rename pa_linux_alsa.c local function GropeDevice() to more descriptive DetermineDeviceInfos(). update related comments.

src/hostapi/alsa/pa_linux_alsa.c

@@ -323,8 +323,10 @@ int _PA_LOCAL_IMPL(snd_pcm_hw_params_get_buffer_size_max) (const snd_pcm_hw_para
     snd_pcm_uframes_t pmax = 0;
     unsigned int      pcnt = 0;
 
+    dir = 0;
     if(( ret = _PA_LOCAL_IMPL(snd_pcm_hw_params_get_period_size_max)(params, &pmax, &dir) ) < 0 )
         return ret;
+    /* REVIEW: why no dir=0 here? is it intended to use the rounding mode of get_period_size_max? either set dir=0 or add explanatory comment. -- rossb 12 May 2019 */
     if(( ret = _PA_LOCAL_IMPL(snd_pcm_hw_params_get_periods_max)(params, &pcnt, &dir) ) < 0 )
         return ret;
 
@@ -825,13 +827,13 @@ static void Terminate( struct PaUtilHostApiRepresentation *hostApi )
     PaAlsa_CloseLibrary();
 }
 
-/** Determine max channels and default latencies.
+/** Determine max channels, default latencies, default sample rate.
  *
- * This function provides functionality to grope an opened (might be opened for capture or playback) pcm device for
+ * This function provides functionality to query an opened (might be opened for capture or playback) pcm device for
  * traits like max channels, suitable default latencies and default sample rate. Upon error, max channels is set to zero,
  * and a suitable result returned. The device is closed before returning.
  */
-static PaError GropeDevice( snd_pcm_t* pcm, int isPlug, StreamDirection mode, int openBlocking,
+static PaError DetermineDeviceInfos( snd_pcm_t* pcm, int isPlug, StreamDirection mode, int openBlocking,
         PaAlsaDeviceInfo* devInfo )
 {
     PaError result = paNoError;
@@ -842,7 +844,6 @@ static PaError GropeDevice( snd_pcm_t* pcm, int isPlug, StreamDirection mode, in
     double * defaultLowLatency, * defaultHighLatency, * defaultSampleRate =
         &devInfo->baseDeviceInfo.defaultSampleRate;
     double defaultSr = *defaultSampleRate;
-    int dir;
 
     assert( pcm );
 
@@ -920,7 +921,7 @@ static PaError GropeDevice( snd_pcm_t* pcm, int isPlug, StreamDirection mode, in
     alsaBufferFrames = 512;
     alsaPeriodFrames = 128;
     ENSURE_( alsa_snd_pcm_hw_params_set_buffer_size_near( pcm, hwParams, &alsaBufferFrames ), paUnanticipatedHostError );
-    ENSURE_( alsa_snd_pcm_hw_params_set_period_size_near( pcm, hwParams, &alsaPeriodFrames, &dir ), paUnanticipatedHostError );
+    ENSURE_( alsa_snd_pcm_hw_params_set_period_size_near( pcm, hwParams, &alsaPeriodFrames, NULL ), paUnanticipatedHostError );
     *defaultLowLatency = (double) (alsaBufferFrames - alsaPeriodFrames) / defaultSr;
 
     /* Base the high latency case on values four times larger */
@@ -930,7 +931,7 @@ static PaError GropeDevice( snd_pcm_t* pcm, int isPlug, StreamDirection mode, in
     ENSURE_( alsa_snd_pcm_hw_params_any( pcm, hwParams ), paUnanticipatedHostError );
     ENSURE_( SetApproximateSampleRate( pcm, hwParams, defaultSr ), paUnanticipatedHostError );
     ENSURE_( alsa_snd_pcm_hw_params_set_buffer_size_near( pcm, hwParams, &alsaBufferFrames ), paUnanticipatedHostError );
-    ENSURE_( alsa_snd_pcm_hw_params_set_period_size_near( pcm, hwParams, &alsaPeriodFrames, &dir ), paUnanticipatedHostError );
+    ENSURE_( alsa_snd_pcm_hw_params_set_period_size_near( pcm, hwParams, &alsaPeriodFrames, NULL ), paUnanticipatedHostError );
     *defaultHighLatency = (double) (alsaBufferFrames - alsaPeriodFrames) / defaultSr;
 
     *minChannels = (int)minChans;
@@ -1166,10 +1167,10 @@ static PaError FillInDevInfo( PaAlsaHostApiRepresentation *alsaApi, HwDevInfo* d
     if( deviceHwInfo->hasCapture &&
         OpenPcm( &pcm, deviceHwInfo->alsaName, SND_PCM_STREAM_CAPTURE, blocking, 0 ) >= 0 )
     {
-        if( GropeDevice( pcm, deviceHwInfo->isPlug, StreamDirection_In, blocking, devInfo ) != paNoError )
+        if( DetermineDeviceInfos( pcm, deviceHwInfo->isPlug, StreamDirection_In, blocking, devInfo ) != paNoError )
         {
             /* Error */
-            PA_DEBUG(( "%s: Failed groping %s for capture\n", __FUNCTION__, deviceHwInfo->alsaName ));
+            PA_DEBUG(( "%s: Failed querying %s for capture device info\n", __FUNCTION__, deviceHwInfo->alsaName ));
             goto end;
         }
     }
@@ -1178,10 +1179,10 @@ static PaError FillInDevInfo( PaAlsaHostApiRepresentation *alsaApi, HwDevInfo* d
     if( deviceHwInfo->hasPlayback &&
         OpenPcm( &pcm, deviceHwInfo->alsaName, SND_PCM_STREAM_PLAYBACK, blocking, 0 ) >= 0 )
     {
-        if( GropeDevice( pcm, deviceHwInfo->isPlug, StreamDirection_Out, blocking, devInfo ) != paNoError )
+        if( DetermineDeviceInfos( pcm, deviceHwInfo->isPlug, StreamDirection_Out, blocking, devInfo ) != paNoError )
         {
             /* Error */
-            PA_DEBUG(( "%s: Failed groping %s for playback\n", __FUNCTION__, deviceHwInfo->alsaName ));
+            PA_DEBUG(( "%s: Failed querying %s for playback device info\n", __FUNCTION__, deviceHwInfo->alsaName ));
             goto end;
         }
     }
@@ -2324,6 +2325,7 @@ static PaError PaAlsaStreamComponent_DetermineFramesPerBuffer( PaAlsaStreamCompo
         /* It may be that the device only supports 2 periods for instance */
         dir = 0;
         ENSURE_( alsa_snd_pcm_hw_params_get_periods_min( hwParams, &minPeriods, &dir ), paUnanticipatedHostError );
+        /* REVIEW: why no dir=0 here? is it intended to use the rounding mode of get_periods_min? either set dir=0 or add explanatory comment. -- rossb 12 May 2019 */
         ENSURE_( alsa_snd_pcm_hw_params_get_periods_max( hwParams, &maxPeriods, &dir ), paUnanticipatedHostError );
         assert( maxPeriods > 1 );
 
@@ -3209,6 +3211,7 @@ error:
         unsigned int _min = 0, _max = 0;
         int _dir = 0;
         ENSURE_( alsa_snd_pcm_hw_params_get_rate_min( hwParams, &_min, &_dir ), paUnanticipatedHostError );
+        /* REVIEW: why no dir=0 here? is it intended to use the rounding mode of get_rate_min? either set dir=0 or add explanatory comment -- rossb 12 May 2019 */
         ENSURE_( alsa_snd_pcm_hw_params_get_rate_max( hwParams, &_max, &_dir ), paUnanticipatedHostError );
         PA_DEBUG(( "%s: SR min = %u, max = %u, req = %u\n", __FUNCTION__, _min, _max, reqRate ));
     }