Update ALSA support to use 1.x API

Despite the comment in ConfigureChecks.cmake which claimed only ALSA 1.x
was supported, the code requested and expected the 0.9 version of some
PCM APIs.

These old APIs were superceded in 2002. ALSA implements backwards
compatibility with the old version of the API using symbol versioning,
which is not supported on all platforms (e.g., musl does not support
it).

This fixes issue #5

Signed-off-by: Bobby Bingham <koorogi@koorogi.info>

ConfigureChecks.cmake

@@ -105,11 +105,7 @@ if( WITH_ALSA )
 
   if( ALSA_FOUND )
 
-    # there is support only for ALSA 1.x
-
     set( HAVE_LIBASOUND2 1 )
-    set( ALSA_PCM_OLD_SW_PARAMS_API 1 )
-    set( ALSA_PCM_OLD_HW_PARAMS_API 1 )
 
     check_include_file( "alsa/asoundlib.h" HAVE_ALSA_ASOUNDLIB_H )
     if( NOT HAVE_ALSA_ASOUNDLIB_H )

config.h.cmake

@@ -35,8 +35,6 @@
 #cmakedefine HAVE_LIBASOUND2 1
 #cmakedefine HAVE_ALSA_ASOUNDLIB_H 1
 #cmakedefine HAVE_SND_PCM_RESUME 1
-#cmakedefine ALSA_PCM_OLD_SW_PARAMS_API 1
-#cmakedefine ALSA_PCM_OLD_HW_PARAMS_API 1
 
 #cmakedefine HAVE_SYS_SOUNDCARD_H 1
 #cmakedefine HAVE_LIBPTHREAD 1

flow/audioioalsa9.cpp

@@ -73,7 +73,8 @@ protected:
         snd_pcm_t *m_pcm_playback;
 	snd_pcm_t *m_pcm_capture;
 	snd_pcm_format_t m_format;
-	int m_period_size, m_periods;
+	snd_pcm_uframes_t m_period_size;
+	unsigned m_periods;
 
         void startIO();
 	int setPcmParams(snd_pcm_t *pcm);
@@ -540,7 +541,11 @@ int AudioIOALSA::setPcmParams(snd_pcm_t *pcm)
 		return 1;
 	}
 
-	unsigned int rate = snd_pcm_hw_params_set_rate_near(pcm, hw, _samplingRate, 0);
+	unsigned rate = _samplingRate;
+	if (snd_pcm_hw_params_set_rate_near(pcm, hw, &rate, 0) < 0) {
+		_error = "Unable to set sampling rate!";
+		return 1;
+	}
 	const unsigned int tolerance = _samplingRate/10+1000;
 	if (abs((int)rate - (int)_samplingRate) > (int)tolerance) {
 		_error = "Can't set requested sampling rate!";
@@ -562,12 +567,12 @@ int AudioIOALSA::setPcmParams(snd_pcm_t *pcm)
 		m_period_size <<= 1;
 	if (_channels > 1)
 	m_period_size /= _channels;
-	if ((m_period_size = snd_pcm_hw_params_set_period_size_near(pcm, hw, m_period_size, 0)) < 0) {
+	if (snd_pcm_hw_params_set_period_size_near(pcm, hw, &m_period_size, 0) < 0) {
 		_error = "Unable to set period size!";
 		return 1;
 	}
 	m_periods = _fragmentCount;
-        if ((m_periods = snd_pcm_hw_params_set_periods_near(pcm, hw, m_periods, 0)) < 0) {
+	if (snd_pcm_hw_params_set_periods_near(pcm, hw, &m_periods, 0) < 0) {
 		_error = "Unable to set periods!";
 		return 1;
 	}