AudioFormat: replace struct audio_format_string with class StringBuffer, return it

src/AudioFormat.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "AudioFormat.hxx"
+#include "util/StringBuffer.hxx"
 
 #include <assert.h>
 #include <stdio.h>
@@ -40,15 +41,13 @@ AudioFormat::ApplyMask(AudioFormat mask)
 	assert(IsValid());
 }
 
-const char *
-audio_format_to_string(const AudioFormat af,
-		       struct audio_format_string *s)
+StringBuffer<24>
+ToString(const AudioFormat af)
 {
-	assert(s != nullptr);
-
-	snprintf(s->buffer, sizeof(s->buffer), "%u:%s:%u",
+	StringBuffer<24> buffer;
+	snprintf(buffer.data(), buffer.capacity(), "%u:%s:%u",
 		 af.sample_rate, sample_format_to_string(af.format),
 		 af.channels);
 
-	return s->buffer;
+	return buffer;
 }

src/AudioFormat.hxx

@@ -23,8 +23,11 @@
 #include "pcm/SampleFormat.hxx"
 #include "Compiler.h"
 
-#include <stdint.h>
 #include <assert.h>
+#include <stdint.h>
+#include <stddef.h>
+
+template<size_t CAPACITY> class StringBuffer;
 
 static constexpr unsigned MAX_CHANNELS = 8;
 
@@ -147,13 +150,6 @@ struct AudioFormat {
 	double GetTimeToSize() const;
 };
 
-/**
- * Buffer for audio_format_string().
- */
-struct audio_format_string {
-	char buffer[24];
-};
-
 /**
  * Checks whether the sample rate is valid.
  *
@@ -226,9 +222,8 @@ AudioFormat::GetTimeToSize() const
  * @param s a buffer to print into
  * @return the string, or nullptr if the #AudioFormat object is invalid
  */
-gcc_pure gcc_malloc
-const char *
-audio_format_to_string(AudioFormat af,
-		       struct audio_format_string *s);
+gcc_const
+StringBuffer<24>
+ToString(AudioFormat af);
 
 #endif

src/command/PlayerCommands.cxx

@@ -30,6 +30,7 @@
 #include "Instance.hxx"
 #include "Idle.hxx"
 #include "AudioFormat.hxx"
+#include "util/StringBuffer.hxx"
 #include "util/ScopeExit.hxx"
 #include "util/Exception.hxx"
 
@@ -171,13 +172,9 @@ handle_status(Client &client, gcc_unused Request args, Response &r)
 			r.Format("duration: %1.3f\n",
 				 player_status.total_time.ToDoubleS());
 
-		if (player_status.audio_format.IsDefined()) {
-			struct audio_format_string af_string;
-
+		if (player_status.audio_format.IsDefined())
 			r.Format(COMMAND_STATUS_AUDIO ": %s\n",
-				 audio_format_to_string(player_status.audio_format,
-							&af_string));
-		}
+				 ToString(player_status.audio_format).c_str());
 	}
 
 #ifdef ENABLE_DATABASE

src/decoder/Bridge.cxx

@@ -32,6 +32,7 @@
 #include "Log.hxx"
 #include "input/InputStream.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/StringBuffer.hxx"
 
 #include <assert.h>
 #include <string.h>
@@ -246,15 +247,13 @@ void
 DecoderBridge::Ready(const AudioFormat audio_format,
 		     bool seekable, SignedSongTime duration)
 {
-	struct audio_format_string af_string;
-
 	assert(convert == nullptr);
 	assert(stream_tag == nullptr);
 	assert(decoder_tag == nullptr);
 	assert(!seeking);
 
 	FormatDebug(decoder_domain, "audio_format=%s, seekable=%s",
-		    audio_format_to_string(audio_format, &af_string),
+		    ToString(audio_format).c_str(),
 		    seekable ? "true" : "false");
 
 	{
@@ -264,8 +263,7 @@ DecoderBridge::Ready(const AudioFormat audio_format,
 
 	if (dc.in_audio_format != dc.out_audio_format) {
 		FormatDebug(decoder_domain, "converting to %s",
-			    audio_format_to_string(dc.out_audio_format,
-						   &af_string));
+			    ToString(dc.out_audio_format).c_str());
 
 		convert = new PcmConvert();
 

src/filter/plugins/ChainFilterPlugin.cxx

@@ -24,6 +24,7 @@
 #include "filter/FilterRegistry.hxx"
 #include "AudioFormat.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/StringBuffer.hxx"
 #include "util/RuntimeError.hxx"
 
 #include <memory>
@@ -108,10 +109,9 @@ PreparedChainFilter::Child::Open(const AudioFormat &prev_audio_format)
 	if (conv_audio_format != prev_audio_format) {
 		delete new_filter;
 
-		struct audio_format_string s;
 		throw FormatRuntimeError("Audio format not supported by filter '%s': %s",
 					 name,
-					 audio_format_to_string(prev_audio_format, &s));
+					 ToString(prev_audio_format).c_str());
 	}
 
 	return new_filter;

src/output/OutputThread.cxx

@@ -35,6 +35,7 @@
 #include "thread/Slack.hxx"
 #include "thread/Name.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/StringBuffer.hxx"
 #include "util/ScopeExit.hxx"
 #include "util/RuntimeError.hxx"
 #include "Log.hxx"
@@ -154,14 +155,11 @@ AudioOutput::Open()
 		}
 	}
 
-	if (f != source.GetInputAudioFormat() || f != out_audio_format) {
-		struct audio_format_string afs1, afs2, afs3;
+	if (f != source.GetInputAudioFormat() || f != out_audio_format)
 		FormatDebug(output_domain, "converting in=%s -> f=%s -> out=%s",
-			    audio_format_to_string(source.GetInputAudioFormat(),
-						   &afs1),
-			    audio_format_to_string(f, &afs2),
-			    audio_format_to_string(out_audio_format, &afs3));
-	}
+			    ToString(source.GetInputAudioFormat()).c_str(),
+			    ToString(f).c_str(),
+			    ToString(out_audio_format).c_str());
 }
 
 void
@@ -176,11 +174,10 @@ AudioOutput::OpenOutputAndConvert(AudioFormat desired_audio_format)
 							  name, plugin.name));
 	}
 
-	struct audio_format_string af_string;
 	FormatDebug(output_domain,
 		    "opened plugin=%s name=\"%s\" audio_format=%s",
 		    plugin.name, name,
-		    audio_format_to_string(out_audio_format, &af_string));
+		    ToString(out_audio_format).c_str());
 
 	try {
 		convert_filter_set(convert_filter.Get(), out_audio_format);

test/FakeDecoderAPI.cxx

@@ -21,6 +21,7 @@
 #include "FakeDecoderAPI.hxx"
 #include "decoder/DecoderAPI.hxx"
 #include "input/InputStream.hxx"
+#include "util/StringBuffer.hxx"
 #include "Compiler.h"
 
 #include <stdexcept>
@@ -33,13 +34,11 @@ FakeDecoder::Ready(const AudioFormat audio_format,
 		   gcc_unused bool seekable,
 		   SignedSongTime duration)
 {
-	struct audio_format_string af_string;
-
 	assert(!initialized);
 	assert(audio_format.IsValid());
 
 	fprintf(stderr, "audio_format=%s duration=%f\n",
-		audio_format_to_string(audio_format, &af_string),
+		ToString(audio_format).c_str(),
 		duration.ToDoubleS());
 
 	initialized = true;

test/TestAudioFormat.cxx

@@ -21,6 +21,7 @@
 #include "TestAudioFormat.hxx"
 #include "AudioFormat.hxx"
 #include "AudioParser.hxx"
+#include "util/StringBuffer.hxx"
 
 #include <cppunit/TestAssert.h>
 
@@ -51,8 +52,7 @@ struct assertion_traits<AudioFormat>
 
 	static std::string toString(AudioFormat x)
 	{
-		struct audio_format_string s;
-		return audio_format_to_string(x, &s);
+		return ToString(x).c_str();
 	}
 };
 }
@@ -80,10 +80,8 @@ static constexpr AudioFormatStringTest af_mask_tests[] = {
 void
 AudioFormatTest::TestToString()
 {
-	struct audio_format_string s;
-
 	for (const auto &i : af_string_tests)
-		CPPUNIT_ASSERT_EQUAL(i.s, audio_format_to_string(i.af, &s));
+		CPPUNIT_ASSERT_EQUAL(i.s, ToString(i.af).c_str());
 }
 
 void

test/run_filter.cxx

@@ -28,6 +28,7 @@
 #include "pcm/Volume.hxx"
 #include "mixer/MixerControl.hxx"
 #include "util/ConstBuffer.hxx"
+#include "util/StringBuffer.hxx"
 #include "system/FatalError.hxx"
 #include "Log.hxx"
 
@@ -62,7 +63,6 @@ load_filter(const char *name)
 
 int main(int argc, char **argv)
 try {
-	struct audio_format_string af_string;
 	char buffer[4096];
 
 	if (argc < 3 || argc > 4) {
@@ -97,7 +97,7 @@ try {
 	const AudioFormat out_audio_format = filter->GetOutAudioFormat();
 
 	fprintf(stderr, "audio_format=%s\n",
-		audio_format_to_string(out_audio_format, &af_string));
+		ToString(out_audio_format).c_str());
 
 	/* play */
 

test/run_output.cxx

@@ -33,6 +33,7 @@
 #include "ReplayGainConfig.hxx"
 #include "pcm/PcmConvert.hxx"
 #include "filter/FilterRegistry.hxx"
+#include "util/StringBuffer.hxx"
 #include "util/RuntimeError.hxx"
 #include "util/ScopeExit.hxx"
 #include "Log.hxx"
@@ -86,9 +87,8 @@ run_output(AudioOutput *ao, AudioFormat audio_format)
 	ao_plugin_open(ao, audio_format);
 	AtScopeExit(ao) { ao_plugin_close(ao); };
 
-	struct audio_format_string af_string;
 	fprintf(stderr, "audio_format=%s\n",
-		audio_format_to_string(audio_format, &af_string));
+		ToString(audio_format).c_str());
 
 	size_t frame_size = audio_format.GetFrameSize();