pcm/Dsd{16,32}: stash odd frames away for the next call

Similar to commit 32380d1db046dc596e9f8198d22050b2beab8a41, these are
the final parts for really fixing
https://github.com/MusicPlayerDaemon/MPD/issues/469

4 files changed, 24 insertions, 21 deletions

diff --git a/src/pcm/Dsd16.cxx b/src/pcm/Dsd16.cxx
index 2052abce0..56a2bd65e 100644
--- a/src/pcm/Dsd16.cxx
+++ b/src/pcm/Dsd16.cxx
@@ -20,6 +20,8 @@
 #include "Dsd16.hxx"
 #include "util/ConstBuffer.hxx"
 
+#include <functional>
+
 /**
  * Construct a 16 bit integer from two bytes.
  */
@@ -54,18 +56,14 @@ void
 Dsd16Converter::Open(unsigned _channels) noexcept
 {
 	channels = _channels;
+
+	rest_buffer.Open(channels);
 }
 
 ConstBuffer<uint16_t>
-Dsd16Converter::Convert(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;
-	const size_t out_samples = out_frames * channels;
-
-	const uint8_t *src = _src.data;
-	const auto dest = buffer.GetT<uint16_t>(out_samples);
-	Dsd8To16(dest, src, out_frames, channels);
-
-	return {dest, out_samples};
+	using namespace std::placeholders;
+	return rest_buffer.Process<uint16_t>(buffer, src, channels,
+					     std::bind(Dsd8To16, _1, _2, _3, channels));
 }
diff --git a/src/pcm/Dsd16.hxx b/src/pcm/Dsd16.hxx
index 227e8d479..18b31b83a 100644
--- a/src/pcm/Dsd16.hxx
+++ b/src/pcm/Dsd16.hxx
@@ -21,6 +21,7 @@
 #define MPD_PCM_DSD_16_HXX
 
 #include "Buffer.hxx"
+#include "RestBuffer.hxx"
 
 #include <stdint.h>
 
@@ -34,10 +35,13 @@ class Dsd16Converter {
 
 	PcmBuffer buffer;
 
+	PcmRestBuffer<uint8_t, 2> rest_buffer;
+
 public:
 	void Open(unsigned _channels) noexcept;
 
 	void Reset() noexcept {
+		rest_buffer.Reset();
 	}
 
 	ConstBuffer<uint16_t> Convert(ConstBuffer<uint8_t> src) noexcept;
diff --git a/src/pcm/Dsd32.cxx b/src/pcm/Dsd32.cxx
index e9c09f633..cefb5932f 100644
--- a/src/pcm/Dsd32.cxx
+++ b/src/pcm/Dsd32.cxx
@@ -18,9 +18,10 @@
  */
 
 #include "Dsd32.hxx"
-#include "Buffer.hxx"
 #include "util/ConstBuffer.hxx"
 
+#include <functional>
+
 /**
  * Construct a 32 bit integer from four bytes.
  */
@@ -57,18 +58,14 @@ void
 Dsd32Converter::Open(unsigned _channels) noexcept
 {
 	channels = _channels;
+
+	rest_buffer.Open(channels);
 }
 
 ConstBuffer<uint32_t>
-Dsd32Converter::Convert(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;
-	const size_t out_samples = out_frames * channels;
-
-	const uint8_t *src = _src.data;
-	const auto dest = buffer.GetT<uint32_t>(out_samples);
-	Dsd8To32(dest, src, out_frames, channels);
-
-	return {dest, out_samples};
+	using namespace std::placeholders;
+	return rest_buffer.Process<uint32_t>(buffer, src, channels,
+					     std::bind(Dsd8To32, _1, _2, _3, channels));
 }
diff --git a/src/pcm/Dsd32.hxx b/src/pcm/Dsd32.hxx
index 0b2d3570d..f6036c527 100644
--- a/src/pcm/Dsd32.hxx
+++ b/src/pcm/Dsd32.hxx
@@ -21,6 +21,7 @@
 #define MPD_PCM_DSD_32_HXX
 
 #include "Buffer.hxx"
+#include "RestBuffer.hxx"
 
 #include <stdint.h>
 
@@ -34,10 +35,13 @@ class Dsd32Converter {
 
 	PcmBuffer buffer;
 
+	PcmRestBuffer<uint8_t, 4> rest_buffer;
+
 public:
 	void Open(unsigned _channels) noexcept;
 
 	void Reset() noexcept {
+		rest_buffer.Reset();
 	}
 
 	ConstBuffer<uint32_t> Convert(ConstBuffer<uint8_t> src) noexcept;