Basic phone number formatting

normalNumber.m

- (NSString *)normalizedPhoneNumber {
    NSString *normalString = self;
    if (!self) return nil;
    
    normalString = [normalString lowercaseString];
    NSCharacterSet *normalizationSet = [[NSCharacterSet characterSetWithCharactersInString:@"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"] invertedSet];
    normalString = [[[normalString componentsSeparatedByCharactersInSet:normalizationSet] componentsJoinedByString:@""] uppercaseString];
    NSMutableString *phoneNumber = [[normalString mutableCopy] autorelease];

    char tmpChar;
    BOOL elevenPlus = NO;
    unsigned int offset = 0;
	switch (normalString.length) {
        case 13:
            offset ++;
        case 12:
            offset ++;
        case 11:

			tmpChar = [phoneNumber characterAtIndex:0+offset];
			elevenPlus = YES;
			[phoneNumber insertString:@" " atIndex:1+offset];
			offset += 2;
		case 10:
			tmpChar = [phoneNumber characterAtIndex:0+offset];
			
			[phoneNumber insertString:@"(" atIndex:0+offset];
			[phoneNumber insertString:@") " atIndex:4+offset];
			offset += 6;
		case 7:
			tmpChar = [phoneNumber characterAtIndex:0+offset];
			
			[phoneNumber insertString:@"-" atIndex:3+offset];
			break;
		default:
			[phoneNumber setString:self];
			elevenPlus = NO;
			break;
	}
    if (elevenPlus) [phoneNumber insertString:@"+" atIndex:0];
    
    return phoneNumber;
}

• INPUT, OUTPUT
• 00-000-000, 00-000-000
• 000-000-0000, (000) 000-0000
• 0000000, 000-0000
• 00-000-000-0000, +00 (000) 000-0000
• 0000000000, (000) 000-0000
• 000000000000, +00 (000) 000-0000
• 1800comcast, +1 (800) COM-CAST