C++ converting a mac id string into an array of uint8_t

Question

I want to read a mac id from command line and convert it to an array of uint8_t values to use it in a struct. I can not get it to work. I have a vector of stri

Answer 1

Your problem may be in the output of the parsed data. The "<<" operator makes decisions on how to display data based on the data type passed it, and uint8_t may be getting interpretted as a char. Make sure you cast the array values to ints when printing, or investigate in a debugger.

The sample program:

uint8_t tgt_mac[6] = {0};
std::stringstream ss( "AA:BB:CC:DD:EE:11" );
char trash;

for ( int i = 0; i < 6; i++ )
{
    int foo;
    ss >> std::hex >> foo >> trash;
    tgt_mac[i] = foo;
    std::cout << std::hex << "Reading: " << foo << std::endl;
}

std::cout << "As int array: " << std::hex
    << (int) tgt_mac[0]
    << ":"
    << (int) tgt_mac[1]
    << ":"
    << (int) tgt_mac[2]
    << ":"
    << (int) tgt_mac[3]
    << ":"
    << (int) tgt_mac[4]
    << ":"
    << (int) tgt_mac[5]
    << std::endl;
std::cout << "As unint8_t array: " << std::hex
    << tgt_mac[0]
    << ":"
    << tgt_mac[1]
    << ":"
    << tgt_mac[2]
    << ":"
    << tgt_mac[3]
    << ":"
    << tgt_mac[4]
    << ":"
    << tgt_mac[5]
    << std::endl;

Gives the following output ( cygwin g++ )

Reading: aa
Reading: bb
Reading: cc
Reading: dd
Reading: ee
Reading: 11
As int array: aa:bb:cc:dd:ee:11
As unint8_t array: ª:»:I:Y:î:◄