bitmask enumerations in objective-c or C - iphone

Question

I'm trying to draw a line, broken out into segments dependent on values. For example, if there are 5 fields, and all 5 fields were true, then my Line would look like
-----
If say the first and last fields were true, and everything else would be false, then it would be
- -
I thought I could do this with a bit mask of some sort. First of all, I've never done a bit mask before, but I think I've seen them here and there. I was wondering how I could go about this, and use enumerations instead of 1/0 for readability. As far as I can see from my data, I would only need values of either 1 or 0 for the different properties. However, it would be good to know how to have one of the values be a three level or higher enumeration for future reference. Thanks!
Trying to do something like:
enum CodingRegions {
Coding = 0x01,
NonCoding = 0x02
};
enum Substitution {
Synonymous = 0x04,
NonSynonmous = 0x05
};
Then based on the value of the object, I could do
bitmask???? = object.CodingRegion | object.Substitution;
Then later, check the value of the bitmask somehow, and then draw the line accordingly based on what the values are.

Answer 1

Not sure exactly what your requirements are, but here is one way it might be written in C:
#include <stdio.h>
typedef enum MyField_ {
hasWombat = 1 << 0,
hasTrinket = 1 << 1,
hasTinRoof = 1 << 2,
hasThreeWheels = 1 << 3,
myFieldEnd = 1 << 4,
} MyField;
void printMyField(MyField data) {
MyField field = 1;
while (field != myFieldEnd) {
printf("%c", data & field ? '-' : ' ');
field <<= 1;
}
printf("\n");
}
int main() {
MyField data = hasTrinket | hasThreeWheels;
printMyField(data);
data |= hasWombat; // set a field
data &= ~hasTrinket; // clear a field
printMyField(data);
return 0;
}

Answer 2

Not sure this is what you want, but:
// assumed Coding/NonCoding, Synonomous/NonSynonymous are opposites of each other. If not, add more bit fields
enum CodingRegions
{
Coding = 1 << 0
} ;
enum Substitution
{
Synonymous = 1 << 1
}
void PrintBitmask( NSUInteger bitmask )
{
printf( "%s", bitmask & Coding != 0 ? "-" : " " ) ;
printf( "%s", bitmask & Substitution != 0 ? "-" : " " ) ;
printf( "\n" ) ;
}
Your PrintBitmask() could also look like this:
void PrintBitmask( NSUInteger bitmask )
{
printf( "%s", bitmask & Coding != 0 ? "Coding" : "Noncoding" ) ;
printf( "|" ) ;
printf( "%s", bitmask & Substitution != 0 ? "Synonymous-" : "Nonsynonymous" ) ;
printf( "\n" ) ;
}

Answer 3

/* I prefer macros over enums (at least for something this simple) */
#define SPACE 0x0
#define DASH 0x1
/* input fields */
int fields[5] = {DASH,SPACE,SPACE,SPACE,DASH};
/* create bitmask */
for (int i=0; i<5; i++) {
mask |= (fields[i] << i);
}
/* interpret bitmask and print the line */
for (int i=0; i<5; i++) {
if (mask & (fields[i] << i)) {
printf("%c", '-');
} else {
printf("%c", ' ');
}
}