X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=filter_common.c;h=cdd9f39855c8add2f5c4f4bdfdd88c65bbe72651;hp=06a1f52bf15012c556b7b3443e8a5e51b5ac4f16;hb=d5538ff0dd9f6531a1a319b49c32bd72597fb2c3;hpb=ffb2eaa90429f6d5c3d369509efcdf91c5463dad

diff --git a/filter_common.c b/filter_common.c
index 06a1f52b..cdd9f398 100644
--- a/filter_common.c
+++ b/filter_common.c
@@ -136,3 +136,43 @@ void generic_filter_pre_select(struct sched *s, struct task *t)
 	if (btr_node_status(fn->btrn, fn->min_iqs, BTR_NT_INTERNAL) != 0)
 		sched_min_delay(s);
 }
+
+#ifdef WORDS_BIGENDIAN
+#define DECODER_SAMPLE_FORMAT SF_S16_BE
+#else
+#define DECODER_SAMPLE_FORMAT SF_S16_LE
+#endif
+
+/**
+ * Execute a btr command for a decoder.
+ *
+ * The buffer tree nodes of the writers ask the parent nodes about sample_rate,
+ * channels count and sample format. This function is called by all decoders to
+ * answer these queries.
+ *
+ * \param cmd The command to be executed by the child node.
+ * \param sample_rate Known to the decoder.
+ * \param channels Known to the decoder.
+ * \param result Ascii representation on the answer is stored here.
+ */
+int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
+		char **result)
+{
+	if (!strcmp(cmd, "sample_rate")) {
+		if (sample_rate == 0)
+			return -E_BTR_NAVAIL;
+		*result = make_message("%u", sample_rate);
+		return 1;
+	}
+	if (!strcmp(cmd, "channels")) {
+		if (channels == 0)
+			return -E_BTR_NAVAIL;
+		*result = make_message("%u", channels);
+		return 1;
+	}
+	if (!strcmp(cmd, "sample_format")) {
+		*result = make_message("%u", DECODER_SAMPLE_FORMAT);
+		return 1;
+	}
+	return -ERRNO_TO_PARA_ERROR(ENOTSUP);
+}