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How to generate random sequence of UTF-8 charactersby ted.byers (Beadle)
|on Dec 20, 2012 at 19:13 UTC||Need Help??|
ted.byers has asked for the
wisdom of the Perl Monks concerning the following question:
If I were to generate a sequence of all possible alphanumeric ASCII characters, it would be trivially simple. I would create an array as follows:my @chars = qw( 1 2 3 4 5 6 7 8 9 0 a b c d e f g h i j k l m n o p q r s t u v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z );
I would then use the mersenne twister random number generator to select a character from the array to add onto one of the random sequences in the sample of such sequences I am attempting to construct. In fact, my favourite password generator uses a modification of this to produce very strong, memorable, passwords. The question is, though, what would I add to @chars in order to be able to generate a set of random sequences that, together, are certain to contain all possible valid UTF-8 characters (some of which, I understand, can need as many as 6 bytes to represent them). Or is there a better way to generate samples of random sequences in which the sample is certain to completely cover the sample space? This is with the caveat that I need only alpha-numeric characters as the purpose involves testing the ability of my code to handle text and numbers entered by a user on a UTF-8 encoded web page. Thus, non-printable characters, control characters, &c, while they may be well defined, are not of interest. I will need to untaint this data, and store it in my DB.
The real problem I need to address is how best to manage a transition of our system (which is in production), from a state in which everything is encoded as latin1 to a state in which everything is encoded in utf-8. I thought, until I have sufficient time to test everything from the transformation of our tables from latin1 through binary to utf-8, and how well our code behaves when it is dealing only with utf-8, I'd first convert one form to utf-8 and then, on the server side, convert the text received from the form from utf-8 to latin1 (and then, when a user wants to see it, convert it back from latin1 to utf-8). But I want a good sample to test to determine whether or not such conversions are reversable.
I'd welcome suggestions for handling either the random sequences of UTF-8 characters or a transaition of a data driven web applcation from latin1 to utf-8, or both, well.