implement alsa source

split off alsa-util.c


git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@76 fefdeb5f-60dc-0310-8127-8f9354f1896f

src/module-alsa-source.c

@@ -0,0 +1,212 @@
+#include <assert.h>
+#include <stdio.h>
+#include <sys/poll.h>
+
+#include <asoundlib.h>
+
+#include "module.h"
+#include "core.h"
+#include "memchunk.h"
+#include "sink.h"
+#include "modargs.h"
+#include "util.h"
+#include "sample-util.h"
+#include "alsa-util.h"
+
+struct userdata {
+    snd_pcm_t *pcm_handle;
+    struct pa_source *source;
+    void **io_sources;
+    unsigned n_io_sources;
+
+    size_t frame_size, fragment_size;
+    struct pa_memchunk memchunk;
+};
+
+static const char* const valid_modargs[] = {
+    "device",
+    "source_name",
+    "format",
+    "channels",
+    "rate",
+    "fragments",
+    "fragment_size",
+    NULL
+};
+
+#define DEFAULT_SOURCE_NAME "alsa_input"
+#define DEFAULT_DEVICE "hw:0,0"
+
+static void xrun_recovery(struct userdata *u) {
+    assert(u);
+
+    fprintf(stderr, "*** ALSA-XRUN (capture) ***\n");
+    
+    if (snd_pcm_prepare(u->pcm_handle) < 0)
+        fprintf(stderr, "snd_pcm_prepare() failed\n");
+}
+
+static void do_read(struct userdata *u) {
+    assert(u);
+
+    for (;;) {
+        struct pa_memchunk post_memchunk;
+        snd_pcm_sframes_t frames;
+        size_t l;
+        
+        if (!u->memchunk.memblock) {
+            u->memchunk.memblock = pa_memblock_new(u->memchunk.length = u->fragment_size);
+            u->memchunk.index = 0;
+        }
+            
+        assert(u->memchunk.memblock && u->memchunk.memblock->data && u->memchunk.length && u->memchunk.memblock->length && (u->memchunk.length % u->frame_size) == 0);
+
+        if ((frames = snd_pcm_readi(u->pcm_handle, u->memchunk.memblock->data + u->memchunk.index, u->memchunk.length / u->frame_size)) < 0) {
+            if (frames == -EAGAIN)
+                return;
+            
+            if (frames == -EPIPE) {
+                xrun_recovery(u);
+                continue;
+            }
+
+            fprintf(stderr, "snd_pcm_readi() failed: %s\n", strerror(-frames));
+            return;
+        }
+
+        l = frames * u->frame_size;
+        
+        post_memchunk = u->memchunk;
+        post_memchunk.length = l;
+
+        pa_source_post(u->source, &post_memchunk);
+
+        u->memchunk.index += l;
+        u->memchunk.length -= l;
+        
+        if (u->memchunk.length == 0) {
+            pa_memblock_unref(u->memchunk.memblock);
+            u->memchunk.memblock = NULL;
+            u->memchunk.index = u->memchunk.length = 0;
+        }
+        
+        break;
+    }
+}
+
+static void io_callback(struct pa_mainloop_api*a, void *id, int fd, enum pa_mainloop_api_io_events events, void *userdata) {
+    struct userdata *u = userdata;
+    assert(u && a && id);
+
+    if (snd_pcm_state(u->pcm_handle) == SND_PCM_STATE_XRUN)
+        xrun_recovery(u);
+
+    do_read(u);
+}
+
+int pa_module_init(struct pa_core *c, struct pa_module*m) {
+    struct pa_modargs *ma = NULL;
+    int ret = -1;
+    struct userdata *u = NULL;
+    const char *dev;
+    struct pa_sample_spec ss;
+    unsigned periods, fragsize;
+    snd_pcm_uframes_t buffer_size;
+    size_t frame_size;
+    
+    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
+        fprintf(stderr, __FILE__": failed to parse module arguments\n");
+        goto fail;
+    }
+
+    ss = c->default_sample_spec;
+    if (pa_modargs_get_sample_spec(ma, &ss) < 0) {
+        fprintf(stderr, __FILE__": failed to parse sample specification\n");
+        goto fail;
+    }
+    frame_size = pa_sample_size(&ss);
+    
+    periods = 12;
+    fragsize = 1024;
+    if (pa_modargs_get_value_u32(ma, "fragments", &periods) < 0 || pa_modargs_get_value_u32(ma, "fragment_size", &fragsize) < 0) {
+        fprintf(stderr, __FILE__": failed to parse buffer metrics\n");
+        goto fail;
+    }
+    buffer_size = fragsize/frame_size*periods;
+    
+    u = malloc(sizeof(struct userdata));
+    assert(u);
+    memset(u, 0, sizeof(struct userdata));
+    m->userdata = u;
+    
+    if (snd_pcm_open(&u->pcm_handle, dev = pa_modargs_get_value(ma, "device", DEFAULT_DEVICE), SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK) < 0) {
+        fprintf(stderr, __FILE__": Error opening PCM device %s\n", dev);
+        goto fail;
+    }
+
+    if (pa_alsa_set_hw_params(u->pcm_handle, &ss, &periods, &buffer_size) < 0) {
+        fprintf(stderr, __FILE__": Failed to set hardware parameters\n");
+        goto fail;
+    }
+
+    u->source = pa_source_new(c, pa_modargs_get_value(ma, "source_name", DEFAULT_SOURCE_NAME), 0, &ss);
+    assert(u->source);
+
+    u->source->userdata = u;
+    pa_source_set_owner(u->source, m);
+    u->source->description = pa_sprintf_malloc("Advanced Linux Sound Architecture PCM on '%s'", dev);
+
+    if (pa_create_io_sources(u->pcm_handle, c->mainloop, &u->io_sources, &u->n_io_sources, io_callback, u) < 0) {
+        fprintf(stderr, __FILE__": failed to obtain file descriptors\n");
+        goto fail;
+    }
+
+    u->frame_size = frame_size;
+    u->fragment_size = buffer_size*u->frame_size/periods;
+
+    fprintf(stderr, __FILE__": using %u fragments of size %u bytes.\n", periods, u->fragment_size);
+
+    u->memchunk.memblock = NULL;
+    u->memchunk.index = u->memchunk.length = 0;
+
+    snd_pcm_start(u->pcm_handle);
+    
+    ret = 0;
+
+finish:
+     if (ma)
+         pa_modargs_free(ma);
+    
+    return ret;
+
+fail:
+    
+    if (u)
+        pa_module_done(c, m);
+
+    goto finish;
+}
+
+void pa_module_done(struct pa_core *c, struct pa_module*m) {
+    struct userdata *u;
+    assert(c && m);
+
+    if ((u = m->userdata)) {
+        if (u->source)
+            pa_source_free(u->source);
+
+        if (u->io_sources)
+            pa_free_io_sources(c->mainloop, u->io_sources, u->n_io_sources);
+        
+        if (u->pcm_handle) {
+            snd_pcm_drop(u->pcm_handle);
+            snd_pcm_close(u->pcm_handle);
+        }
+
+        if (u->memchunk.memblock)
+            pa_memblock_unref(u->memchunk.memblock);
+        
+        free(u);
+    }
+}
+