Load sound from memory

* Remove trailing lines from src/sound_openal.cpp
* Don't do a horribly ugly copy of the file's path, allocating and deallocating a
	10 kb buffer in the process. This copy was needed for backwards compatibility
	with libvorbis 1.3.1 and earlier, as the removed comment explains.
	However, even Ubuntu precise has 1.3.2 already. Dropping support and sparing
	the ugly copy can therefore be considered safe.
* Actually load sounds from the memory, not caching them at the disk first,
	removing the old hack. This is the main motivation for the commit.

src/sound_openal.cpp

@@ -111,31 +111,19 @@ struct SoundBuffer
 	std::vector<char> buffer;
 };
 
-SoundBuffer* loadOggFile(const std::string &filepath)
+SoundBuffer *load_opened_ogg_file(OggVorbis_File *oggFile,
+		const std::string &filename_for_logging)
 {
 	int endian = 0; // 0 for Little-Endian, 1 for Big-Endian
 	int bitStream;
 	long bytes;
 	char array[BUFFER_SIZE]; // Local fixed size array
 	vorbis_info *pInfo;
-	OggVorbis_File oggFile;
-	
-	// Do a dumb-ass static string copy for old versions of ov_fopen
-	// because they expect a non-const char*
-	char nonconst[10000];
-	snprintf(nonconst, 10000, "%s", filepath.c_str());
-	// Try opening the given file
-	//if(ov_fopen(filepath.c_str(), &oggFile) != 0)
-	if(ov_fopen(nonconst, &oggFile) != 0)
-	{
-		infostream<<"Audio: Error opening "<<filepath<<" for decoding"<<std::endl;
-		return NULL;
-	}
 
 	SoundBuffer *snd = new SoundBuffer;
 
 	// Get some information about the OGG file
-	pInfo = ov_info(&oggFile, -1);
+	pInfo = ov_info(oggFile, -1);
 
 	// Check the number of channels... always use 16-bit samples
 	if(pInfo->channels == 1)
@@ -150,12 +138,13 @@ SoundBuffer* loadOggFile(const std::string &filepath)
 	do
 	{
 		// Read up to a buffer's worth of decoded sound data
-		bytes = ov_read(&oggFile, array, BUFFER_SIZE, endian, 2, 1, &bitStream);
+		bytes = ov_read(oggFile, array, BUFFER_SIZE, endian, 2, 1, &bitStream);
 
 		if(bytes < 0)
 		{
-			ov_clear(&oggFile);
-			infostream<<"Audio: Error decoding "<<filepath<<std::endl;
+			ov_clear(oggFile);
+			infostream << "Audio: Error decoding "
+				<< filename_for_logging << std::endl;
 			return NULL;
 		}
 
@@ -175,14 +164,100 @@ SoundBuffer* loadOggFile(const std::string &filepath)
 				<<"preparing sound buffer"<<std::endl;
 	}
 
-	infostream<<"Audio file "<<filepath<<" loaded"<<std::endl;
+	infostream << "Audio file "
+		<< filename_for_logging << " loaded" << std::endl;
 
 	// Clean up!
-	ov_clear(&oggFile);
+	ov_clear(oggFile);
 
 	return snd;
 }
 
+SoundBuffer *load_ogg_from_file(const std::string &path)
+{
+	OggVorbis_File oggFile;
+
+	// Try opening the given file.
+	// This requires libvorbis >= 1.3.2, as
+	// previous versions expect a non-const char *
+	if (ov_fopen(path.c_str(), &oggFile) != 0) {
+		infostream << "Audio: Error opening " << path
+			<< " for decoding" << std::endl;
+		return NULL;
+	}
+
+	return load_opened_ogg_file(&oggFile, path);
+}
+
+struct BufferSource {
+	const char *buf;
+	size_t cur_offset;
+	size_t len;
+};
+
+size_t buffer_sound_read_func(void *ptr, size_t size, size_t nmemb, void *datasource)
+{
+	BufferSource *s = (BufferSource *)datasource;
+	size_t copied_size = MYMIN(s->len - s->cur_offset, size);
+	memcpy(ptr, s->buf + s->cur_offset, copied_size);
+	s->cur_offset += copied_size;
+	return copied_size;
+}
+
+int buffer_sound_seek_func(void *datasource, ogg_int64_t offset, int whence)
+{
+	BufferSource *s = (BufferSource *)datasource;
+	if (whence == SEEK_SET) {
+		if (offset < 0 || (size_t)MYMAX(offset, 0) >= s->len) {
+			// offset out of bounds
+			return -1;
+		}
+		s->cur_offset = offset;
+		return 0;
+	} else if (whence == SEEK_CUR) {
+		if ((size_t)MYMIN(-offset, 0) > s->cur_offset
+				|| s->cur_offset + offset > s->len) {
+			// offset out of bounds
+			return -1;
+		}
+		s->cur_offset += offset;
+		return 0;
+	}
+	// invalid whence param (SEEK_END doesn't have to be supported)
+	return -1;
+}
+
+long BufferSourceell_func(void *datasource)
+{
+	BufferSource *s = (BufferSource *)datasource;
+	return s->cur_offset;
+}
+
+static ov_callbacks g_buffer_ov_callbacks = {
+	&buffer_sound_read_func,
+	&buffer_sound_seek_func,
+	NULL,
+	&BufferSourceell_func
+};
+
+SoundBuffer *load_ogg_from_buffer(const std::string &buf, const std::string &id_for_log)
+{
+	OggVorbis_File oggFile;
+
+	BufferSource s;
+	s.buf = buf.c_str();
+	s.cur_offset = 0;
+	s.len = buf.size();
+
+	if (ov_open_callbacks(&s, &oggFile, NULL, 0, g_buffer_ov_callbacks) != 0) {
+		infostream << "Audio: Error opening " << id_for_log
+			<< " for decoding" << std::endl;
+		return NULL;
+	}
+
+	return load_opened_ogg_file(&oggFile, id_for_log);
+}
+
 struct PlayingSound
 {
 	ALuint source_id;
@@ -449,26 +524,18 @@ public:
 	bool loadSoundFile(const std::string &name,
 			const std::string &filepath)
 	{
-		SoundBuffer *buf = loadOggFile(filepath);
-		if(buf)
+		SoundBuffer *buf = load_ogg_from_file(filepath);
+		if (buf)
 			addBuffer(name, buf);
 		return false;
 	}
 	bool loadSoundData(const std::string &name,
 			const std::string &filedata)
 	{
-		// The vorbis API sucks; just write it to a file and use vorbisfile
-		// TODO: Actually load it directly from memory
-		std::string basepath = porting::path_user + DIR_DELIM + "cache" +
-				DIR_DELIM + "tmp";
-		std::string path = basepath + DIR_DELIM + "tmp.ogg";
-		verbosestream<<"OpenALSoundManager::loadSoundData(): Writing "
-				<<"temporary file to ["<<path<<"]"<<std::endl;
-		fs::CreateAllDirs(basepath);
-		std::ofstream of(path.c_str(), std::ios::binary);
-		of.write(filedata.c_str(), filedata.size());
-		of.close();
-		return loadSoundFile(name, path);
+		SoundBuffer *buf = load_ogg_from_buffer(filedata, name);
+		if (buf)
+			addBuffer(name, buf);
+		return false;
 	}
 
 	void updateListener(v3f pos, v3f vel, v3f at, v3f up)