This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.
Nico Golde nico at ngolde.de---
include/osmocore/gsm_utils.h | 28 ++++++++++++++++++
src/gsm_utils.c | 64 ++++++++++++++++++++++++++++++++----------
2 files changed, 77 insertions(+), 15 deletions(-)
diff --git a/include/osmocore/gsm_utils.h b/include/osmocore/gsm_utils.h
index 7dc2388..661846a 100644
--- a/include/osmocore/gsm_utils.h
+++ b/include/osmocore/gsm_utils.h
@@ -3,6 +3,7 @@
* (C) 2008 by Daniel Willmann <daniel at totalueberwachung.de>
* (C) 2009 by Holger Hans Peter Freyther <zecke at selfish.org>
* (C) 2009-2010 by Harald Welte <laforge at gnumonks.org>
+ * (C) 2010 by Nico Golde <nico at ngolde.de>
*
* All Rights Reserved
*
@@ -53,6 +54,33 @@ enum gsm_band {
GSM_BAND_810 = 0x80,
};
+/* ETSI GSM 03.38 6.2.1 and 6.2.1.1 default alphabet
+ * Greek symbols at hex positions 0x10 and 0x12-0x1a
+ * left out as they can't be handled with a char and
+ * since most phones don't display or write these
+ * characters this would only needlessly make the code
+ * more complex
+*/
+unsigned char gsm_7bit_alphabet[] = {
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0a, 0xff, 0x0a, 0x0d, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0x20, 0x21, 0x22, 0x23, 0x02, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c,
+ 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
+ 0x3c, 0x3d, 0x3e, 0x3f, 0x00, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
+ 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+ 0x5a, 0x3c, 0x2f, 0x3e, 0x14, 0x11, 0xff, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+ 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+ 0x78, 0x79, 0x7a, 0x28, 0x40, 0x29, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x01, 0x24,
+ 0x03, 0xff, 0x5f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x60, 0xff, 0xff, 0xff,
+ 0xff, 0x5b, 0x0e, 0x1c, 0x09, 0xff, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5d,
+ 0xff, 0xff, 0xff, 0xff, 0x5c, 0xff, 0x0b, 0xff, 0xff, 0xff, 0x5e, 0xff, 0xff, 0x1e, 0x7f,
+ 0xff, 0xff, 0xff, 0x7b, 0x0f, 0x1d, 0xff, 0x04, 0x05, 0xff, 0xff, 0x07, 0xff, 0xff, 0xff,
+ 0xff, 0x7d, 0x08, 0xff, 0xff, 0xff, 0x7c, 0xff, 0x0c, 0x06, 0xff, 0xff, 0x7e, 0xff, 0xff
+};
+
const char *gsm_band_name(enum gsm_band band);
enum gsm_band gsm_band_parse(const char *mhz);
diff --git a/src/gsm_utils.c b/src/gsm_utils.c
index dc97cef..ce5cefd 100644
--- a/src/gsm_utils.c
+++ b/src/gsm_utils.c
@@ -2,6 +2,7 @@
* (C) 2008 by Daniel Willmann <daniel at totalueberwachung.de>
* (C) 2009 by Holger Hans Peter Freyther <zecke at selfish.org>
* (C) 2009-2010 by Harald Welte <laforge at gnumonks.org>
+ * (C) 2010 by Nico Golde <nico at ngolde.de>
*
* All Rights Reserved
*
@@ -53,33 +54,66 @@ int gsm_7bit_decode(char *text, const uint8_t *user_data, uint8_t length)
return i - l;
}
+/* GSM 03.38 6.2.1 Prepare character packing */
+static int gsm_septet_encode(uint8_t *result, const char *data)
+{
+ int i, y = 0;
+ uint8_t ch;
+ for(i = 0; i < strlen(data); i++){
+ ch = data[i];
+ switch(ch){
+ case 0x0c:
+ case 0x5e:
+ case 0x7b:
+ case 0x7d:
+ case 0x5c:
+ case 0x5b:
+ case 0x7e:
+ case 0x5d:
+ case 0x7c:
+ result[y] = 0x1b;
+ result[y + 1] = gsm_7bit_alphabet[ch];
+ y++;
+ break;
+ default:
+ result[y] = gsm_7bit_alphabet[ch];
+ break;
+ }
+ y++;
+ }
-/* GSM 03.38 6.2.1 Charachter packing */
+ return y;
+}
+
+/* GSM 03.38 6.2.1 Character packing */
int gsm_7bit_encode(uint8_t *result, const char *data)
{
- int i,j = 0;
- unsigned char ch1, ch2;
+ int i,y,z = 0;
+ /* prepare for the worst case, every character expanding to two bytes */
+ uint8_t *rdata = calloc(strlen(data) * 2, sizeof(uint8_t));
+ uint8_t cb, nb;
int shift = 0;
- for ( i=0; i<strlen(data); i++ ) {
+ y = gsm_septet_encode(rdata, data);
- ch1 = data[i] & 0x7F;
- ch1 = ch1 >> shift;
- ch2 = data[(i+1)] & 0x7F;
- ch2 = ch2 << (7-shift);
+ for(i = 0; i < y; i++) {
+ if(shift == 7 && i + 1 < y){
+ shift = 0;
+ continue;
+ }
- ch1 = ch1 | ch2;
+ cb = (rdata[i] & 0x7f) >> shift;
+ if(i + 1 < y){
+ nb = (rdata[i + 1] & 0x7f) << (7 - shift);
+ cb = cb | nb;
+ }
- result[j++] = ch1;
+ result[z++] = cb;
shift++;
-
- if ((shift == 7) && (i+1<strlen(data))) {
- shift = 0;
- i++;
- }
}
+ free(rdata);
return i;
}
--
1.7.1
--liOOAslEiF7prFVr--