Check return code of FindErrors in Decode

[chris-se]

In cases where the errors could not be corrected (but were detected) make sure Decode returns an error, so that the calling code knows that errors were detected, but could not be corrected.

You can test this by modifying the example. Add one more E so that it can't correct the error and check the return value of Decode:

char message[] = "Some very important message ought to be delivered";
const int msglen = sizeof(message);
const int ecclen = 8;
const int nErrors = 5;

char repaired[msglen];
char encoded[msglen + ecclen];


RS::ReedSolomon<msglen, ecclen> rs;

rs.Encode(message, encoded);

// Corrupting first 8 bytes of message (any 4 bytes can be repaired, no more)
for(uint i = 0; i < nErrors; i++) {
    encoded[i] = 'E';
}

int ok = rs.Decode(encoded, repaired);
if (ok != 0) {
    std::cout << "Couldn't repair the data" << std::endl;
    return;
}

std::cout << "Original:  " << message  << std::endl;
std::cout << "Corrupted: " << encoded  << std::endl;
std::cout << "Repaired:  " << repaired << std::endl;

std::cout << ((memcmp(message, repaired, msglen) == 0) ? "SUCCESS" : "FAILURE") << std::endl;

For nErrors == 5 this will fail the memcmp test but Decode will claim it was successful. (For other values of nErrors, for example 6, it might be the case that Decode will return an error, but for others it also won't.)

My patch fixes this example so that the caller can determine whether this was successful or not.

Otherwise many thanks for writing this!

[mersinvald]

Seems nice, thank you!