reactos/reactos/drivers/wdm/audio/sysaudio/sysaudio.h

#ifndef SYSAUDIO_H__
#define SYSAUDIO_H__

typedef struct
{
    BOOL bHandle;                    // indicates if an audio pin can be instantated more than once
    ULONG PinId;                     // specifies the pin id
    HANDLE hPin;                     // handle to audio irp pin
    HANDLE hMixer;                   // handle to mixer pin
    PVOID DispatchContext;           // pointer to dispatch context
}SYSAUDIO_PIN_HANDLE, *PSYSAUDIO_PIN_HANDLE;


typedef struct
{
    ULONG DeviceId;                         //specifies the device id
    ULONG ClientHandlesCount;               // number of client handles
    PSYSAUDIO_PIN_HANDLE ClientHandles;     // array of client handles
}SYSAUDIO_CLIENT_HANDELS, *PSYSAUDIO_CLIENT_HANDELS;

typedef struct
{
    ULONG NumDevices;                       // number of devices in Devs array
    PSYSAUDIO_CLIENT_HANDELS Devs;          // array of client handles

}SYSAUDIO_CLIENT, *PSYSAUDIO_CLIENT;

typedef struct
{
    ULONG MaxPinInstanceCount;              // maximum times a audio irp pin can be instantiated
    HANDLE PinHandle;                       // handle to audio irp pin
    ULONG References;                       // number of clients having a reference to this audio irp pin
    KSPIN_DATAFLOW DataFlow;                // specifies data flow
    KSPIN_COMMUNICATION Communication;      // pin type
}PIN_INFO;


typedef struct
{
    LIST_ENTRY Entry;                                  // device entry for KsAudioDeviceList
    HANDLE Handle;                                     // handle to audio device
    PFILE_OBJECT FileObject;                           // file object for audio device
    UNICODE_STRING DeviceName;                         // symbolic link of audio device
    ULONG NumberOfClients;                             // number of clients referenced audio device

    ULONG NumberOfPins;                                // number of pins of audio device
    PIN_INFO * Pins;                                   // array of PIN_INFO

    ULONG NumWaveOutPin;                               // number of wave out pins
    ULONG NumWaveInPin;                                // number of wave in pins

}KSAUDIO_DEVICE_ENTRY, *PKSAUDIO_DEVICE_ENTRY;

typedef struct
{
    KSDEVICE_HEADER KsDeviceHeader;                     // ks streaming header - must always be first item in device extension
    PDEVICE_OBJECT PhysicalDeviceObject;                // pdo
    PDEVICE_OBJECT NextDeviceObject;                    // lower device object
    ULONG NumberOfKsAudioDevices;                       // number of audio devices

    LIST_ENTRY KsAudioDeviceList;                       // audio device list
    PVOID KsAudioNotificationEntry;                     // ks audio notification hook
    PVOID EchoCancelNotificationEntry;                  // ks echo cancel notification hook
    KMUTEX Mutex;                                       // audio device list mutex

    PFILE_OBJECT KMixerFileObject;                      // mixer file object
    HANDLE KMixerHandle;                                // mixer file handle

}SYSAUDIODEVEXT, *PSYSAUDIODEVEXT;

// struct DISPATCH_CONTEXT
//
// This structure is used to dispatch read / write / device io requests
// It is stored in the file object FsContext2 member
// Note: FsContext member is reserved for ks object header

typedef struct
{
    HANDLE Handle;                                       // audio irp pin handle
    PFILE_OBJECT FileObject;                             // audio irp pin file object
    ULONG PinId;                                         // pin id of device
    PKSAUDIO_DEVICE_ENTRY AudioEntry;                    // pointer to audio device entry

    HANDLE hMixerPin;                                    // handle to mixer pin
    PFILE_OBJECT MixerFileObject;                        // mixer file object
}DISPATCH_CONTEXT, *PDISPATCH_CONTEXT;

// struct PIN_WORKER_CONTEXT
//
// This structure holds all information required
// to create audio irp pin, mixer pin and virtual sysaudio pin
//
typedef struct
{
    PIRP Irp;
    BOOL CreateRealPin;
    BOOL CreateMixerPin;
    PKSAUDIO_DEVICE_ENTRY Entry;
    KSPIN_CONNECT * PinConnect;
    PDISPATCH_CONTEXT DispatchContext;
    PSYSAUDIO_CLIENT AudioClient;
    PSYSAUDIODEVEXT DeviceExtension;
    PKSDATAFORMAT_WAVEFORMATEX MixerFormat;
}PIN_WORKER_CONTEXT, *PPIN_WORKER_CONTEXT;

NTSTATUS
SysAudioAllocateDeviceHeader(
    IN SYSAUDIODEVEXT *DeviceExtension);

NTSTATUS
SysAudioRegisterDeviceInterfaces(
    IN PDEVICE_OBJECT DeviceObject);

NTSTATUS
SysAudioRegisterNotifications(
    IN PDRIVER_OBJECT  DriverObject,
    IN PDEVICE_OBJECT DeviceObject);

NTSTATUS
SysAudioHandleProperty(
    PDEVICE_OBJECT DeviceObject,
    PIRP Irp);

NTSTATUS
SysAudioOpenKMixer(
    IN SYSAUDIODEVEXT *DeviceExtension);

NTSTATUS
OpenDevice(
    IN PUNICODE_STRING DeviceName,
    IN PHANDLE HandleOut,
    IN PFILE_OBJECT * FileObjectOut);

PKSAUDIO_DEVICE_ENTRY
GetListEntry(
    IN PLIST_ENTRY Head,
    IN ULONG Index);

NTSTATUS
CreateDispatcher(
    IN PIRP Irp);

ULONG
GetDeviceCount(
    PSYSAUDIODEVEXT DeviceExtension,
    BOOL WaveIn);

#endif