Module OLE
 -----------------------------------------------------------------------
 OLE Handling Routines
 -----------------------------------------------------------------------
 Public Methods Supported:
   _shell_OLELibInit           Initialises module
   shell_OLELinkFile           Sets up the OLE link for the specified file
   shell_OLEDeLinkFile         Breaks the link to the file
   shell_OLEScanLinkedFiles    Called during the null event poll
   shell_OLEGetNrOfLinkedFiles Returns nr of files currently linked
   shell_OLEInProgress         Returns TRUE if OLE in progress
 REM Private Methods Supported:
   None
*|Start FN_shell_OLELibInit
_shell_OLELibInit
 Set up global constants for this module
OLE_RecLength%   = 16
OLE_EndOfData%   = -1
 Set up global variables for this module
G_OLE_DataBlock% = 0
G_OLE_NrOfFiles% = 0
 Format of data block is:
   +00 ptr to filename
   +04 ptr to FN name
   +08 low word file datestamp
   +12 hi  word file datestamp (not used at the moment)
   ...
   +nn
   +nn
   +nn
*|Stop FN_shell_OLELibInit
0!*|Start PROCshell_OLELinkFile
shell_OLELinkFile( file_name$, user_FN$ )
 loc_newrecord%
 G_OLE_DataBlock% = 0 
 First time it has been called, so initialise OLE data block...
7@  G_OLE_DataBlock% = 
shell_HeapBlockFetch( OLE_RecLength% )
 Initialise data block (write end of data marker words)
9*  G_OLE_DataBlock%!00 = OLE_EndOfData%
:*  G_OLE_DataBlock%!04 = OLE_EndOfData%
;*  G_OLE_DataBlock%!08 = OLE_EndOfData%
<*  G_OLE_DataBlock%!12 = OLE_EndOfData%
 First check that file to be linked actually exists..
shell_FileExists( file_name$ ) 
 Make space for new OLE data and write new data, terminating OLE data block
 with 'end_of_data' marker words..
ES  G_OLE_DataBlock% = 
shell_HeapBlockExtend( G_OLE_DataBlock%, OLE_RecLength% )
FQ  loc_newrecord%   = G_OLE_DataBlock% + ( G_OLE_NrOfFiles% * OLE_RecLength% )
HE  loc_newrecord%!00 = 
shell_HeapBlockFetch(
( file_name$ ) + 1 )
IE  loc_newrecord%!04 = 
shell_HeapBlockFetch(
( user_FN$   ) + 1 )
J)  $( loc_newrecord%!00 ) = file_name$
K'  $( loc_newrecord%!04 ) = user_FN$
LD  loc_newrecord%!08      = 
shell_FileGetDateStamp( file_name$ )
M   loc_newrecord%!12      = 0
O@  !( loc_newrecord% + OLE_RecLength% + 00 ) = OLE_EndOfData%
P@  !( loc_newrecord% + OLE_RecLength% + 04 ) = OLE_EndOfData%
Q@  !( loc_newrecord% + OLE_RecLength% + 08 ) = OLE_EndOfData%
R@  !( loc_newrecord% + OLE_RecLength% + 12 ) = OLE_EndOfData%
  G_OLE_NrOfFiles% += 1
 99, "Unable to find file '" + file_name$ + "'"
^ *|Stop PROCshell_OLELinkFile
b#*|Start PROCshell_OLEDeLinkFile
shell_OLEDeLinkFile( file_name$ )
 OLE_index%, curr_file_name$
OLE_index%     = 0
shell_FileExists( file_name$ ) 
l:    curr_file_name$ = $( G_OLE_DataBlock%!OLE_index% )
n(    
 curr_file_name$ = file_name$ 
pG      
shell_HeapBlockReturn( G_OLE_DataBlock%!( OLE_index% + 00 ))
qG      
shell_HeapBlockReturn( G_OLE_DataBlock%!( OLE_index% + 04 ))
      fix_ptr% = OLE_index%
      
wc        G_OLE_DataBlock%!( fix_ptr% + 00 ) = G_OLE_DataBlock%!( fix_ptr% + 00 + OLE_RecLength%)
xc        G_OLE_DataBlock%!( fix_ptr% + 04 ) = G_OLE_DataBlock%!( fix_ptr% + 04 + OLE_RecLength%)
yc        G_OLE_DataBlock%!( fix_ptr% + 08 ) = G_OLE_DataBlock%!( fix_ptr% + 08 + OLE_RecLength%)
zc        G_OLE_DataBlock%!( fix_ptr% + 12 ) = G_OLE_DataBlock%!( fix_ptr% + 12 + OLE_RecLength%)
|&        fix_ptr% += OLE_RecLength%
~6      
 G_OLE_DataBlock%!fix_ptr% = OLE_EndOfData%
      G_OLE_NrOfFiles% -= 1
Y      G_OLE_DataBlock% = 
shell_HeapBlockExtend( G_OLE_DataBlock%, - OLE_RecLength% )
	    
$    OLE_index% += OLE_RecLength%
 G_OLE_DataBlock%!OLE_index% = OLE_EndOfData%
"*|Stop PROCshell_OLEDeLinkFile
!*|Start FNshell_OLEFileStatus
shell_OLEFileStatus( file_name$ )
 *|Stop FNshell_OLEFileStatus
(*|Start PROCshell_OLEScanLinkedFiles
shell_OLEScanLinkedFiles
 OLE_index%,  _file_name$, fn_name$, void%
 new_date_stamp%, old_date_stamp%
 Call a user defined FN if any of the files in the OLE 'watching'
 list have changed their datestamp since the last time they
 were scanned. This routine should be called every 1 or 2 seconds
 by the PollIdle handler of a wimp application.
OLE_index%     = 0
shell_OLEInProgress 
 G_OLE_DataBlock%!OLE_index% <> OLE_EndOfData%
@    
 Note '_file_name$' is used so that crunching the BASIC
>    
 program does not change the name of the variable (as
     
 it is EVALuated later)
6    _file_name$ = $( G_OLE_DataBlock%!OLE_index% )
=    old_date_stamp% = G_OLE_DataBlock%!( OLE_index% + 8 )
@    new_date_stamp% = 
shell_FileGetDateStamp( _file_name$ )
.    
 new_date_stamp% <> old_date_stamp% 
?      G_OLE_DataBlock%!( OLE_index% + 8 ) = new_date_stamp%
=      fn_name$ = $( G_OLE_DataBlock%!( OLE_index% + 4 ) )
9      void% = 
( "FN" + fn_name$ + "( _file_name$ )")
	    
$    OLE_index% += OLE_RecLength%
'*|Stop PROCshell_OLEScanLinkedFiles
)*|Start FNshell_OLEGetNrOfLinkedFiles
shell_OLEGetNrOfLinkedFiles
= G_OLE_NrOfFiles%
(*|Stop FNshell_OLEGetNrOfLinkedFiles
!*|Start FNshell_OLEInProgress
shell_OLEInProgress
 G_OLE_NrOfFiles% > 0 
 *|Stop FNshell_OLEInProgress