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RtAudio.h (48307B)


      1 /************************************************************************/
      2 /*! \class RtAudio
      3     \brief Realtime audio i/o C++ classes.
      4 
      5     RtAudio provides a common API (Application Programming Interface)
      6     for realtime audio input/output across Linux (native ALSA, Jack,
      7     and OSS), Macintosh OS X (CoreAudio and Jack), and Windows
      8     (DirectSound, ASIO and WASAPI) operating systems.
      9 
     10     RtAudio GitHub site: https://github.com/thestk/rtaudio
     11     RtAudio WWW site: http://www.music.mcgill.ca/~gary/rtaudio/
     12 
     13     RtAudio: realtime audio i/o C++ classes
     14     Copyright (c) 2001-2019 Gary P. Scavone
     15 
     16     Permission is hereby granted, free of charge, to any person
     17     obtaining a copy of this software and associated documentation files
     18     (the "Software"), to deal in the Software without restriction,
     19     including without limitation the rights to use, copy, modify, merge,
     20     publish, distribute, sublicense, and/or sell copies of the Software,
     21     and to permit persons to whom the Software is furnished to do so,
     22     subject to the following conditions:
     23 
     24     The above copyright notice and this permission notice shall be
     25     included in all copies or substantial portions of the Software.
     26 
     27     Any person wishing to distribute modifications to the Software is
     28     asked to send the modifications to the original developer so that
     29     they can be incorporated into the canonical version.  This is,
     30     however, not a binding provision of this license.
     31 
     32     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     33     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     34     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     35     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
     36     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
     37     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     38     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     39 */
     40 /************************************************************************/
     41 
     42 /*!
     43   \file RtAudio.h
     44  */
     45 
     46 #ifndef __RTAUDIO_H
     47 #define __RTAUDIO_H
     48 
     49 #define RTAUDIO_VERSION "5.1.0"
     50 
     51 #if defined _WIN32 || defined __CYGWIN__
     52   #if defined(RTAUDIO_EXPORT)
     53     #define RTAUDIO_DLL_PUBLIC __declspec(dllexport)
     54   #else
     55     #define RTAUDIO_DLL_PUBLIC
     56   #endif
     57 #else
     58   #if __GNUC__ >= 4
     59     #define RTAUDIO_DLL_PUBLIC __attribute__( (visibility( "default" )) )
     60   #else
     61     #define RTAUDIO_DLL_PUBLIC
     62   #endif
     63 #endif
     64 
     65 #include <string>
     66 #include <vector>
     67 #include <stdexcept>
     68 #include <iostream>
     69 
     70 /*! \typedef typedef unsigned long RtAudioFormat;
     71     \brief RtAudio data format type.
     72 
     73     Support for signed integers and floats.  Audio data fed to/from an
     74     RtAudio stream is assumed to ALWAYS be in host byte order.  The
     75     internal routines will automatically take care of any necessary
     76     byte-swapping between the host format and the soundcard.  Thus,
     77     endian-ness is not a concern in the following format definitions.
     78 
     79     - \e RTAUDIO_SINT8:   8-bit signed integer.
     80     - \e RTAUDIO_SINT16:  16-bit signed integer.
     81     - \e RTAUDIO_SINT24:  24-bit signed integer.
     82     - \e RTAUDIO_SINT32:  32-bit signed integer.
     83     - \e RTAUDIO_FLOAT32: Normalized between plus/minus 1.0.
     84     - \e RTAUDIO_FLOAT64: Normalized between plus/minus 1.0.
     85 */
     86 typedef unsigned long RtAudioFormat;
     87 static const RtAudioFormat RTAUDIO_SINT8 = 0x1;    // 8-bit signed integer.
     88 static const RtAudioFormat RTAUDIO_SINT16 = 0x2;   // 16-bit signed integer.
     89 static const RtAudioFormat RTAUDIO_SINT24 = 0x4;   // 24-bit signed integer.
     90 static const RtAudioFormat RTAUDIO_SINT32 = 0x8;   // 32-bit signed integer.
     91 static const RtAudioFormat RTAUDIO_FLOAT32 = 0x10; // Normalized between plus/minus 1.0.
     92 static const RtAudioFormat RTAUDIO_FLOAT64 = 0x20; // Normalized between plus/minus 1.0.
     93 
     94 /*! \typedef typedef unsigned long RtAudioStreamFlags;
     95     \brief RtAudio stream option flags.
     96 
     97     The following flags can be OR'ed together to allow a client to
     98     make changes to the default stream behavior:
     99 
    100     - \e RTAUDIO_NONINTERLEAVED:   Use non-interleaved buffers (default = interleaved).
    101     - \e RTAUDIO_MINIMIZE_LATENCY: Attempt to set stream parameters for lowest possible latency.
    102     - \e RTAUDIO_HOG_DEVICE:       Attempt grab device for exclusive use.
    103     - \e RTAUDIO_ALSA_USE_DEFAULT: Use the "default" PCM device (ALSA only).
    104     - \e RTAUDIO_JACK_DONT_CONNECT: Do not automatically connect ports (JACK only).
    105 
    106     By default, RtAudio streams pass and receive audio data from the
    107     client in an interleaved format.  By passing the
    108     RTAUDIO_NONINTERLEAVED flag to the openStream() function, audio
    109     data will instead be presented in non-interleaved buffers.  In
    110     this case, each buffer argument in the RtAudioCallback function
    111     will point to a single array of data, with \c nFrames samples for
    112     each channel concatenated back-to-back.  For example, the first
    113     sample of data for the second channel would be located at index \c
    114     nFrames (assuming the \c buffer pointer was recast to the correct
    115     data type for the stream).
    116 
    117     Certain audio APIs offer a number of parameters that influence the
    118     I/O latency of a stream.  By default, RtAudio will attempt to set
    119     these parameters internally for robust (glitch-free) performance
    120     (though some APIs, like Windows DirectSound, make this difficult).
    121     By passing the RTAUDIO_MINIMIZE_LATENCY flag to the openStream()
    122     function, internal stream settings will be influenced in an attempt
    123     to minimize stream latency, though possibly at the expense of stream
    124     performance.
    125 
    126     If the RTAUDIO_HOG_DEVICE flag is set, RtAudio will attempt to
    127     open the input and/or output stream device(s) for exclusive use.
    128     Note that this is not possible with all supported audio APIs.
    129 
    130     If the RTAUDIO_SCHEDULE_REALTIME flag is set, RtAudio will attempt 
    131     to select realtime scheduling (round-robin) for the callback thread.
    132 
    133     If the RTAUDIO_ALSA_USE_DEFAULT flag is set, RtAudio will attempt to
    134     open the "default" PCM device when using the ALSA API. Note that this
    135     will override any specified input or output device id.
    136 
    137     If the RTAUDIO_JACK_DONT_CONNECT flag is set, RtAudio will not attempt
    138     to automatically connect the ports of the client to the audio device.
    139 */
    140 typedef unsigned int RtAudioStreamFlags;
    141 static const RtAudioStreamFlags RTAUDIO_NONINTERLEAVED = 0x1;    // Use non-interleaved buffers (default = interleaved).
    142 static const RtAudioStreamFlags RTAUDIO_MINIMIZE_LATENCY = 0x2;  // Attempt to set stream parameters for lowest possible latency.
    143 static const RtAudioStreamFlags RTAUDIO_HOG_DEVICE = 0x4;        // Attempt grab device and prevent use by others.
    144 static const RtAudioStreamFlags RTAUDIO_SCHEDULE_REALTIME = 0x8; // Try to select realtime scheduling for callback thread.
    145 static const RtAudioStreamFlags RTAUDIO_ALSA_USE_DEFAULT = 0x10; // Use the "default" PCM device (ALSA only).
    146 static const RtAudioStreamFlags RTAUDIO_JACK_DONT_CONNECT = 0x20; // Do not automatically connect ports (JACK only).
    147 
    148 /*! \typedef typedef unsigned long RtAudioStreamStatus;
    149     \brief RtAudio stream status (over- or underflow) flags.
    150 
    151     Notification of a stream over- or underflow is indicated by a
    152     non-zero stream \c status argument in the RtAudioCallback function.
    153     The stream status can be one of the following two options,
    154     depending on whether the stream is open for output and/or input:
    155 
    156     - \e RTAUDIO_INPUT_OVERFLOW:   Input data was discarded because of an overflow condition at the driver.
    157     - \e RTAUDIO_OUTPUT_UNDERFLOW: The output buffer ran low, likely producing a break in the output sound.
    158 */
    159 typedef unsigned int RtAudioStreamStatus;
    160 static const RtAudioStreamStatus RTAUDIO_INPUT_OVERFLOW = 0x1;    // Input data was discarded because of an overflow condition at the driver.
    161 static const RtAudioStreamStatus RTAUDIO_OUTPUT_UNDERFLOW = 0x2;  // The output buffer ran low, likely causing a gap in the output sound.
    162 
    163 //! RtAudio callback function prototype.
    164 /*!
    165    All RtAudio clients must create a function of type RtAudioCallback
    166    to read and/or write data from/to the audio stream.  When the
    167    underlying audio system is ready for new input or output data, this
    168    function will be invoked.
    169 
    170    \param outputBuffer For output (or duplex) streams, the client
    171           should write \c nFrames of audio sample frames into this
    172           buffer.  This argument should be recast to the datatype
    173           specified when the stream was opened.  For input-only
    174           streams, this argument will be NULL.
    175 
    176    \param inputBuffer For input (or duplex) streams, this buffer will
    177           hold \c nFrames of input audio sample frames.  This
    178           argument should be recast to the datatype specified when the
    179           stream was opened.  For output-only streams, this argument
    180           will be NULL.
    181 
    182    \param nFrames The number of sample frames of input or output
    183           data in the buffers.  The actual buffer size in bytes is
    184           dependent on the data type and number of channels in use.
    185 
    186    \param streamTime The number of seconds that have elapsed since the
    187           stream was started.
    188 
    189    \param status If non-zero, this argument indicates a data overflow
    190           or underflow condition for the stream.  The particular
    191           condition can be determined by comparison with the
    192           RtAudioStreamStatus flags.
    193 
    194    \param userData A pointer to optional data provided by the client
    195           when opening the stream (default = NULL).
    196 
    197    \return
    198    To continue normal stream operation, the RtAudioCallback function
    199    should return a value of zero.  To stop the stream and drain the
    200    output buffer, the function should return a value of one.  To abort
    201    the stream immediately, the client should return a value of two.
    202  */
    203 typedef int (*RtAudioCallback)( void *outputBuffer, void *inputBuffer,
    204                                 unsigned int nFrames,
    205                                 double streamTime,
    206                                 RtAudioStreamStatus status,
    207                                 void *userData );
    208 
    209 /************************************************************************/
    210 /*! \class RtAudioError
    211     \brief Exception handling class for RtAudio.
    212 
    213     The RtAudioError class is quite simple but it does allow errors to be
    214     "caught" by RtAudioError::Type. See the RtAudio documentation to know
    215     which methods can throw an RtAudioError.
    216 */
    217 /************************************************************************/
    218 
    219 class RTAUDIO_DLL_PUBLIC RtAudioError : public std::runtime_error
    220 {
    221  public:
    222   //! Defined RtAudioError types.
    223   enum Type {
    224     WARNING,           /*!< A non-critical error. */
    225     DEBUG_WARNING,     /*!< A non-critical error which might be useful for debugging. */
    226     UNSPECIFIED,       /*!< The default, unspecified error type. */
    227     NO_DEVICES_FOUND,  /*!< No devices found on system. */
    228     INVALID_DEVICE,    /*!< An invalid device ID was specified. */
    229     MEMORY_ERROR,      /*!< An error occured during memory allocation. */
    230     INVALID_PARAMETER, /*!< An invalid parameter was specified to a function. */
    231     INVALID_USE,       /*!< The function was called incorrectly. */
    232     DRIVER_ERROR,      /*!< A system driver error occured. */
    233     SYSTEM_ERROR,      /*!< A system error occured. */
    234     THREAD_ERROR       /*!< A thread error occured. */
    235   };
    236 
    237   //! The constructor.
    238   RtAudioError( const std::string& message,
    239                 Type type = RtAudioError::UNSPECIFIED )
    240     : std::runtime_error(message), type_(type) {}
    241 
    242   //! Prints thrown error message to stderr.
    243   virtual void printMessage( void ) const
    244     { std::cerr << '\n' << what() << "\n\n"; }
    245 
    246   //! Returns the thrown error message type.
    247   virtual const Type& getType(void) const { return type_; }
    248 
    249   //! Returns the thrown error message string.
    250   virtual const std::string getMessage(void) const
    251     { return std::string(what()); }
    252 
    253  protected:
    254   Type type_;
    255 };
    256 
    257 //! RtAudio error callback function prototype.
    258 /*!
    259     \param type Type of error.
    260     \param errorText Error description.
    261  */
    262 typedef void (*RtAudioErrorCallback)( RtAudioError::Type type, const std::string &errorText );
    263 
    264 // **************************************************************** //
    265 //
    266 // RtAudio class declaration.
    267 //
    268 // RtAudio is a "controller" used to select an available audio i/o
    269 // interface.  It presents a common API for the user to call but all
    270 // functionality is implemented by the class RtApi and its
    271 // subclasses.  RtAudio creates an instance of an RtApi subclass
    272 // based on the user's API choice.  If no choice is made, RtAudio
    273 // attempts to make a "logical" API selection.
    274 //
    275 // **************************************************************** //
    276 
    277 class RtApi;
    278 
    279 class RTAUDIO_DLL_PUBLIC RtAudio
    280 {
    281  public:
    282 
    283   //! Audio API specifier arguments.
    284   enum Api {
    285     UNSPECIFIED,    /*!< Search for a working compiled API. */
    286     LINUX_ALSA,     /*!< The Advanced Linux Sound Architecture API. */
    287     LINUX_PULSE,    /*!< The Linux PulseAudio API. */
    288     LINUX_OSS,      /*!< The Linux Open Sound System API. */
    289     UNIX_JACK,      /*!< The Jack Low-Latency Audio Server API. */
    290     MACOSX_CORE,    /*!< Macintosh OS-X Core Audio API. */
    291     WINDOWS_WASAPI, /*!< The Microsoft WASAPI API. */
    292     WINDOWS_ASIO,   /*!< The Steinberg Audio Stream I/O API. */
    293     WINDOWS_DS,     /*!< The Microsoft DirectSound API. */
    294     RTAUDIO_DUMMY,  /*!< A compilable but non-functional API. */
    295     NUM_APIS        /*!< Number of values in this enum. */
    296   };
    297 
    298   //! The public device information structure for returning queried values.
    299   struct DeviceInfo {
    300     bool probed;                  /*!< true if the device capabilities were successfully probed. */
    301     std::string name;             /*!< Character string device identifier. */
    302     unsigned int outputChannels{};  /*!< Maximum output channels supported by device. */
    303     unsigned int inputChannels{};   /*!< Maximum input channels supported by device. */
    304     unsigned int duplexChannels{};  /*!< Maximum simultaneous input/output channels supported by device. */
    305     bool isDefaultOutput{false};         /*!< true if this is the default output device. */
    306     bool isDefaultInput{false};          /*!< true if this is the default input device. */
    307     std::vector<unsigned int> sampleRates; /*!< Supported sample rates (queried from list of standard rates). */
    308     unsigned int preferredSampleRate{}; /*!< Preferred sample rate, e.g. for WASAPI the system sample rate. */
    309     RtAudioFormat nativeFormats{};  /*!< Bit mask of supported data formats. */
    310   };
    311 
    312   //! The structure for specifying input or ouput stream parameters.
    313   struct StreamParameters {
    314     unsigned int deviceId{};     /*!< Device index (0 to getDeviceCount() - 1). */
    315     unsigned int nChannels{};    /*!< Number of channels. */
    316     unsigned int firstChannel{}; /*!< First channel index on device (default = 0). */
    317   };
    318 
    319   //! The structure for specifying stream options.
    320   /*!
    321     The following flags can be OR'ed together to allow a client to
    322     make changes to the default stream behavior:
    323 
    324     - \e RTAUDIO_NONINTERLEAVED:    Use non-interleaved buffers (default = interleaved).
    325     - \e RTAUDIO_MINIMIZE_LATENCY:  Attempt to set stream parameters for lowest possible latency.
    326     - \e RTAUDIO_HOG_DEVICE:        Attempt grab device for exclusive use.
    327     - \e RTAUDIO_SCHEDULE_REALTIME: Attempt to select realtime scheduling for callback thread.
    328     - \e RTAUDIO_ALSA_USE_DEFAULT:  Use the "default" PCM device (ALSA only).
    329 
    330     By default, RtAudio streams pass and receive audio data from the
    331     client in an interleaved format.  By passing the
    332     RTAUDIO_NONINTERLEAVED flag to the openStream() function, audio
    333     data will instead be presented in non-interleaved buffers.  In
    334     this case, each buffer argument in the RtAudioCallback function
    335     will point to a single array of data, with \c nFrames samples for
    336     each channel concatenated back-to-back.  For example, the first
    337     sample of data for the second channel would be located at index \c
    338     nFrames (assuming the \c buffer pointer was recast to the correct
    339     data type for the stream).
    340 
    341     Certain audio APIs offer a number of parameters that influence the
    342     I/O latency of a stream.  By default, RtAudio will attempt to set
    343     these parameters internally for robust (glitch-free) performance
    344     (though some APIs, like Windows DirectSound, make this difficult).
    345     By passing the RTAUDIO_MINIMIZE_LATENCY flag to the openStream()
    346     function, internal stream settings will be influenced in an attempt
    347     to minimize stream latency, though possibly at the expense of stream
    348     performance.
    349 
    350     If the RTAUDIO_HOG_DEVICE flag is set, RtAudio will attempt to
    351     open the input and/or output stream device(s) for exclusive use.
    352     Note that this is not possible with all supported audio APIs.
    353 
    354     If the RTAUDIO_SCHEDULE_REALTIME flag is set, RtAudio will attempt 
    355     to select realtime scheduling (round-robin) for the callback thread.
    356     The \c priority parameter will only be used if the RTAUDIO_SCHEDULE_REALTIME
    357     flag is set. It defines the thread's realtime priority.
    358 
    359     If the RTAUDIO_ALSA_USE_DEFAULT flag is set, RtAudio will attempt to
    360     open the "default" PCM device when using the ALSA API. Note that this
    361     will override any specified input or output device id.
    362 
    363     The \c numberOfBuffers parameter can be used to control stream
    364     latency in the Windows DirectSound, Linux OSS, and Linux Alsa APIs
    365     only.  A value of two is usually the smallest allowed.  Larger
    366     numbers can potentially result in more robust stream performance,
    367     though likely at the cost of stream latency.  The value set by the
    368     user is replaced during execution of the RtAudio::openStream()
    369     function by the value actually used by the system.
    370 
    371     The \c streamName parameter can be used to set the client name
    372     when using the Jack API.  By default, the client name is set to
    373     RtApiJack.  However, if you wish to create multiple instances of
    374     RtAudio with Jack, each instance must have a unique client name.
    375   */
    376   struct StreamOptions {
    377     RtAudioStreamFlags flags{};      /*!< A bit-mask of stream flags (RTAUDIO_NONINTERLEAVED, RTAUDIO_MINIMIZE_LATENCY, RTAUDIO_HOG_DEVICE, RTAUDIO_ALSA_USE_DEFAULT). */
    378     unsigned int numberOfBuffers{};  /*!< Number of stream buffers. */
    379     std::string streamName;        /*!< A stream name (currently used only in Jack). */
    380     int priority{};                  /*!< Scheduling priority of callback thread (only used with flag RTAUDIO_SCHEDULE_REALTIME). */
    381   };
    382 
    383   //! A static function to determine the current RtAudio version.
    384   static std::string getVersion( void );
    385 
    386   //! A static function to determine the available compiled audio APIs.
    387   /*!
    388     The values returned in the std::vector can be compared against
    389     the enumerated list values.  Note that there can be more than one
    390     API compiled for certain operating systems.
    391   */
    392   static void getCompiledApi( std::vector<RtAudio::Api> &apis );
    393 
    394   //! Return the name of a specified compiled audio API.
    395   /*!
    396     This obtains a short lower-case name used for identification purposes.
    397     This value is guaranteed to remain identical across library versions.
    398     If the API is unknown, this function will return the empty string.
    399   */
    400   static std::string getApiName( RtAudio::Api api );
    401 
    402   //! Return the display name of a specified compiled audio API.
    403   /*!
    404     This obtains a long name used for display purposes.
    405     If the API is unknown, this function will return the empty string.
    406   */
    407   static std::string getApiDisplayName( RtAudio::Api api );
    408 
    409   //! Return the compiled audio API having the given name.
    410   /*!
    411     A case insensitive comparison will check the specified name
    412     against the list of compiled APIs, and return the one which
    413     matches. On failure, the function returns UNSPECIFIED.
    414   */
    415   static RtAudio::Api getCompiledApiByName( const std::string &name );
    416 
    417   //! The class constructor.
    418   /*!
    419     The constructor performs minor initialization tasks.  An exception
    420     can be thrown if no API support is compiled.
    421 
    422     If no API argument is specified and multiple API support has been
    423     compiled, the default order of use is JACK, ALSA, OSS (Linux
    424     systems) and ASIO, DS (Windows systems).
    425   */
    426   RtAudio( RtAudio::Api api=UNSPECIFIED );
    427 
    428   //! The destructor.
    429   /*!
    430     If a stream is running or open, it will be stopped and closed
    431     automatically.
    432   */
    433   ~RtAudio();
    434 
    435   //! Returns the audio API specifier for the current instance of RtAudio.
    436   RtAudio::Api getCurrentApi( void );
    437 
    438   //! A public function that queries for the number of audio devices available.
    439   /*!
    440     This function performs a system query of available devices each time it
    441     is called, thus supporting devices connected \e after instantiation. If
    442     a system error occurs during processing, a warning will be issued. 
    443   */
    444   unsigned int getDeviceCount( void );
    445 
    446   //! Return an RtAudio::DeviceInfo structure for a specified device number.
    447   /*!
    448 
    449     Any device integer between 0 and getDeviceCount() - 1 is valid.
    450     If an invalid argument is provided, an RtAudioError (type = INVALID_USE)
    451     will be thrown.  If a device is busy or otherwise unavailable, the
    452     structure member "probed" will have a value of "false" and all
    453     other members are undefined.  If the specified device is the
    454     current default input or output device, the corresponding
    455     "isDefault" member will have a value of "true".
    456   */
    457   RtAudio::DeviceInfo getDeviceInfo( unsigned int device );
    458 
    459   //! A function that returns the index of the default output device.
    460   /*!
    461     If the underlying audio API does not provide a "default
    462     device", or if no devices are available, the return value will be
    463     0.  Note that this is a valid device identifier and it is the
    464     client's responsibility to verify that a device is available
    465     before attempting to open a stream.
    466   */
    467   unsigned int getDefaultOutputDevice( void );
    468 
    469   //! A function that returns the index of the default input device.
    470   /*!
    471     If the underlying audio API does not provide a "default
    472     device", or if no devices are available, the return value will be
    473     0.  Note that this is a valid device identifier and it is the
    474     client's responsibility to verify that a device is available
    475     before attempting to open a stream.
    476   */
    477   unsigned int getDefaultInputDevice( void );
    478 
    479   //! A public function for opening a stream with the specified parameters.
    480   /*!
    481     An RtAudioError (type = SYSTEM_ERROR) is thrown if a stream cannot be
    482     opened with the specified parameters or an error occurs during
    483     processing.  An RtAudioError (type = INVALID_USE) is thrown if any
    484     invalid device ID or channel number parameters are specified.
    485 
    486     \param outputParameters Specifies output stream parameters to use
    487            when opening a stream, including a device ID, number of channels,
    488            and starting channel number.  For input-only streams, this
    489            argument should be NULL.  The device ID is an index value between
    490            0 and getDeviceCount() - 1.
    491     \param inputParameters Specifies input stream parameters to use
    492            when opening a stream, including a device ID, number of channels,
    493            and starting channel number.  For output-only streams, this
    494            argument should be NULL.  The device ID is an index value between
    495            0 and getDeviceCount() - 1.
    496     \param format An RtAudioFormat specifying the desired sample data format.
    497     \param sampleRate The desired sample rate (sample frames per second).
    498     \param *bufferFrames A pointer to a value indicating the desired
    499            internal buffer size in sample frames.  The actual value
    500            used by the device is returned via the same pointer.  A
    501            value of zero can be specified, in which case the lowest
    502            allowable value is determined.
    503     \param callback A client-defined function that will be invoked
    504            when input data is available and/or output data is needed.
    505     \param userData An optional pointer to data that can be accessed
    506            from within the callback function.
    507     \param options An optional pointer to a structure containing various
    508            global stream options, including a list of OR'ed RtAudioStreamFlags
    509            and a suggested number of stream buffers that can be used to 
    510            control stream latency.  More buffers typically result in more
    511            robust performance, though at a cost of greater latency.  If a
    512            value of zero is specified, a system-specific median value is
    513            chosen.  If the RTAUDIO_MINIMIZE_LATENCY flag bit is set, the
    514            lowest allowable value is used.  The actual value used is
    515            returned via the structure argument.  The parameter is API dependent.
    516     \param errorCallback A client-defined function that will be invoked
    517            when an error has occured.
    518   */
    519   void openStream( RtAudio::StreamParameters *outputParameters,
    520                    RtAudio::StreamParameters *inputParameters,
    521                    RtAudioFormat format, unsigned int sampleRate,
    522                    unsigned int *bufferFrames, RtAudioCallback callback,
    523                    void *userData = NULL, RtAudio::StreamOptions *options = NULL, RtAudioErrorCallback errorCallback = NULL );
    524 
    525   //! A function that closes a stream and frees any associated stream memory.
    526   /*!
    527     If a stream is not open, this function issues a warning and
    528     returns (no exception is thrown).
    529   */
    530   void closeStream( void );
    531 
    532   //! A function that starts a stream.
    533   /*!
    534     An RtAudioError (type = SYSTEM_ERROR) is thrown if an error occurs
    535     during processing.  An RtAudioError (type = INVALID_USE) is thrown if a
    536     stream is not open.  A warning is issued if the stream is already
    537     running.
    538   */
    539   void startStream( void );
    540 
    541   //! Stop a stream, allowing any samples remaining in the output queue to be played.
    542   /*!
    543     An RtAudioError (type = SYSTEM_ERROR) is thrown if an error occurs
    544     during processing.  An RtAudioError (type = INVALID_USE) is thrown if a
    545     stream is not open.  A warning is issued if the stream is already
    546     stopped.
    547   */
    548   void stopStream( void );
    549 
    550   //! Stop a stream, discarding any samples remaining in the input/output queue.
    551   /*!
    552     An RtAudioError (type = SYSTEM_ERROR) is thrown if an error occurs
    553     during processing.  An RtAudioError (type = INVALID_USE) is thrown if a
    554     stream is not open.  A warning is issued if the stream is already
    555     stopped.
    556   */
    557   void abortStream( void );
    558 
    559   //! Returns true if a stream is open and false if not.
    560   bool isStreamOpen( void ) const;
    561 
    562   //! Returns true if the stream is running and false if it is stopped or not open.
    563   bool isStreamRunning( void ) const;
    564 
    565   //! Returns the number of elapsed seconds since the stream was started.
    566   /*!
    567     If a stream is not open, an RtAudioError (type = INVALID_USE) will be thrown.
    568   */
    569   double getStreamTime( void );
    570 
    571   //! Set the stream time to a time in seconds greater than or equal to 0.0.
    572   /*!
    573     If a stream is not open, an RtAudioError (type = INVALID_USE) will be thrown.
    574   */
    575   void setStreamTime( double time );
    576 
    577   //! Returns the internal stream latency in sample frames.
    578   /*!
    579     The stream latency refers to delay in audio input and/or output
    580     caused by internal buffering by the audio system and/or hardware.
    581     For duplex streams, the returned value will represent the sum of
    582     the input and output latencies.  If a stream is not open, an
    583     RtAudioError (type = INVALID_USE) will be thrown.  If the API does not
    584     report latency, the return value will be zero.
    585   */
    586   long getStreamLatency( void );
    587 
    588  //! Returns actual sample rate in use by the stream.
    589  /*!
    590    On some systems, the sample rate used may be slightly different
    591    than that specified in the stream parameters.  If a stream is not
    592    open, an RtAudioError (type = INVALID_USE) will be thrown.
    593  */
    594   unsigned int getStreamSampleRate( void );
    595 
    596   //! Specify whether warning messages should be printed to stderr.
    597   void showWarnings( bool value = true );
    598 
    599  protected:
    600 
    601   void openRtApi( RtAudio::Api api );
    602   RtApi *rtapi_;
    603 };
    604 
    605 // Operating system dependent thread functionality.
    606 #if defined(__WINDOWS_DS__) || defined(__WINDOWS_ASIO__) || defined(__WINDOWS_WASAPI__)
    607 
    608   #ifndef NOMINMAX
    609     #define NOMINMAX
    610   #endif
    611   #include <windows.h>
    612   #include <process.h>
    613   #include <stdint.h>
    614 
    615   typedef uintptr_t ThreadHandle;
    616   typedef CRITICAL_SECTION StreamMutex;
    617 
    618 #elif defined(__LINUX_ALSA__) || defined(__LINUX_PULSE__) || defined(__UNIX_JACK__) || defined(__LINUX_OSS__) || defined(__MACOSX_CORE__)
    619   // Using pthread library for various flavors of unix.
    620   #include <pthread.h>
    621 
    622   typedef pthread_t ThreadHandle;
    623   typedef pthread_mutex_t StreamMutex;
    624 
    625 #else // Setup for "dummy" behavior
    626 
    627   #define __RTAUDIO_DUMMY__
    628   typedef int ThreadHandle;
    629   typedef int StreamMutex;
    630 
    631 #endif
    632 
    633 // This global structure type is used to pass callback information
    634 // between the private RtAudio stream structure and global callback
    635 // handling functions.
    636 struct CallbackInfo {
    637   void *object{};    // Used as a "this" pointer.
    638   ThreadHandle thread{};
    639   void *callback{};
    640   void *userData{};
    641   void *errorCallback{};
    642   void *apiInfo{};   // void pointer for API specific callback information
    643   bool isRunning{false};
    644   bool doRealtime{false};
    645   int priority{};
    646 };
    647 
    648 // **************************************************************** //
    649 //
    650 // RtApi class declaration.
    651 //
    652 // Subclasses of RtApi contain all API- and OS-specific code necessary
    653 // to fully implement the RtAudio API.
    654 //
    655 // Note that RtApi is an abstract base class and cannot be
    656 // explicitly instantiated.  The class RtAudio will create an
    657 // instance of an RtApi subclass (RtApiOss, RtApiAlsa,
    658 // RtApiJack, RtApiCore, RtApiDs, or RtApiAsio).
    659 //
    660 // **************************************************************** //
    661 
    662 #pragma pack(push, 1)
    663 class S24 {
    664 
    665  protected:
    666   unsigned char c3[3];
    667 
    668  public:
    669   S24() {}
    670 
    671   S24& operator = ( const int& i ) {
    672     c3[0] = (i & 0x000000ff);
    673     c3[1] = (i & 0x0000ff00) >> 8;
    674     c3[2] = (i & 0x00ff0000) >> 16;
    675     return *this;
    676   }
    677 
    678   S24( const double& d ) { *this = (int) d; }
    679   S24( const float& f ) { *this = (int) f; }
    680   S24( const signed short& s ) { *this = (int) s; }
    681   S24( const char& c ) { *this = (int) c; }
    682 
    683   int asInt() {
    684     int i = c3[0] | (c3[1] << 8) | (c3[2] << 16);
    685     if (i & 0x800000) i |= ~0xffffff;
    686     return i;
    687   }
    688 };
    689 #pragma pack(pop)
    690 
    691 #if defined( HAVE_GETTIMEOFDAY )
    692   #include <sys/time.h>
    693 #endif
    694 
    695 #include <sstream>
    696 
    697 class RTAUDIO_DLL_PUBLIC RtApi
    698 {
    699 public:
    700 
    701   RtApi();
    702   virtual ~RtApi();
    703   virtual RtAudio::Api getCurrentApi( void ) = 0;
    704   virtual unsigned int getDeviceCount( void ) = 0;
    705   virtual RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) = 0;
    706   virtual unsigned int getDefaultInputDevice( void );
    707   virtual unsigned int getDefaultOutputDevice( void );
    708   void openStream( RtAudio::StreamParameters *outputParameters,
    709                    RtAudio::StreamParameters *inputParameters,
    710                    RtAudioFormat format, unsigned int sampleRate,
    711                    unsigned int *bufferFrames, RtAudioCallback callback,
    712                    void *userData, RtAudio::StreamOptions *options,
    713                    RtAudioErrorCallback errorCallback );
    714   virtual void closeStream( void );
    715   virtual void startStream( void ) = 0;
    716   virtual void stopStream( void ) = 0;
    717   virtual void abortStream( void ) = 0;
    718   long getStreamLatency( void );
    719   unsigned int getStreamSampleRate( void );
    720   virtual double getStreamTime( void );
    721   virtual void setStreamTime( double time );
    722   bool isStreamOpen( void ) const { return stream_.state != STREAM_CLOSED; }
    723   bool isStreamRunning( void ) const { return stream_.state == STREAM_RUNNING; }
    724   void showWarnings( bool value ) { showWarnings_ = value; }
    725 
    726 
    727 protected:
    728 
    729   static const unsigned int MAX_SAMPLE_RATES;
    730   static const unsigned int SAMPLE_RATES[];
    731 
    732   enum { FAILURE, SUCCESS };
    733 
    734   enum StreamState {
    735     STREAM_STOPPED,
    736     STREAM_STOPPING,
    737     STREAM_RUNNING,
    738     STREAM_CLOSED = -50
    739   };
    740 
    741   enum StreamMode {
    742     OUTPUT,
    743     INPUT,
    744     DUPLEX,
    745     UNINITIALIZED = -75
    746   };
    747 
    748   // A protected structure used for buffer conversion.
    749   struct ConvertInfo {
    750     int channels;
    751     int inJump, outJump;
    752     RtAudioFormat inFormat, outFormat;
    753     std::vector<int> inOffset;
    754     std::vector<int> outOffset;
    755   };
    756 
    757   // A protected structure for audio streams.
    758   struct RtApiStream {
    759     unsigned int device[2];    // Playback and record, respectively.
    760     void *apiHandle;           // void pointer for API specific stream handle information
    761     StreamMode mode;           // OUTPUT, INPUT, or DUPLEX.
    762     StreamState state;         // STOPPED, RUNNING, or CLOSED
    763     char *userBuffer[2];       // Playback and record, respectively.
    764     char *deviceBuffer;
    765     bool doConvertBuffer[2];   // Playback and record, respectively.
    766     bool userInterleaved;
    767     bool deviceInterleaved[2]; // Playback and record, respectively.
    768     bool doByteSwap[2];        // Playback and record, respectively.
    769     unsigned int sampleRate;
    770     unsigned int bufferSize;
    771     unsigned int nBuffers;
    772     unsigned int nUserChannels[2];    // Playback and record, respectively.
    773     unsigned int nDeviceChannels[2];  // Playback and record channels, respectively.
    774     unsigned int channelOffset[2];    // Playback and record, respectively.
    775     unsigned long latency[2];         // Playback and record, respectively.
    776     RtAudioFormat userFormat;
    777     RtAudioFormat deviceFormat[2];    // Playback and record, respectively.
    778     StreamMutex mutex;
    779     CallbackInfo callbackInfo;
    780     ConvertInfo convertInfo[2];
    781     double streamTime;         // Number of elapsed seconds since the stream started.
    782 
    783 #if defined(HAVE_GETTIMEOFDAY)
    784     struct timeval lastTickTimestamp;
    785 #endif
    786 
    787     RtApiStream()
    788       :apiHandle(0), deviceBuffer(0) { device[0] = 11111; device[1] = 11111; }
    789   };
    790 
    791   typedef S24 Int24;
    792   typedef signed short Int16;
    793   typedef signed int Int32;
    794   typedef float Float32;
    795   typedef double Float64;
    796 
    797   std::ostringstream errorStream_;
    798   std::string errorText_;
    799   bool showWarnings_;
    800   RtApiStream stream_;
    801   bool firstErrorOccurred_;
    802 
    803   /*!
    804     Protected, api-specific method that attempts to open a device
    805     with the given parameters.  This function MUST be implemented by
    806     all subclasses.  If an error is encountered during the probe, a
    807     "warning" message is reported and FAILURE is returned. A
    808     successful probe is indicated by a return value of SUCCESS.
    809   */
    810   virtual bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
    811                                 unsigned int firstChannel, unsigned int sampleRate,
    812                                 RtAudioFormat format, unsigned int *bufferSize,
    813                                 RtAudio::StreamOptions *options );
    814 
    815   //! A protected function used to increment the stream time.
    816   void tickStreamTime( void );
    817 
    818   //! Protected common method to clear an RtApiStream structure.
    819   void clearStreamInfo();
    820 
    821   /*!
    822     Protected common method that throws an RtAudioError (type =
    823     INVALID_USE) if a stream is not open.
    824   */
    825   void verifyStream( void );
    826 
    827   //! Protected common error method to allow global control over error handling.
    828   void error( RtAudioError::Type type );
    829 
    830   /*!
    831     Protected method used to perform format, channel number, and/or interleaving
    832     conversions between the user and device buffers.
    833   */
    834   void convertBuffer( char *outBuffer, char *inBuffer, ConvertInfo &info );
    835 
    836   //! Protected common method used to perform byte-swapping on buffers.
    837   void byteSwapBuffer( char *buffer, unsigned int samples, RtAudioFormat format );
    838 
    839   //! Protected common method that returns the number of bytes for a given format.
    840   unsigned int formatBytes( RtAudioFormat format );
    841 
    842   //! Protected common method that sets up the parameters for buffer conversion.
    843   void setConvertInfo( StreamMode mode, unsigned int firstChannel );
    844 };
    845 
    846 // **************************************************************** //
    847 //
    848 // Inline RtAudio definitions.
    849 //
    850 // **************************************************************** //
    851 
    852 inline RtAudio::Api RtAudio :: getCurrentApi( void ) { return rtapi_->getCurrentApi(); }
    853 inline unsigned int RtAudio :: getDeviceCount( void ) { return rtapi_->getDeviceCount(); }
    854 inline RtAudio::DeviceInfo RtAudio :: getDeviceInfo( unsigned int device ) { return rtapi_->getDeviceInfo( device ); }
    855 inline unsigned int RtAudio :: getDefaultInputDevice( void ) { return rtapi_->getDefaultInputDevice(); }
    856 inline unsigned int RtAudio :: getDefaultOutputDevice( void ) { return rtapi_->getDefaultOutputDevice(); }
    857 inline void RtAudio :: closeStream( void ) { return rtapi_->closeStream(); }
    858 inline void RtAudio :: startStream( void ) { return rtapi_->startStream(); }
    859 inline void RtAudio :: stopStream( void )  { return rtapi_->stopStream(); }
    860 inline void RtAudio :: abortStream( void ) { return rtapi_->abortStream(); }
    861 inline bool RtAudio :: isStreamOpen( void ) const { return rtapi_->isStreamOpen(); }
    862 inline bool RtAudio :: isStreamRunning( void ) const { return rtapi_->isStreamRunning(); }
    863 inline long RtAudio :: getStreamLatency( void ) { return rtapi_->getStreamLatency(); }
    864 inline unsigned int RtAudio :: getStreamSampleRate( void ) { return rtapi_->getStreamSampleRate(); }
    865 inline double RtAudio :: getStreamTime( void ) { return rtapi_->getStreamTime(); }
    866 inline void RtAudio :: setStreamTime( double time ) { return rtapi_->setStreamTime( time ); }
    867 inline void RtAudio :: showWarnings( bool value ) { rtapi_->showWarnings( value ); }
    868 
    869 // RtApi Subclass prototypes.
    870 
    871 #if defined(__MACOSX_CORE__)
    872 
    873 #include <CoreAudio/AudioHardware.h>
    874 
    875 class RtApiCore: public RtApi
    876 {
    877 public:
    878 
    879   RtApiCore();
    880   ~RtApiCore();
    881   RtAudio::Api getCurrentApi( void ) override { return RtAudio::MACOSX_CORE; }
    882   unsigned int getDeviceCount( void ) override;
    883   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
    884   unsigned int getDefaultOutputDevice( void ) override;
    885   unsigned int getDefaultInputDevice( void ) override;
    886   void closeStream( void ) override;
    887   void startStream( void ) override;
    888   void stopStream( void ) override;
    889   void abortStream( void ) override;
    890 
    891   // This function is intended for internal use only.  It must be
    892   // public because it is called by the internal callback handler,
    893   // which is not a member of RtAudio.  External use of this function
    894   // will most likely produce highly undesireable results!
    895   bool callbackEvent( AudioDeviceID deviceId,
    896                       const AudioBufferList *inBufferList,
    897                       const AudioBufferList *outBufferList );
    898 
    899   private:
    900 
    901   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
    902                         unsigned int firstChannel, unsigned int sampleRate,
    903                         RtAudioFormat format, unsigned int *bufferSize,
    904                         RtAudio::StreamOptions *options ) override;
    905   static const char* getErrorCode( OSStatus code );
    906 };
    907 
    908 #endif
    909 
    910 #if defined(__UNIX_JACK__)
    911 
    912 class RtApiJack: public RtApi
    913 {
    914 public:
    915 
    916   RtApiJack();
    917   ~RtApiJack();
    918   RtAudio::Api getCurrentApi( void ) override { return RtAudio::UNIX_JACK; }
    919   unsigned int getDeviceCount( void ) override;
    920   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
    921   void closeStream( void ) override;
    922   void startStream( void ) override;
    923   void stopStream( void ) override;
    924   void abortStream( void ) override;
    925 
    926   // This function is intended for internal use only.  It must be
    927   // public because it is called by the internal callback handler,
    928   // which is not a member of RtAudio.  External use of this function
    929   // will most likely produce highly undesireable results!
    930   bool callbackEvent( unsigned long nframes );
    931 
    932   private:
    933 
    934   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
    935                         unsigned int firstChannel, unsigned int sampleRate,
    936                         RtAudioFormat format, unsigned int *bufferSize,
    937                         RtAudio::StreamOptions *options ) override;
    938 
    939   bool shouldAutoconnect_;
    940 };
    941 
    942 #endif
    943 
    944 #if defined(__WINDOWS_ASIO__)
    945 
    946 class RtApiAsio: public RtApi
    947 {
    948 public:
    949 
    950   RtApiAsio();
    951   ~RtApiAsio();
    952   RtAudio::Api getCurrentApi( void ) override { return RtAudio::WINDOWS_ASIO; }
    953   unsigned int getDeviceCount( void ) override;
    954   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
    955   void closeStream( void ) override;
    956   void startStream( void ) override;
    957   void stopStream( void ) override;
    958   void abortStream( void ) override;
    959 
    960   // This function is intended for internal use only.  It must be
    961   // public because it is called by the internal callback handler,
    962   // which is not a member of RtAudio.  External use of this function
    963   // will most likely produce highly undesireable results!
    964   bool callbackEvent( long bufferIndex );
    965 
    966   private:
    967 
    968   std::vector<RtAudio::DeviceInfo> devices_;
    969   void saveDeviceInfo( void );
    970   bool coInitialized_;
    971   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
    972                         unsigned int firstChannel, unsigned int sampleRate,
    973                         RtAudioFormat format, unsigned int *bufferSize,
    974                         RtAudio::StreamOptions *options ) override;
    975 };
    976 
    977 #endif
    978 
    979 #if defined(__WINDOWS_DS__)
    980 
    981 class RtApiDs: public RtApi
    982 {
    983 public:
    984 
    985   RtApiDs();
    986   ~RtApiDs();
    987   RtAudio::Api getCurrentApi( void ) override { return RtAudio::WINDOWS_DS; }
    988   unsigned int getDeviceCount( void ) override;
    989   unsigned int getDefaultOutputDevice( void ) override;
    990   unsigned int getDefaultInputDevice( void ) override;
    991   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
    992   void closeStream( void ) override;
    993   void startStream( void ) override;
    994   void stopStream( void ) override;
    995   void abortStream( void ) override;
    996 
    997   // This function is intended for internal use only.  It must be
    998   // public because it is called by the internal callback handler,
    999   // which is not a member of RtAudio.  External use of this function
   1000   // will most likely produce highly undesireable results!
   1001   void callbackEvent( void );
   1002 
   1003   private:
   1004 
   1005   bool coInitialized_;
   1006   bool buffersRolling;
   1007   long duplexPrerollBytes;
   1008   std::vector<struct DsDevice> dsDevices;
   1009   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
   1010                         unsigned int firstChannel, unsigned int sampleRate,
   1011                         RtAudioFormat format, unsigned int *bufferSize,
   1012                         RtAudio::StreamOptions *options ) override;
   1013 };
   1014 
   1015 #endif
   1016 
   1017 #if defined(__WINDOWS_WASAPI__)
   1018 
   1019 struct IMMDeviceEnumerator;
   1020 
   1021 class RtApiWasapi : public RtApi
   1022 {
   1023 public:
   1024   RtApiWasapi();
   1025   virtual ~RtApiWasapi();
   1026 
   1027   RtAudio::Api getCurrentApi( void ) override { return RtAudio::WINDOWS_WASAPI; }
   1028   unsigned int getDeviceCount( void ) override;
   1029   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
   1030   unsigned int getDefaultOutputDevice( void ) override;
   1031   unsigned int getDefaultInputDevice( void ) override;
   1032   void closeStream( void ) override;
   1033   void startStream( void ) override;
   1034   void stopStream( void ) override;
   1035   void abortStream( void ) override;
   1036 
   1037 private:
   1038   bool coInitialized_;
   1039   IMMDeviceEnumerator* deviceEnumerator_;
   1040 
   1041   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels,
   1042                         unsigned int firstChannel, unsigned int sampleRate,
   1043                         RtAudioFormat format, unsigned int* bufferSize,
   1044                         RtAudio::StreamOptions* options ) override;
   1045 
   1046   static DWORD WINAPI runWasapiThread( void* wasapiPtr );
   1047   static DWORD WINAPI stopWasapiThread( void* wasapiPtr );
   1048   static DWORD WINAPI abortWasapiThread( void* wasapiPtr );
   1049   void wasapiThread();
   1050 };
   1051 
   1052 #endif
   1053 
   1054 #if defined(__LINUX_ALSA__)
   1055 
   1056 class RtApiAlsa: public RtApi
   1057 {
   1058 public:
   1059 
   1060   RtApiAlsa();
   1061   ~RtApiAlsa();
   1062   RtAudio::Api getCurrentApi() override { return RtAudio::LINUX_ALSA; }
   1063   unsigned int getDeviceCount( void ) override;
   1064   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
   1065   void closeStream( void ) override;
   1066   void startStream( void ) override;
   1067   void stopStream( void ) override;
   1068   void abortStream( void ) override;
   1069 
   1070   // This function is intended for internal use only.  It must be
   1071   // public because it is called by the internal callback handler,
   1072   // which is not a member of RtAudio.  External use of this function
   1073   // will most likely produce highly undesireable results!
   1074   void callbackEvent( void );
   1075 
   1076   private:
   1077 
   1078   std::vector<RtAudio::DeviceInfo> devices_;
   1079   void saveDeviceInfo( void );
   1080   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
   1081                         unsigned int firstChannel, unsigned int sampleRate,
   1082                         RtAudioFormat format, unsigned int *bufferSize,
   1083                         RtAudio::StreamOptions *options ) override;
   1084 };
   1085 
   1086 #endif
   1087 
   1088 #if defined(__LINUX_PULSE__)
   1089 
   1090 class RtApiPulse: public RtApi
   1091 {
   1092 public:
   1093   ~RtApiPulse();
   1094   RtAudio::Api getCurrentApi() override { return RtAudio::LINUX_PULSE; }
   1095   unsigned int getDeviceCount( void ) override;
   1096   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
   1097   void closeStream( void ) override;
   1098   void startStream( void ) override;
   1099   void stopStream( void ) override;
   1100   void abortStream( void ) override;
   1101 
   1102   // This function is intended for internal use only.  It must be
   1103   // public because it is called by the internal callback handler,
   1104   // which is not a member of RtAudio.  External use of this function
   1105   // will most likely produce highly undesireable results!
   1106   void callbackEvent( void );
   1107 
   1108   private:
   1109 
   1110   void collectDeviceInfo( void );
   1111   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels,
   1112                         unsigned int firstChannel, unsigned int sampleRate,
   1113                         RtAudioFormat format, unsigned int *bufferSize,
   1114                         RtAudio::StreamOptions *options ) override;
   1115 };
   1116 
   1117 #endif
   1118 
   1119 #if defined(__LINUX_OSS__)
   1120 
   1121 class RtApiOss: public RtApi
   1122 {
   1123 public:
   1124 
   1125   RtApiOss();
   1126   ~RtApiOss();
   1127   RtAudio::Api getCurrentApi() override { return RtAudio::LINUX_OSS; }
   1128   unsigned int getDeviceCount( void ) override;
   1129   RtAudio::DeviceInfo getDeviceInfo( unsigned int device ) override;
   1130   void closeStream( void ) override;
   1131   void startStream( void ) override;
   1132   void stopStream( void ) override;
   1133   void abortStream( void ) override;
   1134 
   1135   // This function is intended for internal use only.  It must be
   1136   // public because it is called by the internal callback handler,
   1137   // which is not a member of RtAudio.  External use of this function
   1138   // will most likely produce highly undesireable results!
   1139   void callbackEvent( void );
   1140 
   1141   private:
   1142 
   1143   bool probeDeviceOpen( unsigned int device, StreamMode mode, unsigned int channels, 
   1144                         unsigned int firstChannel, unsigned int sampleRate,
   1145                         RtAudioFormat format, unsigned int *bufferSize,
   1146                         RtAudio::StreamOptions *options ) override;
   1147 };
   1148 
   1149 #endif
   1150 
   1151 #if defined(__RTAUDIO_DUMMY__)
   1152 
   1153 class RtApiDummy: public RtApi
   1154 {
   1155 public:
   1156 
   1157   RtApiDummy() { errorText_ = "RtApiDummy: This class provides no functionality."; error( RtAudioError::WARNING ); }
   1158   RtAudio::Api getCurrentApi( void ) override { return RtAudio::RTAUDIO_DUMMY; }
   1159   unsigned int getDeviceCount( void ) override { return 0; }
   1160   RtAudio::DeviceInfo getDeviceInfo( unsigned int /*device*/ ) override { RtAudio::DeviceInfo info; return info; }
   1161   void closeStream( void ) override {}
   1162   void startStream( void ) override {}
   1163   void stopStream( void ) override {}
   1164   void abortStream( void ) override {}
   1165 
   1166   private:
   1167 
   1168   bool probeDeviceOpen( unsigned int /*device*/, StreamMode /*mode*/, unsigned int /*channels*/, 
   1169                         unsigned int /*firstChannel*/, unsigned int /*sampleRate*/,
   1170                         RtAudioFormat /*format*/, unsigned int * /*bufferSize*/,
   1171                         RtAudio::StreamOptions * /*options*/ ) override { return false; }
   1172 };
   1173 
   1174 #endif
   1175 
   1176 #endif
   1177 
   1178 // Indentation settings for Vim and Emacs
   1179 //
   1180 // Local Variables:
   1181 // c-basic-offset: 2
   1182 // indent-tabs-mode: nil
   1183 // End:
   1184 //
   1185 // vim: et sts=2 sw=2