1 files changed, 78 insertions, 0 deletions
diff --git a/alc/backends/base.h b/alc/backends/base.h
new file mode 100644
index 00000000..437e31d9
--- /dev/null
+++ b/alc/backends/base.h
@@ -0,0 +1,78 @@
+#ifndef ALC_BACKENDS_BASE_H
+#define ALC_BACKENDS_BASE_H
+
+#include <memory>
+#include <chrono>
+#include <string>
+#include <mutex>
+
+#include "alcmain.h"
+
+
+struct ClockLatency {
+    std::chrono::nanoseconds ClockTime;
+    std::chrono::nanoseconds Latency;
+};
+
+/* Helper to get the current clock time from the device's ClockBase, and
+ * SamplesDone converted from the sample rate.
+ */
+inline std::chrono::nanoseconds GetDeviceClockTime(ALCdevice *device)
+{
+    using std::chrono::seconds;
+    using std::chrono::nanoseconds;
+
+    auto ns = nanoseconds{seconds{device->SamplesDone}} / device->Frequency;
+    return device->ClockBase + ns;
+}
+
+ClockLatency GetClockLatency(ALCdevice *device);
+
+struct BackendBase {
+    virtual ALCenum open(const ALCchar *name) = 0;
+
+    virtual ALCboolean reset();
+    virtual ALCboolean start() = 0;
+    virtual void stop() = 0;
+
+    virtual ALCenum captureSamples(void *buffer, ALCuint samples);
+    virtual ALCuint availableSamples();
+
+    virtual ClockLatency getClockLatency();
+
+    virtual void lock() { mMutex.lock(); }
+    virtual void unlock() { mMutex.unlock(); }
+
+    ALCdevice *mDevice;
+
+    std::recursive_mutex mMutex;
+
+    BackendBase(ALCdevice *device) noexcept;
+    virtual ~BackendBase();
+};
+using BackendPtr = std::unique_ptr<BackendBase>;
+using BackendUniqueLock = std::unique_lock<BackendBase>;
+using BackendLockGuard = std::lock_guard<BackendBase>;
+
+enum class BackendType {
+    Playback,
+    Capture
+};
+
+enum class DevProbe {
+    Playback,
+    Capture
+};
+
+
+struct BackendFactory {
+    virtual bool init() = 0;
+
+    virtual bool querySupport(BackendType type) = 0;
+
+    virtual void probe(DevProbe type, std::string *outnames) = 0;
+
+    virtual BackendPtr createBackend(ALCdevice *device, BackendType type) = 0;
+};
+
+#endif /* ALC_BACKENDS_BASE_H */