Harold Hallikainen wrote:

>> What is the actual requirement... your description is somewhat vague...
>> but I am certain a relatively concise function will suffice given the
>> relative structure of URL's.
> 
> This is part of a closed captioning system for digital cinema. I get a
> Resource Presentation List from the cinema server. It's an XML file that
> includes the URLs for each of the caption files (typically one for each
> reel and language). These URLs are typically absolute, but may be relative
> to the URL of the RPL. So, I need a function where I can pass in my new
> URL, a base URL, and get back an absolute representation of the new URL.
> So, I think I need to be able to handle relative URLs that include such
> things as
> 
> ./file
> ../file
> ../../path/path/file
> /path/file

Not really a problem, I think. 

<basePath>/./file
<basePath>/../file
<basePath>/../../path/path/file
<basePath>//path/file

These should all work fine. (Note that duplication of the slash is
generally not a problem. Depends on the file system of the server, but
at least with Windows and Linux systems this works.)

That's what a relative path is: it's the path portion after the base
path. So I don't really understand what you think you may need to parse.
Just append the relative path to the base path (with a trailing slash,
e.g. "http://myserver/myTopLevelDir/") and you should be done.

To find out whether a path is relative or absolute depends on what kind
of paths you can expect on the input. If it's either a complete http URL
(starting with "http:") or a relative path, then that's it: check for a
starting "http:".

It seems to me that a regex parser is a bit overboard for this :)

Gerhard
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