Move more modern C++ idioms and use std::unique_ptr for moving daat ownership around

simgear/sound/openal_test1.cxx

@@ -75,23 +75,23 @@ ALuint createBufferFromFile(const SGPath& path)
 }
 
 
-int main( int argc, char *argv[] ) 
+int main( int argc, char *argv[] )
 {
     sglog().setLogLevels( SG_ALL, SG_ALERT );
-    
+
     // initialize OpenAL
-    ALCdevice *dev = alcOpenDevice(NULL); 
+    ALCdevice *dev = alcOpenDevice(nullptr);
     if (!dev) {
       SG_LOG( SG_GENERAL, SG_ALERT, "Audio device initialization failed!" );
       return EXIT_FAILURE;
     }
-    
+
-    ALCcontext *context = alcCreateContext(dev, NULL);
+    ALCcontext *context = alcCreateContext(dev, nullptr);
     if (!context) {
       SG_LOG( SG_GENERAL, SG_ALERT, "Audio context initialization failed!" );
       return EXIT_FAILURE;
     }
-    
+
     alcMakeContextCurrent( context );
 
     // Position of the listener.
@@ -111,7 +111,7 @@ int main( int argc, char *argv[] )
     listener_vel[0] = 0.0;
     listener_vel[1] = 0.0;
     listener_vel[2] = 0.0;
-    
+
     listener_ori[0] = 0.0;
     listener_ori[1] = 0.0;
     listener_ori[2] = -1.0;
@@ -163,10 +163,10 @@ int main( int argc, char *argv[] )
     alSourcePlay( source );
 
     sleep(10);
-    
+
-     alcMakeContextCurrent(NULL);
+    alcMakeContextCurrent(nullptr);
-     alcDestroyContext(context);
+    alcDestroyContext(context);
-     alcCloseDevice(dev);
+    alcCloseDevice(dev);
-     
+
     return 0;
 }

simgear/sound/readwav.cxx

@@ -46,7 +46,7 @@ namespace
     ALfloat frequency;
     SGPath path;
       
-    Buffer() : data(NULL), format(AL_NONE), length(0), frequency(0.0f) {}
+    Buffer() : data(nullptr), format(AL_NONE), length(0), frequency(0.0f) {}
     
     ~Buffer()
     {
@@ -119,7 +119,7 @@ namespace
     uint8_t *d = (uint8_t *) b->data;
     size_t newLength = b->length * 2;
     int16_t *buf = (int16_t *) malloc(newLength);
-    if (buf == NULL)
+    if (buf == nullptr)
       throw sg_exception("malloc failed decoing ULaw WAV file");
    
     for (ALsizei i = 0; i < b->length; i++) {
@@ -193,7 +193,7 @@ namespace
     size_t blocks = b->length/block_align;
     size_t newLength = block_align * blocks * 4;
     int16_t *buf = (int16_t *) malloc ( newLength );
-    if (buf == NULL)
+    if (buf == nullptr)
       throw sg_exception("malloc failed decoing IMA4 WAV file");
 
     int16_t *ptr = buf;
@@ -260,7 +260,7 @@ namespace
   
   void loadWavFile(gzFile fd, Buffer* b)
   {
-    assert(b->data == NULL);
+    assert(b->data == nullptr);
     
     bool found_header = false;
     bool compressed = false;
@@ -405,7 +405,7 @@ ALvoid* loadWAVFromFile(const SGPath& path, unsigned int& format, ALsizei& size,
   }
 
   ALvoid* data = b.data;
-  b.data = NULL; // don't free when Buffer does out of scope
+  b.data = nullptr; // don't free when Buffer does out of scope
   format = b.format;
   block_align = b.block_align;
   size = b.length;

simgear/sound/sample.cxx

@@ -88,40 +88,18 @@ SGSoundSample::SGSoundSample(const char *file, const SGPath& currentDir) :
 }
 
 // constructor
-SGSoundSample::SGSoundSample( const unsigned char** data,
+SGSoundSample::SGSoundSample( std::unique_ptr<unsigned char, decltype(free)*>& data,
                               int len, int freq, int format )
 {
     SG_LOG( SG_SOUND, SG_DEBUG, "In memory sounds sample" );
-    _data = (unsigned char*)*data; *data = NULL;
+
+    _data = std::move(data);
 
     set_frequency(freq);
     set_format(format);
     set_size(len);
 }
 
-// constructor
-SGSoundSample::SGSoundSample( void** data, int len, int freq, int format ) :
-    _is_file(false),
-    _changed(true),
-    _valid_source(false),
-    _source(SGSoundMgr::NO_SOURCE),
-    _valid_buffer(false),
-    _buffer(SGSoundMgr::NO_BUFFER)
-{
-    SG_LOG( SG_SOUND, SG_DEBUG, "In memory sounds sample" );
-    _data = (unsigned char*)*data; *data = NULL;
-
-    set_frequency(freq);
-    set_format(format);
-    set_size(len);
-}
-
-
-// destructor
-SGSoundSample::~SGSoundSample() {
-    if ( _data != NULL ) free(_data);
-}
-
 void SGSoundSample::update_pos_and_orientation() {
 
     if (_use_pos_props) {
@@ -148,11 +126,3 @@ SGPath SGSoundSample::file_path() const
 
   return SGPath(_refname);
 }
-
-void SGSoundSample::free_data()
-{
-   if ( _data != NULL ) {
-     free( _data );
-   }
-   _data = NULL;
-}

simgear/sound/sample.hxx

@@ -255,7 +255,8 @@ public:
       * Empty constructor, can be used to read data to the systems
       * memory and not to the driver.
       */
-    SGSoundSample() {};
+    SGSoundSample() = default;
+    virtual ~SGSoundSample () = default;
 
     /**
      * Constructor
@@ -269,20 +270,15 @@ public:
      * @param data Pointer to a memory buffer containing this audio sample data
        The application may free the data by calling free_data(), otherwise it
        will be resident until the class is destroyed. This pointer will be
-       set to NULL after calling this function.
+       set to nullptr after calling this function.
      * @param len Byte length of array
      * @param freq Frequency of the provided data (bytes per second)
      * @param format SimGear format id of the data
      */
-    SGSoundSample( void** data, int len, int freq, int format=SG_SAMPLE_MONO8 );
+    SGSoundSample( std::unique_ptr<unsigned char, decltype(free)*>& data,
-    SGSoundSample( const unsigned char** data, int len, int freq,
+                   int len, int freq,
                    int format = SG_SAMPLE_MONO8 );
 
-    /**
-     * Destructor
-     */
-    virtual ~SGSoundSample ();
-
     /**
      * Test if this audio sample configuration has changed since the last call.
      * Calling this function will reset the flag so calling it a second
@@ -360,25 +356,22 @@ public:
     /**
      * Set the data associated with this audio sample
      * @param data Pointer to a memory block containg this audio sample data.
-       This pointer will be set to NULL after calling this function.
+       This pointer will be set to nullptr after calling this function.
      */
-    inline void set_data( const unsigned char **data ) {
+    inline void set_data( std::unique_ptr<unsigned char, decltype(free)*>& data ) {
-        _data = (unsigned char*)*data; *data = NULL;
+        _data = std::move(data);
-    }
-    inline void set_data( const void **data ) {
-        _data = (unsigned char*)*data; *data = NULL;
     }
 
     /**
      * Return the data associated with this audio sample.
      * @return A pointer to this sound data of this audio sample.
      */
-    inline void* get_data() const { return _data; }
+    inline unsigned char* get_data() const { return _data.get(); }
 
     /**
      * Free the data associated with this audio sample
      */
-    void free_data();
+    inline void free_data() { _data = nullptr; }
 
     /**
      * Set the source id of this source
@@ -607,7 +600,7 @@ protected:
     unsigned int _source = SGSoundMgr::NO_SOURCE;
 
 private:
-    unsigned char* _data = NULL;
+    std::unique_ptr<unsigned char, decltype(free)*> _data = { nullptr, free };
 
     // Buffers hold sound data.
     bool _valid_buffer = false;

simgear/sound/sample_group.cxx

@@ -180,12 +180,12 @@ bool SGSampleGroup::exists( const std::string &refname ) {
 
 
 // return a pointer to the SGSoundSample if the specified sound exists
-// in the sound manager system, otherwise return NULL
+// in the sound manager system, otherwise return nullptr
 SGSoundSample *SGSampleGroup::find( const std::string &refname ) {
     auto sample_it = _samples.find( refname );
     if ( sample_it == _samples.end() ) {
         // sample was not found
-        return NULL;
+        return nullptr;
     }
 
     return sample_it->second;
@@ -241,7 +241,7 @@ bool SGSampleGroup::play( const std::string &refname,
 {
     SGSoundSample *sample = find( refname );
 
-    if ( sample == NULL ) {
+    if ( sample == nullptr ) {
         return false;
     }
 
@@ -254,7 +254,7 @@ bool SGSampleGroup::play( const std::string &refname,
 bool SGSampleGroup::is_playing( const std::string& refname ) {
     SGSoundSample *sample = find( refname );
 
-    if ( sample == NULL ) {
+    if ( sample == nullptr ) {
         return false;
     }
 
@@ -265,7 +265,7 @@ bool SGSampleGroup::is_playing( const std::string& refname ) {
 bool SGSampleGroup::stop( const std::string& refname ) {
     SGSoundSample *sample  = find( refname );
 
-    if ( sample == NULL ) {
+    if ( sample == nullptr ) {
         return false;
     }
 
@@ -357,7 +357,7 @@ void SGSampleGroup::update_sample_config( SGSoundSample *sample )
 
 bool SGSampleGroup::testForError(void *p, std::string s)
 {
-   if (p == NULL) {
+   if (p == nullptr) {
       SG_LOG( SG_SOUND, SG_ALERT, "Error (sample group): " << s);
       return true;
    }

simgear/sound/sample_group.hxx

@@ -39,7 +39,7 @@
 #include "sample.hxx"
 
 
-typedef std::map < std::string, SGSharedPtr<SGSoundSample> > sample_map;
+using sample_map = std::map< std::string, SGSharedPtr<SGSoundSample> >;
 
 class SGSoundMgr;
 
@@ -212,7 +212,7 @@ public:
     void tie_to_listener() { _tied_to_listener = true; }
 
 protected:
-    SGSoundMgr *_smgr = NULL;
+    SGSoundMgr *_smgr = nullptr;
     std::string _refname = "";
     bool _active = false;
 

simgear/sound/soundmgr.hxx

@@ -307,7 +307,7 @@ public:
      * @return true if succesful, false on error
      */
     virtual bool load( const std::string &samplepath,
-                       void **data,
+                       void** data,
                        int *format,
                        size_t *size,
                        int *freq,

simgear/sound/soundmgr_aeonwave.cxx

@@ -48,11 +48,11 @@
 
 
 // We keep track of the emitters ourselves.
-typedef std::map < unsigned int, aax::Emitter > source_map;
+using source_map = std::map< unsigned int, aax::Emitter >;
 
 // The AeonWave class keeps track of the buffers, so use a reference instead.
-typedef std::map < unsigned int, aax::Buffer& > buffer_map;
+using buffer_map = std::map< unsigned int, aax::Buffer& >;
-typedef std::map < std::string, SGSharedPtr<SGSampleGroup> > sample_group_map;
+using sample_group_map = std::map< std::string, SGSharedPtr<SGSampleGroup> >;
 
 #ifndef NDEBUG
 # define TRY(a)	if ((a) == 0) printf("%i: %s\n", __LINE__, d->_aax.strerror())
@@ -64,14 +64,7 @@ typedef std::map < std::string, SGSharedPtr<SGSampleGroup> > sample_group_map;
 class SGSoundMgr::SoundManagerPrivate
 {
 public:
-    SoundManagerPrivate() :
+    SoundManagerPrivate() = default;
-        _absolute_pos(SGVec3d::zeros()),
-        _base_pos(SGVec3d::zeros()),
-        _orientation(SGQuatd::zeros()),
-        _buffer_id(0),
-        _source_id(0)
-    {
-    }
 
     ~SoundManagerPrivate()
     {
@@ -96,11 +89,11 @@ public:
     aax::AeonWave _aax;
     aax::Matrix64 _mtx;
 
-    SGVec3d _absolute_pos;
+    SGVec3d _absolute_pos = SGVec3d::zeros();
-    SGVec3d _base_pos;
+    SGVec3d _base_pos = SGVec3d::zeros();
-    SGQuatd _orientation;
+    SGQuatd _orientation = SGQuatd::zeros();
 
-    unsigned int _buffer_id;
+    unsigned int _buffer_id = 0;
     buffer_map _buffers;
     aax::Buffer nullBuffer;
     aax::Buffer& get_buffer(unsigned int id) {
@@ -110,7 +103,7 @@ public:
         return nullBuffer;
     }
 
-    unsigned int _source_id;
+    unsigned int _source_id = 0;
     source_map _sources;
     aax::Emitter nullEmitter;
     aax::Emitter& get_emitter(unsigned int id) {
@@ -229,10 +222,8 @@ void SGSoundMgr::activate()
     if ( is_working() ) {
         _active = true;
                 
-        for ( auto current = d->_sample_groups.begin();
+        for ( auto current : d->_sample_groups ) {
-                   current != d->_sample_groups.end(); ++current ) {
+            current.second->activate();
-            SGSampleGroup *sgrp = current->second;
-            sgrp->activate();
         }
     }
 #endif
@@ -243,10 +234,8 @@ void SGSoundMgr::stop()
 {
 #ifdef ENABLE_SOUND
     // first stop all sample groups
-    for ( auto current = d->_sample_groups.begin();
+    for ( auto current : d->_sample_groups ) {
-               current != d->_sample_groups.end();  ++ current ) {
+        current.second->stop();
-        SGSampleGroup *sgrp = current->second;
-        sgrp->stop();
     }
 
     d->_buffer_id = 0;
@@ -269,10 +258,8 @@ void SGSoundMgr::suspend()
 {
 #ifdef ENABLE_SOUND
     if (is_working()) {
-        for (auto current = d->_sample_groups.begin();
+        for (auto current : d->_sample_groups ) {
-                  current != d->_sample_groups.end(); ++current ) {
+            current.second->stop();
-            SGSampleGroup *sgrp = current->second;
-            sgrp->stop();
         }
         _active = false;
     }
@@ -283,10 +270,8 @@ void SGSoundMgr::resume()
 {
 #ifdef ENABLE_SOUND
     if (is_working()) {
-        for ( auto current = d->_sample_groups.begin();
+        for ( auto current : d->_sample_groups ) {
-                   current != d->_sample_groups.end(); ++current ) {
+            current.second->resume();
-            SGSampleGroup *sgrp = current->second;
-            sgrp->resume();
         }
         _active = true;
     }
@@ -302,10 +287,8 @@ void SGSoundMgr::update( double dt )
             d->update_pos_and_orientation();
         }
 
-        for ( auto current = d->_sample_groups.begin();
+        for ( auto current : d->_sample_groups ) {
-                   current != d->_sample_groups.end(); ++current ) {
+            current.second->update(dt);
-            SGSampleGroup *sgrp = current->second;
-            sgrp->update(dt);
         }
 
         if (_changed) {
@@ -371,21 +354,21 @@ bool SGSoundMgr::exists( const std::string &refname ) {
 
 
 // return a pointer to the SGSampleGroup if the specified sound exists
-// in the sound manager system, otherwise return NULL
+// in the sound manager system, otherwise return nullptr
 SGSampleGroup *SGSoundMgr::find( const std::string &refname, bool create ) {
     auto sample_grp_it = d->_sample_groups.find( refname );
     if ( sample_grp_it == d->_sample_groups.end() ) {
         // sample group was not found.
         if (create) {
-            SGSampleGroup* sgrp = new SGSampleGroup(this, refname);
+            SGSampleGroup *sgrp = new SGSampleGroup(this, refname);
             add( sgrp, refname );
             return sgrp;
         }
         else 
-            return NULL;
+            return nullptr;
     }
 
-    return sample_grp_it->second;
+    return sample_grp_it->second.get();
 }
 
 
@@ -695,7 +678,7 @@ vector<std::string> SGSoundMgr::get_available_devices()
 
 bool SGSoundMgr::testForError(void *p, std::string s)
 {
-   if (p == NULL) {
+   if (p == nullptr) {
       SG_LOG( SG_SOUND, SG_ALERT, "Error: " << s);
       return true;
    }
@@ -718,7 +701,7 @@ bool SGSoundMgr::testForError(std::string s, std::string name)
 
 bool SGSoundMgr::is_working() const 
 {
-    return ((const void*)d->_aax != NULL ? true : false);
+    return ((const void*)d->_aax != nullptr ? true : false);
 }
 
 const SGQuatd& SGSoundMgr::get_orientation() const

simgear/sound/soundmgr_openal.cxx

@@ -68,8 +68,8 @@ class SGSoundMgr::SoundManagerPrivate
 {
 public:
     SoundManagerPrivate() :
-        _device(NULL),
+        _device(nullptr),
-        _context(NULL),
+        _context(nullptr),
         _absolute_pos(SGVec3d::zeros()),
         _base_pos(SGVec3d::zeros()),
         _orientation(SGQuatd::zeros())
@@ -173,10 +173,10 @@ void SGSoundMgr::init()
     d->_sources_in_use.clear();
     d->_sources_in_use.reserve( MAX_SOURCES );
 
-    ALCdevice *device = NULL;
+    ALCdevice *device = nullptr;
     const char* devname = _device_name.c_str();
     if (_device_name == "")
-        devname = NULL; // use default device
+        devname = nullptr; // use default device
     else
     {
         // try non-default device
@@ -184,13 +184,13 @@ void SGSoundMgr::init()
     }
 
     if ((!devname)||(testForError(device, "Audio device not available, trying default.")) ) {
-        device = alcOpenDevice(NULL);
+        device = alcOpenDevice(nullptr);
         if (testForError(device, "Default audio device not available.") ) {
            return;
         }
     }
 
-    ALCcontext *context = alcCreateContext(device, NULL);
+    ALCcontext *context = alcCreateContext(device, nullptr);
     testForALCError("context creation.");
     if ( testForError(context, "Unable to create a valid context.") ) {
         alcCloseDevice (device);
@@ -204,7 +204,7 @@ void SGSoundMgr::init()
         return;
     }
 
-    if (d->_context != NULL)
+    if (d->_context != nullptr)
     {
         SG_LOG(SG_SOUND, SG_ALERT, "context is already assigned");
     }
@@ -324,8 +324,8 @@ void SGSoundMgr::stop()
         _active = false;
         alcDestroyContext(d->_context);
         alcCloseDevice(d->_device);
-        d->_context = NULL;
+        d->_context = nullptr;
-        d->_device = NULL;
+        d->_device = nullptr;
 
         _renderer = "unknown";
         _vendor = "unknown";
@@ -448,7 +448,7 @@ bool SGSoundMgr::exists( const std::string &refname ) {
 
 
 // return a pointer to the SGSampleGroup if the specified sound exists
-// in the sound manager system, otherwise return NULL
+// in the sound manager system, otherwise return nullptr
 SGSampleGroup *SGSoundMgr::find( const std::string &refname, bool create ) {
     auto sample_grp_it = d->_sample_groups.find( refname );
     if ( sample_grp_it == d->_sample_groups.end() ) {
@@ -459,7 +459,7 @@ SGSampleGroup *SGSoundMgr::find( const std::string &refname, bool create ) {
             return sgrp;
         }
         else 
-            return NULL;
+            return nullptr;
     }
 
     return sample_grp_it->second;
@@ -525,7 +525,7 @@ unsigned int SGSoundMgr::request_buffer(SGSoundSample *sample)
     if ( !sample->is_valid_buffer() ) {
         // sample was not yet loaded or removed again
         std::string sample_name = sample->get_sample_name();
-        void *sample_data = NULL;
+        void* sample_data = nullptr;
 
         // see if the sample name is already cached
         auto buffer_it = d->_buffers.find( sample_name );
@@ -784,7 +784,7 @@ void SGSoundMgr::update_sample_config( SGSoundSample *sample, SGVec3d& position,
 
 
 bool SGSoundMgr::load( const std::string &samplepath,
-                       void **dbuf,
+                       void** dbuf,
                        int *fmt,
                        size_t *sz,
                        int *frq,
@@ -797,18 +797,16 @@ bool SGSoundMgr::load( const std::string &samplepath,
     unsigned int blocksz;
     ALsizei size;
     ALsizei freq;
-    ALvoid *data;
-
     ALfloat freqf;
 
-    data = simgear::loadWAVFromFile(samplepath, format, size, freqf, blocksz);
+    auto data = simgear::loadWAVFromFile(samplepath, format, size, freqf, blocksz);
     freq = (ALsizei)freqf;
-    if (data == NULL) {
+    if (data == nullptr) {
         throw sg_io_exception("Failed to load wav file", sg_location(samplepath));
     }
 
     if (format == AL_FORMAT_STEREO8 || format == AL_FORMAT_STEREO16) {
-        free(data);
+         free(data);
         throw sg_io_exception("Warning: STEREO files are not supported for 3D audio effects: " + samplepath);
     }
 
@@ -827,10 +825,10 @@ vector<std::string> SGSoundMgr::get_available_devices()
 #ifdef ENABLE_SOUND
     const ALCchar *s;
 
-    if (alcIsExtensionPresent(NULL, "ALC_enumerate_all_EXT") == AL_TRUE) {
+    if (alcIsExtensionPresent(nullptr, "ALC_enumerate_all_EXT") == AL_TRUE) {
-        s = alcGetString(NULL, ALC_ALL_DEVICES_SPECIFIER);
+        s = alcGetString(nullptr, ALC_ALL_DEVICES_SPECIFIER);
     } else {
-        s = alcGetString(NULL, ALC_DEVICE_SPECIFIER);
+        s = alcGetString(nullptr, ALC_DEVICE_SPECIFIER);
     }
 
     if (s) {
@@ -851,7 +849,7 @@ vector<std::string> SGSoundMgr::get_available_devices()
 
 bool SGSoundMgr::testForError(void *p, std::string s)
 {
-   if (p == NULL) {
+   if (p == nullptr) {
       SG_LOG( SG_SOUND, SG_ALERT, "Error: " << s);
       return true;
    }
@@ -889,7 +887,7 @@ bool SGSoundMgr::testForALCError(std::string s)
 
 bool SGSoundMgr::is_working() const 
 {
-    return (d->_device != NULL);
+    return (d->_device != nullptr);
 }
 
 const SGQuatd& SGSoundMgr::get_orientation() const

simgear/sound/soundmgr_openal_private.hxx

@@ -63,8 +63,8 @@ struct refUint {
     ~refUint() {};
 };
 
-typedef std::map < std::string, refUint > buffer_map;
+using buffer_map = std::map < std::string, refUint >;
-typedef std::map < std::string, SGSharedPtr<SGSampleGroup> > sample_group_map;
+using sample_group_map = std::map < std::string, SGSharedPtr<SGSampleGroup> >;
 
 inline bool isNaN(float *v) {
    return (SGMisc<float>::isNaN(v[0]) || SGMisc<float>::isNaN(v[1]) || SGMisc<float>::isNaN(v[2]));

simgear/sound/xmlsound.cxx

@@ -150,9 +150,9 @@ SGXmlSound::init( SGPropertyNode *root,
 
       string intern_str = kids[i]->getStringValue("internal", "");
       if (intern_str == "dt_play")
-         volume.intern = &_dt_play;
+         volume.intern = std::make_shared<double>(_dt_play);
       else if (intern_str == "dt_stop")
-         volume.intern = &_dt_stop;
+         volume.intern = std::make_shared<double>(_dt_stop);
 
       if ((volume.factor = kids[i]->getDoubleValue("factor", 1.0)) != 0.0)
          if (volume.factor < 0.0) {
@@ -217,9 +217,9 @@ SGXmlSound::init( SGPropertyNode *root,
 
       string intern_str = kids[i]->getStringValue("internal", "");
       if (intern_str == "dt_play")
-         pitch.intern = &_dt_play;
+         pitch.intern = std::make_shared<double>(_dt_play);
       else if (intern_str == "dt_stop")
-         pitch.intern = &_dt_stop;
+         pitch.intern = std::make_shared<double>(_dt_stop);
 
       if ((pitch.factor = kids[i]->getDoubleValue("factor", 1.0)) != 0.0)
          if (pitch.factor < 0.0) {

simgear/sound/xmlsound.hxx

@@ -138,24 +138,24 @@ protected:
   enum { LEVEL=0, INVERTED, FLIPFLOP };
 
   using _fn_t = std::function<double(double)>;
-  typedef struct {
+  using _snd_prop = struct {
         SGSharedPtr<SGExpressiond> expr;	// sound system version 2.0
+        std::shared_ptr<double> intern;
         SGPropertyNode_ptr prop;
         _fn_t fn;
-        double *intern;
         double factor;
         double offset;
         double min;
         double max;
         bool subtract;
-  } _snd_prop;
+  };
 
   using _sound_fn_t = std::map <std::string, _fn_t>;
   _sound_fn_t _sound_fn;
 
 private:
 
-  SGSampleGroup * _sgrp;
+  SGSharedPtr<SGSampleGroup> _sgrp;
   SGSharedPtr<SGSoundSample> _sample;
 
   SGSharedPtr<SGCondition> _condition;