aboutsummaryrefslogtreecommitdiffstats
path: root/openbsc/src/gsm_utils.c
diff options
context:
space:
mode:
Diffstat (limited to 'openbsc/src/gsm_utils.c')
-rw-r--r--openbsc/src/gsm_utils.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/openbsc/src/gsm_utils.c b/openbsc/src/gsm_utils.c
new file mode 100644
index 00000000..0c25b28c
--- /dev/null
+++ b/openbsc/src/gsm_utils.c
@@ -0,0 +1,73 @@
+/*
+ * (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
+ * (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <openbsc/gsm_utils.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* GSM 03.38 6.2.1 Charachter packing */
+int gsm_7bit_decode(char *text, const u_int8_t *user_data, u_int8_t length)
+{
+ u_int8_t d_off = 0, b_off = 0;
+ u_int8_t i;
+
+ for (i=0;i<length;i++) {
+ text[i] = ((user_data[d_off] + (user_data[d_off+1]<<8)) & (0x7f<<b_off))>>b_off;
+ b_off += 7;
+ if (b_off >= 8) {
+ d_off += 1;
+ b_off -= 8;
+ }
+ }
+ text[i] = '\0';
+ return 0;
+}
+
+/* GSM 03.38 6.2.1 Charachter packing */
+int gsm_7bit_encode(u_int8_t *result, const char *data)
+{
+ int i;
+ u_int8_t d_off = 0, b_off = 0;
+ const int length = strlen(data);
+ int out_length = (length * 8)/7;
+
+ memset(result, 0, out_length);
+
+ for (i = 0; i < length; ++i) {
+ u_int8_t first = (data[i] & 0x7f) << b_off;
+ u_int8_t second = (data[i] & 0x7f) >> (8 - b_off);
+
+ result[d_off] |= first;
+ if (second != 0)
+ result[d_off + 1] = second;
+
+ b_off += 7;
+
+ if (b_off >= 8) {
+ d_off += 1;
+ b_off -= 8;
+ }
+ }
+
+ return out_length;
+}