First Commit

externals/openal-soft/alc/backends/base.h

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+#ifndef ALC_BACKENDS_BASE_H
+#define ALC_BACKENDS_BASE_H
+
+#include <chrono>
+#include <cstdarg>
+#include <memory>
+#include <ratio>
+#include <string>
+
+#include "albyte.h"
+#include "core/device.h"
+#include "core/except.h"
+
+
+using uint = unsigned int;
+
+struct ClockLatency {
+    std::chrono::nanoseconds ClockTime;
+    std::chrono::nanoseconds Latency;
+};
+
+struct BackendBase {
+    virtual void open(const char *name) = 0;
+
+    virtual bool reset();
+    virtual void start() = 0;
+    virtual void stop() = 0;
+
+    virtual void captureSamples(al::byte *buffer, uint samples);
+    virtual uint availableSamples();
+
+    virtual ClockLatency getClockLatency();
+
+    DeviceBase *const mDevice;
+
+    BackendBase(DeviceBase *device) noexcept : mDevice{device} { }
+    virtual ~BackendBase() = default;
+
+protected:
+    /** Sets the default channel order used by most non-WaveFormatEx-based APIs. */
+    void setDefaultChannelOrder();
+    /** Sets the default channel order used by WaveFormatEx. */
+    void setDefaultWFXChannelOrder();
+};
+using BackendPtr = std::unique_ptr<BackendBase>;
+
+enum class BackendType {
+    Playback,
+    Capture
+};
+
+
+/* Helper to get the current clock time from the device's ClockBase, and
+ * SamplesDone converted from the sample rate.
+ */
+inline std::chrono::nanoseconds GetDeviceClockTime(DeviceBase *device)
+{
+    using std::chrono::seconds;
+    using std::chrono::nanoseconds;
+
+    auto ns = nanoseconds{seconds{device->SamplesDone}} / device->Frequency;
+    return device->ClockBase + ns;
+}
+
+/* Helper to get the device latency from the backend, including any fixed
+ * latency from post-processing.
+ */
+inline ClockLatency GetClockLatency(DeviceBase *device, BackendBase *backend)
+{
+    ClockLatency ret{backend->getClockLatency()};
+    ret.Latency += device->FixedLatency;
+    return ret;
+}
+
+
+struct BackendFactory {
+    virtual bool init() = 0;
+
+    virtual bool querySupport(BackendType type) = 0;
+
+    virtual std::string probe(BackendType type) = 0;
+
+    virtual BackendPtr createBackend(DeviceBase *device, BackendType type) = 0;
+
+protected:
+    virtual ~BackendFactory() = default;
+};
+
+namespace al {
+
+enum class backend_error {
+    NoDevice,
+    DeviceError,
+    OutOfMemory
+};
+
+class backend_exception final : public base_exception {
+    backend_error mErrorCode;
+
+public:
+#ifdef __USE_MINGW_ANSI_STDIO
+    [[gnu::format(gnu_printf, 3, 4)]]
+#else
+    [[gnu::format(printf, 3, 4)]]
+#endif
+    backend_exception(backend_error code, const char *msg, ...);
+    ~backend_exception() override;
+
+    backend_error errorCode() const noexcept { return mErrorCode; }
+};
+
+} // namespace al
+
+#endif /* ALC_BACKENDS_BASE_H */