isValidInput method
Optional method to validate if input can be processed by this codec.
input
The string to validate.
Returns true if the input is valid for this codec, false otherwise.
Implementation
@override
bool isValidInput(String input) {
if (input.isEmpty) return false;
// Basic Base64 validation
final base64Pattern = RegExp(r'^[A-Za-z0-9+/]*={0,2}$');
return base64Pattern.hasMatch(input) && input.length % 4 == 0;
}