alc/backends/base.h

   1 #ifndef ALC_BACKENDS_BASE_H
   2 #define ALC_BACKENDS_BASE_H
   3
   4 #include <chrono>
   5 #include <memory>
   6 #include <mutex>
   7 #include <string>
   8
   9 #include "AL/alc.h"
  10
  11 #include "alcmain.h"
  12 #include "albyte.h"
  13
  14
  15 struct ClockLatency {
  16     std::chrono::nanoseconds ClockTime;
  17     std::chrono::nanoseconds Latency;
  18 };
  19
  20 /* Helper to get the current clock time from the device's ClockBase, and
  21  * SamplesDone converted from the sample rate.
  22  */
  23 inline std::chrono::nanoseconds GetDeviceClockTime(ALCdevice *device)
  24 {
  25     using std::chrono::seconds;
  26     using std::chrono::nanoseconds;
  27
  28     auto ns = nanoseconds{seconds{device->SamplesDone}} / device->Frequency;
  29     return device->ClockBase + ns;
  30 }
  31
  32 ClockLatency GetClockLatency(ALCdevice *device);
  33
  34 struct BackendBase {
  35     virtual ALCenum open(const ALCchar *name) = 0;
  36
  37     virtual bool reset();
  38     virtual bool start() = 0;
  39     virtual void stop() = 0;
  40
  41     virtual ALCenum captureSamples(al::byte *buffer, ALCuint samples);
  42     virtual ALCuint availableSamples();
  43
  44     virtual ClockLatency getClockLatency();
  45
  46     virtual void lock() { mMutex.lock(); }
  47     virtual void unlock() { mMutex.unlock(); }
  48
  49     ALCdevice *mDevice;
  50
  51     std::recursive_mutex mMutex;
  52
  53     BackendBase(ALCdevice *device) noexcept;
  54     virtual ~BackendBase();
  55 };
  56 using BackendPtr = std::unique_ptr<BackendBase>;
  57 using BackendUniqueLock = std::unique_lock<BackendBase>;
  58 using BackendLockGuard = std::lock_guard<BackendBase>;
  59
  60 enum class BackendType {
  61     Playback,
  62     Capture
  63 };
  64
  65 enum class DevProbe {
  66     Playback,
  67     Capture
  68 };
  69
  70
  71 struct BackendFactory {
  72     virtual bool init() = 0;
  73
  74     virtual bool querySupport(BackendType type) = 0;
  75
  76     virtual void probe(DevProbe type, std::string *outnames) = 0;
  77
  78     virtual BackendPtr createBackend(ALCdevice *device, BackendType type) = 0;
  79
  80 protected:
  81     virtual ~BackendFactory() = default;
  82 };
  83
  84 #endif /* ALC_BACKENDS_BASE_H */