Short:    How: OS3 V40/43 PicDatatype in 100% C
Author:   Andreas_Kleinert@t-online.de
Uploader: Andreas_Kleinert@t-online.de
Type:     dev/c


  samplePNM.datatype and source-code V43.7 (14.6.97)
  (C) 1996-97 by Andreas R. Kleinert. All rights reserved.

  ---
  This small sample datatype source code demonstrates, how to completely
  write an Amiga OS 3 datatype (V40/V43) without any assembler stubs
  or compiler/linker tricks in PURE C source code (currently SAS/C-based:
  see Aminet:dev/c/CLib37x.LHA on how to adjust for some other compilers).

  You may e.g. use this example source code to write more portable
  Amiga OS 3 datatypes to allow easier porting of these
  to other Amiga OS-derived operating systems, or the native
  OS of an upcoming PowerPC Amiga.

  Translate your 68k-assembler datatype startup-codes smartly
  to C by simply using this source-code as an advice how to do it.


  As a common case, a datatype of class picture, supporting
  PNM-PGM (P5) and PNM-PPM (P6) has been used as an example.

  With picture.datatype V40-42 only PGM is supported,
  and with picture.datatype V43 reading of PPM is offered as well,
  while encountering an PGM file under V43 causes a fallback to V40
  routines (could have been done differently, but was not necessary
  here just for demonstration).

  For testing this datatype, simply use a tool from the NetPBM package
  (or maybe for example a tool supporting superview.library) and save
  a graphics in the binary PGM or PPM format (P5/P6 of the PNM series).

  Then install this datatype and try loading the file via MultiView.
  Should work fine.

  ---
  Feel free to use this source for own projects.

  It is allowed to be spread and distributed anywhere, as far
  as my consent is concerned.

  Amiga Technologies, or the current owner of the technologie,
  is allowed to always put this source on their newest
  Developer CD-ROM.

  Thanks and credits will always be appreciated - for example,
  you MAY, but NEED NOT:
  give me credits in your program's docs, send me keyfiles for
  your programs using the library, and so on.
  But that's simply voluntarily.

  This work was only roughly inspired by David Junod's original
  example source codes for datatypes.

   _________________________________________________________
  |      You may reach me the following way.                |
  |    Send bug-reports, money or whatever to:              |
  |---------------------------------------------------------|
  |        * SuperView Development & Registration *         |
  |          * DRAFU Development & Registration *           |
  |       * Image Engineer Registration Site Europe *       |
  |                                                         |
  |                                                         |
  |                  PerSuaSiVe SoftWorX                    |
  |                                                         |
  |                  Andreas R. Kleinert                    |
  |                  Sandstrasse 1                          |
  |                  D-57072 Siegen                         |
  |                  Germany, Europe                        |
  |                                                         |
  | Any snail mail to the old address will still be routed. |
  |                                                         |
  |                  Phone:  +49-271-22869 also FAX + AM    |
  |                          +49-271-22838                  |
  |                                                         |
  |                  Weekdays after 17.00h.                 |
  |                                                         |
  |         When calling via phone you may leave a message, |
  |         if I'm not available - but don't expect me      |
  |         calling back to USA, Australia, ... since       |
  |         german phone rates are HIGHLY expensive.        |
  |_________________________________________________________|

    http://home.t-online.de/home/Andreas_Kleinert/

  eMail:

        Please send binaries via ARK@News.wwbnet.de, and keep
        them smaller than 16 KB. Please think twice before
        sending them - my postbox is not unlimited in size.

           - Fido    Andreas Kleinert 2:2457/350.18
           - Usenet
                     Andreas_Kleinert@superview.ftn.neckar-alb.de (Fido-Gate)
                     Andreas_Kleinert@t-online.de                 (T-Online)
                     ARK@News.wwbnet.de                           (Z-Netz)
                     ARK@amigaworld.com                           (AmigaWorld)

           - If nothing else works, try one of these public
             Fido-Usenet gateways:

               In Germany:
                 Andreas_Kleinert@p18.f350.n2457.z2.fido.sub.org

               From USA or elsewhere:
                 Andreas_Kleinert@p18.f350.n2457.z2.fidonet.org

        Please note, that the "superview.ftn.sub.org"
        domain will perhaps be renamed soon

 History:

 V43.7 (14.6.97) :  - fixed ftn-email address
                    - updated class dispatcher
                      (-> Roland Mainz)

 V43.6 (27.3.97) :  - did some finetuning
                    - now can simply be turned into a V40 datatype
                      by removing a #define (and/or the corresponding
                      parts of the code)

 V43.5 (25.1.97) :  - now explicitely checks for DTA_SourceType == DTST_File
                    - small changes
                    - updated email information

 V43.4 (3.1.97) :   - fixed PRI entry in resident part
                    - slightly changed SCOPTIONS
                    - fixed some style things (APTR and library casts)
                    - fixed a bug: bitmap would not have been freed
                      on temporary-buffer allocation error
                    - added note about library opening to L_OpenLibs()

 V43.3 (30.11.96) : - added SAS/C specific Ctrl-C disabling code
                    - made some workarounds compiler sensitive
                    - redone all with SAS/C V6.57

 V43.2 (3.11.96)  : - there was a FreeBitMap() call missing (oops)
                    - it's samplePNM.dt, not samplePNG.dt ;-)

 V43.1 (25.10.96) : - added picture datatype V43 support
                    - thus added support for 24 Bit PPM (P6),
                      since PGM only has 256 grayscales
                    - thus renamed to samplePNM.datatype

 V40.3 (13.9.96)  : - fixed more "style" things

 V40.2 (5.9.96)   : - fixed some "style" things

 V40.1 (2.9.96)   : - first release

 ---
 All mentioned trademarks are subject to their owners.


============================= Archive contents =============================

Original  Packed Ratio    Date     Time    Name
-------- ------- ----- --------- --------  -------------
      86      76 11.6% 25-Oct-96 16:26:52 +PGM
     467     279 40.2% 25-Oct-96 16:26:52 +PGM.info
      86      76 11.6% 25-Oct-96 16:27:44 +PPM
     467     279 40.2% 25-Oct-96 16:27:44 +PPM.info
     107     102  4.6% 25-Oct-96 17:34:40 +CompileNote.readme
     739     301 59.2% 25-Oct-96 16:17:50 +libfuncs.h
     835     388 53.5% 25-Oct-96 16:28:52 +samplePNM.datatype.info
     408     156 61.7% 25-Oct-96 16:23:58 +smakefile
     119     104 12.6% 25-Oct-96 16:23:58 +smakefile.wth
     795     364 54.2% 03-Jan-97 15:21:22 +classbase.h
     212     149 29.7% 27-Mar-97 10:44:44 +SCOPTIONS
    4005    1206 69.8% 27-Mar-97 10:36:58 +StartUp.c
     796     476 40.2% 27-Mar-97 10:43:24 +StartUp.o
     803     453 43.5% 27-Mar-97 10:40:40 +Readme.SAS
    4868    2564 47.3% 14-Jun-97 12:44:16 +samplePNM.datatype
   13237    3373 74.5% 14-Jun-97 12:44:00 +libfuncs.c
    3796    2075 45.3% 14-Jun-97 12:44:14 +libfuncs.o
    4782    1434 70.0% 14-Jun-97 12:43:08 +LibInit.c
    1532     838 45.3% 14-Jun-97 12:43:24 +LibInit.o
    4868    2564 47.3% 14-Jun-97 12:44:14 +samplePNM.datatype
    6493    2553 60.6% 14-Jun-97 13:09:10 +README
-------- ------- ----- --------- --------
   49501   19810 59.9% 15-Jun-97 14:19:40   21 files
