iOS判断字符串是否含有emoj表情

//判断是否有emoji
-(BOOL)stringContainsEmoji:(NSString *)string
{
    __block BOOL returnValue = NO;
    
    [string enumerateSubstringsInRange:NSMakeRange(0, [string length])
                               options:NSStringEnumerationByComposedCharacterSequences
                            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                                const unichar high = [substring characterAtIndex: 0];
                                
                                // Surrogate pair (U+1D000-1F9FF)
                                if (0xD800 <= high && high <= 0xDBFF) {
                                    const unichar low = [substring characterAtIndex: 1];
                                    const int codepoint = ((high - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;
                                    
                                    if (0x1D000 <= codepoint && codepoint <= 0x1F9FF){
                                        returnValue = YES;
                                    }
                                    
                                    // Not surrogate pair (U+2100-27BF)
                                } else {
                                    if (0x2100 <= high && high <= 0x27BF){
                                        returnValue = YES;
                                    }
                                }
                            }];
    
    return returnValue;
}