[FEATURE] RFC 4517 Postal Address Syntax

[roubert]

LDAP data using RFC 4517 Postal Address Syntax is stored and retrieved using a simple custom encoding specified in the RFC in order to handle line breaks and other metacharacters. This means that every client which wishes to store or retrieve such data will need to encode or decode it, which isn't particularly complicated to do but it seems to me somewhat silly that each and every such client should have their own implementation of this, instead of using shared utility functions provided by the LDAP library.

Therefore I propose adding such utility functions to go-ldap.

See here for the corresponding utility functions in the Apache Directory LDAP API library:

https://github.com/apache/directory-ldap-api/blob/master/util/src/main/java/org/apache/directory/api/util/PostalAddress.java

[cpuschma]

@roubert Thank you for your suggestion. I created a first basic implementation in #579. Can you check out my branch and see if this fits your needs?

Thank you!

[roubert]

That was quick!

There is indeed nothing particularly complicated about the functionality needed so the functions you provide in your pending PR look fine to me. I would personally have used strings with embedded newline characters instead of arrays of strings, but that's just a matter of preference, I have no argument for why one would be objectively better than the other.

Regarding the implementation, I believe that the \5C escape sequence is intended to be case insensitive, so unless you feel convinced that the RFC requires it to always be uppercase I'd recommend you to add test cases with both \5C and \5c.

[cpuschma]

@roubert You're right that was an oversight, good catch! I changed that and added a test for this as well.