Convert a string from argv to unsigned byte array - c

Question

For example i need an
unsigned code[] {
0x0001,
0x0002,
0x0003,
.. and so on
}
from argv. I would like to input it as a stream like this:
000100020003 and so on

Answer 1

unsigned hextodigit(int hex)
{
unsigned result = 0;
switch(toupper(hex))
{
case '0':
return 0;
break;
case '1':
return 1;
break;
case '2':
return 2;
break;
case '3':
return 3;
break;
case '4':
return 4;
break;
case '5':
return 5;
break;
case '6':
return 6;
break;
case '7':
return 7;
break;
case '8':
return 8;
break;
case '9':
return 9;
break;
case 'A':
return 10;
break;
case 'B':
return 11;
break;
case 'C':
return 12;
break;
case 'D':
return 13;
break;
case 'E':
return 14;
break;
case 'F':
return 15;
break;
default:
break;
}
}
unsigned fromhex4chars(const char *str)
{
return hextodigit(*(str + 3)) + (hextodigit(*(str + 2)) << 4) + (hextodigit(*(str + 1)) << 8) + (hextodigit(*str) << 12);
}
void convert(const char *str, unsigned *buff)
{
size_t len = strlen(str) / 4;
while(len--)
{
*buff++ = fromhex4chars(str);
str += 4;
}
}
int main(int argc, char **argv)
{
unsigned x[100];
convert(argv[1], x);
return 0;
}