path: root/src/H5F.c

/****************************************************************************
* NCSA HDF								   *
* Software Development Group						   *
* National Center for Supercomputing Applications			   *
* University of Illinois at Urbana-Champaign				   *
* 605 E. Springfield, Champaign IL 61820				   *
*									   *
* For conditions of distribution and use, see the accompanying		   *
* hdf/COPYING file.							   *
*
* MODIFICATIONS
*	Robb Matzke, 30 Aug 1997
*	Added `ERRORS' fields to function prologues.
*
****************************************************************************/

#ifdef RCSID
static char		RcsId[] = "@(#)$Revision$";
#endif

/* $Id$ */

/* Predefined file drivers */
#include <H5FDcore.h>		/*temporary in-memory files		  */
#include <H5FDfamily.h>		/*family of files			  */
#include <H5FDmpio.h>		/*MPI-2 I/O				  */
#include <H5FDgass.h>           /*GASS I/O                                */
#include <H5FDdpss.h>           /*Grid Storage I/O                        */
#include <H5FDsrb.h>            /*SRB I/O                                 */
#include <H5FDmulti.h>		/*multiple files partitioned by mem usage */
#include <H5FDsec2.h>		/*Posix unbuffered I/O			  */
#include <H5FDstdio.h>		/* Standard C buffered I/O		  */
#include <H5FDlog.h>        /* sec2 driver with logging, for debugging */

/* Packages needed by this file... */
#include <H5private.h>		/*library functions			  */
#include <H5Aprivate.h>		/*attributes				  */
#include <H5Dprivate.h>		/*datasets				  */
#include <H5FLprivate.h>	/*Free Lists	  */
#include <H5Iprivate.h>		/*object IDs				  */
#include <H5ACprivate.h>	/*cache					  */
#include <H5Eprivate.h>		/*error handling			  */
#include <H5Fprivate.h>         /*file access                             */
#include <H5FDprivate.h>	/*file driver				  */
#include <H5Gprivate.h>		/*symbol tables				  */
#include <H5MMprivate.h>	/*core memory management		  */
#include <H5Pprivate.h>		/*property lists			  */
#include <H5Tprivate.h>		/*data types				  */

#define PABLO_MASK	H5F_mask

/*
 * Define the default file creation property list.
 */
const H5F_create_t	H5F_create_dflt = {
    0,				/* Default user-block size */
    4,				/* Default 1/2 rank for symtab leaf nodes */
    {				/* Default 1/2 rank for btree intern nodes */
	16,			/* Symbol table internal nodes		   */
	32,			/* Indexed storage internal nodes	   */
	0,			/* unused				   */
	0,			/* unused				   */
	0,			/* unused				   */
	0,			/* unused				   */
	0,			/* unused				   */
	0,			/* unused				   */
    },
    sizeof(haddr_t),		/* Default offset size 			   */
    sizeof(hsize_t),		/* Default length size 			   */
    HDF5_BOOTBLOCK_VERSION,	/* Current Boot-Block version #		   */
    HDF5_FREESPACE_VERSION,	/* Current Free-Space info version #	   */
    HDF5_OBJECTDIR_VERSION,	/* Current Object Directory info version # */
    HDF5_SHAREDHEADER_VERSION,	/* Current Shared-Header format version #  */
};

/*
 * Define the default file access property list.  The template is initialized
 * by H5F_init_interface().
 */
H5F_access_t H5F_access_dflt;

/* Default data transfer property list */
/* Not const anymore before some of the VFL drivers modify this struct - QAK */
H5F_xfer_t	H5F_xfer_dflt = {
    1024*1024,			/*Temporary buffer size			    */
    NULL,			/*Type conversion buffer or NULL	    */
    NULL, 			/*Background buffer or NULL		    */
    H5T_BKG_NO,			/*Type of background buffer needed	    */
    {0.1, 0.5, 0.9},		/*B-tree node splitting ratios		    */
#ifndef H5_HAVE_PARALLEL
    1,				/*Cache the hyperslab blocks		    */
#else
    0,				/*Don't cache the hyperslab blocks	    */
#endif /* H5_HAVE_PARALLEL */
    0,              		/*No limit on hyperslab block size to cache */
    NULL,                   	/*Use malloc() for VL data allocations	    */
    NULL,                   	/*No information needed for malloc() calls  */
    NULL,                   	/*Use free() for VL data frees		    */
    NULL,                   	/*No information needed for free() calls    */
    -2,				/*See H5Pget_driver()			    */
    NULL,			/*No file driver-specific information yet   */
#ifdef COALESCE_READS
    0,                          /*coalesce single reads into a read         */
                                /*transaction                               */
#endif
};

/*
 * Define the default mount property list.
 */
const H5F_mprop_t	H5F_mount_dflt = {
    FALSE,			/* Absolute symlinks are wrt mount root	   */
};

/* Interface initialization */
static intn interface_initialize_g = 0;
#define INTERFACE_INIT H5F_init_interface
static herr_t H5F_init_interface(void);

/* PRIVATE PROTOTYPES */
static H5F_t *H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id);
static herr_t H5F_dest(H5F_t *f);
static herr_t H5F_flush(H5F_t *f, H5F_scope_t scope, hbool_t invalidate,
			hbool_t alloc_only);
static haddr_t H5F_locate_signature(H5FD_t *file);
static intn H5F_flush_all_cb(H5F_t *f, const void *_invalidate);

/* Declare a free list to manage the H5F_t struct */
H5FL_DEFINE_STATIC(H5F_t);

/* Declare a free list to manage the H5F_file_t struct */
H5FL_DEFINE_STATIC(H5F_file_t);

/* Declare the external free list for the H5G_t struct */
H5FL_EXTERN(H5G_t);


/*-------------------------------------------------------------------------
 * Function:	H5F_init
 *
 * Purpose:	Initialize the interface from some other layer.
 *
 * Return:	Success:	non-negative
 *
 *		Failure:	negative
 *
 * Programmer:	Robb Matzke
 *              Wednesday, December 16, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_init(void)
{
    FUNC_ENTER(H5F_init, FAIL);
    /* FUNC_ENTER() does all the work */
    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_init_interface
 *
 * Purpose:	Initialize interface-specific information.
 *
 * Return:	Success:	non-negative
 *
 *		Failure:	negative
 *
 * Programmer:	Robb Matzke
 *              Friday, November 20, 1998
 *
 * Modifications:
 * 	Robb Matzke, 4 Aug 1997
 *	Changed pablo mask from H5_mask to H5F_mask for the FUNC_LEAVE call.
 *	It was already H5F_mask for the PABLO_TRACE_ON call.
 *
 *  	Kim Yates, 1998-08-16
 *	Added .disp, .btype, .ftype to H5F_access_t.
 *
 * 	Robb Matzke, 1999-02-19
 *	Added initialization for the H5I_FILE_CLOSING ID group.
 *
 *      Raymond Lu, April 10, 2000
 *      Put SRB into the 'Register predefined file drivers' list.
 *-------------------------------------------------------------------------
 */
static herr_t 
H5F_init_interface(void)
{
    herr_t	ret_value = SUCCEED;
    herr_t	status;
    
    FUNC_ENTER(H5F_init_interface, FAIL);

#ifdef H5_HAVE_PARALLEL
    {
        /* Allow MPI buf-and-file-type optimizations? */
        const char *s = HDgetenv ("HDF5_MPI_1_METAWRITE");
        if (s && HDisdigit(*s)) {
            H5_mpi_1_metawrite_g = (int)HDstrtol (s, NULL, 0);
        }
    }
#endif

    /*
     * Initialize the atom group for the file IDs. There are two groups:
     * the H5I_FILE group contains all the ID's for files which are currently
     * open at the public API level while the H5I_FILE_CLOSING group contains
     * ID's for files for which the application has called H5Fclose() but
     * which are pending completion because there are object headers still
     * open within the file.
     */
    if (H5I_init_group(H5I_FILE, H5I_FILEID_HASHSIZE, 0, (H5I_free_t)H5F_close)<0 ||
        H5I_init_group(H5I_FILE_CLOSING, H5I_FILEID_HASHSIZE, 0, (H5I_free_t)H5F_close)<0) {
            HRETURN_ERROR (H5E_FILE, H5E_CANTINIT, FAIL,
		       "unable to initialize interface");
    }

/* Register the default file creation & access properties */

    /* Register predefined file drivers */
    H5E_BEGIN_TRY {
	if ((status=H5FD_SEC2)<0) goto end_registration;
	if ((status=H5FD_STDIO)<0) goto end_registration;
	if ((status=H5FD_FAMILY)<0) goto end_registration;
#ifdef H5_HAVE_GASS
	if ((status=H5FD_GASS)<0) goto end_registration;
#endif
#ifdef H5_HAVE_GRIDSTORAGE
	if ((status=H5FD_DPSS)<0) goto end_registration;
#endif
#ifdef H5_HAVE_SRB
	if ((status=H5FD_SRB)<0) goto end_registration;
#endif
	if ((status=H5FD_CORE)<0) goto end_registration;
	if ((status=H5FD_MULTI)<0) goto end_registration;
#ifdef H5_HAVE_PARALLEL
	if ((status=H5FD_MPIO)<0) goto end_registration;
#endif
    end_registration: ;
	} H5E_END_TRY;

    if (status<0) {
	HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL,
		      "file driver registration failed");
    }
    
    /* Initialize the default file access property list */
    H5F_access_dflt.mdc_nelmts = H5AC_NSLOTS;
    H5F_access_dflt.rdcc_nelmts = 521;
    H5F_access_dflt.rdcc_nbytes = 1024*1024; /*1MB*/
    H5F_access_dflt.rdcc_w0 = 0.75; /*preempt fully read chunks*/
    H5F_access_dflt.threshold = 1; /*alignment applies to everything*/
    H5F_access_dflt.alignment = 1; /*no alignment*/
    H5F_access_dflt.gc_ref = 0; /*don't garbage-collect references*/
    H5F_access_dflt.meta_block_size = 2048; /* set metadata block allocations to 2KB */
    H5F_access_dflt.driver_id = H5FD_SEC2; /*default driver*/
    H5F_access_dflt.driver_info = NULL; /*driver file access properties*/

    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_term_interface
 *
 * Purpose:	Terminate this interface: free all memory and reset global
 *		variables to their initial values.  Release all ID groups
 *		associated with this interface.
 *
 * Return:	Success:	Positive if anything was done that might
 *				have affected other interfaces; zero
 *				otherwise.
 *
 *		Failure:        Never fails.
 *
 * Programmer:	Robb Matzke
 *              Friday, February 19, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
intn
H5F_term_interface(void)
{
    intn	n = 0;

    if (interface_initialize_g) {
	if ((n=H5I_nmembers(H5I_FILE))) {
	    H5F_close_all();
	} else if (0==(n=H5I_nmembers(H5I_FILE_CLOSING))) {
	    H5I_destroy_group(H5I_FILE);
	    H5I_destroy_group(H5I_FILE_CLOSING);
	    interface_initialize_g = 0;
	    n = 1; /*H5I*/
	}
    }
    return n;
}


/*-------------------------------------------------------------------------
 * Function:	H5F_flush_all_cb
 *
 * Purpose:	Callback function for H5F_flush_all().
 *
 * Return:	Always returns zero.
 *
 * Programmer:	Robb Matzke
 *              Friday, February 19, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static intn
H5F_flush_all_cb(H5F_t *f, const void *_invalidate)
{
    hbool_t	invalidate = *((const hbool_t*)_invalidate);
    H5F_flush(f, H5F_SCOPE_LOCAL, invalidate, FALSE);
    return 0;
}


/*-------------------------------------------------------------------------
 * Function:	H5F_flush_all
 *
 * Purpose:	Flush all open files. If INVALIDATE is true then also remove
 *		everything from the cache.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Thursday, February 18, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_flush_all(hbool_t invalidate)
{
    FUNC_ENTER(H5F_flush_all, FAIL);
    H5I_search(H5I_FILE, (H5I_search_func_t)H5F_flush_all_cb,
	       (void*)&invalidate);
    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_close_all
 *
 * Purpose:	Close all open files. Any file which has open object headers
 *		will be moved from the H5I_FILE group to the H5I_FILE_CLOSING
 *		group.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Friday, February 19, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_close_all(void)
{
    FUNC_ENTER(H5F_close_all, FAIL);
    if (H5I_clear_group(H5I_FILE, FALSE)<0) {
	HRETURN_ERROR(H5E_FILE, H5E_CLOSEERROR, FAIL,
		      "unable to close one or more files");
    }
    FUNC_LEAVE(SUCCEED);
}


/*--------------------------------------------------------------------------
 NAME
       H5F_encode_length_unusual -- encode an unusual length size
 USAGE
       void H5F_encode_length_unusual(f, p, l)
       const H5F_t *f;		   IN: pointer to the file record
       uint8_t **p;		IN: pointer to buffer pointer to encode length in
       uint8_t *l;		IN: pointer to length to encode

 ERRORS

 RETURNS
    none
 DESCRIPTION
    Encode non-standard (i.e. not 2, 4 or 8-byte) lengths in file meta-data.
--------------------------------------------------------------------------*/
void 
H5F_encode_length_unusual(const H5F_t *f, uint8_t **p, uint8_t *l)
{
    intn		    i = (intn)H5F_SIZEOF_SIZE(f)-1;

#ifdef WORDS_BIGENDIAN
    /*
     * For non-little-endian platforms, encode each byte in memory backwards.
     */
    for (/*void*/; i>=0; i--, (*p)++)*(*p) = *(l+i);
#else
    /* platform has little-endian integers */
    HDmemcpy(*p,l,(size_t)(i+1));
    *p+=(i+1);
#endif

}


/*-------------------------------------------------------------------------
 * Function:	H5Fget_create_plist
 *
 * Purpose:	Get an atom for a copy of the file-creation property list for
 *		this file. This function returns an atom with a copy of the
 *		properties used to create a file.
 *
 * Return:	Success:	template ID
 *
 *		Failure:	FAIL
 *
 * Programmer:	Unknown
 *
 * Modifications:
 *
 * 	Robb Matzke, 18 Feb 1998
 *	Calls H5P_copy() to copy the property list and H5P_close() to free
 *	that property list if an error occurs.
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Fget_create_plist(hid_t file_id)
{
    H5F_t		*file = NULL;
    hid_t		ret_value = FAIL;
    H5P_t	    *plist = NULL;

    FUNC_ENTER(H5Fget_create_plist, FAIL);
    H5TRACE1("i","i",file_id);

    /* check args */
    if (H5I_FILE!=H5I_get_type(file_id) || NULL==(file=H5I_object(file_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file");
    }
    
    /* Create the property list object to return */
    if (NULL==(plist=H5P_copy(H5P_FILE_CREATE, file->shared->fcpl))) {
	HRETURN_ERROR(H5E_INTERNAL, H5E_CANTINIT, FAIL,
		      "unable to copy file creation properties");
    }

    /* Create an atom */
    if ((ret_value = H5P_create(H5P_FILE_CREATE, plist)) < 0) {
        H5P_close(plist);
        HRETURN_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL,
		      "unable to register property list");
    }
    
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fget_access_plist
 *
 * Purpose:	Returns a copy of the file access property list of the
 *		specified file.
 *
 * Return:	Success:	Object ID for a copy of the file access
 *				property list.
 *
 *		Failure:	FAIL
 *
 * Programmer:	Robb Matzke
 *              Wednesday, February 18, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Fget_access_plist(hid_t file_id)
{
    H5F_t		*f = NULL;
    H5F_access_t	_fapl;
    H5P_t	    *plist=NULL;
    hid_t		ret_value = FAIL;
    
    FUNC_ENTER(H5Fget_access_plist, FAIL);
    H5TRACE1("i","i",file_id);

    /* Check args */
    if (H5I_FILE!=H5I_get_type(file_id) || NULL==(f=H5I_object(file_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file");
    }

    /* Initialize the property list */
    HDmemset(&_fapl, 0, sizeof _fapl);
    _fapl.mdc_nelmts = f->shared->mdc_nelmts;
    _fapl.rdcc_nelmts = f->shared->rdcc_nelmts;
    _fapl.rdcc_nbytes = f->shared->rdcc_nbytes;
    _fapl.rdcc_w0 = f->shared->rdcc_w0;
    _fapl.threshold = f->shared->threshold;
    _fapl.alignment = f->shared->alignment;
    _fapl.gc_ref = f->shared->gc_ref;
    _fapl.meta_block_size = f->shared->lf->def_meta_block_size;
    _fapl.driver_id = f->shared->lf->driver_id;
    _fapl.driver_info = NULL; /*just for now */

    /* Copy properties */
    if (NULL==(plist=H5P_copy(H5P_FILE_ACCESS, &_fapl))) {
	HRETURN_ERROR(H5E_INTERNAL, H5E_CANTINIT, FAIL,
		      "unable to copy file access properties");
    }

    /* Get the properties for the file driver */
    plist->u.faccess.driver_info = H5FD_fapl_get(f->shared->lf);

    /* Create an atom */
    if ((ret_value = H5P_create(H5P_FILE_ACCESS, plist))<0) {
        H5P_close(plist);
        HRETURN_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL,
		      "unable to register property list");
    }

    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_equal
 *
 * Purpose:	Compares NEEDLE to a file from the HAYSTACK.
 *
 * Return:	Success:	Returns positive if two files are equal,
 *				zero otherwise.
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Monday, August  2, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static intn
H5F_equal(void *_haystack, const void *_needle)
{
    H5F_t		*haystack = (H5F_t*)_haystack;
    const H5FD_t	*needle = (const H5FD_t*)_needle;
    intn		retval;
    
    FUNC_ENTER(H5F_equal, FAIL);
    retval = (0==H5FD_cmp(haystack->shared->lf, needle));
    FUNC_LEAVE(retval);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_locate_signature
 *
 * Purpose:	Finds the HDF5 boot block signature in a file.	The signature
 *		can appear at address 0, or any power of two beginning with
 *		512.
 *
 * Return:	Success:	The absolute format address of the signature.
 *
 *		Failure:	HADDR_UNDEF
 *
 * Programmer:	Robb Matzke
 *		Friday, November  7, 1997
 *
 * Modifications:
 *		Robb Matzke, 1999-08-02
 *		Rewritten to use the virtual file layer.
 *-------------------------------------------------------------------------
 */
static haddr_t
H5F_locate_signature(H5FD_t *file)
{
    haddr_t	    addr, eoa;
    uint8_t	    buf[H5F_SIGNATURE_LEN];
    uintn	    n, maxpow;

    FUNC_ENTER(H5F_locate_signature, HADDR_UNDEF);

    /* Find the least N such that 2^N is larger than the file size */
    if (HADDR_UNDEF==(addr=H5FD_get_eof(file)) ||
	HADDR_UNDEF==(eoa=H5FD_get_eoa(file))) {
	HRETURN_ERROR(H5E_IO, H5E_CANTINIT, HADDR_UNDEF,
		      "unable to obtain EOF/EOA value");
    }
    for (maxpow=0; addr; maxpow++) addr>>=1;
    maxpow = MAX(maxpow, 9);

    /*
     * Search for the file signature at format address zero followed by
     * powers of two larger than 9.
     */
    for (n=8; n<maxpow; n++) {
	addr = (8==n) ? 0 : (haddr_t)1 << n;
	if (H5FD_set_eoa(file, addr+H5F_SIGNATURE_LEN)<0) {
	    HRETURN_ERROR(H5E_IO, H5E_CANTINIT, HADDR_UNDEF,
			  "unable to set EOA value for file signature");
	}
	if (H5FD_read(file, H5P_DEFAULT, addr, H5F_SIGNATURE_LEN, buf)<0) {
	    HRETURN_ERROR(H5E_IO, H5E_CANTINIT, HADDR_UNDEF,
			  "unable to read file signature");
	}
	if (!HDmemcmp(buf, H5F_SIGNATURE, H5F_SIGNATURE_LEN)) break;
    }

    /*
     * If the signature was not found then reset the EOA value and return
     * failure.
     */
    if (n>=maxpow) {
	H5FD_set_eoa(file, eoa);
	HRETURN_ERROR(H5E_IO, H5E_CANTINIT, HADDR_UNDEF,
		      "unable to find a valid file signature");
    }

    /* Success */
    FUNC_LEAVE(addr);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fis_hdf5
 *
 * Purpose:	Check the file signature to detect an HDF5 file.
 *
 * Bugs:	This function is not robust: it only uses the default file
 *		driver when attempting to open the file when in fact it
 *		should use all known file drivers.
 *
 * Return:	Success:	TRUE/FALSE
 *
 *		Failure:	Negative
 *
 * Programmer:	Unknown
 *
 * Modifications:
 *		Robb Matzke, 1999-08-02
 *		Rewritten to use the virtual file layer.
 *-------------------------------------------------------------------------
 */
htri_t
H5Fis_hdf5(const char *name)
{
    H5FD_t	*file = NULL;
    htri_t	ret_value = FAIL;

    FUNC_ENTER(H5Fis_hdf5, FAIL);
    H5TRACE1("b","s",name);

    /* Check args and all the boring stuff. */
    if (!name || !*name) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "no file name specified");
    }

    /* Open the file at the virtual file layer */
    if (NULL==(file=H5FD_open(name, H5F_ACC_RDONLY, H5P_DEFAULT,
			      HADDR_UNDEF))) {
	HGOTO_ERROR(H5E_IO, H5E_CANTINIT, FAIL, "unable to open file");
    }

    /* The file is an hdf5 file if the hdf5 file signature can be found */
    ret_value = (HADDR_UNDEF!=H5F_locate_signature(file));

 done:
    /* Close the file */
    if (file) H5FD_close(file);
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_new
 *
 * Purpose:	Creates a new file object and initializes it.  The
 *		H5Fopen and H5Fcreate functions then fill in various
 *		fields.	 If SHARED is a non-null pointer then the shared info
 *		to which it points has the reference count incremented.
 *		Otherwise a new, empty shared info struct is created and
 *		initialized with the specified file access property list.
 *
 * Errors:
 *
 * Return:	Success:	Ptr to a new file struct.
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 18 1997
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static H5F_t *
H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id)
{
    H5F_t		*f=NULL, *ret_value=NULL;
    intn		n;
    const H5F_create_t	*fcpl=NULL;
    const H5F_access_t	*fapl=NULL;
    
    FUNC_ENTER(H5F_new, NULL);

    if (NULL==(f=H5FL_ALLOC(H5F_t,1))) {
	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL,
		    "memory allocation failed");
    }

    if (shared) {
	f->shared = shared;
    } else {
	f->shared = H5FL_ALLOC(H5F_file_t,1);
	f->shared->boot_addr = HADDR_UNDEF;
	f->shared->base_addr = HADDR_UNDEF;
	f->shared->freespace_addr = HADDR_UNDEF;
	f->shared->driver_addr = HADDR_UNDEF;
    
	/*
	 * Copy the file creation and file access property lists into the
	 * new file handle.  We do this early because some values might need
	 * to change as the file is being opened.
	 */
	fcpl = (H5P_DEFAULT==fcpl_id)? &H5F_create_dflt : (const H5F_create_t *)H5I_object(fcpl_id);
	if (NULL==(f->shared->fcpl=H5P_copy(H5P_FILE_CREATE, fcpl))) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, NULL,
			  "unable to copy file creation property list");
	}

	fapl = (H5P_DEFAULT==fapl_id)? &H5F_access_dflt : (const H5F_access_t *)H5I_object(fapl_id);
	f->shared->mdc_nelmts = fapl->mdc_nelmts;
	f->shared->rdcc_nelmts = fapl->rdcc_nelmts;
	f->shared->rdcc_nbytes = fapl->rdcc_nbytes;
	f->shared->rdcc_w0 = fapl->rdcc_w0;
	f->shared->threshold = fapl->threshold;
	f->shared->alignment = fapl->alignment;
	f->shared->gc_ref = fapl->gc_ref;

#ifdef H5_HAVE_PARALLEL
	/*
	 * Disable cache if file is open using MPIO driver.  Parallel
	 * does not permit caching.  (maybe able to relax it for
	 * read only open.)
	 */
	if (H5FD_MPIO==fapl->driver_id){
	    f->shared->rdcc_nbytes = 0;
	    f->shared->mdc_nelmts = 0;
	}
#endif

	/*
	 * Create a meta data cache with the specified number of elements.
	 * The cache might be created with a different number of elements and
	 * the access property list should be updated to reflect that.
	 */
	if ((n=H5AC_create(f, f->shared->mdc_nelmts))<0) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, NULL,
			  "unable to create meta data cache");
	}
	f->shared->mdc_nelmts = n;
	
	/* Create the chunk cache */
	H5F_istore_init(f);
    }
    
    f->shared->nrefs++;
    f->nrefs = 1;
    ret_value = f;

 done:
    if (!ret_value && f) {
	if (!shared) H5FL_FREE(H5F_file_t,f->shared);
	H5FL_FREE(H5F_t,f);
    }
    
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_dest
 *
 * Purpose:	Destroys a file structure.  This function flushes the cache
 *		but doesn't do any other cleanup other than freeing memory
 *		for the file struct.  The shared info for the file is freed
 *		only when its reference count reaches zero.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 18 1997
 *
 * Modifications:
 *
 * 	Robb Matzke, 1998-10-14
 *	Nothing happens unless the reference count for the H5F_t goes to
 *	zero.  The reference counts are decremented here.
 *
 * 	Robb Matzke, 1999-02-19
 *	More careful about decrementing reference counts so they don't go
 *	negative or wrap around to some huge value.  Nothing happens if a
 *	reference count is already zero.
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_dest(H5F_t *f)
{
    herr_t	ret_value = SUCCEED;
    
    FUNC_ENTER(H5F_dest, FAIL);

    if (f && 1==f->nrefs) {
	if (1==f->shared->nrefs) {
	    /*
	     * Do not close the root group since we didn't count it, but free
	     * the memory associated with it.
	     */
	    H5FL_FREE(H5G_t,f->shared->root_grp);
	    f->shared->root_grp=NULL;
	    if (H5AC_dest(f)) {
		HERROR(H5E_FILE, H5E_CANTINIT, "problems closing file");
		ret_value = FAIL; /*but keep going*/
	    }
	    if (H5F_istore_dest (f)<0) {
		HERROR(H5E_FILE, H5E_CANTINIT, "problems closing file");
		ret_value = FAIL; /*but keep going*/
	    }
	    f->shared->cwfs = H5MM_xfree (f->shared->cwfs);

	    /* Destroy file creation properties */
	    H5P_close(f->shared->fcpl);

	    /* Destroy shared file struct */
	    if (H5FD_close(f->shared->lf)<0) {
		HERROR(H5E_FILE, H5E_CANTINIT, "problems closing file");
		ret_value = FAIL; /*but keep going*/
	    }
	    f->shared = H5FL_FREE(H5F_file_t,f->shared);
	    
	} else if (f->shared->nrefs>0) {
	    /*
	     * There are other references to the shared part of the file.
	     * Only decrement the reference count.
	     */
	    --f->shared->nrefs;
	}

	/* Free the non-shared part of the file */
	f->name = H5MM_xfree(f->name);
	f->mtab.child = H5MM_xfree(f->mtab.child);
	f->mtab.nalloc = 0;
	H5FL_FREE(H5F_t,f);
    } else if (f && f->nrefs>0) {
	/*
	 * There are other references to this file. Only decrement the
	 * reference count.
	 */
	--f->nrefs;
    }
    
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_open
 *
 * Purpose:	Opens (or creates) a file.  This function understands the
 *		following flags which are similar in nature to the Posix
 *		open(2) flags.
 *
 *		H5F_ACC_RDWR:	Open with read/write access. If the file is
 *				currently open for read-only access then it
 *				will be reopened. Absence of this flag
 *				implies read-only access.
 *
 *		H5F_ACC_CREAT:	Create a new file if it doesn't exist yet.
 *				The permissions are 0666 bit-wise AND with
 *				the current umask.  H5F_ACC_WRITE must also
 *				be specified.
 *
 *		H5F_ACC_EXCL:	This flag causes H5F_open() to fail if the
 *				file already exists.
 *
 *		H5F_ACC_TRUNC:	The file is truncated and a new HDF5 superblock
 *				is written.  This operation will fail if the
 *				file is already open.
 *
 *		Unlinking the file name from the group directed graph while
 *		the file is opened causes the file to continue to exist but
 *		one will not be able to upgrade the file from read-only
 *		access to read-write access by reopening it. Disk resources
 *		for the file are released when all handles to the file are
 *		closed. NOTE: This paragraph probably only applies to Unix;
 *		deleting the file name in other OS's has undefined results.
 *
 *		The CREATE_PARMS argument is optional.	A null pointer will
 *		cause the default file creation parameters to be used.
 *
 *		The ACCESS_PARMS argument is optional.  A null pointer will
 *		cause the default file access parameters to be used.
 *
 * Return:	Success:	A new file pointer.
 *
 *		Failure:	NULL
 *
 * Programmer:	Robb Matzke
 *		Tuesday, September 23, 1997
 *
 * Modifications:
 *		Albert Cheng, 1998-02-05
 *		Added the access_parms argument to pass down access template
 *		information.
 *
 * 		Robb Matzke, 1998-02-18
 *		The H5F_access_t changed to allow more generality.  The low
 *		level driver is part of the file access template so the TYPE
 *		argument has been removed.
 *
 * 		Robb Matzke, 1999-08-02
 *		Rewritten to use the virtual file layer.
 *
 * 		Robb Matzke, 1999-08-16
 *		Added decoding of file driver information block, which uses a
 *		formerly reserved address slot in the boot block in order to
 *		be compatible with previous versions of the file format.
 *
 * 		Robb Matzke, 1999-08-20
 *		Optimizations for opening a file. If the driver can't
 *		determine when two file handles refer to the same file then
 *		we open the file in one step.  Otherwise if the first attempt
 *		to open the file fails then we skip the second attempt if the
 *		arguments would be the same.
 *-------------------------------------------------------------------------
 */
H5F_t *
H5F_open(const char *name, uintn flags, hid_t fcpl_id, hid_t fapl_id)
{
    H5F_t		*file=NULL;	/*the success return value	*/
    H5F_t		*ret_value=NULL;/*actual return value		*/
    H5F_file_t		*shared=NULL;	/*shared part of `file'		*/
    H5FD_t		*lf=NULL;	/*file driver part of `shared'	*/
    uint8_t		buf[256];	/*temporary I/O buffer		*/
    const uint8_t	*p;		/*ptr into temp I/O buffer	*/
    size_t		fixed_size=24;	/*fixed sizeof superblock	*/
    size_t		variable_size;	/*variable sizeof superblock	*/
    size_t		driver_size;	/*size of driver info block	*/
    H5G_entry_t		root_ent;	/*root symbol table entry	*/
    haddr_t		eof;		/*end of file address		*/
    haddr_t		stored_eoa;	/*relative end-of-addr in file	*/
    uintn		tent_flags;	/*tentative flags		*/
    char		driver_name[9];	/*file driver name/version	*/
    hbool_t		driver_has_cmp;	/*`cmp' callback defined?	*/
    
    FUNC_ENTER(H5F_open, NULL);

    /*
     * If the driver has a `cmp' method then the driver is capable of
     * determining when two file handles refer to the same file and the
     * library can insure that when the application opens a file twice that
     * the two handles coordinate their operations appropriately. Otherwise
     * it is the application's responsibility to never open the same file
     * more than once at a time.
     */
    driver_has_cmp = H5FD_has_cmp(fapl_id);

    /*
     * Opening a file is a two step process. First we try to open the file in
     * a way which doesn't affect its state (like not truncating or creating
     * it) so we can compare it with files that are already open. If that
     * fails then we try again with the full set of flags (only if they're
     * different than the original failed attempt). However, if the file
     * driver can't distinquish between files then there's no reason to open
     * the file tentatively because it's the application's responsibility to
     * prevent this situation (there's no way for us to detect it here
     * anyway).
     */
    if (driver_has_cmp) {
	tent_flags = flags & ~(H5F_ACC_CREAT|H5F_ACC_TRUNC|H5F_ACC_EXCL);
    } else {
	tent_flags = flags;
    }
    if (NULL==(lf=H5FD_open(name, tent_flags, fapl_id, HADDR_UNDEF))) {
	if (tent_flags == flags) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to open file");
	}
	H5E_clear();
	tent_flags = flags;
	if (NULL==(lf=H5FD_open(name, tent_flags, fapl_id, HADDR_UNDEF))) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to open file");
	}
    }

    /* Is the file already open? */
    if ((file=H5I_search(H5I_FILE, H5F_equal, lf)) ||
	(file=H5I_search(H5I_FILE_CLOSING, H5F_equal, lf))) {
	/*
	 * The file is already open, so use that one instead of the one we
	 * just opened. We only one one H5FD_t* per file so one doesn't
	 * confuse the other.  But fail if this request was to truncate the
	 * file (since we can't do that while the file is open), or if the
	 * request was to create a non-existent file (since the file already
	 * exists), or if the new request adds write access (since the
	 * readers don't expect the file to change under them).
	 */
	H5FD_close(lf);
	if (flags & H5F_ACC_TRUNC) {
	    file = NULL; /*to prevent destruction of wrong file*/
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to truncate a file which is already open");
	}
	if (flags & H5F_ACC_EXCL) {
	    file = NULL; /*to prevent destruction of wrong file*/
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"file exists");
	}
	if ((flags & H5F_ACC_RDWR) && 0==(file->intent & H5F_ACC_RDWR)) {
	    file = NULL; /*to prevent destruction of wrong file*/
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"file is already open for read-only");
	}
	file = H5F_new(file->shared, fcpl_id, fapl_id);
	lf = file->shared->lf;
    } else if (flags!=tent_flags) {
	/*
	 * This file is not yet open by the library and the flags we used to
	 * open it are different than the desired flags. Close the tentative
	 * file and open it for real.
	 */
	H5FD_close(lf);
	if (NULL==(lf=H5FD_open(name, flags, fapl_id, HADDR_UNDEF))) {
	    file = NULL; /*to prevent destruction of wrong file*/
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to open file");
	}
	file = H5F_new(NULL, fcpl_id, fapl_id);
	file->shared->flags = flags;
	file->shared->lf = lf;
    } else {
	/*
	 * This file is not yet open by the library and our tentative opening
	 * above is good enough.
	 */
	file = H5F_new(NULL, fcpl_id, fapl_id);
	file->shared->flags = flags;
	file->shared->lf = lf;
    }

    /* Short cuts */
    shared = file->shared;
    lf = shared->lf;

    /*
     * The intent at the top level file struct are not necessarily the same as
     * the flags at the bottom.	 The top level describes how the file can be
     * accessed through the HDF5 library.  The bottom level describes how the
     * file can be accessed through the C library.
     */
    file->intent = flags;
    file->name = H5MM_xstrdup(name);

    /*
     * Read or write the file superblock, depending on whether the file is
     * empty or not.
     */
    if (0==H5FD_get_eof(lf) && (flags & H5F_ACC_RDWR)) {
	/*
	 * The superblock starts immediately after the user-defined header,
	 * which we have already insured is a proper size.  The base address
	 * is set to the same thing as the superblock for now.
	 */
	shared->boot_addr = shared->fcpl->userblock_size;
	shared->base_addr = shared->boot_addr;
	shared->consist_flags = 0x03;
	if (H5F_flush(file, H5F_SCOPE_LOCAL, FALSE, TRUE)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL,
			"unable to write file superblock");
	}

	/* Create and open the root group */
	if (H5G_mkroot(file, NULL)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL,
			"unable to create/open root group");
	}
	
    } else if (1==shared->nrefs) {
	/* Read the superblock if it hasn't been read before. */
	if (HADDR_UNDEF==(shared->boot_addr=H5F_locate_signature(lf))) {
	    HGOTO_ERROR(H5E_FILE, H5E_NOTHDF5, NULL,
			"unable to find file signature");
	}
	if (H5FD_set_eoa(lf, shared->boot_addr+fixed_size)<0 ||
	    H5FD_read(lf, H5P_DEFAULT, shared->boot_addr, fixed_size, buf)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_READERROR, NULL,
			"unable to read superblock");
	}

	/* Signature, already checked */
	p = buf + H5F_SIGNATURE_LEN;

	/* Superblock version */
	shared->fcpl->bootblock_ver = *p++;
	if (HDF5_BOOTBLOCK_VERSION!=shared->fcpl->bootblock_ver) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad superblock version number");
	}

	/* Freespace version */
	shared->fcpl->freespace_ver = *p++;
	if (HDF5_FREESPACE_VERSION!=shared->fcpl->freespace_ver) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad free space version number");
	}

	/* Root group version number */
	shared->fcpl->objectdir_ver = *p++;
	if (HDF5_OBJECTDIR_VERSION!=shared->fcpl->objectdir_ver) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad root group version number");
	}

	/* reserved */
	p++;

	/* Shared header version number */
	shared->fcpl->sharedheader_ver = *p++;
	if (HDF5_SHAREDHEADER_VERSION!=shared->fcpl->sharedheader_ver) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad shared header version number");
	}

	/* Size of file addresses */
	shared->fcpl->sizeof_addr = *p++;
	if (shared->fcpl->sizeof_addr != 2 &&
	    shared->fcpl->sizeof_addr != 4 &&
	    shared->fcpl->sizeof_addr != 8 &&
	    shared->fcpl->sizeof_addr != 16 &&
	    shared->fcpl->sizeof_addr != 32) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad file sizeof(address)");
	}

	/* Size of file sizes */
	shared->fcpl->sizeof_size = *p++;
	if (shared->fcpl->sizeof_size != 2 &&
	    shared->fcpl->sizeof_size != 4 &&
	    shared->fcpl->sizeof_size != 8 &&
	    shared->fcpl->sizeof_size != 16 &&
	    shared->fcpl->sizeof_size != 32) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad file sizeof(size)");
	}
	
	/* Reserved byte */
	p++;

	/* Various B-tree sizes */
	UINT16DECODE(p, shared->fcpl->sym_leaf_k);
	if (shared->fcpl->sym_leaf_k < 1) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad symbol table leaf node 1/2 rank");
	}
	UINT16DECODE(p, shared->fcpl->btree_k[H5B_SNODE_ID]);
	if (shared->fcpl->btree_k[H5B_SNODE_ID] < 1) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"bad symbol table internal node 1/2 rank");
	}

	/* File consistency flags. Not really used yet */
	UINT32DECODE(p, shared->consist_flags);
	assert((size_t)(p-buf) == fixed_size);

	/* Decode the variable-length part of the superblock... */
	variable_size = H5F_SIZEOF_ADDR(file) +		/*base addr*/
			H5F_SIZEOF_ADDR(file) +		/*global free list*/
			H5F_SIZEOF_ADDR(file) +		/*end-of-address*/
			H5F_SIZEOF_ADDR(file) +		/*reserved address*/
			H5G_SIZEOF_ENTRY(file);		/*root group ptr*/
	assert(variable_size<=sizeof buf);
	if (H5FD_set_eoa(lf, shared->boot_addr+fixed_size+variable_size)<0 ||
	    H5FD_read(lf, H5P_DEFAULT, shared->boot_addr+fixed_size,
		      variable_size, buf)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to read superblock");
	}
	p = buf;
	H5F_addr_decode(file, &p, &(shared->base_addr)/*out*/);
	H5F_addr_decode(file, &p, &(shared->freespace_addr)/*out*/);
	H5F_addr_decode(file, &p, &stored_eoa/*out*/);
	H5F_addr_decode(file, &p, &(shared->driver_addr)/*out*/);
	if (H5G_ent_decode(file, &p, &root_ent/*out*/)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to read root symbol entry");
	}

	/* Decode the optional driver information block */
	if (H5F_addr_defined(shared->driver_addr)) {
	    haddr_t drv_addr = shared->base_addr + shared->driver_addr;
	    if (H5FD_set_eoa(lf, drv_addr+16)<0 ||
		H5FD_read(lf, H5P_DEFAULT, drv_addr, 16, buf)<0) {
		HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			    "unable to read driver information block");
	    }
	    p = buf;

	    /* Version number */
	    if (HDF5_DRIVERINFO_VERSION!=*p++) {
		HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			    "bad driver information block version number");
	    }

	    /* Reserved */
	    p += 3;

	    /* Driver info size */
	    UINT32DECODE(p, driver_size);

	    /* Driver name and/or version */
	    strncpy(driver_name, (const char *)p, 8);
	    driver_name[8] = '\0';

	    /* Read driver information and decode */
	    if (H5FD_set_eoa(lf, drv_addr+16+driver_size)<0 ||
		H5FD_read(lf, H5P_DEFAULT, drv_addr+16, driver_size, buf)<0) {
		HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			    "unable to read file driver information");
	    }
	    if (H5FD_sb_decode(lf, driver_name, buf)<0) {
		HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			    "unable to decode driver information");
	    }
	}
	
	/* Make sure we can open the root group */
	if (H5G_mkroot(file, &root_ent)<0) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to read root group");
	}

	/*
	 * The user-defined data is the area of the file before the base
	 * address.
	 */
	shared->fcpl->userblock_size = shared->base_addr;

	/*
	 * Make sure that the data is not truncated. One case where this is
	 * possible is if the first file of a family of files was opened
	 * individually.
	 */
	if (HADDR_UNDEF==(eof=H5FD_get_eof(lf))) {
	    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			"unable to determine file size");
	}
	if (eof<stored_eoa) {
	    HGOTO_ERROR(H5E_FILE, H5E_TRUNCATED, NULL, "truncated file");
	}

	/*
	 * Tell the file driver how much address space has already been
	 * allocated so that it knows how to allocated additional memory.
	 */
	if (H5FD_set_eoa(lf, stored_eoa)<0) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL,
			  "unable to set end-of-address marker for file");
	}
    }

    /* Success */
    ret_value = file;

 done:
    if (!ret_value && file) H5F_dest(file);
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fcreate
 *
 * Purpose:	This is the primary function for creating HDF5 files . The
 *		flags parameter determines whether an existing file will be
 *		overwritten or not.  All newly created files are opened for
 *		both reading and writing.  All flags may be combined with the
 *		bit-wise OR operator (`|') to change the behavior of the file
 *		create call.
 *
 *		The more complex behaviors of a file's creation and access
 *		are controlled through the file-creation and file-access
 *		property lists.  The value of H5P_DEFAULT for a template
 *		value indicates that the library should use the default
 *		values for the appropriate template.
 *
 * See also:	H5Fpublic.h for the list of supported flags. H5Ppublic.h for
 * 		the list of file creation and file access properties.
 *
 * Return:	Success:	A file ID
 *
 *		Failure:	FAIL
 *
 * Programmer:	Unknown
 *
 * Modifications:
 * 		Robb Matzke, 1997-07-18
 *		File struct creation and destruction is through H5F_new() and
 *		H5F_dest(). Writing the root symbol table entry is done with
 *		H5G_encode().
 *	
 *  		Robb Matzke, 1997-08-29
 *		Moved creation of the boot block to H5F_flush().
 *	
 *  		Robb Matzke, 1997-09-23
 *		Most of the work is now done by H5F_open() since H5Fcreate()
 *		and H5Fopen() originally contained almost identical code.
 *
 * 		Robb Matzke, 1998-02-18
 *		Better error checking for the creation and access property
 *		lists. It used to be possible to swap the two and core the
 *		library.  Also, zero is no longer valid as a default property
 *		list; one must use H5P_DEFAULT instead.
 *
 * 		Robb Matzke, 1999-08-02
 *		The file creation and file access property lists are passed
 *		to the H5F_open() as object IDs.
 *-------------------------------------------------------------------------
 */
hid_t
H5Fcreate(const char *filename, unsigned flags, hid_t fcpl_id,
	  hid_t fapl_id)
{
    
    H5F_t	*new_file = NULL;	/*file struct for new file	*/
    hid_t	ret_value = FAIL;	/*return value			*/

    FUNC_ENTER(H5Fcreate, FAIL);
    H5TRACE4("i","sIuii",filename,flags,fcpl_id,fapl_id);

    /* Check/fix arguments */
    if (!filename || !*filename) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name");
    }
    if (flags & ~(H5F_ACC_EXCL|H5F_ACC_TRUNC|H5F_ACC_DEBUG)) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid flags");
    }
    if ((flags & H5F_ACC_EXCL) && (flags & H5F_ACC_TRUNC)) {
	HGOTO_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL,
		     "mutually exclusive flags for file creation");
    }
    if (H5P_DEFAULT!=fcpl_id &&
	(H5P_FILE_CREATE!=H5P_get_class(fcpl_id) ||
	 NULL==H5I_object(fcpl_id))) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		    "not a file creation property list");
    }
    if (H5P_DEFAULT!=fapl_id &&
	(H5P_FILE_ACCESS!=H5P_get_class(fapl_id) ||
	 NULL==H5I_object(fapl_id))) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		    "not a file access property list");
    }

    /*
     * Adjust bit flags by turning on the creation bit and making sure that
     * the EXCL or TRUNC bit is set.  All newly-created files are opened for
     * reading and writing.
     */
    if (0==(flags & (H5F_ACC_EXCL|H5F_ACC_TRUNC))) {
	flags |= H5F_ACC_EXCL;	 /*default*/
    }
    flags |= H5F_ACC_RDWR | H5F_ACC_CREAT;

    /*
     * Create a new file or truncate an existing file.
     */
    if (NULL==(new_file=H5F_open(filename, flags, fcpl_id, fapl_id))) {
	HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to create file");
    }
    
    /* Get an atom for the file */
    if ((ret_value = H5I_register(H5I_FILE, new_file))<0) {
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL,
		    "unable to atomize file");
    }

  done:
    if (ret_value<0 && new_file) H5F_close(new_file);
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fopen
 *
 * Purpose:	This is the primary function for accessing existing HDF5
 *		files.  The FLAGS argument determines whether writing to an
 *		existing file will be allowed or not.  All flags may be
 *		combined with the bit-wise OR operator (`|') to change the
 *		behavior of the file open call.  The more complex behaviors
 *		of a file's access are controlled through the file-access
 *		property list.
 *
 * See Also:	H5Fpublic.h for a list of possible values for FLAGS.
 *
 * Return:	Success:	A file ID
 *
 *		Failure:	FAIL
 *
 * Programmer:	Unknown
 *
 * Modifications:
 *	  	Robb Matzke, 1997-07-18
 *		File struct creation and destruction is through H5F_new() and
 *		H5F_dest(). Reading the root symbol table entry is done with
 *		H5G_decode().
 *	
 *  		Robb Matzke, 1997-09-23
 *		Most of the work is now done by H5F_open() since H5Fcreate()
 *		and H5Fopen() originally contained almost identical code.
 *
 *	 	Robb Matzke, 1998-02-18
 *		Added better error checking for the flags and the file access
 *		property list.  It used to be possible to make the library
 *		dump core by passing an object ID that was not a file access
 *		property list.
 *
 * 		Robb Matzke, 1999-08-02
 *		The file access property list is passed to the H5F_open() as
 *		object IDs.
 *-------------------------------------------------------------------------
 */
hid_t
H5Fopen(const char *filename, unsigned flags, hid_t fapl_id)
{
    H5F_t	*new_file = NULL;	/*file struct for new file	*/
    hid_t	ret_value = FAIL;	/*return value			*/

    FUNC_ENTER(H5Fopen, FAIL);
    H5TRACE3("i","sIui",filename,flags,fapl_id);

    /* Check/fix arguments. */
    if (!filename || !*filename) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name");
    }
    if ((flags & ~H5F_ACC_PUBLIC_FLAGS) ||
	(flags & H5F_ACC_TRUNC) || (flags & H5F_ACC_EXCL)) {
	HGOTO_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file open flags");
    }
    if (H5P_DEFAULT!=fapl_id &&
	(H5P_FILE_ACCESS!=H5P_get_class(fapl_id) ||
	 NULL==H5I_object(fapl_id))) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		    "not a file access property list");
    }

    /* Open the file */
    if (NULL==(new_file=H5F_open(filename, flags, H5P_DEFAULT, fapl_id))) {
	HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to open file");
    }

    /* Get an atom for the file */
    if ((ret_value = H5I_register(H5I_FILE, new_file))<0) {
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL,
		    "unable to atomize file handle");
    }

 done:
    if (ret_value<0 && new_file) H5F_close(new_file);
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fflush
 *
 * Purpose:	Flushes all outstanding buffers of a file to disk but does
 *		not remove them from the cache.  The OBJECT_ID can be a file,
 *		dataset, group, attribute, or named data type.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Thursday, August  6, 1998
 *
 * Modifications:
 *
 * 		Robb Matzke, 1998-10-16
 *		Added the `scope' argument.
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Fflush(hid_t object_id, H5F_scope_t scope)
{
    H5F_t	*f = NULL;
    H5G_t	*grp = NULL;
    H5T_t	*type = NULL;
    H5D_t	*dset = NULL;
    H5A_t	*attr = NULL;
    H5G_entry_t	*ent = NULL;
    
    FUNC_ENTER(H5Fflush, FAIL);
    H5TRACE2("e","iFs",object_id,scope);

    switch (H5I_get_type(object_id)) {
    case H5I_FILE:
	if (NULL==(f=H5I_object(object_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "invalid file identifier");
	}
	break;

    case H5I_GROUP:
	if (NULL==(grp=H5I_object(object_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "invalid group identifier");
	}
	ent = H5G_entof(grp);
	break;

    case H5I_DATATYPE:
	if (NULL==(type=H5I_object(object_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "invalid type identifier");
	}
	ent = H5T_entof(type);
	break;

    case H5I_DATASET:
	if (NULL==(dset=H5I_object(object_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "invalid dataset identifier");
	}
	ent = H5D_entof(dset);
	break;

    case H5I_ATTR:
	if (NULL==(attr=H5I_object(object_id))) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "invalid attribute identifier");
	}
	ent = H5A_entof(attr);
	break;

    default:
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		      "not a file or file object");
    }

    if (!f) {
	if (!ent) {
	    HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
			  "object is not assocated with a file");
	}
	f = ent->file;
    }
    if (!f) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		      "object is not associated with a file");
    }

    /* Flush the file */
    if (H5F_flush(f, scope, FALSE, FALSE)<0) {
	HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL,
		      "flush failed");
    }

    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_flush
 *
 * Purpose:	Flushes (and optionally invalidates) cached data plus the
 *		file boot block.  If the logical file size field is zero
 *		then it is updated to be the length of the boot block.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug 29 1997
 *
 * Modifications:
 *              rky 1998-08-28
 *		Only p0 writes metadata to disk.
 *
 * 		Robb Matzke, 1998-10-16
 *		Added the `scope' argument to indicate what should be
 *		flushed. If the value is H5F_SCOPE_GLOBAL then the entire
 *		virtual file is flushed; a value of H5F_SCOPE_LOCAL means
 *		that only the specified file is flushed.  A value of
 *		H5F_SCOPE_DOWN means flush the specified file and all
 *		children.
 *
 * 		Robb Matzke, 1999-08-02
 *		If ALLOC_ONLY is non-zero then all this function does is
 *		allocate space for the userblock and superblock. Also
 *		rewritten to use the virtual file layer.
 *
 * 		Robb Matzke, 1999-08-16
 *		The driver information block is encoded and either allocated
 *		or written to disk.
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_flush(H5F_t *f, H5F_scope_t scope, hbool_t invalidate,
	  hbool_t alloc_only)
{
    uint8_t		sbuf[2048], dbuf[2048], *p=NULL;
    uintn		nerrors=0, i;
    hsize_t		superblock_size, driver_size;
    char		driver_name[9];
    
    FUNC_ENTER(H5F_flush, FAIL);
	
    /*
     * Nothing to do if the file is read only.	This determination is made at
     * the shared open(2) flags level, implying that opening a file twice,
     * once for read-only and once for read-write, and then calling
     * H5F_flush() with the read-only handle, still causes data to be flushed.
     */
    if (0 == (H5F_ACC_RDWR & f->shared->flags)) {
	HRETURN(SUCCEED);
    }

    /* Flush other stuff depending on scope */
    if (H5F_SCOPE_GLOBAL==scope) {
	while (f->mtab.parent) f = f->mtab.parent;
	scope = H5F_SCOPE_DOWN;
    }
    if (H5F_SCOPE_DOWN==scope) {
	for (i=0; i<f->mtab.nmounts; i++) {
	    if (H5F_flush(f->mtab.child[i].file, scope, invalidate, FALSE)<0) {
		nerrors++;
	    }
	}
    }

    /* flush the entire raw data cache */
    if (!alloc_only && H5F_istore_flush (f, invalidate)<0) {
	HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
		      "unable to flush raw data cache");
    }
    
    /* flush (and invalidate) the entire meta data cache */
    if (!alloc_only && H5AC_flush(f, NULL, HADDR_UNDEF, invalidate)<0) {
	HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
		      "unable to flush meta data cache");
    }

    /* encode the file boot block */
    p = sbuf;
    HDmemcpy(p, H5F_SIGNATURE, H5F_SIGNATURE_LEN);
    p += H5F_SIGNATURE_LEN;
    *p++ = f->shared->fcpl->bootblock_ver;
    *p++ = f->shared->fcpl->freespace_ver;
    *p++ = f->shared->fcpl->objectdir_ver;
    *p++ = 0;			/*reserved*/
    *p++ = f->shared->fcpl->sharedheader_ver;
    assert (H5F_SIZEOF_ADDR(f)<=255);
    *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
    assert (H5F_SIZEOF_SIZE(f)<=255);
    *p++ = (uint8_t)H5F_SIZEOF_SIZE(f);
    *p++ = 0;			/*reserved */
    UINT16ENCODE(p, f->shared->fcpl->sym_leaf_k);
    UINT16ENCODE(p, f->shared->fcpl->btree_k[H5B_SNODE_ID]);
    UINT32ENCODE(p, f->shared->consist_flags);
    H5F_addr_encode(f, &p, f->shared->base_addr);
    H5F_addr_encode(f, &p, f->shared->freespace_addr);
    H5F_addr_encode(f, &p, H5FD_get_eoa(f->shared->lf));
    H5F_addr_encode(f, &p, f->shared->driver_addr);
    H5G_ent_encode(f, &p, H5G_entof(f->shared->root_grp));
    superblock_size = p-sbuf;

    /*
     * Encode the driver information block.
     */
    if ((driver_size=H5FD_sb_size(f->shared->lf))) {
	driver_size += 16; /*driver block header */
	assert(driver_size<=sizeof dbuf);
	p = dbuf;

	/* Version */
	*p++ = HDF5_DRIVERINFO_VERSION;

	/* Reserved*/
	p += 3;

	/* Driver info size, excluding header */
	UINT32ENCODE(p, driver_size-16);

	/* Encode driver-specific data */
	if (H5FD_sb_encode(f->shared->lf, driver_name, dbuf+16)<0) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL,
			  "unable to encode driver information");
	}

	/* Driver name */
	HDmemcpy(dbuf+8, driver_name, 8);
    }

    if (alloc_only) {
	/*
	 * Allocate space for the userblock, superblock, and driver info
	 * block. We do it with one allocation request because the userblock
	 * and superblock need to be at the beginning of the file and only
	 * the first allocation request is required to return memory at
	 * format address zero.
	 */
	haddr_t addr = H5FD_alloc(f->shared->lf, H5FD_MEM_SUPER,
				  (f->shared->base_addr +
				   superblock_size +
				   driver_size));
	if (HADDR_UNDEF==addr) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL,
			  "unable to allocate file space for userblock "
			  "and/or superblock");
	}
	if (0!=addr) {
	    HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL,
			  "file driver failed to allocate userblock "
			  "and/or superblock at address zero");
	}
	
	/*
	 * The file driver information block begins immediately after the
	 * superblock.
	 */
	if (driver_size>0) {
	    f->shared->driver_addr = superblock_size;
	}
	
    } else {
	/* Write superblock */
#ifdef H5_HAVE_PARALLEL
	if (IS_H5FD_MPIO(f))
	    H5FD_mpio_tas_allsame(f->shared->lf, TRUE); /*only p0 will write*/
#endif
	if (H5FD_write(f->shared->lf, H5FD_MEM_SUPER, H5P_DEFAULT, f->shared->boot_addr,
		       superblock_size, sbuf)<0) {
	    HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL,
			  "unable to write superblock");
	}

	/* Write driver information block */
	if (HADDR_UNDEF!=f->shared->driver_addr) {
#ifdef H5_HAVE_PARALLEL
	    if (IS_H5FD_MPIO(f))
		H5FD_mpio_tas_allsame(f->shared->lf, TRUE); /*only p0 will write*/
#endif
	    if (H5FD_write(f->shared->lf, H5FD_MEM_SUPER, H5P_DEFAULT,
			   f->shared->base_addr+superblock_size, driver_size,
			   dbuf)<0) {
		HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL,
			      "unable to write driver information block");
	    }
	}
    }

    /* Flush file buffers to disk */
    if (!alloc_only && H5FD_flush(f->shared->lf)<0) {
	HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "low level flush failed");
    }

    /* Check flush errors for children - errors are already on the stack */
    if (nerrors) HRETURN(FAIL);
    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_close
 *
 * Purpose:	Closes a file or causes the close operation to be pended.
 *		This function is called two ways: from the API it gets called
 *		by H5Fclose->H5I_dec_ref->H5F_close when H5I_dec_ref()
 *		decrements the file ID reference count to zero.  The file ID
 *		is removed from the H5I_FILE group by H5I_dec_ref() just
 *		before H5F_close() is called. If there are open object
 *		headers then the close is pended by moving the file to the
 *		H5I_FILE_CLOSING ID group (the f->closing contains the ID
 *		assigned to file).
 *
 *		This function is also called directly from H5O_close() when
 *		the last object header is closed for the file and the file
 *		has a pending close.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		Tuesday, September 23, 1997
 *
 * Modifications:
 * 		Robb Matzke, 1998-10-14
 *		Nothing happens unless the H5F_t reference count is one (the
 *		file is flushed anyway).  The reference count is decremented
 *		by H5F_dest().
 *
 * 		Robb Matzke, 1999-08-02
 *		Modified to use the virtual file layer.
 *-------------------------------------------------------------------------
 */
herr_t
H5F_close(H5F_t *f)
{
    uintn	i;

    FUNC_ENTER(H5F_close, FAIL);
    assert(f->nrefs>0);

    /*
     * If this file is referenced more than once then just decrement the
     * count, flush the file, and return.
     */
    if (f->nrefs>1) {
	if (H5F_flush(f, H5F_SCOPE_LOCAL, FALSE, FALSE)<0) {
	    HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
			  "unable to flush cache");
	}
	H5F_dest(f); /*decrement reference counts*/
	HRETURN(SUCCEED);
    }
    
    /*
     * Unmount and close each child before closing the current file.
     */
    assert(NULL==f->mtab.parent);
    for (i=0; i<f->mtab.nmounts; i++) {
	f->mtab.child[i].file->mtab.parent = NULL;
	H5G_close(f->mtab.child[i].group);
	H5F_close(f->mtab.child[i].file);
    }
    f->mtab.nmounts = 0;

    /*
     * If object headers are still open then delay deletion of resources until
     * they have all been closed.  Flush all caches and update the object
     * header anyway so that failing to close all objects isn't a major
     * problem. If the file is on the H5I_FILE list then move it to the
     * H5I_FILE_CLOSING list instead.
     */
    if (f->nopen_objs>0) {
	if (H5F_flush(f, H5F_SCOPE_LOCAL, FALSE, FALSE)<0) {
	    HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
			  "unable to flush cache");
	}
#ifdef H5F_DEBUG
	if (H5DEBUG(F)) {
	    fprintf(H5DEBUG(F), "H5F: H5F_close(%s): %u object header%s still "
		    "open (file close will complete when %s closed)\n",
		    f->name,
		    f->nopen_objs,
		    1 == f->nopen_objs?" is":"s are",
		    1 == f->nopen_objs?"that header is":"those headers are");
	}
#endif
	if (!f->closing) {
	    f->closing  = H5I_register(H5I_FILE_CLOSING, f);
	}
	HRETURN(SUCCEED);
    } else if (f->closing) {
#ifdef H5F_DEBUG
	if (H5DEBUG(F)) {
	    fprintf(H5DEBUG(F), "H5F: H5F_close: operation completing\n");
	}
#endif
    }

    /*
     * If this is the last reference to the shared part of the file then
     * close it also.
     */
    assert(1==f->nrefs);
    if (1==f->shared->nrefs) {
	/* Flush and destroy all caches */
	if (H5F_flush(f, H5F_SCOPE_LOCAL, TRUE, FALSE)<0) {
	    HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
			  "unable to flush cache");
	}

	/* Dump debugging info */
	H5AC_debug(f);
	H5F_istore_stats(f, FALSE);
    } else {
	/*
	 * Flush all caches but do not destroy. As long as all handles for
	 * this file are closed the flush isn't really necessary, but lets
	 * just be safe.
	 */
	if (H5F_flush(f, H5F_SCOPE_LOCAL, TRUE, FALSE)<0) {
	    HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
			  "unable to flush cache");
	}
    }

    /*
     * Destroy the H5F_t struct and decrement the reference count for the
     * shared H5F_file_t struct. If the reference count for the H5F_file_t
     * struct reaches zero then destroy it also.
     */
    if (H5F_dest(f)<0) {
	HRETURN_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "problems closing file");
    }
    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fclose
 *
 * Purpose:	This function closes the file specified by FILE_ID by
 *		flushing all data to storage, and terminating access to the
 *		file through FILE_ID.  If objects (e.g., datasets, groups,
 *		etc.) are open in the file then the underlying storage is not
 *		closed until those objects are closed; however, all data for
 *		the file and the open objects is flushed.
 *
 * Return:	Success:	Non-negative
 *
 *		Failure:	Negative
 *
 * Programmer:	Robb Matzke
 *              Saturday, February 20, 1999
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Fclose(hid_t file_id)
{
    
    herr_t	ret_value = SUCCEED;

    FUNC_ENTER(H5Fclose, FAIL);
    H5TRACE1("e","i",file_id);

    /* Check/fix arguments. */
    if (H5I_FILE != H5I_get_type(file_id)) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file atom");
    }
    if (NULL == H5I_object(file_id)) {
	HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "unable to unatomize file");
    }

    /*
     * Decrement reference count on atom.  When it reaches zero the file will
     * be closed.
     */
    if (H5I_dec_ref (file_id)<0) {
	HGOTO_ERROR (H5E_ATOM, H5E_CANTINIT, FAIL, "problems closing file");
    }
    
done:
    FUNC_LEAVE(ret_value < 0 ? FAIL : SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_mount
 *
 * Purpose:	Mount file CHILD onto the group specified by LOC and NAME,
 *		using mount properties in PLIST.  CHILD must not already be
 *		mouted and must not be a mount ancestor of the mount-point.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Tuesday, October  6, 1998
 *
 * Modifications:
 *
 * 	Robb Matzke, 1998-10-14
 *	The reference count for the mounted H5F_t is incremented.
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_mount(H5G_entry_t *loc, const char *name, H5F_t *child,
	  const H5F_mprop_t UNUSED *plist)
{
    H5G_t	*mount_point = NULL;	/*mount point group		*/
    H5G_entry_t	*mp_ent = NULL;		/*mount point symbol table entry*/
    H5F_t	*ancestor = NULL;	/*ancestor files		*/
    H5F_t	*parent = NULL;		/*file containing mount point	*/
    intn	lt, rt, md, cmp;	/*binary search indices		*/
    H5G_entry_t	*ent = NULL;		/*temporary symbol table entry	*/
    herr_t	ret_value = FAIL;	/*return value			*/
    
    FUNC_ENTER(H5F_mount, FAIL);
    assert(loc);
    assert(name && *name);
    assert(child);
    assert(plist);

    /*
     * Check that the child isn't mounted, that the mount point exists, and
     * that the mount wouldn't introduce a cycle in the mount tree.
     */
    if (child->mtab.parent) {
	HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "file is already mounted");
    }
    if (NULL==(mount_point=H5G_open(loc, name))) {
	HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "mount point not found");
    }
    parent = H5G_fileof(mount_point);
    mp_ent = H5G_entof(mount_point);
    for (ancestor=parent; ancestor; ancestor=ancestor->mtab.parent) {
	if (ancestor==child) {
	    HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL,
			"mount would introduce a cycle");
	}
    }
    
    /*
     * Use a binary search to locate the position that the child should be
     * inserted into the parent mount table.  At the end of this paragraph
     * `md' will be the index where the child should be inserted.
     */
    lt = md = 0;
    rt = parent->mtab.nmounts;
    cmp = -1;
    while (lt<rt && cmp) {
	md = (lt+rt)/2;
	ent = H5G_entof(parent->mtab.child[md].group);
	cmp = H5F_addr_cmp(mp_ent->header, ent->header);
	if (cmp<0) {
	    rt = md;
	} else if (cmp>0) {
	    lt = md+1;
	}
    }
    if (cmp>0) md++;
    if (!cmp) {
	HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL,
		    "mount point is already in use");
    }
    
    /* Make room in the table */
    if (parent->mtab.nmounts>=parent->mtab.nalloc) {
	uintn n = MAX(16, 2*parent->mtab.nalloc);
	H5F_mount_t *x = H5MM_realloc(parent->mtab.child,
				      n*sizeof(parent->mtab.child[0]));
	if (!x) {
	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL,
			"memory allocation failed for mount table");
	}
	parent->mtab.child = x;
	parent->mtab.nalloc = n;
    }

    /* Insert into table */
    HDmemmove(parent->mtab.child+md+1,
	      parent->mtab.child+md,
	      (parent->mtab.nmounts-md)*sizeof(parent->mtab.child[0]));
    parent->mtab.nmounts++;
    parent->mtab.child[md].group = mount_point;
    parent->mtab.child[md].file = child;
    child->mtab.parent = parent;
    child->nrefs++;
    ret_value = SUCCEED;

 done:
    if (ret_value<0 && mount_point) {
	H5G_close(mount_point);
    }
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_unmount
 *
 * Purpose:	Unmount the child which is mounted at the group specified by
 *		LOC and NAME or fail if nothing is mounted there.  Neither
 *		file is closed.
 *
 *		Because the mount point is specified by name and opened as a
 *		group, the H5G_namei() will resolve it to the root of the
 *		mounted file, not the group where the file is mounted.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Tuesday, October  6, 1998
 *
 * Modifications:
 *
 * 	Robb Matzke, 1998-10-14
 *	The ref count for the child is decremented by calling H5F_close().
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5F_unmount(H5G_entry_t *loc, const char *name)
{
    H5G_t	*mounted = NULL;	/*mount point group		*/
    H5G_entry_t	*mnt_ent = NULL;	/*mounted symbol table entry	*/
    H5F_t	*child = NULL;		/*mounted file			*/
    H5F_t	*parent = NULL;		/*file where mounted		*/
    H5G_entry_t	*ent = NULL;		/*temporary symbol table entry	*/
    herr_t	ret_value = FAIL;	/*return value			*/
    uintn	i;			/*coutners			*/
    intn	lt, rt, md=(-1), cmp;	/*binary search indices		*/
    
    FUNC_ENTER(H5F_unmount, FAIL);
    assert(loc);
    assert(name && *name);

    /*
     * Get the mount point, or more precisely the root of the mounted file.
     * If we get the root group and the file has a parent in the mount tree,
     * then we must have found the mount point.
     */
    if (NULL==(mounted=H5G_open(loc, name))) {
	HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "mount point not found");
    }
    child = H5G_fileof(mounted);
    mnt_ent = H5G_entof(mounted);
    ent = H5G_entof(child->shared->root_grp);

    if (child->mtab.parent &&
	H5F_addr_eq(mnt_ent->header, ent->header)) {
	/*
	 * We've been given the root group of the child.  We do a reverse
	 * lookup in the parent's mount table to find the correct entry.
	 */
	parent = child->mtab.parent;
	for (i=0; i<parent->mtab.nmounts; i++) {
	    if (parent->mtab.child[i].file==child) {
		/* Unmount the child */
		parent->mtab.nmounts -= 1;
		H5G_close(parent->mtab.child[i].group);
		child->mtab.parent = NULL;
		H5F_close(child);
		HDmemmove(parent->mtab.child+i,
			  parent->mtab.child+i+1,
			  ((parent->mtab.nmounts-i)*
			   sizeof(parent->mtab.child[0])));
		ret_value = SUCCEED;
	    }
	}
	assert(ret_value>=0);
	
    } else {
	/*
	 * We've been given the mount point in the parent.  We use a binary
	 * search in the parent to locate the mounted file, if any.
	 */
	parent = child; /*we guessed wrong*/
	lt = 0;
	rt = parent->mtab.nmounts;
	cmp = -1;
	while (lt<rt && cmp) {
	    md = (lt+rt)/2;
	    ent = H5G_entof(parent->mtab.child[md].group);
	    cmp = H5F_addr_cmp(mnt_ent->header, ent->header);
	    if (cmp<0) {
		rt = md;
	    } else {
		lt = md+1;
	    }
	}
	if (cmp) {
	    HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "not a mount point");
	}

	/* Unmount the child */
	parent->mtab.nmounts -= 1;
	H5G_close(parent->mtab.child[md].group);
	parent->mtab.child[md].file->mtab.parent = NULL;
	H5F_close(parent->mtab.child[md].file);
	HDmemmove(parent->mtab.child+md,
		  parent->mtab.child+md+1,
		  (parent->mtab.nmounts-md)*sizeof(parent->mtab.child[0]));
	ret_value = SUCCEED;
    }
    
 done:
    if (mounted) H5G_close(mounted);
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_mountpoint
 *
 * Purpose:	If ENT is a mount point then copy the entry for the root
 *		group of the mounted file into ENT.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Tuesday, October  6, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5F_mountpoint(H5G_entry_t *find/*in,out*/)
{
    H5F_t	*parent = find->file;
    intn	lt, rt, md=(-1), cmp;
    H5G_entry_t	*ent = NULL;
    
    FUNC_ENTER(H5F_mountpoint, FAIL);
    assert(find);

    /*
     * The loop is necessary because we might have file1 mounted at the root
     * of file2, which is mounted somewhere in file3.
     */
    do {
	/*
	 * Use a binary search to find the potential mount point in the mount
	 * table for the parent
	 */
	lt = 0;
	rt = parent->mtab.nmounts;
	cmp = -1;
	while (lt<rt && cmp) {
	    md = (lt+rt)/2;
	    ent = H5G_entof(parent->mtab.child[md].group);
	    cmp = H5F_addr_cmp(find->header, ent->header);
	    if (cmp<0) {
		rt = md;
	    } else {
		lt = md+1;
	    }
	}

	/* Copy root info over to ENT */
	if (0==cmp) {
	    ent = H5G_entof(parent->mtab.child[md].file->shared->root_grp);
	    *find = *ent;
	    parent = ent->file;
	}
    } while (!cmp);
    
    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5Fmount
 *
 * Purpose:	Mount file CHILD_ID onto the group specified by LOC_ID and
 *		NAME using mount properties PLIST_ID.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Tuesday, October  6, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Fmount(hid_t loc_id, const char *name, hid_t child_id, hid_t plist_id)
{
    H5G_entry_t		*loc = NULL;
    const H5F_mprop_t	*plist = NULL;
    H5F_t		*child = NULL;
    
    FUNC_ENTER(H5Fmount, FAIL);
    H5TRACE4("e","isii",loc_id,name,child_id,plist_id);

    /* Check arguments */
    if (NULL==(loc=H5G_loc(loc_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location");
    }
    if (!name || !*name) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name");
    }
    if (H5I_FILE!=H5I_get_type(child_id) ||
	NULL==(child=H5I_object(child_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file");
    }
    if (H5P_DEFAULT==plist_id) {
	plist = &H5F_mount_dflt;
    } else if (H5P_MOUNT!=H5P_get_class(plist_id) ||
	       NULL==(plist=H5I_object(plist_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
		      "not a mount property list");
    }

    /* Do the mount */
    if (H5F_mount(loc, name, child, plist)<0) {
	HRETURN_ERROR(H5E_FILE, H5E_MOUNT, FAIL,
		      "unable to mount file");
    }

    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5Funmount
 *
 * Purpose:	Given a mount point, dissassociate the mount point's file
 *		from the file mounted there.  Do not close either file.
 *
 *		The mount point can either be the group in the parent or the
 *		root group of the mounted file (both groups have the same
 *		name).  If the mount point was opened before the mount then
 *		it's the group in the parent, but if it was opened after the
 *		mount then it's the root group of the child.
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *              Tuesday, October  6, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Funmount(hid_t loc_id, const char *name)
{
    H5G_entry_t		*loc = NULL;
    
    FUNC_ENTER(H5Funmount, FAIL);
    H5TRACE2("e","is",loc_id,name);

    /* Check args */
    if (NULL==(loc=H5G_loc(loc_id))) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location");
    }
    if (!name || !*name) {
	HRETURN_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name");
    }

    /* Unmount */
    if (H5F_unmount(loc, name)<0) {
	HRETURN_ERROR(H5E_FILE, H5E_MOUNT, FAIL,
		      "unable to unmount file");
    }

    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5Freopen
 *
 * Purpose:	Reopen a file.  The new file handle which is returned points
 *		to the same file as the specified file handle.  Both handles
 *		share caches and other information.  The only difference
 *		between the handles is that the new handle is not mounted
 *		anywhere and no files are mounted on it.
 *
 * Return:	Success:	New file ID
 *
 *		Failure:	FAIL
 *
 * Programmer:	Robb Matzke
 *              Friday, October 16, 1998
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Freopen(hid_t file_id)
{
    H5F_t	*old_file=NULL;
    H5F_t	*new_file=NULL;
    hid_t	ret_value = -1;
    

    FUNC_ENTER(H5Freopen, FAIL);
    H5TRACE1("i","i",file_id);

    if (H5I_FILE!=H5I_get_type(file_id) ||
	NULL==(old_file=H5I_object(file_id))) {
	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file");
    }
    if (NULL==(new_file=H5F_new(old_file->shared, H5P_DEFAULT, H5P_DEFAULT))) {
	HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to reopen file");
    }
    if ((ret_value=H5I_register(H5I_FILE, new_file))<0) {
	HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL,
		    "unable to atomize file handle");
    }

 done:
    if (ret_value<0 && new_file) {
	H5F_close(new_file);
    }
    FUNC_LEAVE(ret_value);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_block_read
 *
 * Purpose:	Reads some data from a file/server/etc into a buffer.
 *		The data is contiguous.	 The address is relative to the base
 *		address for the file.
 *
 * Errors:
 *		IO	  READERROR	Low-level read failed. 
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 10 1997
 *
 * Modifications:
 *		Albert Cheng, 1998-06-02
 *		Added XFER_MODE argument
 *
 * 		Robb Matzke, 1999-07-28
 *		The ADDR argument is passed by value.
 *
 * 		Robb Matzke, 1999-08-02
 *		Modified to use the virtual file layer. The data transfer
 *		property list is passed in by object ID since that's how the
 *		virtual file layer needs it.
 *-------------------------------------------------------------------------
 */
herr_t
H5F_block_read(H5F_t *f, haddr_t addr, hsize_t size, hid_t dxpl_id,
	       void *buf/*out*/)
{
    haddr_t		    abs_addr;

    FUNC_ENTER(H5F_block_read, FAIL);

    assert(size<SIZET_MAX);

    /* convert the relative address to an absolute address */
    abs_addr = f->shared->base_addr + addr;

    /* Read the data */
    if (H5FD_read(f->shared->lf, dxpl_id, abs_addr, size, buf)<0) {
	HRETURN_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed");
    }
    
    FUNC_LEAVE(SUCCEED);
}

/*-------------------------------------------------------------------------
 * Function:	H5F_block_write
 *
 * Purpose:	Writes some data from memory to a file/server/etc.  The
 *		data is contiguous.  The address is relative to the base
 *		address.
 *
 * Errors:
 *		IO	  WRITEERROR	Low-level write failed. 
 *		IO	  WRITEERROR	No write intent. 
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Jul 10 1997
 *
 * Modifications:
 *		Albert Cheng, 1998-06-02
 *		Added XFER_MODE argument
 *
 * 		Robb Matzke, 1999-07-28
 *		The ADDR argument is passed by value.
 *
 * 		Robb Matzke, 1999-08-02
 *		Modified to use the virtual file layer. The data transfer
 *		property list is passed in by object ID since that's how the
 *		virtual file layer needs it.
 *-------------------------------------------------------------------------
 */
herr_t
H5F_block_write(H5F_t *f, H5FD_mem_t type, haddr_t addr, hsize_t size,
        hid_t dxpl_id, const void *buf)
{
    haddr_t		    abs_addr;

    FUNC_ENTER(H5F_block_write, FAIL);

    assert (size<SIZET_MAX);

    if (0==(f->intent & H5F_ACC_RDWR)) {
	HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "no write intent");
    }

    /* Convert the relative address to an absolute address */
    abs_addr = f->shared->base_addr + addr;

    /* Write the data */
    if (H5FD_write(f->shared->lf, type, dxpl_id, abs_addr, size, buf)) {
	HRETURN_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed");
    }

    FUNC_LEAVE(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_addr_encode
 *
 * Purpose:	Encodes an address into the buffer pointed to by *PP and
 *		then increments the pointer to the first byte after the
 *		address.  An undefined value is stored as all 1's.
 *
 * Return:	void
 *
 * Programmer:	Robb Matzke
 *		Friday, November  7, 1997
 *
 * Modifications:
 *		Robb Matzke, 1999-07-28
 *		The ADDR argument is passed by value.
 *-------------------------------------------------------------------------
 */
void
H5F_addr_encode(H5F_t *f, uint8_t **pp/*in,out*/, haddr_t addr)
{
    uintn		    i;
    haddr_t		    tmp;

    assert(f);
    assert(pp && *pp);

    if (H5F_addr_defined(addr)) {
	tmp = addr;
	for (i=0; i<H5F_SIZEOF_ADDR(f); i++) {
	    *(*pp)++ = (uint8_t)(tmp & 0xff);
	    tmp >>= 8;
	}
	assert("overflow" && 0 == tmp);

    } else {
	for (i=0; i<H5F_SIZEOF_ADDR(f); i++) {
	    *(*pp)++ = 0xff;
	}
    }
}


/*-------------------------------------------------------------------------
 * Function:	H5F_addr_decode
 *
 * Purpose:	Decodes an address from the buffer pointed to by *PP and
 *		updates the pointer to point to the next byte after the
 *		address.
 *
 *		If the value read is all 1's then the address is returned
 *		with an undefined value.
 *
 * Return:	void
 *
 * Programmer:	Robb Matzke
 *		Friday, November  7, 1997
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
void
H5F_addr_decode(H5F_t *f, const uint8_t **pp/*in,out*/, haddr_t *addr_p/*out*/)
{
    uintn		    i;
    haddr_t		    tmp;
    uint8_t		    c;
    hbool_t		    all_zero = TRUE;

    assert(f);
    assert(pp && *pp);
    assert(addr_p);

    *addr_p = 0;

    for (i=0; i<H5F_SIZEOF_ADDR(f); i++) {
	c = *(*pp)++;
	if (c != 0xff) all_zero = FALSE;

	if (i<sizeof(*addr_p)) {
	    tmp = c;
	    tmp <<= i * 8;	/*use tmp to get casting right */
	    *addr_p |= tmp;
	} else if (!all_zero) {
	    assert(0 == **pp);	/*overflow */
	}
    }
    if (all_zero) *addr_p = HADDR_UNDEF;
}


/*-------------------------------------------------------------------------
 * Function:	H5F_addr_pack
 *
 * Purpose:	Converts a long[2] array (usually returned from
 *		H5G_get_objinfo) back into a haddr_t
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Quincey Koziol
 *		Tuesday, October  23, 1998
 *
 * Modifications:
 *		Albert Cheng, 1999-02-18
 *		Changed objno to unsigned long type to be consistent with
 *      	addr->offset and how it is being called.
 *-------------------------------------------------------------------------
 */
herr_t
H5F_addr_pack(H5F_t UNUSED *f, haddr_t *addr_p/*out*/,
	      const unsigned long objno[2])
{
    assert(f);
    assert(objno);
    assert(addr_p);

    *addr_p = objno[0];
#if SIZEOF_LONG<SIZEOF_UINT64_T
    *addr_p |= ((uint64_t)objno[1]) << (8*sizeof(long));
#endif
    
    return(SUCCEED);
}


/*-------------------------------------------------------------------------
 * Function:	H5F_debug
 *
 * Purpose:	Prints a file header to the specified stream.  Each line
 *		is indented and the field name occupies the specified width
 *		number of characters.
 *
 * Errors:
 *
 * Return:	Non-negative on success/Negative on failure
 *
 * Programmer:	Robb Matzke
 *		matzke@llnl.gov
 *		Aug  1 1997
 *
 * Modifications:
 *		Robb Matzke, 1999-07-28
 *		The ADDR argument is passed by value.
 *-------------------------------------------------------------------------
 */
herr_t
H5F_debug(H5F_t *f, haddr_t UNUSED addr, FILE * stream, intn indent,
	  intn fwidth)
{
    FUNC_ENTER(H5F_debug, FAIL);

    /* check args */
    assert(f);
    assert(H5F_addr_defined(addr));
    assert(stream);
    assert(indent >= 0);
    assert(fwidth >= 0);

    /* debug */
    HDfprintf(stream, "%*sFile Boot Block...\n", indent, "");

    HDfprintf(stream, "%*s%-*s %s\n", indent, "", fwidth,
	      "File name:",
	      f->name);
    HDfprintf(stream, "%*s%-*s 0x%08x\n", indent, "", fwidth,
	      "Flags",
	      (unsigned) (f->shared->flags));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Reference count:",
	      (unsigned) (f->shared->nrefs));
    HDfprintf(stream, "%*s%-*s 0x%08lx\n", indent, "", fwidth,
	      "Consistency flags:",
	      (unsigned long) (f->shared->consist_flags));
    HDfprintf(stream, "%*s%-*s %a (abs)\n", indent, "", fwidth,
	      "Address of boot block:", f->shared->boot_addr);
    HDfprintf(stream, "%*s%-*s %a (abs)\n", indent, "", fwidth,
	      "Base address:", f->shared->base_addr);
    HDfprintf(stream, "%*s%-*s %a (rel)\n", indent, "", fwidth,
	      "Free list address:", f->shared->freespace_addr);
    HDfprintf(stream, "%*s%-*s %a (rel)\n", indent, "", fwidth,
	      "Driver information block:", f->shared->driver_addr);
    HDfprintf(stream, "%*s%-*s %lu bytes\n", indent, "", fwidth,
	      "Size of user block:",
	      (unsigned long) (f->shared->fcpl->userblock_size));
    HDfprintf(stream, "%*s%-*s %u bytes\n", indent, "", fwidth,
	      "Size of file size_t type:",
	      (unsigned) (f->shared->fcpl->sizeof_size));
    HDfprintf(stream, "%*s%-*s %u bytes\n", indent, "", fwidth,
	      "Size of file haddr_t type:",
	      (unsigned) (f->shared->fcpl->sizeof_addr));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Symbol table leaf node 1/2 rank:",
	      (unsigned) (f->shared->fcpl->sym_leaf_k));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Symbol table internal node 1/2 rank:",
	      (unsigned) (f->shared->fcpl->btree_k[H5B_SNODE_ID]));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Boot block version number:",
	      (unsigned) (f->shared->fcpl->bootblock_ver));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Free list version number:",
	      (unsigned) (f->shared->fcpl->freespace_ver));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Object directory version number:",
	      (unsigned) (f->shared->fcpl->objectdir_ver));
    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
	      "Shared header version number:",
	      (unsigned) (f->shared->fcpl->sharedheader_ver));

    HDfprintf(stream, "%*s%-*s %s\n", indent, "", fwidth,
	      "Root group symbol table entry:",
	      f->shared->root_grp ? "" : "(none)");
    if (f->shared->root_grp) {
	H5G_ent_debug(f, H5G_entof(f->shared->root_grp), stream,
		      indent+3, MAX(0, fwidth-3), HADDR_UNDEF);
    }
    FUNC_LEAVE(SUCCEED);
}