H5Aint.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * 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 LICENSE file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*-------------------------------------------------------------------------
 *
 * Created:        H5Aint.c
 *
 * Purpose:        Internal routines for managing attributes.
 *
 *-------------------------------------------------------------------------
 */

/****************/
/* Module Setup */
/****************/

#include "H5Amodule.h" /* This source code file is part of the H5A module */
#define H5O_FRIEND     /*suppress error about including H5Opkg      */

/***********/
/* Headers */
/***********/
#include "H5private.h"   /* Generic Functions                        */
#include "H5Apkg.h"      /* Attributes                               */
#include "H5Eprivate.h"  /* Error handling                           */
#include "H5FLprivate.h" /* Free Lists                               */
#include "H5Iprivate.h"  /* IDs                                      */
#include "H5MMprivate.h" /* Memory management                        */
#include "H5Opkg.h"      /* Object headers                           */
#include "H5SMprivate.h" /* Shared Object Header Messages            */
#include "H5VLprivate.h" /* Virtual Object Layer                     */

/****************/
/* Local Macros */
/****************/

/******************/
/* Local Typedefs */
/******************/

/* Data exchange structure to use when building table of compact attributes for an object */
typedef struct {
    H5F_t            *f;             /* Pointer to file that fractal heap is in */
    H5A_attr_table_t *atable;        /* Pointer to attribute table to build */
    bool              bogus_crt_idx; /* Whether bogus creation index values need to be set */
} H5A_compact_bt_ud_t;

/* Data exchange structure to use when copying an attribute from _SRC to _DST */
typedef struct {
    const H5O_ainfo_t *ainfo;          /* dense information    */
    H5F_t             *file;           /* file                 */
    bool              *recompute_size; /* Flag to indicate if size changed */
    H5O_copy_t        *cpy_info;       /* Information on copying options   */
    const H5O_loc_t   *oloc_src;
    H5O_loc_t         *oloc_dst;
} H5A_dense_file_cp_ud_t;

/********************/
/* Package Typedefs */
/********************/

/********************/
/* Local Prototypes */
/********************/

static herr_t H5A__close_cb(void *attr_vol_obj, void **request);
static herr_t H5A__compact_build_table_cb(H5O_t *oh, H5O_mesg_t *mesg /*in,out*/, unsigned sequence,
                                          void *_udata /*in,out*/);
static herr_t H5A__dense_build_table_cb(const H5A_t *attr, void *_udata);
static int    H5A__attr_cmp_name_inc(const void *attr1, const void *attr2);
static int    H5A__attr_cmp_name_dec(const void *attr1, const void *attr2);
static int    H5A__attr_cmp_corder_inc(const void *attr1, const void *attr2);
static int    H5A__attr_cmp_corder_dec(const void *attr1, const void *attr2);
static herr_t H5A__attr_sort_table(H5A_attr_table_t *atable, H5_index_t idx_type, H5_iter_order_t order);
static herr_t H5A__iterate_common(hid_t loc_id, H5_index_t idx_type, H5_iter_order_t order, hsize_t *idx,
                                  H5A_attr_iter_op_t *attr_op, void *op_data);

/*********************/
/* Package Variables */
/*********************/

/* Package initialization variable */
bool H5_PKG_INIT_VAR = false;

/* Format version bounds for attribute */
const unsigned H5O_attr_ver_bounds[] = {
    H5O_ATTR_VERSION_1,     /* H5F_LIBVER_EARLIEST */
    H5O_ATTR_VERSION_3,     /* H5F_LIBVER_V18 */
    H5O_ATTR_VERSION_3,     /* H5F_LIBVER_V110 */
    H5O_ATTR_VERSION_3,     /* H5F_LIBVER_V112 */
    H5O_ATTR_VERSION_3,     /* H5F_LIBVER_V114 */
    H5O_ATTR_VERSION_3,     /* H5F_LIBVER_V200 */
    H5O_ATTR_VERSION_LATEST /* H5F_LIBVER_LATEST */
};

/*****************************/
/* Library Private Variables */
/*****************************/

/*******************/
/* Local Variables */
/*******************/

/* Declare the free lists of H5A_t */
H5FL_DEFINE(H5A_t);

/* Declare the free lists for H5A_shared_t's */
H5FL_DEFINE(H5A_shared_t);

/* Declare a free list to manage blocks of type conversion data */
H5FL_BLK_DEFINE(attr_buf);

typedef H5A_t *H5A_t_ptr;
H5FL_SEQ_DEFINE_STATIC(H5A_t_ptr);

/* Attribute ID class */
static const H5I_class_t H5I_ATTR_CLS[1] = {{
    H5I_ATTR,     /* ID class value */
    0,            /* Class flags */
    0,            /* # of reserved IDs for class */
    H5A__close_cb /* Callback routine for closing objects of this class */
}};

/* Flag indicating "top" of interface has been initialized */
static bool H5A_top_package_initialize_s = false;

/*-------------------------------------------------------------------------
 * Function: H5A_init
 *
 * Purpose:  Initialize the interface from some other layer.
 *
 * Return:   Success:    non-negative
 *
 *           Failure:    negative
 *-------------------------------------------------------------------------
 */
herr_t
H5A_init(void)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI(FAIL)
    /* FUNC_ENTER() does all the work */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A_init() */

/*--------------------------------------------------------------------------
NAME
   H5A__init_package -- Initialize interface-specific information
USAGE
    herr_t H5A__init_package()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.

--------------------------------------------------------------------------*/
herr_t
H5A__init_package(void)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /*
     * Create attribute ID type.
     */
    if (H5I_register_type(H5I_ATTR_CLS) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "unable to initialize interface");

    /* Mark "top" of interface as initialized, too */
    H5A_top_package_initialize_s = true;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__init_package() */

/*--------------------------------------------------------------------------
 NAME
    H5A_top_term_package
 PURPOSE
    Terminate various H5A objects
 USAGE
    void H5A_top_term_package()
 RETURNS
 DESCRIPTION
    Release IDs for the atom group, deferring full interface shutdown
    until later (in H5A_term_package).
 GLOBAL VARIABLES
 COMMENTS, BUGS, ASSUMPTIONS
     Can't report errors...
 EXAMPLES
 REVISION LOG
--------------------------------------------------------------------------*/
int
H5A_top_term_package(void)
{
    int n = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (H5A_top_package_initialize_s) {
        if (H5I_nmembers(H5I_ATTR) > 0) {
            (void)H5I_clear_type(H5I_ATTR, false, false);
            n++; /*H5I*/
        }        /* end if */

        /* Mark closed */
        if (0 == n)
            H5A_top_package_initialize_s = false;
    } /* end if */

    FUNC_LEAVE_NOAPI(n)
} /* H5A_top_term_package() */

/*--------------------------------------------------------------------------
 NAME
    H5A_term_package
 PURPOSE
    Terminate various H5A objects
 USAGE
    void H5A_term_package()
 RETURNS
 DESCRIPTION
    Release any other resources allocated.
 GLOBAL VARIABLES
 COMMENTS, BUGS, ASSUMPTIONS
     Can't report errors...

     Finishes shutting down the interface, after H5A_top_term_package()
     is called
 EXAMPLES
 REVISION LOG
--------------------------------------------------------------------------*/
int
H5A_term_package(void)
{
    int n = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    if (H5_PKG_INIT_VAR) {
        /* Sanity checks */
        assert(0 == H5I_nmembers(H5I_ATTR));
        assert(false == H5A_top_package_initialize_s);

        /* Destroy the attribute object id group */
        n += (H5I_dec_type_ref(H5I_ATTR) > 0);

        /* Mark closed */
        if (0 == n)
            H5_PKG_INIT_VAR = false;
    } /* end if */

    FUNC_LEAVE_NOAPI(n)
} /* H5A_term_package() */

/*-------------------------------------------------------------------------
 * Function:    H5A__create
 *
 * Purpose:     This is the guts of creating an attribute.
 *
 * Return:      Attribute structure on success, NULL on Failure.
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__create(const H5G_loc_t *loc, const char *attr_name, const H5T_t *type, const H5S_t *space, hid_t acpl_id)
{
    H5A_t   *attr = NULL;      /* Attribute created */
    hssize_t snelmts;          /* elements in attribute */
    size_t   nelmts;           /* elements in attribute */
    bool     exists;           /* Whether attribute exists */
    H5A_t   *ret_value = NULL; /* Return value */

    FUNC_ENTER_PACKAGE_TAG(loc->oloc->addr)

    /* Check args */
    assert(loc);
    assert(attr_name);
    assert(type);
    assert(space);

    /* Check for existing attribute with same name */
    /* (technically, the "attribute create" operation will fail for a duplicated
     *  name, but it's going to be hard to unwind all the special cases on
     *  failure, so just check first, for now - QAK)
     */
    exists = false;
    if (H5O__attr_exists(loc->oloc, attr_name, &exists) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "error checking attributes");
    if (exists)
        HGOTO_ERROR(H5E_ATTR, H5E_ALREADYEXISTS, NULL, "attribute already exists");

    /* Check if the dataspace has an extent set (or is NULL) */
    if (!(H5S_has_extent(space)))
        HGOTO_ERROR(H5E_ATTR, H5E_BADVALUE, NULL, "dataspace extent has not been set");

    /* Check if the datatype is "sensible" for use in a dataset */
    if (H5T_is_sensible(type) != true)
        HGOTO_ERROR(H5E_ATTR, H5E_BADTYPE, NULL, "datatype is not sensible");

    /* Build the attribute information */
    if (NULL == (attr = H5FL_CALLOC(H5A_t)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, NULL, "memory allocation failed for attribute info");

    if (NULL == (attr->shared = H5FL_CALLOC(H5A_shared_t)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, NULL, "can't allocate shared attr structure");

    /* If the creation property list is H5P_ATTRIBUTE_CREATE_DEFAULT, use the default character encoding */
    assert(acpl_id != H5P_DEFAULT);
    if (acpl_id == H5P_ATTRIBUTE_CREATE_DEFAULT)
        attr->shared->encoding = H5F_DEFAULT_CSET;
    else {
        H5P_genplist_t *ac_plist; /* ACPL Property list */

        /* Get a local copy of the attribute creation property list */
        if (NULL == (ac_plist = (H5P_genplist_t *)H5I_object(acpl_id)))
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a property list");

        if (H5P_get(ac_plist, H5P_STRCRT_CHAR_ENCODING_NAME, &(attr->shared->encoding)) < 0)
            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get character encoding flag");
    } /* end else */

    /* Copy the attribute name */
    attr->shared->name = H5MM_xstrdup(attr_name);

    /* Copy datatype */
    if (NULL == (attr->shared->dt = H5T_copy(type, H5T_COPY_ALL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, NULL, "can't get shared datatype info");

    /* Convert a datatype (if committed) to a transient type if the committed datatype's file
       location is different from the file location where the attribute will be created */
    if (H5T_convert_committed_datatype(attr->shared->dt, loc->oloc->file) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, NULL, "can't get shared datatype info");

    /* Mark datatype as being on disk now */
    if (H5T_set_loc(attr->shared->dt, H5F_VOL_OBJ(loc->oloc->file), H5T_LOC_DISK) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "invalid datatype location");

    /* Set the version for datatype */
    if (H5T_set_version(loc->oloc->file, attr->shared->dt) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set version of datatype");

    /* Copy the dataspace for the attribute */
    attr->shared->ds = H5S_copy(space, false, true);

    /* Set the version for dataspace */
    if (H5S_set_version(loc->oloc->file, attr->shared->ds) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, NULL, "can't set version of dataspace");

    /* Copy the object header information */
    if (H5O_loc_copy_deep(&(attr->oloc), loc->oloc) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to copy entry");

    /* Deep copy of the group hierarchy path */
    if (H5G_name_copy(&(attr->path), loc->path, H5_COPY_DEEP) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, NULL, "unable to copy path");

    /* Check if any of the pieces should be (or are already) shared in the
     * SOHM table
     */
    if (H5SM_try_share(attr->oloc.file, NULL, 0, H5O_DTYPE_ID, attr->shared->dt, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, NULL, "trying to share datatype failed");
    if (H5SM_try_share(attr->oloc.file, NULL, 0, H5O_SDSPACE_ID, attr->shared->ds, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, NULL, "trying to share dataspace failed");

    /* Check whether datatype is committed & increment ref count
     * (to maintain ref. count incr/decr similarity with "shared message"
     *      type of datatype sharing)
     */
    if (H5T_is_named(attr->shared->dt))
        /* Increment the reference count on the shared datatype */
        if (H5T_link(attr->shared->dt, 1) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_LINKCOUNT, NULL, "unable to adjust shared datatype link count");

    /* Compute the size of pieces on disk.  This is either the size of the
     * datatype and dataspace messages themselves, or the size of the "shared"
     * messages if either or both of them are shared.
     */
    attr->shared->dt_size = H5O_msg_raw_size(attr->oloc.file, H5O_DTYPE_ID, false, attr->shared->dt);
    attr->shared->ds_size = H5O_msg_raw_size(attr->oloc.file, H5O_SDSPACE_ID, false, attr->shared->ds);

    /* Get # of elements for attribute's dataspace */
    if ((snelmts = H5S_GET_EXTENT_NPOINTS(attr->shared->ds)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOUNT, NULL, "dataspace is invalid");
    H5_CHECKED_ASSIGN(nelmts, size_t, snelmts, hssize_t);

    assert(attr->shared->dt_size > 0);
    assert(attr->shared->ds_size > 0);
    attr->shared->data_size = nelmts * H5T_GET_SIZE(attr->shared->dt);

    /* Hold the symbol table entry (and file) open */
    if (H5O_open(&(attr->oloc)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to open");
    attr->obj_opened = true;

    /* Set the version to encode the attribute with */
    if (H5A__set_version(attr->oloc.file, attr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, NULL, "unable to update attribute version");

    /* Insert the attribute into the object header */
    if (H5O__attr_create(&(attr->oloc), attr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINSERT, NULL, "unable to create attribute in object header");

    /* Set return value */
    ret_value = attr;

done:
    /* Cleanup on failure */
    if (NULL == ret_value && attr && H5A__close(attr))
        HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI_TAG(ret_value)
} /* H5A__create() */

/*-------------------------------------------------------------------------
 * Function:    H5A__create_by_name
 *
 * Purpose:     Create an attribute on object, according to it's name
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__create_by_name(const H5G_loc_t *loc, const char *obj_name, const char *attr_name, const H5T_t *type,
                    const H5S_t *space, hid_t acpl_id)
{
    H5G_loc_t  obj_loc;           /* Location used to open group */
    H5G_name_t obj_path;          /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;          /* Opened object object location */
    bool       loc_found = false; /* Entry at 'obj_name' found */
    H5A_t     *attr      = NULL;  /* Attribute from object header */
    H5A_t     *ret_value = NULL;  /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(loc);
    assert(obj_name);
    assert(attr_name);

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "object not found");
    loc_found = true;

    /* Go do the real work for attaching the attribute to the object */
    if (NULL == (attr = H5A__create(&obj_loc, attr_name, type, space, acpl_id)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to create attribute");

    /* Set return value */
    ret_value = attr;

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, NULL, "can't free location");

    /* Cleanup on failure */
    if (ret_value == NULL)
        if (attr && H5A__close(attr) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__create_by_name() */

/*-------------------------------------------------------------------------
 * Function:    H5A__open_common
 *
 * Purpose:     Finishes initializing an attributes the open
 *
 * Usage:
 *  herr_t H5A__open_common(loc, name)
 *      const H5G_loc_t *loc;   IN: Pointer to group location for object
 *      H5A_t *attr;            IN/OUT: Pointer to attribute to initialize
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__open_common(const H5G_loc_t *loc, H5A_t *attr)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(loc);
    assert(attr);

#if defined(H5_USING_MEMCHECKER) || !defined(NDEBUG)
    /* Clear object location */
    if (H5O_loc_reset(&(attr->oloc)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to reset location");
#endif /* H5_USING_MEMCHECKER */

    /* Free any previous group hier. path */
    if (H5G_name_free(&(attr->path)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release group hier. path");

    /* Deep copy of the symbol table entry */
    if (H5O_loc_copy_deep(&(attr->oloc), loc->oloc) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to copy entry");

    /* Deep copy of the group hier. path */
    if (H5G_name_copy(&(attr->path), loc->path, H5_COPY_DEEP) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, FAIL, "unable to copy entry");

    /* Hold the symbol table entry (and file) open */
    if (H5O_open(&(attr->oloc)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to open");
    attr->obj_opened = true;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__open_common() */

/*-------------------------------------------------------------------------
 * Function:    H5A__open
 *
 * Purpose:     Open an attribute in an object header
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__open(const H5G_loc_t *loc, const char *attr_name)
{
    H5A_t *attr      = NULL; /* Attribute from object header */
    H5A_t *ret_value = NULL; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(loc);
    assert(attr_name);

    /* Read in attribute from object header */
    if (NULL == (attr = H5O__attr_open_by_name(loc->oloc, attr_name)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL,
                    "unable to load attribute info from object header for attribute: '%s'", attr_name);

    /* Finish initializing attribute */
    if (H5A__open_common(loc, attr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to initialize attribute");

    /* Set return value */
    ret_value = attr;

done:
    /* Cleanup on failure */
    if (ret_value == NULL)
        if (attr && H5A__close(attr) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__open() */

/*-------------------------------------------------------------------------
 * Function:    H5A__open_by_idx
 *
 * Purpose:     Open an attribute according to its index order
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__open_by_idx(const H5G_loc_t *loc, const char *obj_name, H5_index_t idx_type, H5_iter_order_t order,
                 hsize_t n)
{
    H5G_loc_t  obj_loc;           /* Location used to open group */
    H5G_name_t obj_path;          /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;          /* Opened object object location */
    bool       loc_found = false; /* Entry at 'obj_name' found */
    H5A_t     *attr      = NULL;  /* Attribute from object header */
    H5A_t     *ret_value = NULL;  /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(loc);
    assert(obj_name);

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "object not found");
    loc_found = true;

    /* Read in attribute from object header */
    if (NULL == (attr = H5O__attr_open_by_idx(obj_loc.oloc, idx_type, order, n)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, NULL, "unable to load attribute info from object header");

    /* Finish initializing attribute */
    if (H5A__open_common(&obj_loc, attr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to initialize attribute");

    /* Set return value */
    ret_value = attr;

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, NULL, "can't free location");

    /* Cleanup on failure */
    if (ret_value == NULL)
        if (attr && H5A__close(attr) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__open_by_idx() */

/*-------------------------------------------------------------------------
 * Function:    H5A__open_by_name
 *
 * Purpose:     Open an attribute in an object header, according to it's name
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__open_by_name(const H5G_loc_t *loc, const char *obj_name, const char *attr_name)
{
    H5G_loc_t  obj_loc;           /* Location used to open group */
    H5G_name_t obj_path;          /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;          /* Opened object object location */
    bool       loc_found = false; /* Entry at 'obj_name' found */
    H5A_t     *attr      = NULL;  /* Attribute from object header */
    H5A_t     *ret_value = NULL;  /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(loc);
    assert(obj_name);
    assert(attr_name);

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, NULL, "object not found");
    loc_found = true;

    /* Read in attribute from object header */
    if (NULL == (attr = H5O__attr_open_by_name(obj_loc.oloc, attr_name)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to load attribute info from object header");

    /* Finish initializing attribute */
    if (H5A__open_common(loc, attr) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, NULL, "unable to initialize attribute");

    /* Set return value */
    ret_value = attr;

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, NULL, "can't free location");

    /* Cleanup on failure */
    if (ret_value == NULL)
        if (attr && H5A__close(attr) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__open_by_name() */

/*--------------------------------------------------------------------------
 NAME
    H5A__read
 PURPOSE
    Actually read in data from an attribute
 USAGE
    herr_t H5A__read (attr, mem_type, buf)
        H5A_t *attr;         IN: Attribute to read
        const H5T_t *mem_type;     IN: Memory datatype of buffer
        void *buf;           IN: Buffer for data to read
 RETURNS
    Non-negative on success/Negative on failure

 DESCRIPTION
    This function reads a complete attribute from disk.
--------------------------------------------------------------------------*/
herr_t
H5A__read(const H5A_t *attr, const H5T_t *mem_type, void *buf)
{
    uint8_t    *tconv_buf = NULL; /* datatype conv buffer*/
    uint8_t    *bkg_buf   = NULL; /* background buffer */
    hssize_t    snelmts;          /* elements in attribute */
    size_t      nelmts;           /* elements in attribute*/
    H5T_path_t *tpath = NULL;     /* type conversion info    */
    size_t      src_type_size;    /* size of source type     */
    size_t      dst_type_size;    /* size of destination type */
    size_t      buf_size;         /* desired buffer size    */
    herr_t      ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE_TAG(attr->oloc.addr)

    assert(attr);
    assert(mem_type);
    assert(buf);

    /* Patch the top level file pointer in attr->shared->dt->shared->u.vlen.f if needed */
    if (H5T_patch_vlen_file(attr->shared->dt, H5F_VOL_OBJ(attr->oloc.file)) < 0)
        HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "can't patch VL datatype file pointer");

    /* Create buffer for data to store on disk */
    if ((snelmts = H5S_GET_EXTENT_NPOINTS(attr->shared->ds)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOUNT, FAIL, "dataspace is invalid");
    H5_CHECKED_ASSIGN(nelmts, size_t, snelmts, hssize_t);

    if (nelmts > 0) {
        /* Get the memory and file datatype sizes */
        src_type_size = H5T_GET_SIZE(attr->shared->dt);
        dst_type_size = H5T_GET_SIZE(mem_type);

        /* Check if the attribute has any data yet, if not, fill with zeroes */
        if (attr->obj_opened && !attr->shared->data)
            memset(buf, 0, (dst_type_size * nelmts));
        else { /* Attribute exists and has a value */
            /* Convert memory buffer into disk buffer */
            /* Set up type conversion function */
            if (NULL == (tpath = H5T_path_find(attr->shared->dt, mem_type)))
                HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, FAIL,
                            "unable to convert between src and dst datatypes");

            /* Check for type conversion required */
            if (!H5T_path_noop(tpath)) {
                H5T_bkg_t need_bkg; /* Background buffer type */

                /* Get the maximum buffer size needed and allocate it */
                buf_size = nelmts * MAX(src_type_size, dst_type_size);
                if (NULL == (tconv_buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                    HGOTO_ERROR(H5E_ATTR, H5E_NOSPACE, FAIL, "memory allocation failed");

                /* Copy the attribute data into the buffer for conversion */
                H5MM_memcpy(tconv_buf, attr->shared->data, (src_type_size * nelmts));

                /* Check if we need a background buffer */
                need_bkg = H5T_path_bkg(tpath);

                if (need_bkg) {
                    /* Allocate background buffer */
                    if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
                        HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed");

                    /* Copy the application buffer into the background buffer if necessary */
                    if (need_bkg == H5T_BKG_YES) {
                        assert(buf_size >= (dst_type_size * nelmts));
                        H5MM_memcpy(bkg_buf, buf, dst_type_size * nelmts);
                    }
                }

                /* Perform datatype conversion.  */
                if (H5T_convert(tpath, attr->shared->dt, mem_type, nelmts, (size_t)0, (size_t)0, tconv_buf,
                                bkg_buf) < 0)
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTCONVERT, FAIL, "datatype conversion failed");

                /* Copy the converted data into the user's buffer */
                H5MM_memcpy(buf, tconv_buf, (dst_type_size * nelmts));
            } /* end if */
            /* No type conversion necessary */
            else {
                assert(dst_type_size == src_type_size);

                /* Copy the attribute data into the user's buffer */
                H5MM_memcpy(buf, attr->shared->data, (dst_type_size * nelmts));
            } /* end else */
        }     /* end else */
    }         /* end if */

done:
    /* Release resources */
    if (tconv_buf)
        tconv_buf = H5FL_BLK_FREE(attr_buf, tconv_buf);
    if (bkg_buf)
        bkg_buf = H5FL_BLK_FREE(attr_buf, bkg_buf);

    FUNC_LEAVE_NOAPI_TAG(ret_value)
} /* H5A__read() */

/*--------------------------------------------------------------------------
 NAME
    H5A__write
 PURPOSE
    Actually write out data to an attribute
 USAGE
    herr_t H5A__write (attr, mem_type, buf)
        H5A_t *attr;         IN: Attribute to write
        const H5T_t *mem_type;     IN: Memory datatype of buffer
        const void *buf;           IN: Buffer of data to write
 RETURNS
    Non-negative on success/Negative on failure
 DESCRIPTION
    This function writes a complete attribute to disk.
--------------------------------------------------------------------------*/
herr_t
H5A__write(H5A_t *attr, const H5T_t *mem_type, const void *buf)
{
    uint8_t    *tconv_buf = NULL; /* datatype conv buffer */
    uint8_t    *bkg_buf   = NULL; /* temp conversion buffer */
    hssize_t    snelmts;          /* elements in attribute */
    size_t      nelmts;           /* elements in attribute */
    H5T_path_t *tpath = NULL;     /* conversion information*/
    size_t      src_type_size;    /* size of source type    */
    size_t      dst_type_size;    /* size of destination type*/
    size_t      buf_size;         /* desired buffer size    */
    herr_t      ret_value = SUCCEED;

    FUNC_ENTER_PACKAGE_TAG(attr->oloc.addr)

    assert(attr);
    assert(mem_type);
    assert(buf);

    /* Patch the top level file pointer in attr->shared->dt->shared->u.vlen.f if needed */
    if (H5T_patch_vlen_file(attr->shared->dt, H5F_VOL_OBJ(attr->oloc.file)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "can't patch VL datatype file pointer");

    /* Get # of elements for attribute's dataspace */
    if ((snelmts = H5S_GET_EXTENT_NPOINTS(attr->shared->ds)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOUNT, FAIL, "dataspace is invalid");
    H5_CHECKED_ASSIGN(nelmts, size_t, snelmts, hssize_t);

    /* If there's actually data elements for the attribute, make a copy of the data passed in */
    if (nelmts > 0) {
        /* Get the memory and file datatype sizes */
        src_type_size = H5T_GET_SIZE(mem_type);
        dst_type_size = H5T_GET_SIZE(attr->shared->dt);

        /* Convert memory buffer into disk buffer */
        /* Set up type conversion function */
        if (NULL == (tpath = H5T_path_find(mem_type, attr->shared->dt)))
            HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, FAIL, "unable to convert between src and dst datatypes");

        /* Check for type conversion required */
        if (!H5T_path_noop(tpath)) {
            H5T_bkg_t need_bkg; /* Background buffer type */

            /* Get the maximum buffer size needed and allocate it */
            buf_size = nelmts * MAX(src_type_size, dst_type_size);
            if (NULL == (tconv_buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed");

            /* Copy the user's data into the buffer for conversion */
            H5MM_memcpy(tconv_buf, buf, (src_type_size * nelmts));

            /* Check if we need a background buffer */
            if (H5T_detect_class(attr->shared->dt, H5T_VLEN, false))
                need_bkg = H5T_BKG_YES;
            else
                need_bkg = H5T_path_bkg(tpath);

            if (need_bkg) {
                /* Use the existing attribute data buffer, if present, as the background buffer,
                 * otherwise allocate one.  Note we don't need to track which one it is since both
                 * use the "attr_buf" free list block. */
                if (attr->shared->data) {
                    bkg_buf            = attr->shared->data;
                    attr->shared->data = NULL;

                    /* Clear background buffer if it's not supposed to be initialized with file
                     * contents */
                    if (need_bkg == H5T_BKG_TEMP)
                        memset(bkg_buf, 0, dst_type_size * nelmts);
                }
                else if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed");
            }

            /* Perform datatype conversion */
            if (H5T_convert(tpath, mem_type, attr->shared->dt, nelmts, (size_t)0, (size_t)0, tconv_buf,
                            bkg_buf) < 0)
                HGOTO_ERROR(H5E_ATTR, H5E_CANTCONVERT, FAIL, "datatype conversion failed");

            /* Free the previous attribute data buffer, if there is one */
            if (attr->shared->data)
                attr->shared->data = H5FL_BLK_FREE(attr_buf, attr->shared->data);

            /* Set the pointer to the attribute data to the converted information */
            attr->shared->data = tconv_buf;
            tconv_buf          = NULL;
        } /* end if */
        /* No type conversion necessary */
        else {
            assert(dst_type_size == src_type_size);

            /* Allocate the attribute buffer, if there isn't one */
            if (attr->shared->data == NULL)
                if (NULL == (attr->shared->data = H5FL_BLK_MALLOC(attr_buf, dst_type_size * nelmts)))
                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");

            /* Copy the attribute data into the attribute data buffer */
            H5MM_memcpy(attr->shared->data, buf, (dst_type_size * nelmts));
        } /* end else */

        /* Modify the attribute in the object header */
        if (H5O__attr_write(&(attr->oloc), attr) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "unable to modify attribute");
    } /* end if */

done:
    /* Release resources */
    if (tconv_buf)
        tconv_buf = H5FL_BLK_FREE(attr_buf, tconv_buf);
    if (bkg_buf)
        bkg_buf = H5FL_BLK_FREE(attr_buf, bkg_buf);

    FUNC_LEAVE_NOAPI_TAG(ret_value)
} /* H5A__write() */

/*--------------------------------------------------------------------------
 NAME
    H5A__get_name
 PURPOSE
    Gets a copy of the name for an attribute
 RETURNS
    Non-negative on success/Negative on failure
 DESCRIPTION
        This function retrieves the name of an attribute for an attribute ID.
    Up to 'buf_size' characters are stored in 'buf' followed by a '\0' string
    terminator.  If the name of the attribute is longer than 'buf_size'-1,
    the string terminator is stored in the last position of the buffer to
    properly terminate the string.
        This function returns the length of the attribute's name (which may be
    longer than 'buf_size') in the 'attr_name_len' parameter.
--------------------------------------------------------------------------*/
herr_t
H5A__get_name(H5A_t *attr, size_t buf_size, char *buf, size_t *attr_name_len)
{
    size_t copy_len, nbytes;

    FUNC_ENTER_PACKAGE_NOERR

    /* Sanity checks */
    assert(attr);
    assert(attr_name_len);

    /* Get the real attribute length */
    nbytes = strlen(attr->shared->name);

    /* Compute the string length which will fit into the user's buffer */
    copy_len = MIN(buf_size - 1, nbytes);

    /* Copy all/some of the name */
    if (buf && copy_len > 0) {
        H5MM_memcpy(buf, attr->shared->name, copy_len);

        /* Terminate the string */
        buf[copy_len] = '\0';
    } /* end if */

    /* Set actual attribute name length */
    *attr_name_len = nbytes;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* H5A__get_name() */

/*-------------------------------------------------------------------------
 * Function:    H5A_get_space
 *
 * Purpose:     Returns dataspace of the attribute.
 *
 * Return:      Success:    A valid ID for the dataspace of an attribute
 *
 *              Failure:    H5I_INVALID_ID
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5A_get_space(H5A_t *attr)
{
    H5S_t *ds        = NULL;
    hid_t  ret_value = H5I_INVALID_HID;

    FUNC_ENTER_NOAPI_NOINIT

    assert(attr);

    /* Copy the attribute's dataspace */
    if (NULL == (ds = H5S_copy(attr->shared->ds, false, true)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5I_INVALID_HID, "unable to copy dataspace");

    /* Register */
    if ((ret_value = H5I_register(H5I_DATASPACE, ds, true)) < 0)
        HGOTO_ERROR(H5E_ID, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register dataspace ID");

done:
    if (H5I_INVALID_HID == ret_value && ds && H5S_close(ds) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "unable to release dataspace");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A_get_space() */

/*-------------------------------------------------------------------------
 * Function:    H5A__get_type
 *
 * Purpose:     Returns an ID for the datatype of an attribute
 *
 * Return:      Success:    A valid ID for the datatype of an attribute
 *              Failure:    H5I_INVALID_HID
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5A__get_type(H5A_t *attr)
{
    H5T_t *dt        = NULL;
    hid_t  ret_value = H5I_INVALID_HID;

    FUNC_ENTER_PACKAGE

    assert(attr);

    /* Patch the datatype's "top level" file pointer */
    if (H5T_patch_file(attr->shared->dt, attr->oloc.file) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5I_INVALID_HID, "unable to patch datatype's file pointer");

    /* Copy the attribute's datatype.  If the type is a named type then
     * reopen the type before returning it to the user. Make the type
     * read-only.
     */
    if (NULL == (dt = H5T_copy_reopen(attr->shared->dt)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, H5I_INVALID_HID, "unable to copy datatype");

    /* Mark any datatypes as being in memory now */
    if (H5T_set_loc(dt, NULL, H5T_LOC_MEMORY) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, H5I_INVALID_HID, "invalid datatype location");

    /* Lock copied type */
    if (H5T_lock(dt, false) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, H5I_INVALID_HID, "unable to lock transient datatype");

    /* Register */
    if (H5T_is_named(dt)) {
        /* If this is a committed datatype, we need to recreate the
         * two level IDs, where the VOL object is a copy of the
         * returned datatype
         */
        if ((ret_value = H5VL_wrap_register(H5I_DATATYPE, dt, true)) < 0)
            HGOTO_ERROR(H5E_ID, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register file handle");
    }
    else {
        if ((ret_value = H5I_register(H5I_DATATYPE, dt, true)) < 0)
            HGOTO_ERROR(H5E_ID, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register datatype");
    }

done:
    if (H5I_INVALID_HID == ret_value)
        if (dt && H5T_close(dt) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5I_INVALID_HID, "unable to release datatype");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__get_type() */

/*--------------------------------------------------------------------------
 NAME
    H5A__get_create_plist
 PURPOSE
    Private version of H5Aget_create_plist
 RETURNS
    This function returns the ID of a copy of the attribute's creation
    property list, or negative on failure.
 DESCRIPTION
        This function returns a copy of the creation property list for
    an attribute.  The resulting ID must be closed with H5Pclose() or
    resource leaks will occur.
--------------------------------------------------------------------------*/
hid_t
H5A__get_create_plist(H5A_t *attr)
{
    H5P_genplist_t *plist;                       /* Default property list */
    hid_t           new_plist_id;                /* ID of ACPL to return */
    H5P_genplist_t *new_plist;                   /* ACPL to return */
    hid_t           ret_value = H5I_INVALID_HID; /* Return value */

    FUNC_ENTER_PACKAGE

    if (NULL == (plist = (H5P_genplist_t *)H5I_object(H5P_LST_ATTRIBUTE_CREATE_ID_g)))
        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "can't get default ACPL");

    /* Create the property list object to return */
    if ((new_plist_id = H5P_copy_plist(plist, true)) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTINIT, FAIL, "unable to copy attribute creation properties");
    if (NULL == (new_plist = (H5P_genplist_t *)H5I_object(new_plist_id)))
        HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL, "can't get property list");

    /* Set the character encoding on the new property list */
    if (H5P_set(new_plist, H5P_STRCRT_CHAR_ENCODING_NAME, &(attr->shared->encoding)) < 0)
        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set character encoding");

    ret_value = new_plist_id;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__get_create_plist() */

/*-------------------------------------------------------------------------
 * Function:    H5A__get_info
 *
 * Purpose:    Retrieve information about an attribute.
 *
 * Return:    Success:    Non-negative
 *        Failure:    Negative
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__get_info(const H5A_t *attr, H5A_info_t *ainfo)
{
    FUNC_ENTER_PACKAGE_NOERR

    /* Check args */
    assert(attr);
    assert(ainfo);

    /* Set info for attribute */
    ainfo->cset      = attr->shared->encoding;
    ainfo->data_size = attr->shared->data_size;
    if (attr->shared->crt_idx == H5O_MAX_CRT_ORDER_IDX) {
        ainfo->corder_valid = false;
        ainfo->corder       = 0;
    } /* end if */
    else {
        ainfo->corder_valid = true;
        ainfo->corder       = attr->shared->crt_idx;
    } /* end else */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5A__get_info() */

/*-------------------------------------------------------------------------
 * Function:    H5A__copy
 *
 * Purpose:     Copies attribute OLD_ATTR.
 *
 * Return:      Success:    Pointer to a new copy of the OLD_ATTR argument.
 *              Failure:    NULL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__copy(H5A_t *_new_attr, const H5A_t *old_attr)
{
    H5A_t *new_attr       = NULL;
    bool   allocated_attr = false; /* Whether the attribute was allocated */
    H5A_t *ret_value      = NULL;  /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(old_attr);

    /* Allocate attribute structure */
    if (_new_attr == NULL) {
        if (NULL == (new_attr = H5FL_CALLOC(H5A_t)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
        allocated_attr = true;
    } /* end if */
    else
        new_attr = _new_attr;

    /* Copy the top level of the attribute */
    new_attr->sh_loc = old_attr->sh_loc;

    /* Deep copy of the group hierarchy path */
    if (H5G_name_copy(&(new_attr->path), &(old_attr->path), H5_COPY_DEEP) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, NULL, "unable to copy path");

    /* Share some attribute information */
    new_attr->shared = old_attr->shared;

    /* Increment reference count for shared object */
    new_attr->shared->nrefs++;

    /* Don't open the object header for a copy */
    new_attr->obj_opened = false;

    /* Set the return value */
    ret_value = new_attr;

done:
    if (ret_value == NULL)
        if (allocated_attr && new_attr && H5A__close(new_attr) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__copy() */

/*-------------------------------------------------------------------------
 * Function:    H5A__shared_free
 *
 * Purpose:     Cleans up the shared attribute data. This will free
 *              the attribute's shared structure as well.
 *
 *              attr and attr->shared must not be NULL
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__shared_free(H5A_t *attr)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    assert(attr);
    assert(attr->shared);

    /* Free dynamically allocated items.
     * When possible, keep trying to shut things down (via HDONE_ERROR).
     */
    if (attr->shared->name) {
        H5MM_xfree(attr->shared->name);
        attr->shared->name = NULL;
    }
    if (attr->shared->dt) {
        if (H5T_close_real(attr->shared->dt) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release datatype info");
        attr->shared->dt = NULL;
    }
    if (attr->shared->ds) {
        if (H5S_close(attr->shared->ds) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release dataspace info");
        attr->shared->ds = NULL;
    }
    if (attr->shared->data)
        attr->shared->data = H5FL_BLK_FREE(attr_buf, attr->shared->data);

    /* Destroy shared attribute struct */
    attr->shared = H5FL_FREE(H5A_shared_t, attr->shared);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__shared_free() */

/*-------------------------------------------------------------------------
 * Function:    H5A__close_cb
 *
 * Purpose:     Called when the ref count reaches zero on the attribute's ID
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__close_cb(void *attr_vol_obj, void **request)
{
    H5VL_object_t *attr_vol_obj_p = (H5VL_object_t *)attr_vol_obj;
    herr_t         ret_value      = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(attr_vol_obj_p);

    /* Close the attribute */
    if (H5VL_attr_close(attr_vol_obj_p, H5P_DATASET_XFER_DEFAULT, request) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CLOSEERROR, FAIL, "problem closing attribute");

    /* Free the VOL object */
    if (H5VL_free_object(attr_vol_obj_p) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to free VOL object");

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__close_cb() */

/*-------------------------------------------------------------------------
 * Function:    H5A__close
 *
 * Purpose:     Frees an attribute and all associated memory.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__close(H5A_t *attr)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    assert(attr);
    assert(attr->shared);

    /* Close the object's symbol-table entry */
    if (attr->obj_opened && (H5O_close(&(attr->oloc), NULL) < 0))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release object header info");

    /* Reference count can be 0.  It only happens when H5A__create fails. */
    if (attr->shared->nrefs <= 1) {
        /* Free dynamically allocated items */
        if (attr->shared)
            if (H5A__shared_free(attr) < 0)
                HGOTO_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release attribute info");
    } /* end if */
    else {
        /* There are other references to the shared part of the attribute.
         * Only decrement the reference count. */
        --attr->shared->nrefs;
    } /* end else */

    /* Free group hierarchy path */
    if (H5G_name_free(&(attr->path)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't release group hier. path");

    attr->shared = NULL;
    attr         = H5FL_FREE(H5A_t, attr);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__close() */

/*-------------------------------------------------------------------------
 * Function:    H5A_oloc
 *
 * Purpose:    Return the object location for an attribute.  It's the
 *        object location for the object to which the attribute
 *        belongs, not the attribute itself.
 *
 * Return:    Success:    Ptr to entry
 *        Failure:    NULL
 *
 *-------------------------------------------------------------------------
 */
H5O_loc_t *
H5A_oloc(H5A_t *attr)
{
    H5O_loc_t *ret_value = NULL; /* Return value */

    FUNC_ENTER_NOAPI(NULL)

    assert(attr);

    /* Set return value */
    ret_value = &(attr->oloc);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A_oloc() */

/*-------------------------------------------------------------------------
 * Function:    H5A_nameof
 *
 * Purpose:    Return the group hier. path for an attribute.  It's the
 *        group hier. path for the object to which the attribute
 *        belongs, not the attribute itself.
 *
 * Return:    Success:    Ptr to entry
 *        Failure:    NULL
 *
 *-------------------------------------------------------------------------
 */
H5G_name_t *
H5A_nameof(H5A_t *attr)
{
    H5G_name_t *ret_value = NULL; /* Return value */

    FUNC_ENTER_NOAPI(NULL)

    assert(attr);

    /* Set return value */
    ret_value = &(attr->path);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A_nameof() */

/*-------------------------------------------------------------------------
 * Function:    H5A_type
 *
 * Purpose:     Return the datatype for an attribute.
 *
 * Return:      Success:        Ptr to entry
 *              Failure:        NULL
 *
 *-------------------------------------------------------------------------
 */
H5T_t *
H5A_type(const H5A_t *attr)
{
    H5T_t *ret_value = NULL; /* Return value */

    FUNC_ENTER_NOAPI(NULL)

    assert(attr);

    /* Set return value */
    ret_value = attr->shared->dt;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A_type() */

/*-------------------------------------------------------------------------
 * Function:    H5A__exists_by_name
 *
 * Purpose:     Private version of H5Aexists_by_name
 *
 * Return:      true/false/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__exists_by_name(H5G_loc_t loc, const char *obj_name, const char *attr_name, bool *attr_exists)
{
    H5G_loc_t  obj_loc;             /* Location used to open group */
    H5G_name_t obj_path;            /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;            /* Opened object object location */
    bool       loc_found = false;   /* Entry at 'obj_name' found */
    herr_t     ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(obj_name);
    assert(attr_name);
    assert(attr_exists);

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(&loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "object not found");
    loc_found = true;

    /* Check if the attribute exists */
    if (H5O__attr_exists(obj_loc.oloc, attr_name, attr_exists) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "unable to determine if attribute exists");

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__exists_by_name() */

/*-------------------------------------------------------------------------
 * Function:    H5A__compact_build_table_cb
 *
 * Purpose:    Object header iterator callback routine to copy attribute
 *              into table.
 *
 * Return:    Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__compact_build_table_cb(H5O_t H5_ATTR_UNUSED *oh, H5O_mesg_t *mesg /*in,out*/, unsigned sequence,
                            void *_udata /*in,out*/)
{
    H5A_compact_bt_ud_t *udata     = (H5A_compact_bt_ud_t *)_udata; /* Operator user data */
    herr_t               ret_value = H5_ITER_CONT;                  /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(mesg);

    /* Re-allocate the table if necessary */
    if (udata->atable->num_attrs == udata->atable->max_attrs) {
        H5A_t **new_table;      /* New table for attributes */
        size_t  new_table_size; /* Number of attributes in new table */

        /* Allocate larger table */
        new_table_size = MAX(1, 2 * udata->atable->max_attrs);
        if (NULL == (new_table = (H5A_t **)H5FL_SEQ_REALLOC(H5A_t_ptr, udata->atable->attrs, new_table_size)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, H5_ITER_ERROR, "unable to extend attribute table");

        /* Update table information in user data */
        udata->atable->attrs     = new_table;
        udata->atable->max_attrs = new_table_size;
    } /* end if */

    /* Copy attribute into table */
    if (NULL ==
        (udata->atable->attrs[udata->atable->num_attrs] = H5A__copy(NULL, (const H5A_t *)mesg->native)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy attribute");

    /* Assign [somewhat arbitrary] creation order value, if requested */
    if (udata->bogus_crt_idx)
        ((udata->atable->attrs[udata->atable->num_attrs])->shared)->crt_idx = sequence;

    /* Increment attribute count */
    udata->atable->num_attrs++;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__compact_build_table_cb() */

/*-------------------------------------------------------------------------
 * Function:    H5A__compact_build_table
 *
 * Purpose:     Builds a table containing a sorted list of attributes for
 *              an object
 *
 * Note:        Used for building table of attributes in non-native iteration
 *              order for an index
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__compact_build_table(H5F_t *f, H5O_t *oh, H5_index_t idx_type, H5_iter_order_t order,
                         H5A_attr_table_t *atable)
{
    H5A_compact_bt_ud_t udata;                 /* User data for iteration callback */
    H5O_mesg_operator_t op;                    /* Wrapper for operator */
    bool                iter_set_up = false;   /* Is everything set up for iteration */
    herr_t              ret_value   = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(f);
    assert(oh);
    assert(atable);

    /* Initialize table */
    atable->attrs     = NULL;
    atable->num_attrs = 0;
    atable->max_attrs = 0;

    /* Set up user data for iteration */
    udata.f      = f;
    udata.atable = atable;
    udata.bogus_crt_idx =
        (bool)((oh->version == H5O_VERSION_1 || !(oh->flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED)) ? true
                                                                                               : false);

    /* Iterate over existing attributes, checking for attribute with same name */
    op.op_type  = H5O_MESG_OP_LIB;
    op.u.lib_op = H5A__compact_build_table_cb;
    iter_set_up = true;
    if (H5O__msg_iterate_real(f, oh, H5O_MSG_ATTR, &op, &udata) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_BADITER, FAIL, "error building attribute table");

    /* Don't sort an empty table. */
    if (atable->num_attrs > 0)
        /* Sort attribute table in correct iteration order */
        if (H5A__attr_sort_table(atable, idx_type, order) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTSORT, FAIL, "error sorting attribute table");

done:
    if (ret_value < 0)
        /* Clean up partially built table on error */
        if (iter_set_up)
            if (atable->attrs && H5A__attr_release_table(atable) < 0)
                HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, FAIL, "unable to release attribute table");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__compact_build_table() */

/*-------------------------------------------------------------------------
 * Function:    H5A__dense_build_table_cb
 *
 * Purpose:    Callback routine for building table of attributes from dense
 *              attribute storage.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__dense_build_table_cb(const H5A_t *attr, void *_udata)
{
    H5A_attr_table_t *atable    = (H5A_attr_table_t *)_udata; /* 'User data' passed in */
    herr_t            ret_value = H5_ITER_CONT;               /* Return value */

    FUNC_ENTER_PACKAGE

    /* check arguments */
    assert(attr);
    assert(atable);
    assert(atable->num_attrs < atable->max_attrs);

    /* Allocate attribute for entry in the table */
    if (NULL == (atable->attrs[atable->num_attrs] = H5FL_CALLOC(H5A_t)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, H5_ITER_ERROR, "can't allocate attribute");

    /* Copy attribute information.  Share the attribute object in copying. */
    if (NULL == H5A__copy(atable->attrs[atable->num_attrs], attr))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy attribute");

    /* Increment number of attributes stored */
    atable->num_attrs++;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__dense_build_table_cb() */

/*-------------------------------------------------------------------------
 * Function:    H5A__dense_build_table
 *
 * Purpose:     Builds a table containing a sorted list of attributes for
 *              an object
 *
 * Note:        Used for building table of attributes in non-native iteration
 *              order for an index.  Uses the "name" index to retrieve records,
 *              but the 'idx_type' index for sorting them.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__dense_build_table(H5F_t *f, const H5O_ainfo_t *ainfo, H5_index_t idx_type, H5_iter_order_t order,
                       H5A_attr_table_t *atable)
{
    H5B2_t *bt2_name = NULL;     /* v2 B-tree handle for name index */
    hsize_t nrec;                /* # of records in v2 B-tree */
    herr_t  ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(f);
    assert(ainfo);
    assert(H5_addr_defined(ainfo->fheap_addr));
    assert(H5_addr_defined(ainfo->name_bt2_addr));
    assert(atable);

    /* Open the name index v2 B-tree */
    if (NULL == (bt2_name = H5B2_open(f, ainfo->name_bt2_addr, NULL)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to open v2 B-tree for name index");

    /* Retrieve # of records in "name" B-tree */
    /* (should be same # of records in all indices) */
    if (H5B2_get_nrec(bt2_name, &nrec) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "can't retrieve # of records in index");

    /* Allocate space for the table entries */
    if (nrec > 0) {
        H5A_attr_iter_op_t attr_op; /* Attribute operator */

        /* Check for overflow on the downcast */
        H5_CHECK_OVERFLOW(nrec, /* From: */ hsize_t, /* To: */ size_t);

        /* Allocate the table to store the attributes */
        if (NULL == (atable->attrs = (H5A_t **)H5FL_SEQ_CALLOC(H5A_t_ptr, (size_t)nrec)))
            HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "memory allocation failed");
        atable->num_attrs = 0;
        atable->max_attrs = (size_t)nrec;

        /* Build iterator operator */
        attr_op.op_type  = H5A_ATTR_OP_LIB;
        attr_op.u.lib_op = H5A__dense_build_table_cb;

        /* Iterate over the links in the group, building a table of the link messages */
        if (H5A__dense_iterate(f, (hid_t)0, ainfo, H5_INDEX_NAME, H5_ITER_NATIVE, (hsize_t)0, NULL, &attr_op,
                               atable) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "error building attribute table");

        /* Sort attribute table in correct iteration order */
        if (H5A__attr_sort_table(atable, idx_type, order) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTSORT, FAIL, "error sorting attribute table");
    } /* end if */
    else
        atable->attrs = NULL;

done:
    /* Release resources */
    if (bt2_name && H5B2_close(bt2_name) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, FAIL, "can't close v2 B-tree for name index");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__dense_build_table() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_cmp_name_inc
 *
 * Purpose:     Callback routine for comparing two attribute names, in
 *              increasing alphabetic order
 *
 * Return:      An integer less than, equal to, or greater than zero if the
 *              first argument is considered to be respectively less than,
 *              equal to, or greater than the second.  If two members compare
 *              as equal, their order in the sorted array is undefined.
 *              (i.e. same as strcmp())
 *
 *-------------------------------------------------------------------------
 */
static int
H5A__attr_cmp_name_inc(const void *attr1, const void *attr2)
{
    FUNC_ENTER_PACKAGE_NOERR

    FUNC_LEAVE_NOAPI(
        strcmp((*(const H5A_t *const *)attr1)->shared->name, (*(const H5A_t *const *)attr2)->shared->name))
} /* end H5A__attr_cmp_name_inc() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_cmp_name_dec
 *
 * Purpose:    Callback routine for comparing two attribute names, in
 *              decreasing alphabetic order
 *
 * Return:    An integer less than, equal to, or greater than zero if the
 *              second argument is considered to be respectively less than,
 *              equal to, or greater than the first.  If two members compare
 *              as equal, their order in the sorted array is undefined.
 *              (i.e. opposite of strcmp())
 *
 *-------------------------------------------------------------------------
 */
static int
H5A__attr_cmp_name_dec(const void *attr1, const void *attr2)
{
    FUNC_ENTER_PACKAGE_NOERR

    FUNC_LEAVE_NOAPI(
        strcmp((*(const H5A_t *const *)attr2)->shared->name, (*(const H5A_t *const *)attr1)->shared->name))
} /* end H5A__attr_cmp_name_dec() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_cmp_corder_inc
 *
 * Purpose:    Callback routine for comparing two attributes, in
 *              increasing creation order
 *
 * Return:    An integer less than, equal to, or greater than zero if the
 *              first argument is considered to be respectively less than,
 *              equal to, or greater than the second.  If two members compare
 *              as equal, their order in the sorted array is undefined.
 *
 *-------------------------------------------------------------------------
 */
static int
H5A__attr_cmp_corder_inc(const void *attr1, const void *attr2)
{
    int ret_value = 0; /* Return value */

    FUNC_ENTER_PACKAGE_NOERR

    if ((*(const H5A_t *const *)attr1)->shared->crt_idx < (*(const H5A_t *const *)attr2)->shared->crt_idx)
        ret_value = -1;
    else if ((*(const H5A_t *const *)attr1)->shared->crt_idx >
             (*(const H5A_t *const *)attr2)->shared->crt_idx)
        ret_value = 1;
    else
        ret_value = 0;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__attr_cmp_corder_inc() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_cmp_corder_dec
 *
 * Purpose:     Callback routine for comparing two attributes, in
 *              decreasing creation order
 *
 * Return:      An integer less than, equal to, or greater than zero if the
 *              second argument is considered to be respectively less than,
 *              equal to, or greater than the first.  If two members compare
 *              as equal, their order in the sorted array is undefined.
 *
 *-------------------------------------------------------------------------
 */
static int
H5A__attr_cmp_corder_dec(const void *attr1, const void *attr2)
{
    int ret_value = 0; /* Return value */

    FUNC_ENTER_PACKAGE_NOERR

    if ((*(const H5A_t *const *)attr1)->shared->crt_idx < (*(const H5A_t *const *)attr2)->shared->crt_idx)
        ret_value = 1;
    else if ((*(const H5A_t *const *)attr1)->shared->crt_idx >
             (*(const H5A_t *const *)attr2)->shared->crt_idx)
        ret_value = -1;
    else
        ret_value = 0;

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__attr_cmp_corder_dec() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_sort_table
 *
 * Purpose:     Sort table containing a list of attributes for an object
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__attr_sort_table(H5A_attr_table_t *atable, H5_index_t idx_type, H5_iter_order_t order)
{
    FUNC_ENTER_PACKAGE_NOERR

    /* Sanity check */
    assert(atable);

    /* Pick appropriate comparison routine */
    if (idx_type == H5_INDEX_NAME) {
        if (order == H5_ITER_INC)
            qsort(atable->attrs, atable->num_attrs, sizeof(H5A_t *), H5A__attr_cmp_name_inc);
        else if (order == H5_ITER_DEC)
            qsort(atable->attrs, atable->num_attrs, sizeof(H5A_t *), H5A__attr_cmp_name_dec);
        else
            assert(order == H5_ITER_NATIVE);
    } /* end if */
    else {
        assert(idx_type == H5_INDEX_CRT_ORDER);
        if (order == H5_ITER_INC)
            qsort(atable->attrs, atable->num_attrs, sizeof(H5A_t *), H5A__attr_cmp_corder_inc);
        else if (order == H5_ITER_DEC)
            qsort(atable->attrs, atable->num_attrs, sizeof(H5A_t *), H5A__attr_cmp_corder_dec);
        else
            assert(order == H5_ITER_NATIVE);
    } /* end else */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5A__attr_sort_table() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_iterate_table
 *
 * Purpose:     Iterate over table containing a list of attributes for an object,
 *              making appropriate callbacks
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__attr_iterate_table(const H5A_attr_table_t *atable, hsize_t skip, hsize_t *last_attr, hid_t loc_id,
                        const H5A_attr_iter_op_t *attr_op, void *op_data)
{
    size_t u;                        /* Local index variable */
    herr_t ret_value = H5_ITER_CONT; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(atable);
    assert(attr_op);

    /* Skip over attributes, if requested */
    if (last_attr)
        *last_attr = skip;

    /* Iterate over attribute messages */
    H5_CHECKED_ASSIGN(u, size_t, skip, hsize_t);
    for (; u < atable->num_attrs && !ret_value; u++) {
        /* Check which type of callback to make */
        switch (attr_op->op_type) {
            case H5A_ATTR_OP_APP2: {
                H5A_info_t ainfo; /* Info for attribute */

                /* Get the attribute information */
                if (H5A__get_info(atable->attrs[u], &ainfo) < 0)
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, H5_ITER_ERROR, "unable to get attribute info");

                /* Prepare & restore library for user callback */
                H5_BEFORE_USER_CB(H5_ITER_ERROR)
                    {
                        /* Make the application callback */
                        ret_value =
                            (attr_op->u.app_op2)(loc_id, ((atable->attrs[u])->shared)->name, &ainfo, op_data);
                    }
                H5_AFTER_USER_CB(H5_ITER_ERROR)
                break;
            }

#ifndef H5_NO_DEPRECATED_SYMBOLS
            case H5A_ATTR_OP_APP:
                /* Prepare & restore library for user callback */
                H5_BEFORE_USER_CB(H5_ITER_ERROR)
                    {
                        /* Make the application callback */
                        ret_value = (attr_op->u.app_op)(loc_id, ((atable->attrs[u])->shared)->name, op_data);
                    }
                H5_AFTER_USER_CB(H5_ITER_ERROR)
                break;
#endif /* H5_NO_DEPRECATED_SYMBOLS */

            case H5A_ATTR_OP_LIB:
                /* Call the library's callback */
                ret_value = (attr_op->u.lib_op)((atable->attrs[u]), op_data);
                break;

            default:
                assert("unknown attribute op type" && 0);
#ifdef NDEBUG
                HGOTO_ERROR(H5E_ATTR, H5E_UNSUPPORTED, FAIL, "unsupported attribute op type");
#endif    /* NDEBUG */
        } /* end switch */

        /* Increment the number of entries passed through */
        if (last_attr)
            (*last_attr)++;
    } /* end for */

    /* Check for callback failure and pass along return value */
    if (ret_value < 0)
        HERROR(H5E_ATTR, H5E_CANTNEXT, "iteration operator failed");

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__attr_iterate_table() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_release_table
 *
 * Purpose:     Release table containing a list of attributes for an object
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__attr_release_table(H5A_attr_table_t *atable)
{
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Sanity check */
    assert(atable);

    /* Release attribute info, if any. */
    if (atable->num_attrs > 0) {
        size_t u; /* Local index variable */

        /* Free attribute message information */
        for (u = 0; u < atable->num_attrs; u++)
            if (atable->attrs[u] && H5A__close(atable->attrs[u]) < 0)
                HGOTO_ERROR(H5E_ATTR, H5E_CANTFREE, FAIL, "unable to release attribute");

        /* Release array */
        atable->attrs = (H5A_t **)H5FL_SEQ_FREE(H5A_t_ptr, atable->attrs);
    } /* end if */
    else
        assert(atable->attrs == NULL);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__attr_release_table() */

/*-------------------------------------------------------------------------
 * Function:    H5A__get_ainfo
 *
 * Purpose:     Retrieves the "attribute info" message for an object.  Also
 *              sets the number of attributes correctly, if it isn't set up yet.
 *
 * Return:      true/false/FAIL
 *
 *-------------------------------------------------------------------------
 */
htri_t
H5A__get_ainfo(H5F_t *f, H5O_t *oh, H5O_ainfo_t *ainfo)
{
    H5B2_t *bt2_name  = NULL; /* v2 B-tree handle for name index */
    htri_t  ret_value = FAIL; /* Return value */

    FUNC_ENTER_PACKAGE_TAG(oh->cache_info.addr)

    /* check arguments */
    assert(f);
    assert(oh);
    assert(ainfo);

    /* Check if the "attribute info" message exists */
    if ((ret_value = H5O_msg_exists_oh(oh, H5O_AINFO_ID)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "unable to check object header");
    if (ret_value > 0) {
        /* Retrieve the "attribute info" structure */
        if (NULL == H5O_msg_read_oh(f, oh, H5O_AINFO_ID, ainfo))
            HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "can't read AINFO message");

        /* Check if we don't know how many attributes there are */
        if (ainfo->nattrs == HSIZET_MAX) {
            /* Check if we are using "dense" attribute storage */
            if (H5_addr_defined(ainfo->fheap_addr)) {
                /* Open the name index v2 B-tree */
                if (NULL == (bt2_name = H5B2_open(f, ainfo->name_bt2_addr, NULL)))
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to open v2 B-tree for name index");

                /* Retrieve # of records in "name" B-tree */
                /* (should be same # of records in all indices) */
                if (H5B2_get_nrec(bt2_name, &ainfo->nattrs) < 0)
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "can't retrieve # of records in index");
            } /* end if */
            else
                /* Retrieve # of attributes from object header */
                ainfo->nattrs = oh->attr_msgs_seen;
        } /* end if */
    }     /* end if */

done:
    /* Release resources */
    if (bt2_name && H5B2_close(bt2_name) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, FAIL, "can't close v2 B-tree for name index");

    FUNC_LEAVE_NOAPI_TAG(ret_value)
} /* end H5A__get_ainfo() */

/*-------------------------------------------------------------------------
 * Function:    H5A__set_version
 *
 * Purpose:     Sets the correct version to encode attribute with.
 *              Chooses the oldest version possible, unless the
 *              file's low bound indicates otherwise.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__set_version(const H5F_t *f, H5A_t *attr)
{
    bool type_shared, space_shared; /* Flags to indicate that shared messages are used for this attribute */
    uint8_t version;                /* Message version */
    herr_t  ret_value = SUCCEED;    /* Return value */

    FUNC_ENTER_PACKAGE

    /* check arguments */
    assert(f);
    assert(attr);

    /* Check whether datatype and dataspace are shared */
    if (H5O_msg_is_shared(H5O_DTYPE_ID, attr->shared->dt) > 0)
        type_shared = true;
    else
        type_shared = false;

    if (H5O_msg_is_shared(H5O_SDSPACE_ID, attr->shared->ds) > 0)
        space_shared = true;
    else
        space_shared = false;

    /* Check which version to encode attribute with */
    if (attr->shared->encoding != H5T_CSET_ASCII)
        version = H5O_ATTR_VERSION_3; /* Write version which includes the character encoding */
    else if (type_shared || space_shared)
        version =
            H5O_ATTR_VERSION_2; /* Write out version with flag for indicating shared datatype or dataspace */
    else
        version = H5O_ATTR_VERSION_1; /* Write out basic version */

    /* Upgrade to the version indicated by the file's low bound if higher */
    version = (uint8_t)MAX(version, (uint8_t)H5O_attr_ver_bounds[H5F_LOW_BOUND(f)]);

    /* Version bounds check */
    if (version > H5O_attr_ver_bounds[H5F_HIGH_BOUND(f)])
        HGOTO_ERROR(H5E_ATTR, H5E_BADRANGE, FAIL, "attribute version out of bounds");

    /* Set the message version */
    attr->shared->version = version;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__set_version() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_copy_file
 *
 * Purpose:     Copies a message from _MESG to _DEST in file
 *
 *              Note that this function assumes that it is copying *all*
 *              the attributes in the object, specifically when it copies
 *              the creation order from source to destination.  If this is
 *              to be used to copy only a single attribute, then the
 *              creation order must be handled differently.  -NAF
 *
 * Return:      Success:        Ptr to _DEST
 *
 *              Failure:        NULL
 *
 *-------------------------------------------------------------------------
 */
H5A_t *
H5A__attr_copy_file(const H5A_t *attr_src, H5F_t *file_dst, bool *recompute_size,
                    H5O_copy_t H5_ATTR_NDEBUG_UNUSED *cpy_info)
{
    H5A_t   *attr_dst    = NULL; /* Destination attribute */
    H5T_t   *dt_mem      = NULL; /* Memory datatype */
    H5S_t   *buf_space   = NULL; /* Dataspace describing buffer */
    void    *buf         = NULL; /* Buffer for copying data */
    void    *reclaim_buf = NULL; /* Buffer for reclaiming data */
    void    *bkg_buf     = NULL; /* Background buffer */
    hssize_t sdst_nelmts;        /* # of elements in destination attribute (signed) */
    size_t   dst_nelmts;         /* # of elements in destination attribute */
    size_t   dst_dt_size;        /* Size of destination attribute datatype */
    H5A_t   *ret_value = NULL;   /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(attr_src);
    assert(file_dst);
    assert(cpy_info);
    assert(!cpy_info->copy_without_attr);

    /* Allocate space for the destination message */
    if (NULL == (attr_dst = H5FL_CALLOC(H5A_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");

    /* Copy the top level of the attribute */
    *attr_dst = *attr_src;

    if (NULL == (attr_dst->shared = H5FL_CALLOC(H5A_shared_t)))
        HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, NULL, "can't allocate shared attr structure");

    /* Don't have an opened group location for copy */
    H5O_loc_reset(&(attr_dst->oloc));
    H5G_name_reset(&(attr_dst->path));
    attr_dst->obj_opened = false;

    /* Reference count for the header message in the cache */
    attr_dst->shared->nrefs = 1;

    /* Copy attribute's name */
    attr_dst->shared->name = H5MM_strdup(attr_src->shared->name);
    assert(attr_dst->shared->name);
    attr_dst->shared->encoding = attr_src->shared->encoding;

    /* Copy attribute's datatype */
    /* If source is named, we will keep dst as named, but we will not actually
     * copy the target and update the message until post copy */
    if (NULL == (attr_dst->shared->dt = H5T_copy(attr_src->shared->dt, H5T_COPY_ALL)))
        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, NULL, "cannot copy datatype");

    /* Set the location of the destination datatype */
    if (H5T_set_loc(attr_dst->shared->dt, H5F_VOL_OBJ(file_dst), H5T_LOC_DISK) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "cannot mark datatype on disk");

    if (!H5T_is_named(attr_src->shared->dt)) {
        /* If the datatype is not named, it may have been shared in the
         * source file's heap.  Un-share it for now. We'll try to shared
         * it in the destination file below.
         */
        if (H5O_msg_reset_share(H5O_DTYPE_ID, attr_dst->shared->dt) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to reset datatype sharing");
    }

    /* Copy the dataspace for the attribute. Make sure the maximal dimension is also copied.
     * Otherwise the comparison in the test may complain about it. SLU 2011/4/12 */
    attr_dst->shared->ds = H5S_copy(attr_src->shared->ds, false, true);
    assert(attr_dst->shared->ds);

    /* Reset the dataspace's sharing in the source file before trying to share
     * it in the destination.
     */
    if (H5O_msg_reset_share(H5O_SDSPACE_ID, attr_dst->shared->ds) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "unable to reset dataspace sharing");

    /* Simulate trying to share both the datatype and dataset, to determine the
     * final size of the messages.  This does nothing if the datatype is
     * committed or sharing is disabled.
     */
    if (H5SM_try_share(file_dst, NULL, H5SM_DEFER, H5O_DTYPE_ID, attr_dst->shared->dt, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, NULL, "can't share attribute datatype");
    if (H5SM_try_share(file_dst, NULL, H5SM_DEFER, H5O_SDSPACE_ID, attr_dst->shared->ds, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, NULL, "can't share attribute dataspace");

    /* Compute the sizes of the datatype and dataspace. This is their raw
     * size unless they're shared.
     */
    attr_dst->shared->dt_size = H5O_msg_raw_size(file_dst, H5O_DTYPE_ID, false, attr_dst->shared->dt);
    assert(attr_dst->shared->dt_size > 0);
    attr_dst->shared->ds_size = H5O_msg_raw_size(file_dst, H5O_SDSPACE_ID, false, attr_dst->shared->ds);
    assert(attr_dst->shared->ds_size > 0);

    /* Check whether to recompute the size of the attribute */
    /* (happens when the datatype or dataspace changes sharing status) */
    if (attr_dst->shared->dt_size != attr_src->shared->dt_size ||
        attr_dst->shared->ds_size != attr_src->shared->ds_size)
        *recompute_size = true;

    /* Get # of elements for destination attribute's dataspace */
    if ((sdst_nelmts = H5S_GET_EXTENT_NPOINTS(attr_dst->shared->ds)) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOUNT, NULL, "dataspace is invalid");
    H5_CHECKED_ASSIGN(dst_nelmts, size_t, sdst_nelmts, hssize_t);

    /* Get size of destination attribute's datatype */
    if (0 == (dst_dt_size = H5T_get_size(attr_dst->shared->dt)))
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "unable to determine datatype size");

    /* Compute the size of the data */
    attr_dst->shared->data_size = dst_nelmts * dst_dt_size;

    /* Copy (& convert) the data, if necessary */
    if (attr_src->shared->data) {
        if (NULL == (attr_dst->shared->data = H5FL_BLK_MALLOC(attr_buf, attr_dst->shared->data_size)))
            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");

        /* Check if we need to convert data */
        if (H5T_detect_class(attr_src->shared->dt, H5T_VLEN, false) > 0) {
            H5T_path_t *tpath_src_mem, *tpath_mem_dst; /* Datatype conversion paths */
            size_t      src_dt_size;                   /* Source datatype size */
            size_t      tmp_dt_size;                   /* Temp. datatype size */
            size_t      max_dt_size;                   /* Max atatype size */
            hsize_t     buf_dim;                       /* Dimension for buffer */
            size_t      nelmts;                        /* Number of elements in buffer */
            size_t      buf_size;                      /* Size of copy buffer */

            /* create a memory copy of the variable-length datatype */
            if (NULL == (dt_mem = H5T_copy(attr_src->shared->dt, H5T_COPY_TRANSIENT)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "unable to copy");

            /* Set up the conversion functions */
            if (NULL == (tpath_src_mem = H5T_path_find(attr_src->shared->dt, dt_mem)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL,
                            "unable to convert between src and mem datatypes");
            if (NULL == (tpath_mem_dst = H5T_path_find(dt_mem, attr_dst->shared->dt)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL,
                            "unable to convert between mem and dst datatypes");

            /* Determine largest datatype size */
            if (0 == (src_dt_size = H5T_get_size(attr_src->shared->dt)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "unable to determine datatype size");
            if (0 == (tmp_dt_size = H5T_get_size(dt_mem)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "unable to determine datatype size");
            max_dt_size = MAX(src_dt_size, tmp_dt_size);
            if (0 == (tmp_dt_size = H5T_get_size(attr_dst->shared->dt)))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "unable to determine datatype size");
            max_dt_size = MAX(max_dt_size, tmp_dt_size);

            /* Set number of whole elements that fit in buffer */
            if (0 == (nelmts = attr_src->shared->data_size / src_dt_size))
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "element size too large");

            /* Set up number of bytes to copy, and initial buffer size */
            buf_size = nelmts * max_dt_size;

            /* Create dataspace for number of elements in buffer */
            buf_dim = nelmts;

            /* Create the space and set the initial extent */
            if (NULL == (buf_space = H5S_create_simple((unsigned)1, &buf_dim, NULL)))
                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCREATE, NULL, "can't create simple dataspace");

            /* Allocate memory for recclaim buf */
            if (NULL == (reclaim_buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation NULLed for raw data chunk");

            /* Allocate memory for copying the chunk */
            if (NULL == (buf = H5FL_BLK_MALLOC(attr_buf, buf_size)))
                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation NULLed for raw data chunk");

            H5MM_memcpy(buf, attr_src->shared->data, attr_src->shared->data_size);

            /* Allocate background memory */
            if (H5T_path_bkg(tpath_src_mem) || H5T_path_bkg(tpath_mem_dst))
                if (NULL == (bkg_buf = H5FL_BLK_CALLOC(attr_buf, buf_size)))
                    HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, NULL, "memory allocation failed");

            /* Convert from source file to memory */
            if (H5T_convert(tpath_src_mem, attr_src->shared->dt, dt_mem, nelmts, (size_t)0, (size_t)0, buf,
                            bkg_buf) < 0)
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "datatype conversion NULLed");

            H5MM_memcpy(reclaim_buf, buf, buf_size);

            /* Set background buffer to all zeros */
            if (bkg_buf)
                memset(bkg_buf, 0, buf_size);

            /* Convert from memory to destination file */
            if (H5T_convert(tpath_mem_dst, dt_mem, attr_dst->shared->dt, nelmts, (size_t)0, (size_t)0, buf,
                            bkg_buf) < 0)
                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, NULL, "datatype conversion NULLed");

            H5MM_memcpy(attr_dst->shared->data, buf, attr_dst->shared->data_size);

            if (H5T_reclaim(dt_mem, buf_space, reclaim_buf) < 0)
                HGOTO_ERROR(H5E_DATASET, H5E_BADITER, NULL, "unable to reclaim variable-length data");
        } /* end if */
        else {
            assert(attr_dst->shared->data_size == attr_src->shared->data_size);
            H5MM_memcpy(attr_dst->shared->data, attr_src->shared->data, attr_src->shared->data_size);
        } /* end else */
    }     /* end if(attr_src->shared->data) */

    /* Copy the creation order */
    attr_dst->shared->crt_idx = attr_src->shared->crt_idx;

    /* Recompute the version to encode the destination attribute */
    if (H5A__set_version(file_dst, attr_dst) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, NULL, "unable to update attribute version");

    /* Recompute the destination attribute's size, if it's a different version */
    if (attr_src->shared->version != attr_dst->shared->version)
        *recompute_size = true;

    /* Set return value */
    ret_value = attr_dst;

done:
    if (dt_mem && (H5T_close(dt_mem) < 0))
        HDONE_ERROR(H5E_ATTR, H5E_CANTCLOSEOBJ, NULL, "can't close temporary datatype");
    if (buf_space && H5S_close(buf_space) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTCLOSEOBJ, NULL, "can't close temporary dataspace");
    if (buf)
        buf = H5FL_BLK_FREE(attr_buf, buf);
    if (reclaim_buf)
        reclaim_buf = H5FL_BLK_FREE(attr_buf, reclaim_buf);
    if (bkg_buf)
        bkg_buf = H5FL_BLK_FREE(attr_buf, bkg_buf);

    /* Release destination attribute information on failure */
    if (!ret_value && attr_dst && H5A__close(attr_dst) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTFREE, NULL, "can't close attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__attr_copy_file() */

/*-------------------------------------------------------------------------
 * Function:    H5A__attr_post_copy_file
 *
 * Purpose:     Finish copying a message from between files.
 *              We have to copy the values of a reference attribute in the
 *              post copy because H5O_post_copy_file() fails at the case that
 *              an object may have a reference attribute that points to the
 *              object itself.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__attr_post_copy_file(const H5O_loc_t *src_oloc, const H5A_t *attr_src, H5O_loc_t *dst_oloc,
                         const H5A_t *attr_dst, H5O_copy_t *cpy_info)
{
    H5F_t *file_src, *file_dst;
    herr_t ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check args */
    assert(src_oloc);
    assert(dst_oloc);
    assert(attr_dst);
    assert(attr_src);

    file_src = src_oloc->file;
    file_dst = dst_oloc->file;

    assert(file_src);
    assert(file_dst);

    if (H5T_is_named(attr_src->shared->dt)) {
        H5O_loc_t *src_oloc_dt; /* Pointer to source datatype's object location */
        H5O_loc_t *dst_oloc_dt; /* Pointer to dest. datatype's object location */

        /* Get group entries for source & destination */
        src_oloc_dt = H5T_oloc(attr_src->shared->dt);
        assert(src_oloc_dt);
        dst_oloc_dt = H5T_oloc(attr_dst->shared->dt);
        assert(dst_oloc_dt);

        /* Reset object location for new object */
        H5O_loc_reset(dst_oloc_dt);
        dst_oloc_dt->file = file_dst;

        /* Copy the shared object from source to destination */
        if (H5O_copy_header_map(src_oloc_dt, dst_oloc_dt, cpy_info, false, NULL, NULL) < 0)
            HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object");

        /* Update shared message info from named datatype info */
        H5T_update_shared(attr_dst->shared->dt);
    }

    /* Try to share both the datatype and dataset.  This does nothing if the
     * datatype is committed or sharing is disabled.
     */
    if (H5SM_try_share(file_dst, NULL, H5SM_WAS_DEFERRED, H5O_DTYPE_ID, attr_dst->shared->dt, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "can't share attribute datatype");
    if (H5SM_try_share(file_dst, NULL, H5SM_WAS_DEFERRED, H5O_SDSPACE_ID, attr_dst->shared->ds, NULL) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "can't share attribute dataspace");

    /* Only need to fix reference attribute with real data being copied to
     *  another file.
     */
    if ((NULL != attr_dst->shared->data) && (H5T_get_class(attr_dst->shared->dt, false) == H5T_REFERENCE)) {

        /* copy object pointed by reference. The current implementation does not
         *  deal with nested reference such as reference in a compound structure
         */

        /* Check for expanding references */
        if (cpy_info->expand_ref) {
            /* Copy objects referenced in source buffer to destination file and set destination elements */
            if (H5O_copy_expand_ref(file_src, attr_src->shared->dt, attr_src->shared->data,
                                    attr_src->shared->data_size, file_dst, attr_dst->shared->data,
                                    cpy_info) < 0)
                HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, FAIL, "unable to copy reference attribute");
        } /* end if */
        else
            /* Reset value to zero */
            memset(attr_dst->shared->data, 0, attr_dst->shared->data_size);
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__attr_post_copy_file() */

/*-------------------------------------------------------------------------
 * Function:    H5A__dense_post_copy_file_cb
 *
 * Purpose:     Callback routine for copying a dense attribute from SRC to DST.
 *
 * Return:      Success:        Non-negative
 *              Failure:        Negative
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__dense_post_copy_file_cb(const H5A_t *attr_src, void *_udata)
{
    H5A_dense_file_cp_ud_t *udata     = (H5A_dense_file_cp_ud_t *)_udata;
    H5A_t                  *attr_dst  = NULL;
    herr_t                  ret_value = H5_ITER_CONT; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check arguments */
    assert(attr_src);
    assert(udata);
    assert(udata->ainfo);
    assert(udata->file);
    assert(udata->cpy_info);

    /* Set the location of the src datatype */
    if (H5T_set_loc(attr_src->shared->dt, H5F_VOL_OBJ(udata->oloc_src->file), H5T_LOC_DISK) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, H5_ITER_ERROR, "cannot mark datatype on disk");

    if (NULL ==
        (attr_dst = H5A__attr_copy_file(attr_src, udata->file, udata->recompute_size, udata->cpy_info)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy attribute");

    if (H5A__attr_post_copy_file(udata->oloc_src, attr_src, udata->oloc_dst, attr_dst, udata->cpy_info) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "can't copy attribute");

    /* Reset shared location information */
    if (H5O_msg_reset_share(H5O_ATTR_ID, attr_dst) < 0)
        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, H5_ITER_ERROR, "unable to reset attribute sharing");

    /* Set COPIED tag for destination object's metadata */
    H5_BEGIN_TAG(H5AC__COPIED_TAG)

    /* Insert attribute into dense storage */
    if (H5A__dense_insert(udata->file, udata->ainfo, attr_dst) < 0)
        HGOTO_ERROR_TAG(H5E_OHDR, H5E_CANTINSERT, H5_ITER_ERROR, "unable to add to dense storage");

    /* Reset metadata tag */
    H5_END_TAG

done:
    if (attr_dst && H5A__close(attr_dst) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CLOSEERROR, H5_ITER_ERROR, "can't close destination attribute");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__dense_post_copy_file_cb() */

/*-------------------------------------------------------------------------
 * Function:    H5A__dense_post_copy_file_all
 *
 * Purpose:     Copy all dense attributes from SRC to DST.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__dense_post_copy_file_all(const H5O_loc_t *src_oloc, const H5O_ainfo_t *ainfo_src, H5O_loc_t *dst_oloc,
                              H5O_ainfo_t *ainfo_dst, H5O_copy_t *cpy_info)
{
    H5A_dense_file_cp_ud_t udata;                    /* User data for iteration callback */
    H5A_attr_iter_op_t     attr_op;                  /* Attribute operator */
    bool                   recompute_size = false;   /* recompute the size */
    herr_t                 ret_value      = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* check arguments */
    assert(ainfo_src);
    assert(ainfo_dst);

    udata.ainfo          = ainfo_dst;       /* Destination dense information    */
    udata.file           = dst_oloc->file;  /* Destination file                 */
    udata.recompute_size = &recompute_size; /* Flag to indicate if size changed */
    udata.cpy_info       = cpy_info;        /* Information on copying options   */
    udata.oloc_src       = src_oloc;
    udata.oloc_dst       = dst_oloc;

    attr_op.op_type  = H5A_ATTR_OP_LIB;
    attr_op.u.lib_op = H5A__dense_post_copy_file_cb;

    if (H5A__dense_iterate(src_oloc->file, (hid_t)0, ainfo_src, H5_INDEX_NAME, H5_ITER_NATIVE, (hsize_t)0,
                           NULL, &attr_op, &udata) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTINIT, FAIL, "error building attribute table");

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__dense_post_copy_file_all */

/*-------------------------------------------------------------------------
 * Function:    H5A__rename_by_name
 *
 * Purpose:     Private version of H5Arename_by_name
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__rename_by_name(H5G_loc_t loc, const char *obj_name, const char *old_attr_name, const char *new_attr_name)
{
    H5G_loc_t  obj_loc;             /* Location used to open group */
    H5G_name_t obj_path;            /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;            /* Opened object object location */
    bool       loc_found = false;   /* Entry at 'obj_name' found */
    herr_t     ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Avoid thrashing things if the names are the same */
    if (strcmp(old_attr_name, new_attr_name) != 0) {
        /* Set up opened group location to fill in */
        obj_loc.oloc = &obj_oloc;
        obj_loc.path = &obj_path;
        H5G_loc_reset(&obj_loc);

        /* Find the object's location */
        if (H5G_loc_find(&loc, obj_name, &obj_loc /*out*/) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "object not found");
        loc_found = true;

        /* Call attribute rename routine */
        if (H5O__attr_rename(obj_loc.oloc, old_attr_name, new_attr_name) < 0)
            HGOTO_ERROR(H5E_ATTR, H5E_CANTRENAME, FAIL, "can't rename attribute");
    } /* end if */

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__rename_by_name() */

/*-------------------------------------------------------------------------
 * Function:    H5A__iterate_common
 *
 * Purpose:     Internal common version of H5Aiterate
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5A__iterate_common(hid_t loc_id, H5_index_t idx_type, H5_iter_order_t order, hsize_t *idx,
                    H5A_attr_iter_op_t *attr_op, void *op_data)
{
    hsize_t start_idx;           /* Index of attribute to start iterating at */
    hsize_t last_attr;           /* Index of last attribute examined */
    herr_t  ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE_NOERR

    /* Call attribute iteration routine */
    last_attr = start_idx = (idx ? *idx : 0);
    if ((ret_value = H5O__attr_iterate(loc_id, idx_type, order, start_idx, &last_attr, attr_op, op_data)) < 0)
        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");

    /* Set the last attribute information */
    if (idx)
        *idx = last_attr;

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__iterate_common() */

/*-------------------------------------------------------------------------
 * Function:    H5A__iterate
 *
 * Purpose:     Private version of H5Aiterate2
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__iterate(const H5G_loc_t *loc, const char *obj_name, H5_index_t idx_type, H5_iter_order_t order,
             hsize_t *idx, H5A_operator2_t op, void *op_data)
{
    H5G_loc_t          obj_loc;                      /* Location used to open group */
    H5G_name_t         obj_path;                     /* Opened object group hier. path */
    H5O_loc_t          obj_oloc;                     /* Opened object object location */
    bool               loc_found  = false;           /* Entry at 'obj_name' found */
    hid_t              obj_loc_id = H5I_INVALID_HID; /* ID for object located */
    H5A_attr_iter_op_t attr_op;                      /* Attribute operator */
    void              *temp_obj = NULL;
    H5I_type_t         obj_type;
    herr_t             ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Build attribute operator info */
    attr_op.op_type   = H5A_ATTR_OP_APP2;
    attr_op.u.app_op2 = op;

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "object not found");
    loc_found = true;

    /* Open the object */
    if (NULL == (temp_obj = H5O_open_by_loc(&obj_loc, &obj_type)))
        HGOTO_ERROR(H5E_ATTR, H5E_CANTOPENOBJ, FAIL, "unable to open object");

    /* Get an ID for the object */
    if ((obj_loc_id = H5VL_wrap_register(obj_type, temp_obj, true)) < 0)
        HGOTO_ERROR(H5E_ID, H5E_CANTREGISTER, FAIL, "unable to register datatype");

    /* Call internal attribute iteration routine */
    if ((ret_value = H5A__iterate_common(obj_loc_id, idx_type, order, idx, &attr_op, op_data)) < 0)
        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");

done:
    /* Release resources */
    if (obj_loc_id != H5I_INVALID_HID) {
        if (H5I_dec_app_ref(obj_loc_id) < 0)
            HDONE_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to close temporary object");
    } /* end if */
    else if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5A__iterate() */

#ifndef H5_NO_DEPRECATED_SYMBOLS

/*-------------------------------------------------------------------------
 * Function:    H5A__iterate_old
 *
 * Purpose:     Private version of H5Aiterate1
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__iterate_old(hid_t loc_id, unsigned *attr_num, H5A_operator1_t op, void *op_data)
{
    H5A_attr_iter_op_t attr_op;             /* Attribute operator */
    hsize_t            idx;                 /* Index of attribute to start iterating at */
    herr_t             ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE_NOERR

    /* Build attribute operator info */
    attr_op.op_type  = H5A_ATTR_OP_APP;
    attr_op.u.app_op = op;

    /* Set up index */
    idx = (hsize_t)(attr_num ? *attr_num : 0);

    /* Call internal attribute iteration routine */
    if ((ret_value = H5A__iterate_common(loc_id, H5_INDEX_CRT_ORDER, H5_ITER_INC, &idx, &attr_op, op_data)) <
        0)
        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");

    /* Translate hsize_t index value to legacy unsigned index value*/
    if (attr_num)
        *attr_num = (unsigned)idx;

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__iterate_old() */
#endif /* H5_NO_DEPRECATED_SYMBOLS */

/*-------------------------------------------------------------------------
 * Function:    H5A__delete_by_name
 *
 * Purpose:     Private version of H5Adelete_by_name
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__delete_by_name(const H5G_loc_t *loc, const char *obj_name, const char *attr_name)
{
    H5G_loc_t  obj_loc;             /* Location used to open group */
    H5G_name_t obj_path;            /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;            /* Opened object object location */
    bool       loc_found = false;   /* Entry at 'obj_name' found */
    herr_t     ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "object not found");
    loc_found = true;

    /* Delete the attribute from the location */
    if (H5O__attr_remove(obj_loc.oloc, attr_name) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute");

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__delete_by_name() */

/*-------------------------------------------------------------------------
 * Function:    H5A__delete_by_idx
 *
 * Purpose:     Private version of H5Adelete_by_idx
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5A__delete_by_idx(const H5G_loc_t *loc, const char *obj_name, H5_index_t idx_type, H5_iter_order_t order,
                   hsize_t n)
{
    H5G_loc_t  obj_loc;             /* Location used to open group */
    H5G_name_t obj_path;            /* Opened object group hier. path */
    H5O_loc_t  obj_oloc;            /* Opened object object location */
    bool       loc_found = false;   /* Entry at 'obj_name' found */
    herr_t     ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_PACKAGE

    /* Set up opened group location to fill in */
    obj_loc.oloc = &obj_oloc;
    obj_loc.path = &obj_path;
    H5G_loc_reset(&obj_loc);

    /* Find the object's location */
    if (H5G_loc_find(loc, obj_name, &obj_loc /*out*/) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_NOTFOUND, FAIL, "object not found");
    loc_found = true;

    /* Delete the attribute from the location */
    if (H5O__attr_remove_by_idx(obj_loc.oloc, idx_type, order, n) < 0)
        HGOTO_ERROR(H5E_ATTR, H5E_CANTDELETE, FAIL, "unable to delete attribute");

done:
    /* Release resources */
    if (loc_found && H5G_loc_free(&obj_loc) < 0)
        HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");

    FUNC_LEAVE_NOAPI(ret_value)
} /* H5A__delete_by_idx() */