*: add "noexcept" to many, many function prototypes

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

src/output/plugins/AlsaOutputPlugin.cxx

@@ -249,7 +249,7 @@ alsa_test_default_device()
  */
 gcc_const
 static snd_pcm_format_t
-ToAlsaPcmFormat(SampleFormat sample_format)
+ToAlsaPcmFormat(SampleFormat sample_format) noexcept
 {
 	switch (sample_format) {
 	case SampleFormat::UNDEFINED:
@@ -287,7 +287,7 @@ ToAlsaPcmFormat(SampleFormat sample_format)
  * SND_PCM_FORMAT_UNKNOWN if the format cannot be byte-swapped.
  */
 static snd_pcm_format_t
-ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt)
+ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt) noexcept
 {
 	switch (fmt) {
 	case SND_PCM_FORMAT_S16_LE: return SND_PCM_FORMAT_S16_BE;

src/output/plugins/FifoOutputPlugin.cxx

@@ -66,7 +66,7 @@ public:
 	void Open(AudioFormat &audio_format);
 	void Close();
 
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 	size_t Play(const void *chunk, size_t size);
 	void Cancel();
 };
@@ -205,7 +205,7 @@ FifoOutput::Cancel()
 }
 
 inline std::chrono::steady_clock::duration
-FifoOutput::Delay() const
+FifoOutput::Delay() const noexcept
 {
 	return timer->IsStarted()
 		? timer->GetDelay()

src/output/plugins/JackOutputPlugin.cxx

@@ -119,7 +119,7 @@ struct JackOutput {
 	 * on all channels.
 	 */
 	gcc_pure
-	jack_nframes_t GetAvailable() const;
+	jack_nframes_t GetAvailable() const noexcept;
 
 	void Process(jack_nframes_t nframes);
 
@@ -128,7 +128,7 @@ struct JackOutput {
 	 */
 	size_t WriteSamples(const float *src, size_t n_frames);
 
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return base.pause && pause && !shutdown
 			? std::chrono::seconds(1)
 			: std::chrono::steady_clock::duration::zero();
@@ -215,7 +215,7 @@ JackOutput::JackOutput(const ConfigBlock &block)
 }
 
 inline jack_nframes_t
-JackOutput::GetAvailable() const
+JackOutput::GetAvailable() const noexcept
 {
 	size_t min = jack_ringbuffer_read_space(ringbuffer[0]);
 

src/output/plugins/NullOutputPlugin.cxx

@@ -49,7 +49,7 @@ public:
 			delete timer;
 	}
 
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return sync && timer->IsStarted()
 			? timer->GetDelay()
 			: std::chrono::steady_clock::duration::zero();

src/output/plugins/OpenALOutputPlugin.cxx

@@ -58,7 +58,7 @@ class OpenALOutput {
 	void Close();
 
 	gcc_pure
-	std::chrono::steady_clock::duration Delay() const {
+	std::chrono::steady_clock::duration Delay() const noexcept {
 		return filled < NUM_BUFFERS || HasProcessed()
 			? std::chrono::steady_clock::duration::zero()
 			/* we don't know exactly how long we must wait

src/output/plugins/OssOutputPlugin.cxx

@@ -391,7 +391,7 @@ oss_setup_sample_rate(int fd, AudioFormat &audio_format)
  */
 gcc_const
 static int
-sample_format_to_oss(SampleFormat format)
+sample_format_to_oss(SampleFormat format) noexcept
 {
 	switch (format) {
 	case SampleFormat::UNDEFINED:
@@ -430,7 +430,7 @@ sample_format_to_oss(SampleFormat format)
  */
 gcc_const
 static SampleFormat
-sample_format_from_oss(int format)
+sample_format_from_oss(int format) noexcept
 {
 	switch (format) {
 	case AFMT_S8:

src/output/plugins/PulseOutputPlugin.cxx

@@ -90,7 +90,6 @@ public:
 		Signal();
 	}
 
-	gcc_const
 	static bool TestDefaultDevice();
 
 	static PulseOutput *Create(const ConfigBlock &block);

src/output/plugins/RoarOutputPlugin.cxx

@@ -73,7 +73,7 @@ static constexpr Domain roar_output_domain("roar_output");
 
 gcc_pure
 static int
-GetConfiguredRole(const ConfigBlock &block)
+GetConfiguredRole(const ConfigBlock &block) noexcept
 {
 	const char *role = block.GetBlockValue("role");
 	return role != nullptr

src/output/plugins/ShoutOutputPlugin.cxx

@@ -63,7 +63,7 @@ struct ShoutOutput final {
 	void Open(AudioFormat &audio_format);
 	void Close();
 
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 	void SendTag(const Tag &tag);
 	size_t Play(const void *chunk, size_t size);
 	void Cancel();
@@ -361,7 +361,7 @@ ShoutOutput::Open(AudioFormat &audio_format)
 }
 
 std::chrono::steady_clock::duration
-ShoutOutput::Delay() const
+ShoutOutput::Delay() const noexcept
 {
 	int delay = shout_delay(shout_conn);
 	if (delay < 0)

src/output/plugins/httpd/HttpdClient.cxx

@@ -260,7 +260,7 @@ HttpdClient::TryWritePageN(const Page &page, size_t position, ssize_t n)
 }
 
 ssize_t
-HttpdClient::GetBytesTillMetaData() const
+HttpdClient::GetBytesTillMetaData() const noexcept
 {
 	if (metadata_requested &&
 	    current_page->size - current_position > metaint - metadata_fill)

src/output/plugins/httpd/HttpdClient.hxx

@@ -168,7 +168,7 @@ public:
 	bool SendResponse();
 
 	gcc_pure
-	ssize_t GetBytesTillMetaData() const;
+	ssize_t GetBytesTillMetaData() const noexcept;
 
 	ssize_t TryWritePage(const Page &page, size_t position);
 	ssize_t TryWritePageN(const Page &page, size_t position, ssize_t n);

src/output/plugins/httpd/HttpdInternal.hxx

@@ -218,7 +218,7 @@ public:
 	void SendHeader(HttpdClient &client) const;
 
 	gcc_pure
-	std::chrono::steady_clock::duration Delay() const;
+	std::chrono::steady_clock::duration Delay() const noexcept;
 
 	/**
 	 * Reads data from the encoder (as much as available) and

src/output/plugins/httpd/HttpdOutputPlugin.cxx

@@ -345,7 +345,7 @@ HttpdOutput::SendHeader(HttpdClient &client) const
 }
 
 inline std::chrono::steady_clock::duration
-HttpdOutput::Delay() const
+HttpdOutput::Delay() const noexcept
 {
 	if (!LockHasClients() && base.pause) {
 		/* if there's no client and this output is paused,
@@ -366,7 +366,7 @@ HttpdOutput::Delay() const
 }
 
 static std::chrono::steady_clock::duration
-httpd_output_delay(AudioOutput *ao)
+httpd_output_delay(AudioOutput *ao) noexcept
 {
 	HttpdOutput *httpd = HttpdOutput::Cast(ao);