Add OSS buffer parameters

3 files changed, 60 insertions, 3 deletions

diff --git a/drumgizmo/drumgizmoc.cc b/drumgizmo/drumgizmoc.cc
index 01025e7..4ad2550 100644
--- a/drumgizmo/drumgizmoc.cc
+++ b/drumgizmo/drumgizmoc.cc
@@ -88,7 +88,9 @@ static const char usage_str[] =
     "  alsa:      dev=<device> (default 'default'), frames=<frames> (default "
     "32)\n"
     "             srate=<samplerate> (default 441000)\n"
-    "  oss:       dev=<device> (default '/dev/dsp'), srate=<samplerate>\n"
+    "  oss:       dev=<device> (default '/dev/dsp'), srate=<samplerate>,\n"
+    "             max_fragments=<number> (default 4, see man page for more info),\n"
+    "             fragment_size=<selector> (default 8, see man page for more info)\n"
     "  wavfile:   file=<filename> (default 'output'), srate=<samplerate> "
     "(default 44100)\n"
     "  jackaudio:\n"
diff --git a/drumgizmo/output/oss.cc b/drumgizmo/output/oss.cc
index 4e02e97..ee13a84 100644
--- a/drumgizmo/output/oss.cc
+++ b/drumgizmo/output/oss.cc
@@ -38,6 +38,8 @@ OSSOutputEngine::OSSOutputEngine()
 	, srate{44100}
 	, format{AFMT_S32_NE}
 	, data{}
+	, max_fragments{4}
+	, fragment_size{8}
 {
 	data.clear();
 	data.resize(1024 * num_channels);
@@ -45,7 +47,7 @@ OSSOutputEngine::OSSOutputEngine()
 
 bool OSSOutputEngine::init(const Channels& channels)
 {
-	int tmp, mode = O_WRONLY;
+	int tmp, mode = O_WRONLY, fragments;
 	num_channels = channels.size();
 
 	if((fd = open(dev.data(), mode, 0)) == -1)
@@ -54,6 +56,14 @@ bool OSSOutputEngine::init(const Channels& channels)
 		return false;
 	}
 
+	fragments = max_fragments << 16 | fragment_size;
+	tmp = fragments;
+	if (ioctl(fd, SNDCTL_DSP_SETFRAGMENT, &tmp) == -1 || tmp != fragments)
+	{
+		perror("SNDCTL_DSP_SETFRAGMENT");
+		exit(-1);
+	}
+
 	tmp = format;
 	if(ioctl(fd, SNDCTL_DSP_SETFMT, &tmp) == -1 || tmp != format)
 	{
@@ -99,6 +109,44 @@ void OSSOutputEngine::setParm(const std::string& parm, const std::string& value)
 			std::cerr << value << std::endl;
 		}
 	}
+	else if(parm == "max_fragments")
+	{
+		try
+		{
+			max_fragments = std::stoi(value);
+		}
+		catch(...)
+		{
+			std::cerr << "[OSSOutputEngine] Invalid max_fragments ";
+			std::cerr << value << std::endl;
+		}
+		if(max_fragments < 2)
+		{
+			std::cerr << "[OSSoutputEngine] max_fragments must be at least 2\n";
+			std::cerr << "Setting max_fragments to 2" << std::endl;
+			max_fragments = 2;
+		}
+	}
+	else if(parm == "fragment_size")
+	{
+		try
+		{
+			fragment_size = std::stoi(value);
+		}
+		catch(...)
+		{
+			std::cerr << "[OSSOutputEngine] Invalid fragment_size ";
+			std::cerr << value << std::endl;
+		}
+		if(fragment_size < 4)
+		{
+			std::cerr << "[OSSoutputEngine] fragment_size must be at least 4\n";
+			std::cerr << "Setting fragment_size to 4 (";
+			fragment_size = 4;
+			auto fragment_byte_size = 1 << fragment_size;
+			std::cerr << fragment_byte_size << "Bytes)" << std::endl;
+		}
+	}
 	else
 	{
 		std::cerr << "[OSSOutputEngine] Unsupported parameter '";
@@ -106,6 +154,11 @@ void OSSOutputEngine::setParm(const std::string& parm, const std::string& value)
 	}
 }
 
+void OSSOutputEngine::pre(size_t nsamples)
+{
+	data.resize(nsamples * num_channels);
+}
+
 void OSSOutputEngine::run(int ch, sample_t* samples, size_t nsamples)
 {
 	// Convert to int format and
diff --git a/drumgizmo/output/oss.h b/drumgizmo/output/oss.h
index d44cd1c..889021f 100644
--- a/drumgizmo/output/oss.h
+++ b/drumgizmo/output/oss.h
@@ -39,7 +39,7 @@ public:
 	void setParm(const std::string& parm, const std::string& value) override;
 	bool start() override { return true; };
 	void stop() override {};
-	void pre(size_t nsamples) override { data.resize(nsamples * num_channels); };
+	void pre(size_t nsamples) override;
 	void run(int ch, sample_t* samples, size_t nsamples) override;
 	void post(size_t nsamples) override;
 	bool isFreewheeling() const override { return false; };
@@ -52,5 +52,7 @@ private:
 	std::size_t num_channels;
 	unsigned int srate;
 	unsigned int format;
+	unsigned int max_fragments;
+	unsigned int fragment_size;
 	std::vector<std::int32_t> data;
 };