func ContainsOnlyValidXChars()

in matcher.go [18:45]

• 17 lines of code
• 8 McCabe index (conditional complexity)

func ContainsOnlyValidXChars(number *PhoneNumber, candidate string) bool {
	// The characters 'x' and 'X' can be (1) a carrier code, in which
	// case they always precede the national significant number or (2)
	// an extension sign, in which case they always precede the extension
	// number. We assume a carrier code is more than 1 digit, so the first
	// case has to have more than 1 consecutive 'x' or 'X', whereas the
	// second case can only have exactly 1 'x' or 'X'. We ignore the
	// character if it appears as the last character of the string.
	for index := 0; index < len(candidate)-1; index++ {
		var charAtIndex = candidate[index]
		if charAtIndex == 'x' || charAtIndex == 'X' {
			var charAtNextIndex = candidate[index+1]
			if charAtNextIndex == 'x' || charAtNextIndex == 'X' {
				// This is the carrier code case, in which the 'X's
				// always precede the national significant number.
				index++
				if IsNumberMatchWithOneNumber(number, candidate[index:]) != NSN_MATCH {
					return false
				}
				// This is the extension sign case, in which the 'x'
				// or 'X' should always precede the extension number.
			} else if NormalizeDigitsOnly(candidate[index:]) != number.GetExtension() {
				return false
			}
		}
	}
	return true
}