X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=53854e08c012dd7952df4d94ce50dae987dc004a;hp=ba844db2b2b419363b01d1d1d21e28411ae92b37;hb=dc26e5bc49d839fd966b7ad6f596e444ac8908d3;hpb=c5e38315901ea63efd169af5d4ba3f3c66db7de9

diff --git a/alsa_write.c b/alsa_write.c
index ba844db2..53854e08 100644
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -15,7 +15,6 @@
 #include <regex.h>
 #include <sys/types.h>
 #include <alsa/asoundlib.h>
-#include <sys/time.h>
 
 #include "para.h"
 #include "fd.h"
@@ -35,16 +34,21 @@ struct private_alsa_write_data {
 	snd_pcm_t *handle;
 	/** Determined and set by alsa_init(). */
 	int bytes_per_frame;
-	/**
-	 * The sample rate given by command line option or the decoder
-	 * of the writer node group.
+	/*
+	 * If the sample rate is not given at the command line and no wav
+	 * header was detected, the btr exec mechanism is employed to query the
+	 * ancestor buffer tree nodes for this information. In a typical setup
+	 * the decoder passes the sample rate back to the alsa writer.
+	 *
+	 *  \sa \ref btr_exec_up().
 	 */
 	unsigned sample_rate;
-	snd_pcm_format_t sample_format;
-	/**
-	 * The number of channels, given by command line option or the
-	 * decoder of the writer node group.
+	/*
+	 * The sample format (8/16 bit, signed/unsigned, little/big endian) is
+	 * determined in the same way as the \a sample_rate.
 	 */
+	snd_pcm_format_t sample_format;
+	/* The number of channels, again determined like \a sample_rate. */
 	unsigned channels;
 	struct timeval drain_barrier;
 	/* File descriptor for select(). */
@@ -165,17 +169,18 @@ static int alsa_init(struct private_alsa_write_data *pad,
 		goto fail;
 	ret = snd_output_buffer_open(&output_log);
 	if (ret == 0) {
-		char *buf;
+		char *buf, *p;
+		size_t sz;
 		PARA_INFO_LOG("dumping alsa configuration\n");
 		snd_pcm_dump(pad->handle, output_log);
-		snd_output_buffer_string(output_log, &buf);
-		for (;;) {
-			char *p = strchr(buf, '\n');
-			if (!p) /* omit last output line, it's empty */
+		sz = snd_output_buffer_string(output_log, &buf);
+		for (p = buf; p < buf + sz;) {
+			char *q = memchr(p, '\n', buf + sz - p);
+			if (!q)
 				break;
-			*p = '\0';
-			PARA_INFO_LOG("%s\n", buf);
-			buf = p + 1;
+			*q = '\0';
+			PARA_INFO_LOG("%s\n", p);
+			p = q + 1;
 		}
 		snd_output_close(output_log);
 	}
@@ -211,7 +216,6 @@ static void alsa_write_pre_select(struct sched *s, struct task *t)
 	if (ret < 0) {
 		PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
 			snd_strerror(-ret));
-		t->error = -E_ALSA;
 		return;
 	}
 	pad->poll_fd = pfd.fd;
@@ -236,7 +240,7 @@ static void alsa_close(struct writer_node *wn)
 	free(pad);
 }
 
-static void alsa_write_post_select(__a_unused struct sched *s,
+static int alsa_write_post_select(__a_unused struct sched *s,
 		struct task *t)
 {
 	struct writer_node *wn = container_of(t, struct writer_node, task);
@@ -253,7 +257,7 @@ static void alsa_write_post_select(__a_unused struct sched *s,
 again:
 	ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 	if (ret == 0)
-		return;
+		return 0;
 	btr_merge(btrn, wn->min_iqs);
 	bytes = btr_next_buffer(btrn, &data);
 	if (ret < 0 || bytes < wn->min_iqs) { /* eof */
@@ -266,17 +270,17 @@ again:
 			PARA_DEBUG_LOG("waiting for device to drain\n");
 			tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
 				&pad->drain_barrier);
-			return;
+			return 0;
 		}
 		if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 			goto err;
-		return;
+		return 0;
 	}
 	if (!pad) {
 		int32_t val;
 
 		if (bytes == 0) /* no data available */
-			return;
+			return 0;
 		pad = para_calloc(sizeof(*pad));
 		get_btr_sample_rate(btrn, &val);
 		pad->sample_rate = val;
@@ -297,7 +301,7 @@ again:
 		goto again;
 	}
 	if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
-		return;
+		return 0;
 	frames = bytes / pad->bytes_per_frame;
 	frames = snd_pcm_writei(pad->handle, data, frames);
 	if (frames == 0 || frames == -EAGAIN) {
@@ -311,7 +315,7 @@ again:
 		char buf[100];
 		if (read(pad->poll_fd, buf, 100))
 			do_nothing;
-		return;
+		return 0;
 	}
 	if (frames > 0) {
 		btr_consume(btrn, frames * pad->bytes_per_frame);
@@ -320,14 +324,14 @@ again:
 	if (frames == -EPIPE) {
 		PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
 		snd_pcm_prepare(pad->handle);
-		return;
+		return 0;
 	}
 	PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
 	ret = -E_ALSA;
 err:
 	assert(ret < 0);
 	btr_remove_node(&wn->btrn);
-	t->error = ret;
+	return ret;
 }
 
 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
@@ -361,9 +365,6 @@ void alsa_write_init(struct writer *w)
 	w->post_select = alsa_write_post_select;
 	w->parse_config_or_die = alsa_parse_config_or_die;
 	w->free_config = alsa_free_config;
-	w->help = (struct ggo_help) {
-		.short_help = alsa_write_args_info_help,
-		.detailed_help = alsa_write_args_info_detailed_help
-	};
+	w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
 	alsa_write_cmdline_parser_free(&dummy);
 }