how to determine if NSString is normalized in NFD

Question

Hi,

i need to determine if a given NSString is in NFD form. how do i do that ?

Context :

the file path i get from mac OS (in form of NSString) is in canonical decomposed form ( NFD ) .. this is true especially when the filesystem is HFSPlus. http://developer.apple.com/mac/library/technotes/tn/tn1150.html#CanonicalDecomposition

i need a precomposed string out of this ...

Now, i want to run the precomposedStringWithCanonicalMapping function only if i know that the filename is decomposed in NFD form.

Solution that i could think of -

 //works on the idea that NFD(NFD(x)) = NFD(x)
 BOOL IsCanonicallyDecompsed(NSString *initialFilePath)
 {
    //decompose the string to NFD form - 
    NSString *nfdFormOfStr = [initialFilePath decomposedStringWithCanonicalMapping];

    char *ndfFormUTF8 = [nfdFormOfStr  UTF8String];

    char *intialPathUTF8 = [initialFilePath UTF8String];

   return (strcmp(ndfFormUTF8, intialPathUTF8) == 0);

 }

Is my solution OK ? also, is my understanding about the filesystem output ( in NFD ) correct ?

thanks