pcm/Dsd2Pcm: add integer-only implementation

src/pcm/Dsd2Pcm.cxx

@@ -31,6 +31,7 @@ or implied, of Sebastian Gesemann.
  */
 
 #include "Dsd2Pcm.hxx"
+#include "Traits.hxx"
 #include "util/bit_reverse.h"
 #include "util/GenerateArray.hxx"
 
@@ -150,6 +151,29 @@ GenerateCtable(int t) noexcept
 
 static constexpr auto ctables = GenerateArray<CTABLES>(GenerateCtable);
 
+template<typename Traits=SampleTraits<SampleFormat::S24_P32>>
+static constexpr auto
+CalculateCtableS24Value(size_t i, size_t j) noexcept
+{
+	return typename Traits::value_type(ctables[i][j] * Traits::MAX);
+}
+
+struct GenerateCtableS24Value {
+	size_t i;
+
+	constexpr auto operator()(size_t j) const noexcept {
+		return CalculateCtableS24Value(i, j);
+	}
+};
+
+static constexpr auto
+GenerateCtableS24(size_t i) noexcept
+{
+	return GenerateArray<256>(GenerateCtableS24Value{i});
+}
+
+static constexpr auto ctables_s24 = GenerateArray<CTABLES>(GenerateCtableS24);
+
 void
 Dsd2Pcm::Reset() noexcept
 {
@@ -191,6 +215,25 @@ Dsd2Pcm::TranslateSample(size_t ffp, uint8_t src) noexcept
 	return CalcOutputSample(ffp);
 }
 
+inline int32_t
+Dsd2Pcm::CalcOutputSampleS24(size_t ffp) const noexcept
+{
+	int32_t acc = 0;
+	for (size_t i = 0; i < CTABLES; ++i) {
+		uint8_t bite1 = fifo[(ffp              -i) & FIFOMASK];
+		uint8_t bite2 = fifo[(ffp-(CTABLES*2-1)+i) & FIFOMASK];
+		acc += ctables_s24[i][bite1] + ctables_s24[i][bite2];
+	}
+	return acc;
+}
+
+inline int32_t
+Dsd2Pcm::TranslateSampleS24(size_t ffp, uint8_t src) noexcept
+{
+	ApplySample(ffp, src);
+	return CalcOutputSampleS24(ffp);
+}
+
 void
 Dsd2Pcm::Translate(size_t samples,
 		   const uint8_t *gcc_restrict src, ptrdiff_t src_stride,
@@ -208,6 +251,22 @@ Dsd2Pcm::Translate(size_t samples,
 }
 
 void
+Dsd2Pcm::TranslateS24(size_t samples,
+		      const uint8_t *gcc_restrict src, ptrdiff_t src_stride,
+		      int32_t *dst, ptrdiff_t dst_stride) noexcept
+{
+	size_t ffp = fifopos;
+	while (samples-- > 0) {
+		uint8_t bite1 = *src;
+		src += src_stride;
+		*dst = TranslateSampleS24(ffp, bite1);
+		dst += dst_stride;
+		ffp = (ffp + 1) & FIFOMASK;
+	}
+	fifopos = ffp;
+}
+
+void
 MultiDsd2Pcm::Translate(unsigned channels, size_t n_frames,
 			const uint8_t *src, float *dest) noexcept
 {
@@ -237,3 +296,34 @@ MultiDsd2Pcm::TranslateStereo(size_t n_frames,
 	}
 	fifopos = ffp;
 }
+
+void
+MultiDsd2Pcm::TranslateS24(unsigned channels, size_t n_frames,
+			   const uint8_t *src, int32_t *dest) noexcept
+{
+	assert(channels <= per_channel.max_size());
+
+	if (channels == 2) {
+		TranslateStereoS24(n_frames, src, dest);
+		return;
+	}
+
+	for (unsigned i = 0; i < channels; ++i) {
+		per_channel[i].TranslateS24(n_frames,
+					    src++, channels,
+					    dest++, channels);
+	}
+}
+
+inline void
+MultiDsd2Pcm::TranslateStereoS24(size_t n_frames,
+				 const uint8_t *src, int32_t *dest) noexcept
+{
+	size_t ffp = fifopos;
+	while (n_frames-- > 0) {
+		*dest++ = per_channel[0].TranslateSampleS24(ffp, *src++);
+		*dest++ = per_channel[1].TranslateSampleS24(ffp, *src++);
+		ffp = (ffp + 1) & Dsd2Pcm::FIFOMASK;
+	}
+	fifopos = ffp;
+}

src/pcm/Dsd2Pcm.hxx

@@ -79,10 +79,17 @@ public:
 		       const uint8_t *src, ptrdiff_t src_stride,
 		       float *dst, ptrdiff_t dst_stride) noexcept;
 
+	void TranslateS24(size_t samples,
+			  const uint8_t *src, ptrdiff_t src_stride,
+			  int32_t *dst, ptrdiff_t dst_stride) noexcept;
+
 private:
 	void ApplySample(size_t ffp, uint8_t src) noexcept;
 	float CalcOutputSample(size_t ffp) const noexcept;
 	float TranslateSample(size_t ffp, uint8_t src) noexcept;
+
+	int32_t CalcOutputSampleS24(size_t ffp) const noexcept;
+	int32_t TranslateSampleS24(size_t ffp, uint8_t src) noexcept;
 };
 
 class MultiDsd2Pcm {
@@ -100,12 +107,18 @@ public:
 	void Translate(unsigned channels, size_t n_frames,
 		       const uint8_t *src, float *dest) noexcept;
 
+	void TranslateS24(unsigned channels, size_t n_frames,
+			  const uint8_t *src, int32_t *dest) noexcept;
+
 private:
 	/**
 	 * Optimized implementation for the common case.
 	 */
 	void TranslateStereo(size_t n_frames,
 			     const uint8_t *src, float *dest) noexcept;
+
+	void TranslateStereoS24(size_t n_frames,
+				const uint8_t *src, int32_t *dest) noexcept;
 };
 
 #endif /* include guard DSD2PCM_H_INCLUDED */

src/pcm/PcmDsd.cxx

@@ -38,3 +38,19 @@ PcmDsd::ToFloat(unsigned channels, ConstBuffer<uint8_t> src) noexcept
 	dsd2pcm.Translate(channels, num_frames, src.data, dest);
 	return { dest, num_samples };
 }
+
+ConstBuffer<int32_t>
+PcmDsd::ToS24(unsigned channels, ConstBuffer<uint8_t> src) noexcept
+{
+	assert(!src.IsNull());
+	assert(!src.empty());
+	assert(src.size % channels == 0);
+
+	const size_t num_samples = src.size;
+	const size_t num_frames = src.size / channels;
+
+	auto *dest = buffer.GetT<int32_t>(num_samples);
+
+	dsd2pcm.TranslateS24(channels, num_frames, src.data, dest);
+	return { dest, num_samples };
+}

src/pcm/PcmDsd.hxx

@@ -42,6 +42,9 @@ public:
 
 	ConstBuffer<float> ToFloat(unsigned channels,
 				   ConstBuffer<uint8_t> src) noexcept;
+
+	ConstBuffer<int32_t> ToS24(unsigned channels,
+				   ConstBuffer<uint8_t> src) noexcept;
 };
 
 #endif