};
} FDIDECRYPT; /* fdid */
typedef FDIDECRYPT FAR *PFDIDECRYPT; /* pfdid */


/***    FNALLOC - Memory Allocation
 *      FNFREE  - Memory Free
 *
 *  These are modeled after the C run-time routines malloc() and free()
 *  FDI expects error handling to be identical to these C run-time routines.
 *
 *  As long as you faithfully copy the semantics of malloc() and free(),
 *  you can supply any functions you like!
 *
 *  WARNING: You should never assume anything about the sequence of
 *           PFNALLOC and PFNFREE calls -- incremental releases of
 *           FDI may have radically different numbers of
 *           PFNALLOC calls and allocation sizes!
 */
//** Memory functions for FDI
typedef void HUGE * (FAR DIAMONDAPI *PFNALLOC)(ULONG cb); /* pfna */
#define FNALLOC(fn) void HUGE * FAR DIAMONDAPI fn(ULONG cb)

typedef void (FAR DIAMONDAPI *PFNFREE)(void HUGE *pv); /* pfnf */
#define FNFREE(fn) void FAR DIAMONDAPI fn(void HUGE *pv)


/***    PFNOPEN  - File I/O callbacks for FDI
 *      PFNREAD
 *      PFNWRITE
 *      PFNCLOSE
 *      PFNSEEK
 *
 *  These are modeled after the C run-time routines _open, _read,
 *  _write, _close, and _lseek.  The values for the PFNOPEN oflag
 *  and pmode calls are those defined for _open.  FDI expects error
 *  handling to be identical to these C run-time routines.
 *
 *  As long as you faithfully copy these aspects, you can supply
 *  any functions you like!
 *
 *  WARNING: You should never assume you know what file is being
 *           opened at any one point in time!  FDI will usually
 *           stick to opening cabinet files, but it is possible
 *           that in a future implementation it may open temporary
 *           files or open cabinet files in a different order.
 *
 *  Notes for Memory Mapped File fans:
 *      You can write wrapper routines to allow FDI to work on memory
 *      mapped files.  You'll have to create your own "handle" type so that
 *      you can store the base memory address of the file and the current
 *      seek position, and then you'll allocate and fill in one of these
 *      structures and return a pointer to it in response to the PFNOPEN
 *      call and the fdintCOPY_FILE call.  Your PFNREAD and PFNWRITE
 *      functions will do memcopy(), and update the seek position in your
 *      "handle" structure.  PFNSEEK will just change the seek position
 *      in your "handle" structure.
 */
//** File I/O functions for FDI
typedef int  (FAR DIAMONDAPI *PFNOPEN) (char FAR *pszFile, int oflag, int pmode);
typedef UINT (FAR DIAMONDAPI *PFNREAD) (int hf, void FAR *pv, UINT cb);
typedef UINT (FAR DIAMONDAPI *PFNWRITE)(int hf, void FAR *pv, UINT cb);
typedef int  (FAR DIAMONDAPI *PFNCLOSE)(int hf);
typedef long (FAR DIAMONDAPI *PFNSEEK) (int hf, long dist, int seektype);

#define FNOPEN(fn) int FAR DIAMONDAPI fn(char FAR *pszFile, int oflag, int pmode)
#define FNREAD(fn) UINT FAR DIAMONDAPI fn(int hf, void FAR *pv, UINT cb)
#define FNWRITE(fn) UINT FAR DIAMONDAPI fn(int hf, void FAR *pv, UINT cb)
#define FNCLOSE(fn) int FAR DIAMONDAPI fn(int hf)
#define FNSEEK(fn) long FAR DIAMONDAPI fn(int hf, long dist, int seektype)



/***    PFNFDIDECRYPT - FDI Decryption callback
 *
 *  If this function is passed on the FDICopy() call, then FDI calls it
 *  at various times to update the decryption state and to decrypt FCDATA
 *  blocks.
 *
 *  Common Entry Conditions:
 *      pfdid->fdidt  - Command type
 *      pfdid->pvUser - pvUser value from FDICopy() call
 *
 *  fdidtNEW_CABINET:   //** Notification of a new cabinet
 *      Entry:
 *        pfdid->cabinet.
 *          pHeaderReserve  - RESERVE section from CFHEADER
 *          cbHeaderReserve - Size of pHeaderReserve
 *          setID           - Cabinet set ID
 *          iCabinet        - Cabinet number in set (0 based)
 *      Exit-Success:
 *          returns anything but -1;
 *      Exit-Failure:
 *          returns -1; FDICopy() is aborted.
 *      Notes:
 *      (1) This call allows the decryption code to pick out any information
 *          from the cabinet header reserved area (placed there by DIACRYPT)
 *          needed to perform decryption.  If there is no such information,
 *          this call would presumably be ignored.
 *      (2) This call is made very soon after fdintCABINET_INFO.
 *
 *  fdidtNEW_FOLDER:    //** Notification of a new folder
 *      Entry:
 *        pfdid->folder.
 *          pFolderReserve  - RESERVE section from CFFOLDER
 *          cbFolderReserve - Size of pFolderReserve
 *          iFolder         - Folder number in cabinet (0 based)
 *      Exit-Success:
 *          returns anything but -1;
 *      Exit-Failure:
 *          returns -1; FDICopy() is aborted.
 *      Notes:
 *          This call allows the decryption code to pick out any information
 *          from the folder reserved area (placed there by DIACRYPT) needed
 *          to perform decryption.  If there is no such information, this
 *          call would presumably be ignored.
 *
 *  fdidtDECRYPT:       //** Decrypt a data buffer
 *      Entry:
 *        pfdid->folder.
 *          pDataReserve  - RESERVE section for this CFDATA block
 *          cbDataReserve - Size of pDataReserve
 *          pbData        - Data buffer
 *          cbData        - Size of data buffer
 *          fSplit        - TRUE if this is a split data block
 *          cbPartial     - 0 if this is not a split block, or the first
 *                              piece of a split block; Greater than 0 if
 *                              this is the second piece of a split block.
 *      Exit-Success:
 *          returns TRUE;
 *      Exit-Failure:
 *          returns FALSE; error during decrypt
 *          returns -1; FDICopy() is aborted.
 *      Notes:
 *          FCI will split CFDATA blocks across cabinet boundaries if
 *          necessary.  To provide maximum flexibility, FDI will call the
 *          fdidtDECRYPT function twice on such split blocks, once when
 *          the first portion is read, and again when the second portion
 *          is read.  And, of course, most data blocks will not be split.
 *          So, there are three cases:
 *
 *           1) fSplit == FALSE
 *              You have the entire data block, so decrypt it.
 *
 *           2) fSplit == TRUE, cbPartial == 0
 *              This is the first portion of a split data block, so cbData
 *              is the size of this portion.  You can either choose to decrypt
 *              this piece, or ignore this call and decrypt the full CFDATA
 *              block on the next (second) fdidtDECRYPT call.
 *
 *           3) fSplit == TRUE, cbPartial > 0
 *              This is the second portion of a split data block (indeed,
 *              cbPartial will have the same value as cbData did on the
 *              immediately preceeding fdidtDECRYPT call!).  If you decrypted
 *              the first portion on the first call, then you can decrypt the
 *              second portion now.  If you ignored the first call, then you
 *              can decrypt the entire buffer.
 *              NOTE: pbData points to the second portion of the split data
 *                    block in this case, *not* the entire data block.  If
 *                    you want to wait until the second piece to decrypt the
 *                    *entire* block, pbData-cbPartial is the address of the
 *                    start of the whole block, and cbData+cbPartial is its
 *                    size.
 */
typedef int (FAR DIAMONDAPI *PFNFDIDECRYPT)(PFDIDECRYPT pfdid); /* pfnfdid */
#define FNFDIDECRYPT(fn) int FAR DIAMONDAPI fn(PFDIDECRYPT pfdid)


/***    FDINOTIFICATION - Notification structure for PFNFDINOTIFY
 *
 *  See the FDINOTIFICATIONTYPE definition for information on usage and
 *  meaning of these fields.
 */
typedef struct {
// long fields
    long      cb;
    char FAR *psz1;
    char FAR *psz2;
    char FAR *psz3;                     // Points to a 256 character buffer
    void FAR *pv;                       // Value for client

// int fields
    int       hf;

// short fields
    USHORT    date;
    USHORT    time;
    USHORT    attribs;

    USHORT    setID;                    // Cabinet set ID
    USHORT    iCabinet;                 // Cabinet number (0-based)
    USHORT    iFolder;                  // Folder number (0-based)

    FDIERROR  fdie;
} FDINOTIFICATION, FAR *PFDINOTIFICATION;  /* fdin, pfdin */


/***    FDINOTIFICATIONTYPE - FDICopy notification types
 *
 *  The notification function for FDICopy can be called with the following
 *  values for the fdint parameter.  In all cases, the pfdin->pv field is
 *  filled in with the value of the pvUser argument passed in to FDICopy().
 *
 *  A typical sequence of calls will be something like this:
 *      fdintCABINET_INFO     // Info about the cabinet
 *      fdintENUMERATE        // Starting enumeration
 *      fdintPARTIAL_FILE     // Only if this is not the first cabinet, and
 *                            // one or more files were continued from the
 *                            // previous cabinet.
 *      ...
 *      fdintPARTIAL_FILE
 *      fdintCOPY_FILE        // The first file that starts in this cabinet
 *      ...
 *      fdintCOPY_FILE        // Now let's assume you want this file...
 *      // PFNWRITE called multiple times to write to this file.
 *      fdintCLOSE_FILE_INFO  // File done, set date/time/attributes
 *
 *      fdintCOPY_FILE        // Now let's assume you want this file...
 *      // PFNWRITE called multiple times to write to this file.
 *      fdintNEXT_CABINET     // File was continued to next cabinet!
 *      fdintCABINET_INFO     // Info about the new cabinet
 *      // PFNWRITE called multiple times to write to this file.
 *      fdintCLOSE_FILE_INFO  // File done, set date/time/attributes
 *      ...
 *      fdintENUMERATE        // Ending enumeration
 *
 *  fdintCABINET_INFO:
 *        Called exactly once for each cabinet opened by FDICopy(), including
 *        continuation cabinets opened due to file(s) spanning cabinet
 *        boundaries. Primarily intended to permit EXTRACT.EXE to
 *        automatically select the next cabinet in a cabinet sequence even if
 *        not copying files that span cabinet boundaries.
 *      Entry:
 *          pfdin->psz1     = name of next cabinet
 *          pfdin->psz2     = name of next disk
 *          pfdin->psz3     = cabinet path name
 *          pfdin->setID    = cabinet set ID (a random 16-bit number)
 *          pfdin->iCabinet = Cabinet number within cabinet set (0-based)
 *      Exit-Success:
 *          Return anything but -1
 *      Exit-Failure:
 *          Returns -1 => Abort FDICopy() call
 *      Notes:
 *          This call is made *every* time a new cabinet is examined by
 *          FDICopy().  So if "foo2.cab" is examined because a file is
 *          continued from "foo1.cab", and then you call FDICopy() again
 *          on "foo2.cab", you will get *two* fdintCABINET_INFO calls all
 *          told.
 *
 *  fdintCOPY_FILE:
 *        Called for each file that *starts* in the current cabinet, giving
 *        the client the opportunity to request that the file be copied or
 *        skipped.
 *      Entry:
 *          pfdin->psz1    = file name in cabinet
 *          pfdin->cb      = uncompressed size of file
 *          pfdin->date    = file date
 *          pfdin->time    = file time
 *          pfdin->attribs = file attributes
 *          pfdin->iFolder = file's folder index
 *      Exit-Success:
 *          Return non-zero file handle for destination file; FDI writes
 *          data to this file use the PFNWRITE function supplied to FDICreate,
 *          and then calls fdintCLOSE_FILE_INFO to close the file and set
 *          the date, time, and attributes.  NOTE: This file handle returned
 *          must also be closeable by the PFNCLOSE function supplied to
 *          FDICreate, since if an error occurs while writing to this handle,
 *          FDI will use the PFNCLOSE function to close the file so that the