1 files changed, 102 insertions, 0 deletions
diff --git a/lib/virtual_oss/null/null.c b/lib/virtual_oss/null/null.c
new file mode 100644
index 000000000000..149c6e3e8c6a
--- /dev/null
+++ b/lib/virtual_oss/null/null.c
@@ -0,0 +1,102 @@
+/*-
+ * Copyright (c) 2015-2022 Hans Petter Selasky
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/queue.h>
+#include <sys/filio.h>
+#include <sys/soundcard.h>
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <err.h>
+#include <time.h>
+
+#include "backend.h"
+#include "int.h"
+
+static void
+null_close(struct voss_backend *pbe __unused)
+{
+}
+
+static int
+null_open(struct voss_backend *pbe __unused, const char *devname __unused,
+    int samplerate __unused, int bufsize __unused, int *pchannels __unused,
+    int *pformat)
+{
+	int value[3];
+	int i;
+
+	value[0] = *pformat & VPREFERRED_SNE_AFMT;
+	value[1] = *pformat & VPREFERRED_SLE_AFMT;
+	value[2] = *pformat & VPREFERRED_SBE_AFMT;
+
+	for (i = 0; i != 3; i++) {
+		if (value[i] == 0)
+			continue;
+		*pformat = value[i];
+		return (0);
+	}
+	return (-1);
+}
+
+static int
+null_rec_transfer(struct voss_backend *pbe  __unused, void *ptr, int len)
+{
+
+	if (voss_has_synchronization == 0)
+		virtual_oss_wait();
+	memset(ptr, 0, len);
+	return (len);
+}
+
+static int
+null_play_transfer(struct voss_backend *pbe __unused, void *ptr __unused,
+    int len)
+{
+	return (len);
+}
+
+static void
+null_delay(struct voss_backend *pbe __unused, int *pdelay)
+{
+	*pdelay = -1;
+}
+
+struct voss_backend voss_backend_null_rec = {
+	.open = null_open,
+	.close = null_close,
+	.transfer = null_rec_transfer,
+	.delay = null_delay,
+};
+
+struct voss_backend voss_backend_null_play = {
+	.open = null_open,
+	.close = null_close,
+	.transfer = null_play_transfer,
+	.delay = null_delay,
+};