Reading the reference from HEAD in a git repo at path

gistfile1.m

-(NSString*)currentBranch {
    const char *refAnfang = "ref: ";
    NSString *branch;
    
    const char *filename = [[path stringByAppendingPathComponent:@"HEAD"] cStringUsingEncoding:NSUTF8StringEncoding];
    FILE *file = fopen (filename, "r");
    if (file != NULL) {
        char line [256];
        if (fgets(line, sizeof line, file) != NULL) {
            line[strlen(line)-1] = 0;
            if (strncmp(refAnfang, line, 5) == 0) {
                const char *reference = line + 5;
                branch = [NSString stringWithCString:reference encoding:NSUTF8StringEncoding];
            }
        }
        fclose(file);
    }
    
    return branch;
}