Initial Audio plugin

Signed-off-by: Manuel Bachmann <manuel.bachmann@iot.bzh>

1 files changed, 82 insertions, 0 deletions

diff --git a/plugins/audio/audio-alsa.c b/plugins/audio/audio-alsa.c
new file mode 100644
index 00000000..8c08c8db
--- /dev/null
+++ b/plugins/audio/audio-alsa.c
@@ -0,0 +1,82 @@
+#include "audio-api.h"
+#include "audio-alsa.h"
+
+PUBLIC unsigned char _alsa_init (const char *name, audioCtxHandleT *ctx) {
+
+    snd_pcm_t *dev;
+    snd_pcm_hw_params_t *params;
+    int num;
+
+    if (snd_pcm_open (&dev, name, SND_PCM_STREAM_PLAYBACK, 0) < 0)
+        return 0;
+
+    snd_pcm_hw_params_malloc (&params);
+    snd_pcm_hw_params_any (dev, params);
+    snd_pcm_hw_params_set_access (dev, params, SND_PCM_ACCESS_RW_INTERLEAVED);
+    snd_pcm_hw_params_set_format (dev, params, SND_PCM_FORMAT_S16_LE);
+    snd_pcm_hw_params_set_rate_near (dev, params, &ctx->rate, 0);
+    snd_pcm_hw_params_set_channels (dev, params, ctx->channels);
+    if (snd_pcm_hw_params (dev, params) < 0) {
+        snd_pcm_hw_params_free (params);
+        return 0;
+    }
+    snd_pcm_prepare (dev);
+    
+    /* allocate the global array if it hasn't been done */
+    if (!dev_ctx) {
+        dev_ctx = (dev_ctx_T**) malloc (sizeof(dev_ctx_T));
+        dev_ctx[0] = (dev_ctx_T*) malloc (sizeof(dev_ctx_T));
+        dev_ctx[0]->name = NULL;
+        dev_ctx[0]->dev = NULL;
+    }
+
+    /* is a card with similar name already opened ? */
+    for (num = 0; num < (sizeof(dev_ctx)/sizeof(dev_ctx_T)); num++) {
+        if (dev_ctx[num]->name &&
+           !strcmp (dev_ctx[num]->name, name))
+            return 0;
+    }
+    num++;
+
+    /* it's not... let us add it to the global array */
+    dev_ctx[num] = (dev_ctx_T*) malloc (sizeof(dev_ctx_T));
+    dev_ctx[num]->name = strdup (name);
+    dev_ctx[num]->dev = dev;
+    dev_ctx[num]->params = params;
+
+    return 1;
+}
+
+PUBLIC void _alsa_free (const char *name) {
+
+    int num;
+
+    for (num = 0; num < (sizeof(dev_ctx)/sizeof(dev_ctx_T)); num++) {
+        if (dev_ctx[num]->name &&
+           !strcmp (dev_ctx[num]->name, name)) {
+            snd_pcm_close (dev_ctx[num]->dev);
+            snd_pcm_hw_params_free (dev_ctx[num]->params);
+            free (dev_ctx[num]->name);
+            dev_ctx[num]->name = NULL;
+            dev_ctx[num]->dev = NULL;
+            free(dev_ctx[num]);
+            return;
+        }
+    }
+}
+
+PUBLIC void _alsa_play (unsigned int num, void *buf, int len) {
+
+    if (!dev_ctx || !dev_ctx[num])
+        return;
+
+    int16_t *cbuf = (int16_t *)buf;
+    int frames = len / 2;
+    int res;
+
+    if ((res = snd_pcm_writei (dev_ctx[num]->dev, cbuf, frames)) != frames) {
+        snd_pcm_recover (dev_ctx[num]->dev, res, 0);
+        snd_pcm_prepare (dev_ctx[num]->dev);
+    }
+    /* snd_pcm_drain (dev_ctx[num]->dev); */
+}
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