auddspeakerchannel.h

at91sam9260-ek library file

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/*
    Title: AUDDSpeakerChannel

    About: Purpose
        Manipulation of the channels of an USB audio speaker device.

    About: Usage
        1 - Initialize a AUDDSpeakerChannel instance using
            <AUDDSpeakerChannel_Initialize>.
        2 - Retrieves the current status of a channel with the
            <AUDDSpeakerChannel_IsMuted> method.
        3 - Re-implement the <AUDDSpeakerChannel_MuteChanged> callback to get
            notified when the status of a channel changes.
*/

#ifndef AUDDSPEAKERCHANNEL_H
#define AUDDSPEAKERCHANNEL_H

//------------------------------------------------------------------------------
//         Types
//------------------------------------------------------------------------------
/*
    Type: AUDDSpeakerChannel
        Modelizes a channel of an USB audio speaker device.

    Variables:
        number - Zero-based channel number in the audio function.
        muted - Indicates if the channel is currently muted.
*/
typedef struct {

    unsigned char number;
    unsigned char muted;

} AUDDSpeakerChannel;

//------------------------------------------------------------------------------
//         Callbacks
//------------------------------------------------------------------------------
/*
    Function: AUDDSpeakerChannel_MuteChanged
        Callback triggered when the mute status of a channel changes. This is
        a default implementation which does nothing and must be overriden.

    Parameters:
        channel - Pointer to a AUDDSpeakerChannel instance.
        muted - Indicates the new mute status of the channel.
*/
extern void AUDDSpeakerChannel_MuteChanged(AUDDSpeakerChannel *channel,
                                           unsigned char muted);

//------------------------------------------------------------------------------
//         Exported functions
//------------------------------------------------------------------------------
/*
    Function: AUDDSpeakerChannel_Initialize
        Initializes the member variables of an AUDDSpeakerChannel object to the
        given values.

    Parameters:
        channel - Pointer to an AUDDSpeakerChannel instance.
        number - Channel number in the audio function.
        muted - Indicates if the channel is muted.
*/
extern void AUDDSpeakerChannel_Initialize(AUDDSpeakerChannel *channel,
                                          unsigned char number,
                                          unsigned char muted);

/*
    Function: AUDDSpeakerChannel_GetNumber
        Indicates the number of a channel.

    Parameters:
        channel - Pointer to an AUDDSpeakerChannel instance.

    Returns:
        Channel number.
*/
extern unsigned char AUDDSpeakerChannel_GetNumber(
    const AUDDSpeakerChannel *channel);

/*
    Function: AUDDSpeakerChannel_Mute
        Mutes the given channel and triggers the MuteChanged callback if
        necessary.

    Parameters:
        channel - Pointer to an AUDDSpeakerChannelInstance.
*/
extern void AUDDSpeakerChannel_Mute(AUDDSpeakerChannel *channel);

/*
    Function: AUDDSpeakerChannel_Unute
        Unmutes the given channel and triggers the MuteChanged callback if
        necessary.

    Parameters:
        channel - Pointer to an AUDDSpeakerChannelInstance.
*/
extern void AUDDSpeakerChannel_Unmute(AUDDSpeakerChannel *channel);

/*
    Function: AUDDSpeakerChannel_IsMuted
        Indicates if the given channel is currently muted or not.

    Parameters:
        channel - Pointer an AUDDSpeakerChannel instance.

    Returns:
        1 if the channel is muted; otherwise 0.
*/
extern unsigned char AUDDSpeakerChannel_IsMuted(
    const AUDDSpeakerChannel *channel);

#endif //#ifndef AUDDSPEAKERCHANNEL_H