The Best of Mecomp Multimedia 1/Mecomp-CD.iso/amiga/tools/uhren/tolleuhr/source/libinit.c

C/C++ Source or Header | 1997-06-05 | 5.1 KB | 209 lines

/*
** tolleuhr.library
** Written by Gunther Nikl ([e-mail])
*/

#include <exec/types.h>

#if !defined(__GNUC__)
#define REG(x)
#else
#define REG(x) asm(#x)
#endif

#include <exec/resident.h>
#include <exec/execbase.h>
#include <proto/exec.h>

struct LibBase {
  struct Library  LibNode;
  UWORD           Pad;
  BPTR            SegList;
  struct Library *SysBase;
};

LONG Start();

/****************************************************************************/

#define VERSION  37
#define REVISION  1
#define LIBNAME  "tolleuhr.library\0tolleuhr 37.1 (15.11.95) by M.Fleischer and G.Nikl\r\n"

#if !defined(mc68020) && !defined(mc68030) && !defined(mc68040) && !defined(mc68060)
#define REQUIRES_68020(x) (0)
#else
#define REQUIRES_68020(x) ((((struct ExecBase *)x)->AttnFlags & AFF_68020) == 0)
#endif

/****************************************************************************/

  // First executable routine of this library; must return an error
  // to the unsuspecting caller

LONG
ReturnError(VOID)
{
  return -1;
}

/****************************************************************************/

  /* LibReserved(VOID):
   *
   *  The mandatory reserved library function.
   */

LONG
LibReserved(VOID)
{
  return 0;
}

  /* LibExpunge(REG(a6) struct LibBase *lib):
   *
   *  Expunge the library, remove it from memory
   */

BPTR
LibExpunge(struct LibBase *lib REG(a6))
{
  BPTR Result = 0;

  // Expunge it later

  lib->LibNode.lib_Flags |= LIBF_DELEXP;

  // Can we get away with this?

  if (!lib->LibNode.lib_OpenCnt) {

    struct Library *SysBase = lib->SysBase;

    // Return the seglist, so it can be unloaded

    Result = lib->SegList;

    // Remove the library from the public list

    Remove((struct Node *)lib);

    // Free the vector table and the library data

    FreeMem((UBYTE *)lib-lib->LibNode.lib_NegSize,lib->LibNode.lib_NegSize+lib->LibNode.lib_PosSize);
  }

  // Return the segment pointer, if any

  return Result;
}

  /* LibClose(REG(a6) struct LibBase *lib):
   *
   *  Close the library, as called by CloseLibrary()
   */

BPTR
LibClose(struct LibBase *lib REG(a6))
{
  BPTR Result = 0;

  // Decrement usage count and check how
  // many customers we still have

  if (!--lib->LibNode.lib_OpenCnt && (lib->LibNode.lib_Flags & LIBF_DELEXP))
    Result = LibExpunge(lib);

  return Result;
}

  /* LibOpen(REG(a6) struct LibBase *lib):
   *
   *  Open the library, as called via OpenLibrary()
   */

struct LibBase *
LibOpen(struct LibBase *lib REG(a6))
{
  // Increment the user count and prevent delayed expunge

  lib->LibNode.lib_OpenCnt++;
  lib->LibNode.lib_Flags &= ~LIBF_DELEXP;

  return lib;
}

  /* LibInit():
   *
   *  Initialize the library.
   */

struct LibBase *
LibInit(BPTR SegList REG(a0),struct LibBase *lib REG(d0),struct Library *SysBase REG(a6))
{
  // Set up the header data; everything that doesn't get set
  // up here will have been set up by InitResident().

  lib->LibNode.lib_Revision = REVISION;

  // Remember the segment pointer

  lib->SegList = SegList;

  // Remember the exec library base pointer

  lib->SysBase = SysBase;

  if (37>SysBase->lib_Version || REQUIRES_68020(SysBase)) {
    FreeMem((UBYTE *)lib-lib->LibNode.lib_NegSize,lib->LibNode.lib_NegSize+lib->LibNode.lib_PosSize);
    lib = NULL;
  }

  return lib;
}

/****************************************************************************/

  // This is the table of functions that make up the library. The first
  // four are mandatory, everything following it are user callable
  // routines. The table is terminated by the value -1.

const APTR LibVectors[] = {
  LibOpen,
  LibClose,
  LibExpunge,
  LibReserved,
  Start,
  (APTR) -1
};

  // The following data structures and data are responsible for
  // setting up the Library base data structure and the library
  // function vector.

const ULONG LibInitTable[] = {
  (ULONG)sizeof(struct LibBase), // Size of the base data structure
  (ULONG)LibVectors,             // Points to the function vector
  (ULONG)NULL,                   // Library base data structure setup table
  (ULONG)LibInit                 // The address of the routine to do the setup
};

/****************************************************************************/

  // The library loader looks for this marker in the memory
  // the library code and data will occupy. It is responsible
  // setting up the Library base data structure.

const struct Resident RomTag = {
  RTC_MATCHWORD,                // Marker value.
  (struct Resident *)&RomTag,   // This points back to itself.
  (struct Resident *)&RomTag+1, // This points behind this marker.
  RTF_AUTOINIT,                 // The Library should be set up according to the given table.
  VERSION,                      // The version of this Library.
  NT_LIBRARY,                   // This defines this module as a Library.
  0,                            // Initialization priority of this Library; unused.
  LIBNAME,                      // Points to the name of the Library.
  LIBNAME+17,                   // The identification string of this Library.
  (APTR)&LibInitTable           // This table is for initializing the Library.
};