Emoji's, ranges and attributed strings

gistfile1.m

// The issue: the Twitter API returns so called 'tweet entities' for each tweet. These entities contain the ranges
// of hashtags, mentions and urls in the tweet. In iOS, emoji's have a length of 2. The Twitter API uses 1 as length 
// for the emoji's. So when you try to change the foreground color attribute in the range Twitter gives, you change 
// the foreground color of a part of the emoji. The affected thread will freeze and ultimately crash.
// This code fixes the issue with emoji's, but does not yet work with composed character sequences longer than 2. 
// Feel free to fork/comment.

NSRange range; // The old, corrupted range that doesn't take emoji's in account
NSString *string; // The string

__block NSRange adjustedRange = range;
__block NSInteger count = 0;
[string enumerateSubstringsInRange:NSMakeRange(0, string.length) options:NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop)
 {
     adjustedRange.length += (substring.length > 1) ? 1 : 0;
     adjustedRange.location += (substring.length > 1) ? 1 : 0;
     count += 1;
     if (range.length == count) *stop = YES;
 }];

// Do something with the adjusted range