/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at the  *
 * root level of an installed copy of the electronic HDF5 document set and   *
 * is linked from the top-level documents page.  It can also be found at     *
 * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
 * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  Robb Matzke <matzke@llnl.gov>
 *              Thursday, July 29, 1999
 *
 * Purpose:  The POSIX unbuffered file driver using only the HDF5 public
 *    API and with a few optimizations: the lseek() call is made
 *    only when the current file position is unknown or needs to be
 *    changed based on previous I/O through this driver (don't mix
 *    I/O from this driver with I/O from other parts of the
 *    application to the same file).
 */

/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC  H5FD_sec2_init_interface


#include "H5private.h"    /* Generic Functions      */
#include "H5Eprivate.h"    /* Error handling        */
#include "H5Fprivate.h"    /* File access        */
#include "H5FDprivate.h"  /* File drivers        */
#include "H5FDsec2.h"    /* Sec2 file driver      */
#include "H5FLprivate.h"  /* Free Lists                           */
#include "H5Iprivate.h"    /* IDs            */
#include "H5MMprivate.h"  /* Memory management      */
#include "H5Pprivate.h"    /* Property lists      */

/* The driver identification number, initialized at runtime */
static hid_t H5FD_SEC2_g = 0;

/* File operations */
#define OP_UNKNOWN  0
#define OP_READ    1
#define OP_WRITE  2

/*
 * The description of a file belonging to this driver. The `eoa' and `eof'
 * determine the amount of hdf5 address space in use and the high-water mark
 * of the file (the current size of the underlying Unix file). The `pos'
 * value is used to eliminate file position updates when they would be a
 * no-op. Unfortunately we've found systems that use separate file position
 * indicators for reading and writing so the lseek can only be eliminated if
 * the current operation is the same as the previous operation.  When opening
 * a file the `eof' will be set to the current file size, `eoa' will be set
 * to zero, `pos' will be set to H5F_ADDR_UNDEF (as it is when an error
 * occurs), and `op' will be set to H5F_OP_UNKNOWN.
 */
typedef struct H5FD_sec2_t {
    H5FD_t  pub;      /*public stuff, must be first  */
    int    fd;      /*the unix file      */
    haddr_t  eoa;      /*end of allocated region  */
    haddr_t  eof;      /*end of file; current file size*/
    haddr_t  pos;      /*current file I/O position  */
    int    op;      /*last operation    */
#ifndef WIN32
    /*
     * On most systems the combination of device and i-node number uniquely
     * identify a file.
     */
    dev_t  device;      /*file device number    */
    ino_t  inode;      /*file i-node number    */
#else
    /*
     * On WIN32 the low-order word of a unique identifier associated with the
     * file and the volume serial number uniquely identify a file. This number
     * (which, both? -rpm) may change when the system is restarted or when the
     * file is opened. After a process opens a file, the identifier is
     * constant until the file is closed. An application can use this
     * identifier and the volume serial number to determine whether two
     * handles refer to the same file.
     */
    DWORD fileindexlo;
    DWORD fileindexhi;
#endif
} H5FD_sec2_t;


/*
 * This driver supports systems that have the lseek64() function by defining
 * some macros here so we don't have to have conditional compilations later
 * throughout the code.
 *
 * file_offset_t:  The datatype for file offsets, the second argument of
 *      the lseek() or lseek64() call.
 *
 * file_seek:    The function which adjusts the current file position,
 *      either lseek() or lseek64().
 */
/* adding for windows NT file system support. */

#ifdef H5_HAVE_LSEEK64
#   define file_offset_t  off64_t
#   define file_seek    lseek64
#   define file_truncate  ftruncate64
#elif defined (WIN32) && !defined(__MWERKS__)
# /*MSVC*/
#   define file_offset_t __int64
#   define file_seek _lseeki64
#   define file_truncate  _chsize
#else
#   define file_offset_t  off_t
#   define file_seek    lseek
#   define file_truncate  HDftruncate
#endif

/*
 * These macros check for overflow of various quantities.  These macros
 * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
 *
 * ADDR_OVERFLOW:  Checks whether a file address of type `haddr_t'
 *      is too large to be represented by the second argument
 *      of the file seek function.
 *
 * SIZE_OVERFLOW:  Checks whether a buffer size of type `hsize_t' is too
 *      large to be represented by the `size_t' type.
 *
 * REGION_OVERFLOW:  Checks whether an address and size pair describe data
 *      which can be addressed entirely by the second
 *      argument of the file seek function.
 */
#define MAXADDR (((haddr_t)1<<(8*sizeof(file_offset_t)-1))-1)
#define ADDR_OVERFLOW(A)  (HADDR_UNDEF==(A) ||            \
         ((A) & ~(haddr_t)MAXADDR))
#define SIZE_OVERFLOW(Z)  ((Z) & ~(hsize_t)MAXADDR)
#define REGION_OVERFLOW(A,Z)  (ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) ||      \
                                 HADDR_UNDEF==(A)+(Z) ||          \
         (file_offset_t)((A)+(Z))<(file_offset_t)(A))

/* Prototypes */
static H5FD_t *H5FD_sec2_open(const char *name, unsigned flags, hid_t fapl_id,
            haddr_t maxaddr);
static herr_t H5FD_sec2_close(H5FD_t *_file);
static int H5FD_sec2_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static herr_t H5FD_sec2_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t H5FD_sec2_get_eoa(H5FD_t *_file);
static herr_t H5FD_sec2_set_eoa(H5FD_t *_file, haddr_t addr);
static haddr_t H5FD_sec2_get_eof(H5FD_t *_file);
static herr_t  H5FD_sec2_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle);
static herr_t H5FD_sec2_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
           size_t size, void *buf);
static herr_t H5FD_sec2_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
            size_t size, const void *buf);
static herr_t H5FD_sec2_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing);

static const H5FD_class_t H5FD_sec2_g = {
    "sec2",          /*name      */
    MAXADDR,          /*maxaddr    */
    H5F_CLOSE_WEAK,        /* fc_degree    */
    NULL,          /*sb_size    */
    NULL,          /*sb_encode    */
    NULL,          /*sb_decode    */
    0,             /*fapl_size    */
    NULL,          /*fapl_get    */
    NULL,          /*fapl_copy    */
    NULL,           /*fapl_free    */
    0,            /*dxpl_size    */
    NULL,          /*dxpl_copy    */
    NULL,          /*dxpl_free    */
    H5FD_sec2_open,              /*open      */
    H5FD_sec2_close,                    /*close      */
    H5FD_sec2_cmp,              /*cmp      */
    H5FD_sec2_query,                    /*query      */
    NULL,          /*alloc      */
    NULL,          /*free      */
    H5FD_sec2_get_eoa,        /*get_eoa    */
    H5FD_sec2_set_eoa,         /*set_eoa    */
    H5FD_sec2_get_eof,        /*get_eof    */
    H5FD_sec2_get_handle,                       /*get_handle            */
    H5FD_sec2_read,        /*read      */
    H5FD_sec2_write,        /*write      */
    H5FD_sec2_flush,        /*flush      */
    NULL,                                       /*lock                  */
    NULL,                                       /*unlock                */
    H5FD_FLMAP_SINGLE         /*fl_map    */
};

/* Declare a free list to manage the H5FD_sec2_t struct */
H5FL_DEFINE_STATIC(H5FD_sec2_t);


/*--------------------------------------------------------------------------
NAME
   H5FD_sec2_init_interface -- Initialize interface-specific information
USAGE
    herr_t H5FD_sec2_init_interface()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.  (Just calls
    H5FD_sec2_init currently).

--------------------------------------------------------------------------*/
static herr_t
H5FD_sec2_init_interface(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5FD_sec2_init_interface)

    FUNC_LEAVE_NOAPI(H5FD_sec2_init())
} /* H5FD_sec2_init_interface() */


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_init
 *
 * Purpose:  Initialize this driver by registering the driver with the
 *    library.
 *
 * Return:  Success:  The driver ID for the sec2 driver.
 *
 *    Failure:  Negative.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_sec2_init(void)
{
    hid_t ret_value;        /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_init, FAIL)

    if (H5I_VFL!=H5I_get_type(H5FD_SEC2_g))
        H5FD_SEC2_g = H5FD_register(&H5FD_sec2_g,sizeof(H5FD_class_t));

    /* Set return value */
    ret_value=H5FD_SEC2_g;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*---------------------------------------------------------------------------
 * Function:  H5FD_sec2_term
 *
 * Purpose:  Shut down the VFD
 *
 * Return:  <none>
 *
 * Programmer:  Quincey Koziol
 *              Friday, Jan 30, 2004
 *
 * Modification:
 *
 *---------------------------------------------------------------------------
 */
void
H5FD_sec2_term(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5FD_sec2_term)

    /* Reset VFL ID */
    H5FD_SEC2_g=0;

    FUNC_LEAVE_NOAPI_VOID
} /* end H5FD_sec2_term() */


/*-------------------------------------------------------------------------
 * Function:  H5Pset_fapl_sec2
 *
 * Purpose:  Modify the file access property list to use the H5FD_SEC2
 *    driver defined in this source file.  There are no driver
 *    specific properties.
 *
 * Return:  Non-negative on success/Negative on failure
 *
 * Programmer:  Robb Matzke
 *    Thursday, February 19, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_fapl_sec2(hid_t fapl_id)
{
    H5P_genplist_t *plist;      /* Property list pointer */
    herr_t ret_value;

    FUNC_ENTER_API(H5Pset_fapl_sec2, FAIL)
    H5TRACE1("e","i",fapl_id);

    if(NULL == (plist = H5P_object_verify(fapl_id,H5P_FILE_ACCESS)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")

    ret_value= H5P_set_driver(plist, H5FD_SEC2, NULL);

done:
    FUNC_LEAVE_API(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_open
 *
 * Purpose:  Create and/or opens a Unix file as an HDF5 file.
 *
 * Return:  Success:  A pointer to a new file data structure. The
 *        public fields will be initialized by the
 *        caller, which is always H5FD_open().
 *
 *    Failure:  NULL
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static H5FD_t *
H5FD_sec2_open(const char *name, unsigned flags, hid_t UNUSED fapl_id,
         haddr_t maxaddr)
{
    int  o_flags;
    int    fd=(-1);
    H5FD_sec2_t  *file=NULL;
#ifdef WIN32
    HFILE filehandle;
    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
#endif
    h5_stat_t  sb;
    H5FD_t  *ret_value;

    FUNC_ENTER_NOAPI(H5FD_sec2_open, NULL)

    /* Sanity check on file offsets */
    assert(sizeof(file_offset_t)>=sizeof(size_t));

    /* Check arguments */
    if (!name || !*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name")
    if (0==maxaddr || HADDR_UNDEF==maxaddr)
        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr")
    if (ADDR_OVERFLOW(maxaddr))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, NULL, "bogus maxaddr")

    /* Build the open flags */
    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
    if (H5F_ACC_TRUNC & flags) o_flags |= O_TRUNC;
    if (H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
    if (H5F_ACC_EXCL & flags) o_flags |= O_EXCL;

    /* Open the file */
    if ((fd=HDopen(name, o_flags, 0666))<0)
        HSYS_GOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
    if (HDfstat(fd, &sb)<0)
        HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")

    /* Create the new file struct */
    if (NULL==(file=H5FL_CALLOC(H5FD_sec2_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate file struct")

    file->fd = fd;
    H5_ASSIGN_OVERFLOW(file->eof,sb.st_size,h5_stat_size_t,haddr_t);
    file->pos = HADDR_UNDEF;
    file->op = OP_UNKNOWN;
#ifdef WIN32
    filehandle = _get_osfhandle(fd);
    (void)GetFileInformationByHandle((HANDLE)filehandle, &fileinfo);
    file->fileindexhi = fileinfo.nFileIndexHigh;
    file->fileindexlo = fileinfo.nFileIndexLow;
#else
    file->device = sb.st_dev;
    file->inode = sb.st_ino;
#endif

    /* Set return value */
    ret_value=(H5FD_t*)file;

done:
    if(ret_value==NULL) {
        if(fd>=0)
            HDclose(fd);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_close
 *
 * Purpose:  Closes a Unix file.
 *
 * Return:  Success:  0
 *
 *    Failure:  -1, file not closed.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_close(H5FD_t *_file)
{
    H5FD_sec2_t  *file = (H5FD_sec2_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_close, FAIL)

    if (HDclose(file->fd)<0)
        HSYS_GOTO_ERROR(H5E_IO, H5E_CANTCLOSEFILE, FAIL, "unable to close file")

    H5FL_FREE(H5FD_sec2_t,file);

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_cmp
 *
 * Purpose:  Compares two files belonging to this driver using an
 *    arbitrary (but consistent) ordering.
 *
 * Return:  Success:  A value like strcmp()
 *
 *    Failure:  never fails (arguments were checked by the
 *        caller).
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static int
H5FD_sec2_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
{
    const H5FD_sec2_t  *f1 = (const H5FD_sec2_t*)_f1;
    const H5FD_sec2_t  *f2 = (const H5FD_sec2_t*)_f2;
    int ret_value=0;

    FUNC_ENTER_NOAPI(H5FD_sec2_cmp, H5FD_VFD_DEFAULT)

#ifdef WIN32
    if (f1->fileindexhi < f2->fileindexhi) HGOTO_DONE(-1)
    if (f1->fileindexhi > f2->fileindexhi) HGOTO_DONE(1)

    if (f1->fileindexlo < f2->fileindexlo) HGOTO_DONE(-1)
    if (f1->fileindexlo > f2->fileindexlo) HGOTO_DONE(1)

#else
#ifdef H5_DEV_T_IS_SCALAR
    if (f1->device < f2->device) HGOTO_DONE(-1)
    if (f1->device > f2->device) HGOTO_DONE(1)
#else /* H5_DEV_T_IS_SCALAR */
    /* If dev_t isn't a scalar value on this system, just use memcmp to
     * determine if the values are the same or not.  The actual return value
     * shouldn't really matter...
     */
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) HGOTO_DONE(-1)
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) HGOTO_DONE(1)
#endif /* H5_DEV_T_IS_SCALAR */

    if (f1->inode < f2->inode) HGOTO_DONE(-1)
    if (f1->inode > f2->inode) HGOTO_DONE(1)
#endif

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_query
 *
 * Purpose:  Set the flags that this VFL driver is capable of supporting.
 *              (listed in H5FDpublic.h)
 *
 * Return:  Success:  non-negative
 *
 *    Failure:  negative
 *
 * Programmer:  Quincey Koziol
 *              Friday, August 25, 2000
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_sec2_query(const H5FD_t UNUSED * _f, unsigned long *flags /* out */)
{
    herr_t ret_value=SUCCEED;

    FUNC_ENTER_NOAPI(H5FD_sec2_query, FAIL)

    /* Set the VFL feature flags that this driver supports */
    if(flags) {
        *flags = 0;
        *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
        *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
        *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_get_eoa
 *
 * Purpose:  Gets the end-of-address marker for the file. The EOA marker
 *    is the first address past the last byte allocated in the
 *    format address space.
 *
 * Return:  Success:  The end-of-address marker.
 *
 *    Failure:  HADDR_UNDEF
 *
 * Programmer:  Robb Matzke
 *              Monday, August  2, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_sec2_get_eoa(H5FD_t *_file)
{
    H5FD_sec2_t  *file = (H5FD_sec2_t*)_file;
    haddr_t ret_value;  /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_get_eoa, HADDR_UNDEF)

    /* Set return value */
    ret_value=file->eoa;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_set_eoa
 *
 * Purpose:  Set the end-of-address marker for the file. This function is
 *    called shortly after an existing HDF5 file is opened in order
 *    to tell the driver where the end of the HDF5 data is located.
 *
 * Return:  Success:  0
 *
 *    Failure:  -1
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_set_eoa(H5FD_t *_file, haddr_t addr)
{
    H5FD_sec2_t  *file = (H5FD_sec2_t*)_file;
    herr_t ret_value=SUCCEED;   /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_set_eoa, FAIL)

    file->eoa = addr;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_get_eof
 *
 * Purpose:  Returns the end-of-file marker, which is the greater of
 *    either the Unix end-of-file or the HDF5 end-of-address
 *    markers.
 *
 * Return:  Success:  End of file address, the first address past
 *        the end of the "file", either the Unix file
 *        or the HDF5 file.
 *
 *    Failure:  HADDR_UNDEF
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_sec2_get_eof(H5FD_t *_file)
{
    H5FD_sec2_t  *file = (H5FD_sec2_t*)_file;
    haddr_t ret_value;  /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_get_eof, HADDR_UNDEF)

    /* Set return value */
    ret_value=MAX(file->eof, file->eoa);

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:       H5FD_sec2_get_handle
 *
 * Purpose:        Returns the file handle of sec2 file driver.
 *
 * Returns:        Non-negative if succeed or negative if fails.
 *
 * Programmer:     Raymond Lu
 *                 Sept. 16, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_sec2_get_handle(H5FD_t *_file, hid_t UNUSED fapl, void** file_handle)
{
    H5FD_sec2_t         *file = (H5FD_sec2_t *)_file;
    herr_t              ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(H5FD_sec2_get_handle, FAIL)

    if(!file_handle)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "file handle not valid")
    *file_handle = &(file->fd);

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_read
 *
 * Purpose:  Reads SIZE bytes of data from FILE beginning at address ADDR
 *    into buffer BUF according to data transfer properties in
 *    DXPL_ID.
 *
 * Return:  Success:  Zero. Result is stored in caller-supplied
 *        buffer BUF.
 *
 *    Failure:  -1, Contents of buffer BUF are undefined.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_sec2_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
         size_t size, void *buf/*out*/)
{
    H5FD_sec2_t    *file = (H5FD_sec2_t*)_file;
    ssize_t    nbytes;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_read, FAIL)

    assert(file && file->pub.cls);
    assert(buf);

    /* Check for overflow conditions */
    if (HADDR_UNDEF==addr)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined")
    if (REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
    if (addr+size>file->eoa)
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")

    /* Seek to the correct location */
    if ((addr!=file->pos || OP_READ!=file->op) &&
            file_seek(file->fd, (file_offset_t)addr, SEEK_SET)<0)
        HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")

    /*
     * Read data, being careful of interrupted system calls, partial results,
     * and the end of the file.
     */
    while (size>0) {
        do {
            nbytes = HDread(file->fd, buf, size);
        } while (-1==nbytes && EINTR==errno);
        if (-1==nbytes) /* error */
            HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed")
        if (0==nbytes) {
            /* end of file but not end of format address space */
            HDmemset(buf, 0, size);
            break;
        }
        assert(nbytes>=0);
        assert((size_t)nbytes<=size);
        H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t);
        size -= (size_t)nbytes;
        H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t);
        addr += (haddr_t)nbytes;
        buf = (char*)buf + nbytes;
    }

    /* Update current position */
    file->pos = addr;
    file->op = OP_READ;

done:
    if(ret_value<0) {
        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_write
 *
 * Purpose:  Writes SIZE bytes of data to FILE beginning at address ADDR
 *    from buffer BUF according to data transfer properties in
 *    DXPL_ID.
 *
 * Return:  Success:  Zero
 *
 *    Failure:  -1
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_sec2_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, haddr_t addr,
    size_t size, const void *buf)
{
    H5FD_sec2_t    *file = (H5FD_sec2_t*)_file;
    ssize_t    nbytes;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_write, FAIL)

    assert(file && file->pub.cls);
    assert(buf);

    /* Check for overflow conditions */
    if (HADDR_UNDEF==addr)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined")
    if (REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")
    if (addr+size>file->eoa)
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow")

    /* Seek to the correct location */
    if ((addr!=file->pos || OP_WRITE!=file->op) &&
            file_seek(file->fd, (file_offset_t)addr, SEEK_SET)<0)
        HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")

    /*
     * Write the data, being careful of interrupted system calls and partial
     * results
     */
    while (size>0) {
        do {
            nbytes = HDwrite(file->fd, buf, size);
        } while (-1==nbytes && EINTR==errno);
        if (-1==nbytes) /* error */
            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed")
        assert(nbytes>0);
        assert((size_t)nbytes<=size);
        H5_CHECK_OVERFLOW(nbytes,ssize_t,size_t);
        size -= (size_t)nbytes;
        H5_CHECK_OVERFLOW(nbytes,ssize_t,haddr_t);
        addr += (haddr_t)nbytes;
        buf = (const char*)buf + nbytes;
    }

    /* Update current position and eof */
    file->pos = addr;
    file->op = OP_WRITE;
    if (file->pos>file->eof)
        file->eof = file->pos;

done:
    if(ret_value<0) {
        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:  H5FD_sec2_flush
 *
 * Purpose:  Makes sure that the true file size is the same (or larger)
 *    than the end-of-address.
 *
 * Return:  Success:  Non-negative
 *
 *    Failure:  Negative
 *
 * Programmer:  Robb Matzke
 *              Wednesday, August  4, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
/* ARGSUSED */
static herr_t
H5FD_sec2_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing)
{
    H5FD_sec2_t  *file = (H5FD_sec2_t*)_file;
    herr_t      ret_value=SUCCEED;       /* Return value */

    FUNC_ENTER_NOAPI(H5FD_sec2_flush, FAIL)

    assert(file);

    /* Extend the file to make sure it's large enough */
    if (file->eoa!=file->eof) {
#ifdef WIN32
        HFILE filehandle;   /* Windows file handle */
        LARGE_INTEGER li;   /* 64-bit integer for SetFilePointer() call */

        /* Map the posix file handle to a Windows file handle */
        filehandle = _get_osfhandle(file->fd);

        /* Translate 64-bit integers into form Windows wants */
        /* [This algorithm is from the Windows documentation for SetFilePointer()] */
        li.QuadPart = (LONGLONG)file->eoa;
        (void)SetFilePointer((HANDLE)filehandle,li.LowPart,&li.HighPart,FILE_BEGIN);
        if(SetEndOfFile((HANDLE)filehandle)==0)
            HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#else /* WIN32 */
        if (-1==file_truncate(file->fd, (file_offset_t)file->eoa))
            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#endif /* WIN32 */

        /* Update the eof value */
        file->eof = file->eoa;

        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
}
