Read/Write Binary Files

[Ahankhah]

Dear all:),

Is it possible to read/write a binary file from Visual LISP:?

[Lee Mac]

You could use the methods associated with the FileSystemObject as demonstrated by these courtesy of MP:

 

http://www.theswamp.org/index.php?topic=17465.0

 

Or you could use the ADO Stream object:

 

;;-----------------=={ Read Binary Stream }==-----------------;;
;;                                                            ;;
;;  Uses the ADO Stream Object to read a supplied file and    ;;
;;  returns a variant of bytes.                               ;;
;;------------------------------------------------------------;;
;;  Author: Lee Mac, Copyright © 2011 - www.lee-mac.com       ;;
;;------------------------------------------------------------;;
;;  Arguments:                                                ;;
;;  filename - filename of file to read.                      ;;
;;  len      - number of bytes to read                        ;;
;;  (if non-numerical, less than 1, or greater than the size  ;;
;;   of the file, everything is returned).                    ;;
;;------------------------------------------------------------;;
;;  Returns:                                                  ;;
;;  Variant of Binary data which may be converted to a list   ;;
;;  bytes using the relevant VL Variant functions or used     ;;
;;  with LM:WriteBinaryStream.                                ;;
;;------------------------------------------------------------;;

(defun LM:ReadBinaryStream ( filename len / ADOStream result ) (vl-load-com)
 
 (setq result
   (vl-catch-all-apply
     (function
       (lambda ( / size )
         (setq ADOStream (vlax-create-object "ADODB.Stream"))
         (vlax-invoke ADOStream 'Open)
         (vlax-put-property   ADOStream 'type 1)
         (vlax-invoke-method  ADOStream 'loadfromfile filename)
         (vlax-put-property   ADOStream 'position 0)
         (setq size (vlax-get ADOStream 'size))
         (vlax-invoke-method  ADOStream 'read (if (and (numberp len) (< 0 len size)) (fix len) -1))
       )
     )
   )
 )
 (if ADOStream (vlax-release-object ADOStream))

 (if (not (vl-catch-all-error-p result))
   result
 )
)

;;-----------------=={ Write Binary Stream }==----------------;;
;;                                                            ;;
;;  Uses the ADO Stream Object to write a variant of bytes to ;;
;;  a specified file. File is created if non-existent or      ;;
;;  overwritten if found.                                     ;;
;;------------------------------------------------------------;;
;;  Author: Lee Mac, Copyright © 2011 - www.lee-mac.com       ;;
;;------------------------------------------------------------;;
;;  Arguments:                                                ;;
;;  filename - filename of file to read.                      ;;
;;  data     - variant of binary data to write to the file.   ;;
;;             (as returned by LM:ReadBinaryStream)           ;;
;;------------------------------------------------------------;;
;;  Returns:  Filename of specified file, else nil.           ;;
;;------------------------------------------------------------;;

(defun LM:WriteBinaryStream ( filename data / ADOStream result ) (vl-load-com)
 
 (setq result
   (vl-catch-all-apply
     (function
       (lambda ( )
         (setq ADOStream (vlax-create-object "ADODB.Stream"))
         (vlax-put-property ADOStream 'type 1)
         (vlax-invoke ADOStream 'open)
         (vlax-invoke-method ADOStream 'write data)
         (vlax-invoke ADOStream 'savetofile filename 2)
       )
     )
   )
 )
 (if ADOStream (vlax-release-object ADOStream))

 (if (not (vl-catch-all-error-p result))
   file
 )
)

Edited March 2, 2011 by Lee Mac

[Ahankhah]

Excellent Lee Mac:D