#define  _USEOLDEXEC_ 1
#include <exec/types.h>
#include <exec/nodes.h>
#include <exec/memory.h>
#include <exec/resident.h>
#include <exec/libraries.h>
#include <libraries/dos.h>
#include <proto/exec.h>
#include <proto/dos.h>
#include <string.h>


/* Prototypes */
ULONG __saveds __asm _LibExpunge( register __a6 struct MyLibrary *libbase );
ULONG __saveds __asm _LibInit( register __a0 APTR seglist,
                                register __d0 struct MyLibrary *libbase );
void __saveds __asm _UserLibInit(register __a6 struct MyLibrary *libbase );
void __saveds __asm _UserLibCleanup(register __a6 struct MyLibrary *libbase);

struct MyLibrary {
        struct       Library ml_Lib;
        ULONG        ml_SegList;
        ULONG        ml_Flags;
        APTR         ml_ExecBase;      /*              pointer to exec base */
};

typedef LONG (*PFL)();   /* pointer to function returning 32-bit int        */

/* library initialization table, used for AUTOINIT libraries                */
struct InitTable {
        ULONG        *it_DataSize;       /* library data space size         */
        PFL          *it_FuncTable;      /* table of entry points           */
        APTR         it_DataInit;        /* table of data initializers      */
        PFL          it_InitFunc;        /* initialization function to run  */
};


/* symbols generated by blink */
extern char __far _LibID[];             /* ID string                        */
extern char __far _LibName[];           /* Name string                      */
extern char __far RESLEN;               /* size of init data                */
extern long __far NEWDATAL;             /* size of global data              */
extern PFL _LibFuncTab[];               /* my function table                */
#define DATAWORDS ((long)&NEWDATAL)     /* magic to get right tpye of reloc */ 
#define SIZEJMPTAB ((long)libbase->ml_origbase->ml_numjmps)
                                        /* size in bytes of jmp table       */
#define MYREVISION 0                    /* revision number                  */

/* From libent.o, needed to determine where data is loaded by loadseg       */
extern long far _Libmergeddata; 


struct InitTable __far _LibInitTab =  {
        (long *)(&RESLEN+sizeof(struct MyLibrary)),
        _LibFuncTab,
        NULL,                        /* will initialize my own data */
        _LibInit,
};

__saveds __asm
ULONG _LibInit( register __a0 APTR seglist,
        register __d0 struct MyLibrary *libbase )
{
    long *reloc;
    long *sdata;
    char *ddata;
    long nrelocs;

      
    libbase->ml_SegList = (ULONG) seglist;

    /* init. library structure (since I don't do automatic data init.) */
    libbase->ml_Lib.lib_Node.ln_Type = NT_LIBRARY;
    libbase->ml_Lib.lib_Node.ln_Name =  _LibName;
    libbase->ml_Lib.lib_Flags = LIBF_SUMUSED | LIBF_CHANGED;
    libbase->ml_Lib.lib_Version = 1;
    libbase->ml_Lib.lib_Revision = MYREVISION;
    libbase->ml_Lib.lib_IdString = (APTR) _LibID;

     /* Start of copy of global data after structure */
    ddata = (char *)libbase + sizeof(struct MyLibrary); 

    sdata = (long *)&_Libmergeddata; /* where loadseg loaded the data */
    memcpy(ddata, (void *)sdata, DATAWORDS*4);

    /* perform relocs if we want one global section for all programs */
    /* that have this lib open. If we want a global section for each */
    /* open, copy the relocs, and do them on each open call.         */
    sdata = sdata + DATAWORDS;
    nrelocs = *sdata;
    sdata++;
    while (nrelocs > 0)
    {
       reloc = (long *)((long)ddata + *sdata++);
       *reloc += (long)ddata;
       nrelocs--;
    }
    _UserLibInit(libbase);

    return ( (ULONG) libbase );
}

LONG __saveds __asm
_LibOpen( register __a6 struct        MyLibrary *libbase )
{
    /* mark us as having another customer */
    libbase->ml_Lib.lib_OpenCnt++;

    /* clear delayed expunges (standard procedure)                */
    libbase->ml_Lib.lib_Flags &= ~LIBF_DELEXP;

    return ( (LONG) libbase );
}

ULONG __saveds __asm
_LibClose( register __a6 struct MyLibrary *libbase )
{
    ULONG retval = 0;
    
    if (( --libbase->ml_Lib.lib_OpenCnt == 0 ) &&
                        ( libbase->ml_Lib.lib_Flags & LIBF_DELEXP ))
    {
        /* no more people have me open,
         * and I have a delayed expunge pending
         */
         retval = _LibExpunge( libbase ); /* return segment list        */
    }

    return (retval);
}

ULONG __saveds __asm
_LibExpunge( register __a6 struct MyLibrary *libbase )
{
    ULONG seglist = 0;
    LONG  libsize;

    libbase->ml_Lib.lib_Flags |= LIBF_DELEXP;
    if ( libbase->ml_Lib.lib_OpenCnt == 0 )
    {
        /* really expunge: remove libbase and freemem        */
        _UserLibCleanup(libbase);
        seglist = libbase->ml_SegList;

        Remove( (struct Node *) libbase);

        libsize = libbase->ml_Lib.lib_NegSize + libbase->ml_Lib.lib_PosSize;
        FreeMem( (char *) libbase - libbase->ml_Lib.lib_NegSize,(LONG) libsize );
    }

    /* return NULL or real seglist                                */
    return ( (ULONG) seglist );
}