Club Amiga de Montreal - CAM/CAM_CD_1.iso/files/177.lha/DRes_v1.3/core/library.c

C/C++ Source or Header | 1988-04-28 | 4.8 KB | 194 lines

/*
 *  LIBRARY.C
 *
 *  Example fully working library for Aztec C ... with comments (which is
 *  a miracle in itself).   By Matthew Dillon.    PUBLIC DOMAIN.
 *
 *  Aztec Compile with +BCDLp
 *        +B    No startup reference
 *        +C    Large code
 *        +D    Large data
 *        +L    32 bit Integers
 *        +p    compatibility mode  (D2/D3 preserved)
 *
 *  Since Original release, the following has been fixed:
 *    -slight bug in LibClose() .. did not expunge library if DELEXP set
 *     on final close.  (thanks to Rico Mariani for finding the bug)
 *    -Now uses MakeLibrary call rather than a hardwired Library structure.
 */

#define NULL 0L

typedef struct Library    LIB;

extern LIB *MakeLibrary();

#define VERSION     1        /*    NOTE!  String in dc.b below must also be */
#define REVISION    3        /*           Changed!              */

#asm
VERSION     equ     1

    ;   RLIB.ASM
    ;
    ;   Run-time library tag

        FAR     data

        public  _CInit
        public  _LibOpen
        public  _LibClose
        public  _LibExpunge

Start:        clr.l   D0
        rts

InitDesc:   dc.w    $4AFC    ;RTC_MATCHWORD
        dc.l    InitDesc    ;Pointer to beginning
        dc.l    EndCode    ;Note sure it matters
        dc.b    0        ;flags (NO RTF_AUTOINIT)
        dc.b    VERSION    ;version
        dc.b    9        ;NT_LIBRARY
        dc.b    0        ;priority (doesn't matter)
        dc.l    _Libname    ;Name of library
        dc.l    _Libid    ;ID string (note CR-LF at end)
        dc.l    Init    ;Pointer to init routine

_Libname:   dc.b    "dres.library",0
_Libid:     dc.b    "dres.library 1.3 (29 Sep 1988)",13,10,0
EndCode:

Init:        move.l  A6,-(sp)    ;Must save A6
        move.l  A0,-(sp)    ;Segment list
        jsr     _CInit
        addq.l  #4,sp
        move.l  (sp)+,A6
        rts

cifc        macro
        move.l  D0,-(sp)    ;Make a C call and save A6 to boot
        move.l  A6,-(sp)
        jsr     \1
        move.l  (sp)+,A6
        addq.l  #4,sp
        rts
        endm

__LibOpen:    cifc    _LibOpen
__LibClose:    cifc    _LibClose
__LibExpunge:    cifc    _LibExpunge

#endasm

extern char Libname[1];
extern char Libid[1];

LIB  *Lib, *DResBase;         /*  Library Base pointer     */
long Seglist;            /*  Save the DOS seglist    */


/*
 *    The Initialization routine is given only a seglist pointer.  Since
 *    we are NOT AUTOINIT we must construct and add the library ourselves
 *    and return either NULL or the library pointer.  Exec has Forbid()
 *    for us during the call.
 *
 *    If you have an extended library structure you must specify the size
 *    of the extended structure in MakeLibrary().
 */

#include "libfuncs.h"

LIB *
CInit(segment)
{
    extern long SysBase;
    extern long DOSBase;

    SysBase = *(long *)4;
    DOSBase = OpenLibrary("dos.library", 0);
    if (DOSBase == NULL)
    return(NULL);
    DResBase = Lib = MakeLibrary(LibVectors,NULL,NULL,sizeof(LIB),NULL);
    Lib->lib_Node.ln_Type = NT_LIBRARY;
    Lib->lib_Node.ln_Name = Libname;
    Lib->lib_Flags = LIBF_CHANGED|LIBF_SUMUSED;
    Lib->lib_Version  = VERSION;
    Lib->lib_Revision = REVISION;
    Lib->lib_IdString = (APTR)Libid;
    Seglist = segment;
    AddLibrary(Lib);
    return(Lib);
}

/*
 *    Open is given the library pointer and the version request.  Either
 *    return the library pointer or NULL.  Remove the DELAYED-EXPUNGE flag.
 *    Exec has Forbid() for us during the call.
 */

LIB *
LibOpen(lib,version)
LIB *lib;
{
    ++lib->lib_OpenCnt;
    lib->lib_Flags &= ~LIBF_DELEXP;
    return(lib);
}

/*
 *    Close is given the library pointer and the version request.  Be sure
 *    not to decrement the open count if already zero.    If the open count
 *    is or becomes zero AND there is a LIBF_DELEXP, we expunge the library
 *    and return the seglist.  Otherwise we return NULL.
 *
 *    Note that this routine never sets LIBF_DELEXP on its own.
 *
 *    Exec has Forbid() for us during the call.
 */

LibClose(lib)
LIB *lib;
{
    if (lib->lib_OpenCnt && --lib->lib_OpenCnt)
    return(NULL);
    if (lib->lib_Flags & LIBF_DELEXP)
    return(LibExpunge(lib));
    return(NULL);
}

/*
 *    We expunge the library and return the Seglist ONLY if the open count
 *    is zero.    If the open count is not zero we set the DELAYED-EXPUNGE
 *    flag and return NULL.
 *
 *    Exec has Forbid() for us during the call.  NOTE ALSO that Expunge
 *    might be called from the memory allocator and thus we CANNOT DO A
 *    Wait() or otherwise take a long time to complete (straight from RKM).
 *
 *    Apparently RemLibrary(lib) calls our expunge routine and would
 *    therefore freeze if we called it ourselves.  As far as I can tell
 *    from RKM, LibExpunge(lib) must remove the library itself as shown
 *    below.
 */

LibExpunge(lib)
LIB *lib;
{
    extern long DOSBase;

    if (lib->lib_OpenCnt) {
    lib->lib_Flags |= LIBF_DELEXP;
    return(NULL);
    }
    if (DOSBase) {
    CloseLibrary(DOSBase);
    DOSBase = NULL;
    }
    Remove(lib);
    FreeMem((char *)lib-lib->lib_NegSize, lib->lib_NegSize+lib->lib_PosSize);
    return(Seglist);
}