/************************** Module Header ***********************************
 * fileio.h
 *      Function Prototypes for File I/O in Kernel mode.
 *
 * NOTE:  these functions perform File read, seek operations.
 *
 * Copyright (C) 1991 - 1995  Microsoft Corporation
 *
 ****************************************************************************/

#define         CURRENTFILEPTR(pFile)  (LPVOID)((LPBYTE)(pFile->pvFilePointer)\
                                                + pFile->dwCurrentByteOffset)

#define         ENDOFFILEPTR(pFile)       ( pFile->pvFilePointer + \
                                            pFile->dwTotalSize )

#define         STARTFILEPTR(pFile)     ( pFile->pvFilePointer )

#define         STARTFILEOFFSETPTR(pFile,offset) ( pFile->pvFilePointer + \
                                                    offset )

#define         NUMBYTESREMAINING(pFile) ( pFile->dwTotalSize - \
                                             pFile->dwCurrentByteOffset )

#define         UPDATECURROFFSET(pFile,offset) (pFile->dwCurrentByteOffset +=\
                                                offset )

#define         DRV_FILE_BEGIN       0

#define         DRV_FILE_CURRENT     1

#define         INVALID_HANDLE_VALUE (HANDLE)-1

typedef struct _FILE
{
    HANDLE   hHandle;  /* Handle to the file, returned by EngLoadModule */
    DWORD    dwTotalSize;  /* Total Size of the file, as returned by
                            * EngMapModule.
                            */
    DWORD    dwCurrentByteOffset; /* Current Byte Offset in the file.
                                   * Updated after each read and DrvSetFile-
                                   * Pointer.
                                   */
    PVOID    pvFilePointer;       /* Start of the file pointer, as returned
                                   * EngMapModule
                                   */
    struct _FILE *pNext;           /* Next File Pointer.*/

}FILE, * PFILE;


HANDLE
DrvOpenFile
( 
    PWSTR pwstrFileName,          /* File to Open */
    PDEV   *pPDEV                /* Pointer to PDEV */
);

BOOL
DrvReadFile
(
    HANDLE   hFile,             /* Handle to the file */
    LPVOID   lpBuffer,          /* Buffer to Fill */
    DWORD    nNumBytesToRead,   /* Number of Bytes to Read */
    LPDWORD  lpNumBytesRead,    /* Number of Bytes Read */
    PDEV     *pPDev             /* Pointer to PDEV */
);

DWORD
DrvSetFilePointer
(
    HANDLE   hFile,
    LONG     iDistanceToMove,
    DWORD    dwMoveMethod,
    PDEV     *pPDev
);


BOOL
DrvCloseFile
(
    HANDLE   hFile,          /* Handle to the file */
    PDEV    *pPDEV           /* Pointer to PDEV for file List */
);