TWebFile

 Create a Web file object. A web file is the same as a read-only
 TFile except that it is being read via a HTTP server. The url
 argument must be of the form: http://host.dom.ain/file.root.
 If the file specified in the URL does not exist or is not accessible
 the kZombie bit will be set in the TWebFile object. Use IsZombie()
 to see if the file is accessible. The preferred interface to this
 constructor is via TFile::Open().

 Create a Web file object. A web file is the same as a read-only
 TFile except that it is being read via a HTTP server. Make sure url
 is a valid TUrl object.
 If the file specified in the URL does not exist or is not accessible
 the kZombie bit will be set in the TWebFile object. Use IsZombie()
 to see if the file is accessible.

 Initialize a TWebFile object.

 A TWebFile that has been correctly constructed is always considered open.

 Reopen a file with a different access mode, like from READ to
 UPDATE or from NEW, CREATE, RECREATE, UPDATE to READ. Thus the
 mode argument can be either "READ" or "UPDATE". The method returns
 0 in case the mode was successfully modified, 1 in case the mode
 did not change (was already as requested or wrong input arguments)
 and -1 in case of failure, in which case the file cannot be used
 anymore. A TWebFile cannot be reopened in update mode.

 Read specified byte range from remote file via HTTP daemon. This
 routine connects to the remote host, sends the request and returns
 the buffer. Returns kTRUE in case of error.

 Read the nbuf blocks described in arrays pos and len,
 where pos[i] is the seek position of block i of length len[i].
 Note that for nbuf=1, this call is equivalent to TFile::ReafBuffer
 This function is overloaded by TNetFile, TWebFile, etc.
 Returns kTRUE in case of failure.

 Read request from web server. Returns -1 in case of error,
 0 in case of success.

 Set position from where to start reading.

 Return maximum file size.