Short:        Script driven messageport monitor
Author:       schettler@informatik.fh-wuerzburg.de  (Michael Schettler)
Uploader:     schettler informatik fh-wuerzburg de  (Michael Schettler)
Type:         dev/misc
Architecture: m68k-amigaos

This is just a small hack i needed some time ago. The  programm  reads  an
ascii  scriptfile  where  a  messageport  name  and  the  structure of the
incomming messages is given, and monitors the port. If a message  arrives,
it's dumped to the specified output using the defined structure.
To exit press CTRL-C use the break command.

Example scriptfile:

;  Cmd  Offset         Text
;  --------------------------------------------------------------------
   OUTPUT              "CON:0/100/640/156/PortSnoop/auto/smart/close"
   PORT                "REXX"
   TEXT                $0c,"Monitoring 'REXX' port",$0a
   MPTR                "Message ($%06lx)",$0a
   TEXT                $0a
   BYTE=$08            "LN_TYPE        $%02lx",$0a
   BYTE=$09            "LN_PRI         $%02lx",$0a
   ASTR=$0a            "LN_NAME        $%08lx ('%s')",$0a
   APTR=$0e            "MN_REPLYPORT   $%08lx",$0a
   APTR=$0e.ASTR=$0a   "   LN_NAME     $%08lx ('%s')",$0a
   WORD=$12            "MN_LENGTH      $%04lx",$0a
   TEXT                $0a
   LONG=$1c            "rm_Action      $%08lx",$0a
   LONG=$20            "rm_Result1     $%08lx",$0a
   LONG=$24            "rm_Result2     $%08lx",$0a
   ASTR=$28            "rm_Args,16*4   $%08lx ('%s')",$0a
   APTR=$68            "rm_PassPort    $%08lx",$0a
   APTR=$68.ASTR=$0a   "   LN_NAME     $%08lx ('%s')",$0a
   END
;  --------------------------------------------------------------------


Any field of  the  message  can  be  displayed.  It's  even  possible,  to
reference values. That means that the value, which is contained at offset,
is taken as a new structure address.

Example:

  APTR=$0e             "MN_REPLYPORT   $%08lx",$0a

      -> the address of the replyport is printed.

  APTR=$0e.ASTR=$0a    "   LN_NAME     $%08lx ('%s')",$0a
      1        2

      -> the address of the reply-port (1) contained at offset $0e of  the
	 message  is  taken  as a pointer to a new structure (in this case
	 the node structure of the  message  replyport).  The  pointer  at
	 offset  $0a  (2)  of the new (actual) structure is taken again as
	 pointer to another structure (in this case  the  LN_NAME  field).
	 Finally  the name of the replyport (LN_NAME), which is pointed to
	 at offset $0a (2), is printed together with the  address  of  the
	 last (the node) structure.


Syntax of the script file:

each line consists of COMMAND [OFFSET] ['TEXT' | "TEXT" | $xx]

where

   COMMAND          see syntax below

   OFFSET           a hexadecimal offset into the message, wich  is  given
		    with an equal sign

		       example: $09 to access the LN_PRI field of a node

   TEXT             surrounded by  either  single-  or  doublequote.  Also
		    single  chars  given  in  hexadecimal  can  be printed
		    (including PrintF()-style formatting).

		       example: $09,"LN_PRI = %02lx",$0a
		       note1:   add a carrige-return (= $0a) to each line!
		       note2:   always specify long size in PrintF()-style


Syntax of the commands:

  Command   Argument                            Description
  ----------------------------------------------------------------------
  ;                                             comment introducer

  OUTPUT    <filename>                          specifies the output
	    e.g. OUTPUT "CON:0/0/640/256/Snoop"
	    or   OUTPUT "RAM:output.txt"

  PORT      [text | $address]                   the name or the address
	    e.g. PORT "REXX"                    of the port to monitor
	    or   PORT $BADC0DE

  TEXT      <text>                              displays given text
	    e.g. TEXT $0c,"Hello!",$0a

  MPTR      <textfmt>          (1)              insert the adress of
	    e.g. MPTR "Adr of Msg = %lx",$0a    the message

  BYTE      <offset textfmt>   (1)              reads the value which
	    e.g. BYTE=$09 "LN_PRI=%02lx",$0a    is stored at offset as
						byte.

  WORD      see BYTE, only as word
  LONG      see BYTE, only as long
  APTR      see LONG
  BPTR      see LONG, shown as value*4

  ASTR      <offset textfmt>   (2)              reads the value and
	    e.g. ASTR=$0a $0c,"LN_NAME %s",$0a  displays the text, which
						is pointed to
  BSTR      see ASTR, only value*4

  END                                           signals the end of the
						script. (important!)
  ----------------------------------------------------------------------

  <textfmt> means PrintF() style format parameters.

  (1) Has only one format parameter: "%lx"
  (2) Has two format parameters: "%s" and "%lx"