Dsd32.hxx

@@ -20,16 +20,27 @@
 #ifndef MPD_PCM_DSD_32_HXX
 #define MPD_PCM_DSD_32_HXX
 
+#include "Buffer.hxx"
+
 #include <stdint.h>
 
 template<typename T> struct ConstBuffer;
-class PcmBuffer;
 
 /**
  * Convert DSD_U8 to DSD_U32 (native endian, oldest bits in MSB).
  */
-ConstBuffer<uint32_t>
-Dsd8To32(PcmBuffer &buffer, unsigned channels,
-	 ConstBuffer<uint8_t> src) noexcept;
+class Dsd32Converter {
+	unsigned channels;
+
+	PcmBuffer buffer;
+
+public:
+	void Open(unsigned _channels) noexcept;
+
+	void Reset() noexcept {
+	}
+
+	ConstBuffer<uint32_t> Convert(ConstBuffer<uint8_t> src) noexcept;
+};
 
 #endif

src/pcm/Export.cxx

@@ -24,13 +24,6 @@
 #include "util/ByteReverse.hxx"
 #include "util/ConstBuffer.hxx"
 
-#ifdef ENABLE_DSD
-#include "Dsd16.hxx"
-#include "Dsd32.hxx"
-#include "PcmDsd.hxx"
-#include "Dop.hxx"
-#endif
-
 #include <assert.h>
 
 void
@@ -57,12 +50,16 @@ PcmExport::Open(SampleFormat sample_format, unsigned _channels,
 		break;
 
 	case DsdMode::U16:
+		dsd16_converter.Open(_channels);
+
 		/* after the conversion to DSD_U16, the DSD samples
 		   are stuffed inside fake 16 bit samples */
 		sample_format = SampleFormat::S16;
 		break;
 
 	case DsdMode::U32:
+		dsd32_converter.Open(_channels);
+
 		/* after the conversion to DSD_U32, the DSD samples
 		   are stuffed inside fake 32 bit samples */
 		sample_format = SampleFormat::S32;
@@ -101,8 +98,14 @@ PcmExport::Reset() noexcept
 #ifdef ENABLE_DSD
 	switch (dsd_mode) {
 	case DsdMode::NONE:
+		break;
+
 	case DsdMode::U16:
+		dsd16_converter.Reset();
+		break;
+
 	case DsdMode::U32:
+		dsd32_converter.Reset();
 		break;
 
 	case DsdMode::DOP:
@@ -211,14 +214,12 @@ PcmExport::Export(ConstBuffer<void> data) noexcept
 		break;
 
 	case DsdMode::U16:
-		data = Dsd8To16(dsd_buffer, channels,
-				ConstBuffer<uint8_t>::FromVoid(data))
+		data = dsd16_converter.Convert(ConstBuffer<uint8_t>::FromVoid(data))
 			.ToVoid();
 		break;
 
 	case DsdMode::U32:
-		data = Dsd8To32(dsd_buffer, channels,
-				ConstBuffer<uint8_t>::FromVoid(data))
+		data = dsd32_converter.Convert(ConstBuffer<uint8_t>::FromVoid(data))
 			.ToVoid();
 		break;
 

src/pcm/Export.hxx

@@ -25,6 +25,8 @@
 #include "config.h"
 
 #ifdef ENABLE_DSD
+#include "Dsd16.hxx"
+#include "Dsd32.hxx"
 #include "Dop.hxx"
 #endif
 
@@ -48,11 +50,14 @@ class PcmExport {
 
 #ifdef ENABLE_DSD
 	/**
-	 * The buffer is used to convert DSD samples to DSD_U16 or DSD_U32.
-	 *
-	 * @see DsdMode::U16, DsdMode::U32
+	 * @see DsdMode::U16
+	 */
+	Dsd16Converter dsd16_converter;
+
+	/**
+	 * @see DsdMode::U32
 	 */
-	PcmBuffer dsd_buffer;
+	Dsd32Converter dsd32_converter;
 
 	/**
 	 * @see DsdMode::DOP