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Made verifying the checksum of a message optional #18

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Made verifying the checksum of a message optional #18

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48 changes: 32 additions & 16 deletions src/dsmr/parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -306,7 +306,7 @@ struct P1Parser {
* pointer in the result will indicate the next unprocessed byte.
*/
template <typename... Ts>
static ParseResult<void> parse(ParsedData<Ts...> *data, const char *str, size_t n, bool unknown_error = false) {
static ParseResult<void> parse(ParsedData<Ts...> *data, const char *str, size_t n, bool unknown_error = false, bool checksum = true) {
ParseResult<void> res;
if (!n || str[0] != '/')
return res.fail(F("Data should start with /"), str);
Expand All @@ -316,27 +316,43 @@ struct P1Parser {

// Look for ! that terminates the data
const char *data_end = data_start;
uint16_t crc = _crc16_update(0, *str); // Include the / in CRC
while (data_end < str + n && *data_end != '!') {
crc = _crc16_update(crc, *data_end);
++data_end;
}
const char *next = NULL;
if(checksum) {
uint16_t crc = _crc16_update(0, *str); // Include the / in CRC
while (data_end < str + n && *data_end != '!') {
crc = _crc16_update(crc, *data_end);
++data_end;
}

if (data_end >= str + n)
return res.fail(F("No checksum found"), data_end);
if (data_end >= str + n)
return res.fail(F("No checksum found"), data_end);

crc = _crc16_update(crc, *data_end); // Include the ! in CRC
crc = _crc16_update(crc, *data_end); // Include the ! in CRC

ParseResult<uint16_t> check_res = CrcParser::parse(data_end + 1, str + n);
if (check_res.err)
return check_res;
ParseResult<uint16_t> check_res = CrcParser::parse(data_end + 1, str + n);
if (check_res.err)
return check_res;

// Check CRC
if (check_res.result != crc)
return res.fail(F("Checksum mismatch"), data_end + 1);
// Check CRC
if (check_res.result != crc)
return res.fail(F("Checksum mismatch"), data_end + 1);

next = check_res.next;
} else {
// There's no CRC check, still need to know where the message ends (!)
while (data_end < str + n && *data_end != '!') {
++data_end;
}

// Skip to end-of-line, everything afther that is not yet processed.
next = data_end;
while (next < str + n && *next != '\r' && *next != '\n') {
++next;
}
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Is this needed? Is there a CRLF after the !? If I read the v4 spec correctly, there should be no CRLF after the last line (which I think is the checksum line in v4, and the ! line in v3)? Are you seeing a CRLF in your messages?

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Hmm, you could be right, I've checked the v3 spec and there's no CRLF. Need to check if that's somehow added to my recording.

}

res = parse_data(data, data_start, data_end, unknown_error);
res.next = check_res.next;
res.next = next;
return res;
}

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