Userspace: Add simple AudioServer and LibAudio

userspace/libraries/LibAudio/AudioLoader.cpp

@@ -0,0 +1,66 @@
+#include <LibAudio/AudioLoader.h>
+#include <LibAudio/AudioLoaders/WAVLoader.h>
+
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+namespace LibAudio
+{
+
+	BAN::ErrorOr<BAN::UniqPtr<AudioLoader>> AudioLoader::load(BAN::StringView path)
+	{
+		if (path.empty())
+			return BAN::Error::from_errno(ENOENT);
+
+		const bool malloced = (path.data()[path.size()] != '\0');
+
+		const char* path_cstr = path.data();
+		if (malloced && (path_cstr = strndup(path.data(), path.size())) == nullptr)
+			return BAN::Error::from_errno(errno);
+		const int file_fd = open(path_cstr, O_RDONLY);
+		if (malloced)
+			free(const_cast<char*>(path_cstr));
+		if (file_fd == -1)
+			return BAN::Error::from_errno(errno);
+
+		struct stat st;
+		if (fstat(file_fd, &st) == -1)
+		{
+			close(file_fd);
+			return BAN::Error::from_errno(errno);
+		}
+
+		uint8_t* mmap_addr = static_cast<uint8_t*>(mmap(nullptr, st.st_size, PROT_READ, MAP_PRIVATE, file_fd, 0));
+		close(file_fd);
+		if (mmap_addr == MAP_FAILED)
+			return BAN::Error::from_errno(errno);
+
+		BAN::ErrorOr<BAN::UniqPtr<AudioLoader>> result_or_error { BAN::Error::from_errno(ENOTSUP) };
+
+		auto file_span = BAN::ConstByteSpan(mmap_addr, st.st_size);
+		if (WAVAudioLoader::can_load_from(file_span))
+			result_or_error = WAVAudioLoader::create(file_span);
+
+		if (result_or_error.is_error())
+		{
+			munmap(mmap_addr, st.st_size);
+			return result_or_error.release_error();
+		}
+
+		auto result = result_or_error.release_value();
+		result->m_mmap_addr = mmap_addr;
+		result->m_mmap_size = st.st_size;
+		return result;
+	}
+
+	AudioLoader::~AudioLoader()
+	{
+		if (m_mmap_addr)
+			munmap(m_mmap_addr, m_mmap_size);
+		m_mmap_addr = nullptr;
+		m_mmap_size = 0;
+	}
+
+}