simpleaudio: generalized simpleaudio_open_stream

src/minimodem.c

@@ -284,17 +284,13 @@ main( int argc, char*argv[] )
     float	carrier_autodetect_threshold = 0.0;
     float	bfsk_confidence_threshold = 0.6;
 
-    simpleaudio * (*simpleaudio_open_system_audio)() = NULL;
+    sa_backend_t sa_backend = SA_BACKEND_SYSDEFAULT;
 
     unsigned int sample_rate = 48000;
     unsigned int nchannels = 1; // FIXME: only works with one channel
 
-    /* configure the default system audio mechanism */
+    /* validate the default system audio mechanism */
-#if USE_PULSEAUDIO
+#if !(USE_PULSEAUDIO || USE_ALSA)
-    simpleaudio_open_system_audio = simpleaudio_open_stream_pulseaudio;
-#elif USE_ALSA
-    simpleaudio_open_system_audio = simpleaudio_open_stream_alsa;
-#else
 # define _MINIMODEM_NO_SYSTEM_AUDIO
 # if !USE_SNDFILE
 #  error At least one of {USE_PULSEAUDIO,USE_ALSA,USE_SNDFILE} must be enabled!
@@ -391,7 +387,7 @@ main( int argc, char*argv[] )
 			break;
 	    case 'A':
 #if USE_ALSA
-			simpleaudio_open_system_audio = simpleaudio_open_stream_alsa;
+			sa_backend = SA_BACKEND_ALSA;
 #else
 			fprintf(stderr, "E: This build of minimodem was configured without alsa support.\n");
 			exit(1);
@@ -508,31 +504,29 @@ main( int argc, char*argv[] )
 	band_width = bfsk_data_rate;
 
 
+    char *stream_name = NULL;;
+
+    if ( filename ) {
+	sa_backend = SA_BACKEND_FILE;
+	stream_name = filename;
+    }
+
     /*
      * Handle transmit mode
      */
     if ( TX_mode ) {
 
-	simpleaudio *sa_out = NULL;
+	int tx_interactive = 0;
-	int tx_interactive = 1;
+	if ( ! stream_name ) {
-
+	    tx_interactive = 1;
-	if ( filename ) {
+	    stream_name = "output audio";
-	    tx_interactive = 0;
-#if USE_SNDFILE
-	    sa_out = simpleaudio_open_stream_sndfile(SA_STREAM_PLAYBACK,
-					SA_SAMPLE_FORMAT_FLOAT,
-					sample_rate, nchannels,
-					filename);
-#endif
-	    if ( ! sa_out )
-		return 1;
 	}
 
-	if ( ! sa_out )
+	simpleaudio *sa_out;
-	    sa_out = simpleaudio_open_system_audio(SA_STREAM_PLAYBACK,
+	sa_out = simpleaudio_open_stream(sa_backend, SA_STREAM_PLAYBACK,
 					SA_SAMPLE_FORMAT_FLOAT,
 					sample_rate, nchannels,
-					program_name, "output audio");
+					program_name, stream_name);
 	if ( ! sa_out )
 	    return 1;
 
@@ -543,6 +537,9 @@ main( int argc, char*argv[] )
 				bfsk_txstopbits,
 				bfsk_framebits_encode
 				);
+
+	simpleaudio_close(sa_out);
+
 	return 0;
     }
 
@@ -550,23 +547,15 @@ main( int argc, char*argv[] )
     /*
      * Open the input audio stream
      */
-    simpleaudio *sa = NULL;
-    if ( filename ) {
-#if USE_SNDFILE
-	sa = simpleaudio_open_stream_sndfile(SA_STREAM_RECORD,
-				SA_SAMPLE_FORMAT_FLOAT,
-				sample_rate, nchannels,
-				filename);
-#endif
-	if ( ! sa )
-	    return 1;
-    }
 
-    if ( ! sa )
+    if ( ! stream_name )
-	sa = simpleaudio_open_system_audio(SA_STREAM_RECORD,
+	stream_name = "input audio";
+
+    simpleaudio *sa;
+    sa = simpleaudio_open_stream(sa_backend, SA_STREAM_RECORD,
 				SA_SAMPLE_FORMAT_FLOAT,
 				sample_rate, nchannels,
-				program_name, "input audio");
+				program_name, stream_name);
     if ( ! sa )
         return 1;
 

src/simpleaudio-alsa.c

@@ -95,17 +95,11 @@ sa_alsa_close( simpleaudio *sa )
     snd_pcm_close(sa->backend_handle);
 }
 
-
+static int
-static const struct simpleaudio_backend simpleaudio_backend_alsa = {
+sa_alsa_open_stream(
-    sa_alsa_read,
+		simpleaudio *sa,
-    sa_alsa_write,
+		sa_direction_t sa_stream_direction,
-    sa_alsa_close,
+		sa_format_t sa_format,
-};
-
-simpleaudio *
-simpleaudio_open_stream_alsa(
-		int sa_stream_direction,
-		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name )
 {
@@ -118,10 +112,10 @@ simpleaudio_open_stream_alsa(
 		0 /*mode*/);
     if (error) {
 	fprintf(stderr, "E: Cannot create ALSA stream: %s\n", snd_strerror(error));
-	return NULL;
+	return 0;
     }
 
-    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+    assert( sa_format == SA_SAMPLE_FORMAT_FLOAT );
 
     /* set up ALSA hardware params */
     error = snd_pcm_set_params(pcm,
@@ -134,7 +128,7 @@ simpleaudio_open_stream_alsa(
     if (error) {
 	fprintf(stderr, "E: %s\n", snd_strerror(error));
 	snd_pcm_close(pcm);
-	return NULL;
+	return 0;
     }
 
 #if 0
@@ -157,21 +151,18 @@ simpleaudio_open_stream_alsa(
     }
 #endif
 
-    simpleaudio *sa = malloc(sizeof(simpleaudio));
-    if ( !sa ) {
-	perror("malloc");
-	snd_pcm_close(pcm);
-        return NULL;
-    }
-    sa->format = sa_sample_format;
-    sa->rate = rate;
-    sa->channels = channels;
-    sa->samplesize = sizeof(float);
-    sa->backend = &simpleaudio_backend_alsa;
     sa->backend_handle = pcm;
     sa->backend_framesize = sa->channels * sa->samplesize; 
 
-    return sa;
+    return 1;
 }
 
-#endif /* USE_PULSEAUDIO */
+
+const struct simpleaudio_backend simpleaudio_backend_alsa = {
+    sa_alsa_open_stream,
+    sa_alsa_read,
+    sa_alsa_write,
+    sa_alsa_close,
+};
+
+#endif /* USE_ALSA */

src/simpleaudio-pulse.c

@@ -79,17 +79,11 @@ sa_pulse_close( simpleaudio *sa )
     pa_simple_free(sa->backend_handle);
 }
 
-
+static int
-static const struct simpleaudio_backend simpleaudio_backend_pulse = {
+sa_pulse_open_stream(
-    sa_pulse_read,
+		simpleaudio *sa,
-    sa_pulse_write,
+		sa_direction_t sa_stream_direction,
-    sa_pulse_close,
+		sa_format_t sa_format,
-};
-
-simpleaudio *
-simpleaudio_open_stream_pulseaudio(
-		int sa_stream_direction,
-		sa_sample_format_t sa_sample_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name )
 {
@@ -98,7 +92,7 @@ simpleaudio_open_stream_pulseaudio(
     // FIXME - use source for something
     // just take the default pulseaudio source for now
 
-    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+    assert( sa_format == SA_SAMPLE_FORMAT_FLOAT );
 
     /* The sample type to use */
     pa_sample_spec ss = {
@@ -128,26 +122,25 @@ simpleaudio_open_stream_pulseaudio(
 	    &ss, NULL, &attr, &error);
     if ( !s ) {
         fprintf(stderr, "E: Cannot create PulseAudio stream: %s\n ", pa_strerror(error));
-        return NULL;
+        return 0;
     }
 
-    simpleaudio *sa = malloc(sizeof(simpleaudio));
+    /* good or bad to override these? */
-    if ( !sa ) {
-	perror("malloc");
-	pa_simple_free(s);
-        return NULL;
-    }
-    sa->format = sa_sample_format;
     sa->rate = ss.rate;
     sa->channels = ss.channels;
-    sa->samplesize = sizeof(float);
+
-    sa->backend = &simpleaudio_backend_pulse;
     sa->backend_handle = s;
     sa->backend_framesize = pa_frame_size(&ss);
 
-    assert( sa->backend_framesize == sa->channels * sa->samplesize );
+    return 1;
-
-    return sa;
 }
 
+
+const struct simpleaudio_backend simpleaudio_backend_pulseaudio = {
+    sa_pulse_open_stream,
+    sa_pulse_read,
+    sa_pulse_write,
+    sa_pulse_close,
+};
+
 #endif /* USE_PULSEAUDIO */

src/simpleaudio-sndfile.c

@@ -76,13 +76,6 @@ sa_sndfile_close( simpleaudio *sa )
 }
 
 
-static const struct simpleaudio_backend simpleaudio_backend_sndfile = {
-    sa_sndfile_read,
-    sa_sndfile_write,
-    sa_sndfile_close,
-};
-
-
 /* (Why) doesn't libsndfile provide an API for this?... */
 static const struct sndfile_format {
     unsigned int major_format;
@@ -132,14 +125,17 @@ sndfile_format_from_path( const char *path )
     return SF_FORMAT_WAV;
 }
 
-simpleaudio *
+static int
-simpleaudio_open_stream_sndfile(
+sa_sndfile_open_stream(
-		int sa_stream_direction,
+		simpleaudio *sa,
-		sa_sample_format_t sa_sample_format,
+		sa_direction_t sa_stream_direction,
+		sa_format_t sa_format,
 		unsigned int rate, unsigned int channels,
-		char *path )
+		char *app_name, char *stream_name )
 {
-    assert( sa_sample_format == SA_SAMPLE_FORMAT_FLOAT );
+    const char *path = stream_name;
+
+    assert( sa_format == SA_SAMPLE_FORMAT_FLOAT );
 
     /* setting for SA_STREAM_PLAYBACK (file write) */
     SF_INFO sfinfo = {
@@ -159,24 +155,25 @@ simpleaudio_open_stream_sndfile(
     if ( !s ) {
 	fprintf(stderr, "%s: ", path);
 	sf_perror(s);
-        return NULL;
+        return 0;
     }
 
-    simpleaudio *sa = malloc(sizeof(simpleaudio));
+    /* good or bad to override these? */
-    if ( !sa ) {
-	perror("malloc");
-	sf_close(s);
-        return NULL;
-    }
-    sa->format = sa_sample_format;
     sa->rate = sfinfo.samplerate;
     sa->channels = sfinfo.channels;
-    sa->samplesize = sizeof(float);
+
-    sa->backend = &simpleaudio_backend_sndfile;
     sa->backend_handle = s;
     sa->backend_framesize = sa->channels * sa->samplesize; 
 
-    return sa;
+    return 1;
 }
 
+
+const struct simpleaudio_backend simpleaudio_backend_sndfile = {
+    sa_sndfile_open_stream,
+    sa_sndfile_read,
+    sa_sndfile_write,
+    sa_sndfile_close,
+};
+
 #endif /* USE_SNDFILE */

src/simpleaudio.c

@@ -19,9 +19,101 @@
 
 #include "simpleaudio.h"
 #include "simpleaudio_internal.h"
-#include "malloc.h"
 
-sa_sample_format_t
+#include <malloc.h>
+#include <assert.h>
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#else
+# define USE_PULSEAUDIO 1
+# define USE_ALSA 1
+#endif
+
+simpleaudio *
+simpleaudio_open_stream(
+		sa_backend_t	sa_backend,
+		sa_direction_t	sa_stream_direction,
+		sa_format_t sa_format,
+		unsigned int rate, unsigned int channels,
+		char *app_name, char *stream_name )
+{
+    simpleaudio *sa = calloc(1, sizeof(simpleaudio));
+    if ( !sa ) {
+	perror("malloc");
+        return NULL;
+    }
+
+    sa->format = sa_format;
+    sa->rate = rate;
+    sa->channels = channels;
+
+    switch ( sa_format ) {
+	case SA_SAMPLE_FORMAT_FLOAT:
+	    assert( sizeof(float) == 4 );
+	    sa->samplesize = sizeof(float);
+	    break;
+	case SA_SAMPLE_FORMAT_S16:
+	    assert( sizeof(short) == 2 );
+	    sa->samplesize = sizeof(short);
+	    break;
+	default:
+	    fprintf(stderr, "simpleaudio_open_stream: no such sa_format (%d)\n", sa_format);
+	    goto err_out;
+	    break;
+    }
+
+    switch ( sa_backend ) {
+
+#if USE_SNDFILE
+	case SA_BACKEND_FILE:
+	    sa->backend = &simpleaudio_backend_sndfile;
+	    break;
+#endif
+
+	case SA_BACKEND_SYSDEFAULT:
+#if USE_PULSEAUDIO
+	    sa->backend = &simpleaudio_backend_pulseaudio;
+#elif USE_ALSA
+	    sa->backend = &simpleaudio_backend_alsa;
+#else
+	    fprintf(stderr, "simpleaudio_open_stream: no SA_BACKEND_SYSDEFAULT was configured\n");
+	    goto err_out;
+#endif
+	    break;
+
+#if USE_ALSA
+	case SA_BACKEND_ALSA:
+	    sa->backend = &simpleaudio_backend_alsa;
+	    break;
+#endif
+
+#if USE_PULSEAUDIO
+	case SA_BACKEND_PULSEAUDIO:
+	    sa->backend = &simpleaudio_backend_pulseaudio;
+	    break;
+#endif
+
+	default:
+	    fprintf(stderr, "simpleaudio_open_stream: no such sa_backend (%d).  not configured at build?\n", sa_backend);
+	    goto err_out;
+    }
+
+    int ok = sa->backend->simpleaudio_open_stream(sa,
+		sa_stream_direction, sa_format,
+		rate, channels, app_name, stream_name);
+
+    if ( ok ) {
+	assert( sa->backend_framesize == sa->channels * sa->samplesize );
+	return sa;
+    }
+
+err_out:
+    free(sa);
+    return NULL;
+}
+
+sa_format_t
 simpleaudio_get_format( simpleaudio *sa )
 {
     return sa->format;

src/simpleaudio.h

@@ -31,43 +31,34 @@ typedef struct simpleaudio simpleaudio;
  *
  */
 
+/* sa_backend */
+typedef enum {
+	SA_BACKEND_SYSDEFAULT=0,
+	SA_BACKEND_FILE,
+	SA_BACKEND_ALSA,
+	SA_BACKEND_PULSEAUDIO,
+} sa_backend_t;
+
 /* sa_stream_direction */
-enum {
+typedef enum {
 	SA_STREAM_PLAYBACK,
 	SA_STREAM_RECORD,
-};
+} sa_direction_t;
 
 /* sa_stream_format */
 typedef enum {
 	SA_SAMPLE_FORMAT_S16,
 	SA_SAMPLE_FORMAT_FLOAT,
-} sa_sample_format_t;
+} sa_format_t;
 
 simpleaudio *
-simpleaudio_open_stream_pulseaudio(
+simpleaudio_open_stream(
-		int sa_stream_direction,
+		sa_backend_t	sa_backend,
-		sa_sample_format_t sa_sample_format,
+		sa_direction_t	sa_stream_direction,
+		sa_format_t	sa_format,
 		unsigned int rate, unsigned int channels,
 		char *app_name, char *stream_name );
 
-simpleaudio *
-simpleaudio_open_stream_alsa(
-		int sa_stream_direction,
-		sa_sample_format_t sa_sample_format,
-		unsigned int rate, unsigned int channels,
-		char *app_name, char *stream_name );
-
-simpleaudio *
-simpleaudio_open_stream_sndfile(
-		int sa_stream_direction,
-		sa_sample_format_t sa_sample_format,
-		unsigned int rate, unsigned int channels,
-		char *path );
-
-/*
- * common simpleaudio_ API routines available to any backend:
- */
-
 unsigned int
 simpleaudio_get_rate( simpleaudio *sa );
 
@@ -77,7 +68,7 @@ simpleaudio_get_channels( simpleaudio *sa );
 unsigned int
 simpleaudio_get_framesize( simpleaudio *sa );
 
-sa_sample_format_t
+sa_format_t
 simpleaudio_get_format( simpleaudio *sa );
 
 unsigned int

src/simpleaudio_internal.h

@@ -23,17 +23,13 @@
 
 #include "simpleaudio.h"
 
-/*
- * Backend modules must provide an "open" routine which returns a
- * (simpleaudio *) to the caller.
- */
 
 struct simpleaudio_backend;
 typedef struct simpleaudio_backend simpleaudio_backend;
 
 struct simpleaudio {
 	const struct simpleaudio_backend	*backend;
-	sa_sample_format_t	format;
+	sa_format_t	format;
 	unsigned int	rate;
 	unsigned int	channels;
 	void *		backend_handle;
@@ -42,13 +38,27 @@ struct simpleaudio {
 };
 
 struct simpleaudio_backend {
+
+	int /* boolean 'ok' value */
+	(*simpleaudio_open_stream)(
+		simpleaudio *	sa,
+		sa_direction_t	sa_stream_direction,
+		sa_format_t sa_format,
+		unsigned int rate, unsigned int channels,
+		char *app_name, char *stream_name );
+
 	ssize_t
 	(*simpleaudio_read)( simpleaudio *sa, float *buf, size_t nframes );
+
 	ssize_t
 	(*simpleaudio_write)( simpleaudio *sa, float *buf, size_t nframes );
+
 	void
 	(*simpleaudio_close)( simpleaudio *sa );
 };
 
+extern const struct simpleaudio_backend simpleaudio_backend_sndfile;
+extern const struct simpleaudio_backend simpleaudio_backend_alsa;
+extern const struct simpleaudio_backend simpleaudio_backend_pulseaudio;
 
 #endif