
  samplePNM.datatype and source-code V43.5 (25.1.97)
  (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.                |
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  |                                                         |
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  |                  PerSuaSiVe SoftWorX                    |
  |                                                         |
  |                  Andreas R. Kleinert                    |
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  |                                                         |
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  |                                                         |
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  |                                                         |
  |                  Weekdays after 17.00h.                 |
  |                                                         |
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    http://home.t-online.de/home/Andreas_Kleinert/

  eMail:

        Please send binaries via ARK@COB.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.sub.org  (Fido-Gate)
                     Andreas_Kleinert@t-online.de            (T-Online)
                     ARK@COB.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:

 V43.5 (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

 ---
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