Fix gsm_7bit_{en,de}code function and sms user_data calculations
With the 7bit alphabet the user_data_len field needs to be in
septets (characters) and not in octets occupied.
diff --git a/openbsc/src/gsm_utils.c b/openbsc/src/gsm_utils.c
index 185918e..de18dba 100644
--- a/openbsc/src/gsm_utils.c
+++ b/openbsc/src/gsm_utils.c
@@ -30,48 +30,50 @@
/* 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;
+ int i = 0;
+ int l = 0;
- 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;
+ /* FIXME: We need to account for user data headers here */
+ i += l;
+ for (; i < length; i ++)
+ *(text ++) =
+ ((user_data[(i * 7 + 7) >> 3] <<
+ (7 - ((i * 7 + 7) & 7))) |
+ (user_data[(i * 7) >> 3] >>
+ ((i * 7) & 7))) & 0x7f;
+ *text = '\0';
+
+ return i - l;
}
+
/* 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;
+ int i,j = 0;
+ unsigned char ch1, ch2;
+ int shift = 0;
- memset(result, 0, out_length);
+ for ( i=0; i<strlen(data); i++ ) {
- 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;
+ ch1 = data[i] & 0x7F;
+ ch1 = ch1 >> shift;
+ ch2 = data[(i+1)] & 0x7F;
+ ch2 = ch2 << (7-shift);
- b_off += 7;
+ ch1 = ch1 | ch2;
- if (b_off >= 8) {
- d_off += 1;
- b_off -= 8;
+ result[j++] = ch1;
+
+ shift++;
+
+ if ((shift == 7) && (i+1<strlen(data))) {
+ shift = 0;
+ i++;
}
}
- return out_length;
+ return i;
}
/* determine power control level for given dBm value, as indicated