src: add function to obtain bytes depending on AMR frame code

1 files changed, 42 insertions, 0 deletions

diff --git a/src/amr.c b/src/amr.c
new file mode 100644
index 0000000..b52acc3
--- /dev/null
+++ b/src/amr.c
@@ -0,0 +1,42 @@
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@gnumonks.org>
+ * (C) 2012 by On Waves ehf <http://www.on-waves.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <osmocom/netif/amr.h>
+
+/* According to TS 26.101:
+ *
+ * Frame type    AMR code    bits  bytes
+ *      0          4.75       95    12
+ *      1          5.15      103    13
+ *      2          5.90      118    15
+ *      3          6.70      134    17
+ *      4          7.40      148    19
+ *      5          7.95      159    20
+ *      6         10.20      204    26
+ *      7         12.20      244    31
+ */
+
+static size_t amr_cmr_to_bytes[AMR_CMR_MAX] = {
+	[AMR_CMR_0]	= 12,
+	[AMR_CMR_1]	= 13,
+	[AMR_CMR_2]	= 15,
+	[AMR_CMR_3]	= 17,
+	[AMR_CMR_4]	= 19,
+	[AMR_CMR_5]	= 20,
+	[AMR_CMR_6]	= 26,
+	[AMR_CMR_7]	= 31,
+};
+
+size_t osmo_amr_bytes(uint8_t amr_cmr)
+{
+	return amr_cmr_to_bytes[amr_cmr];
+}