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NMT: Caller ID support

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This commit is contained in:
Andreas Eversberg
2016-07-20 11:58:12 +02:00
parent ba8bf0e9d5
commit 4745b29115
11 changed files with 333 additions and 73 deletions
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78
src/nmt/frame.c
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@@ -111,6 +111,84 @@ uint16_t nmt_encode_area_no(uint8_t area_no)
}
}
/* convert given number to caller ID frame with given index
* return next index */
int nmt_encode_a_number(frame_t *frame, int index, enum number_type type, const char *number)
{
int number_offset = 0;
int number_len = strlen(number);
int nframes;
uint8_t sum, ntype = 0, digit;
int i, shift;
/* number of frames
* 0..5 digits need one frame, 6..12 digits need two frames, ... */
nframes = (number_len + 8) / 7;
/* cycle index */
index %= nframes;
/* number offset for second frame is 5, and then additional 7 for the following frames */
if (index)
number_offset = index * 7 - 2;
/* encode */
frame->index = NMT_MESSAGE_8;
frame->seq_number = index;
if (index == 0) {
/* number type */
switch (type) {
case TYPE_NOTAVAIL:
ntype = 3;
break;
case TYPE_ANONYMOUS:
ntype = 4;
break;
case TYPE_UNKNOWN:
ntype = 0;
break;
case TYPE_SUBSCRIBER:
ntype = 0;
break;
case TYPE_NATIONAL:
ntype = 1;
break;
case TYPE_INTERNATIONAL:
ntype = 2;
break;
}
/* first 5 digits */
frame->additional_info = ((nframes - 1) << 24) | (ntype << 20);
shift = 16;
} else {
/* next digits */
frame->additional_info = 0;
shift = 24;
}
for (i = number_offset; number[i] && shift >= 0; i++, shift -= 4) {
digit = number[i];
if (digit >= '1' && digit <= '9')
digit -= '0';
else if (digit == '0')
digit = 10;
else
digit = 13; /* '+' and illegal digits */
frame->additional_info |= (digit << shift);
}
/* checksum */
sum = (frame->seq_number << 4) | frame->additional_info >> 24;
sum += (frame->additional_info >> 16);
sum += (frame->additional_info >> 8);
sum += frame->additional_info;
frame->checksum = sum;
/* return next frame index or cycle to first frame */
if (++index == nframes)
index = 0;
return index;
}
/* NMT Doc 450-1 4.3.2 */
static struct nmt_frame {
enum nmt_mt message_type;