path: root/src/H5Tnative.c

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

/*
 * Module Info: This module contains the functionality for querying
 *      a "native" datatype for the H5T interface.
 */

#define H5T_PACKAGE		/*suppress error about including H5Tpkg	  */

/* Interface initialization */
#define H5_INTERFACE_INIT_FUNC	H5T_init_native_interface


#include "H5private.h"		/* Generic Functions			*/
#include "H5Eprivate.h"		/* Error handling		  	*/
#include "H5Iprivate.h"		/* IDs			  		*/
#include "H5Pprivate.h"		/* Property lists			*/
#include "H5MMprivate.h"	/* Memory management			*/
#include "H5Tpkg.h"		/* Datatypes				*/

/* Static local functions */
static H5T_t *H5T_get_native_type(H5T_t *dt, H5T_direction_t direction,
                                  size_t *struct_align, size_t *offset, size_t *comp_size);
static H5T_t *H5T_get_native_integer(size_t prec, H5T_sign_t sign, H5T_direction_t direction,
                                     size_t *struct_align, size_t *offset, size_t *comp_size);
static H5T_t *H5T_get_native_float(size_t size, H5T_direction_t direction,
                                   size_t *struct_align, size_t *offset, size_t *comp_size);
static herr_t H5T_cmp_offset(size_t *comp_size, size_t *offset, size_t elem_size,
                         size_t nelems, size_t align, size_t *struct_align);


/*--------------------------------------------------------------------------
NAME
   H5T_init_native_interface -- Initialize interface-specific information
USAGE
    herr_t H5T_init_native_interface()

RETURNS
    Non-negative on success/Negative on failure
DESCRIPTION
    Initializes any interface-specific data or routines.  (Just calls
    H5T_init_iterface currently).

--------------------------------------------------------------------------*/
static herr_t
H5T_init_native_interface(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5T_init_native_interface)

    FUNC_LEAVE_NOAPI(H5T_init())
} /* H5T_init_native_interface() */


/*-------------------------------------------------------------------------
 * Function:    H5Tget_native_type
 *
 * Purpose:     High-level API to return the native type of a datatype.
 *              The native type is chosen by matching the size and class of
 *              querried datatype from the following native premitive
 *              datatypes:
 *                      H5T_NATIVE_CHAR         H5T_NATIVE_UCHAR
 *                      H5T_NATIVE_SHORT        H5T_NATIVE_USHORT
 *                      H5T_NATIVE_INT          H5T_NATIVE_UINT
 *                      H5T_NATIVE_LONG         H5T_NATIVE_ULONG
 *                      H5T_NATIVE_LLONG        H5T_NATIVE_ULLONG
 *
 *                      H5T_NATIVE_FLOAT
 *                      H5T_NATIVE_DOUBLE
 *                      H5T_NATIVE_LDOUBLE
 *
 *              Compound, array, enum, and VL types all choose among these
 *              types for theire members.  Time, Bifield, Opaque, Reference
 *              types are only copy out.
 *
 * Return:      Success:        Returns the native data type if successful.
 *
 *              Failure:        negative
 *
 * Programmer:  Raymond Lu
 *              Oct 3, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5Tget_native_type(hid_t type_id, H5T_direction_t direction)
{
    H5T_t       *dt;                /* Datatype to create native datatype from */
    H5T_t       *new_dt=NULL;       /* Datatype for native datatype created */
    size_t      comp_size=0;        /* Compound datatype's size */
    hid_t       ret_value;          /* Return value */

    FUNC_ENTER_API(H5Tget_native_type, FAIL)
    H5TRACE2("i", "iTd", type_id, direction);

    /* check argument */
    if(NULL==(dt=H5I_object_verify(type_id, H5I_DATATYPE)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type")

    if(direction!=H5T_DIR_DEFAULT && direction!=H5T_DIR_ASCEND
            && direction!=H5T_DIR_DESCEND)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not valid direction value")

    if((new_dt = H5T_get_native_type(dt, direction, NULL, NULL, &comp_size))==NULL)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "cannot retrieve native type")

    if((ret_value=H5I_register(H5I_DATATYPE, new_dt)) < 0)
        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREGISTER, FAIL, "unable to register data type")

done:
    /* Error cleanup */
    if(ret_value<0) {
        if(new_dt)
            if(H5T_close(new_dt)<0)
                HDONE_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, FAIL, "unable to release datatype")
    } /* end if */

    FUNC_LEAVE_API(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:    H5T_get_native_type
 *
 * Purpose:     Returns the native type of a datatype.
 *
 * Return:      Success:        Returns the native data type if successful.
 *
 *              Failure:        negative
 *
 * Programmer:  Raymond Lu
 *              Oct 3, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static H5T_t*
H5T_get_native_type(H5T_t *dtype, H5T_direction_t direction, size_t *struct_align, size_t *offset, size_t *comp_size)
{
    H5T_t       *dt;                /* Datatype to make native */
    H5T_class_t h5_class;           /* Class of datatype to make native */
    size_t      size;               /* Size of datatype to make native */
    size_t      prec;               /* Precision of datatype to make native */
    int         snmemb;             /* Number of members in compound & enum types */
    unsigned    nmemb;              /* Number of members in compound & enum types */
    H5T_t       *super_type;        /* Super type of VL, array and enum datatypes */
    H5T_t       *nat_super_type;    /* Native form of VL, array & enum super datatype */
    H5T_t       *new_type=NULL;     /* New native datatype */
    unsigned    i;                  /* Local index variable */
    H5T_t       *ret_value;         /* Return value */

    FUNC_ENTER_NOAPI(H5T_get_native_type, NULL)

    assert(dtype);

    if((h5_class = H5T_get_class(dtype, FALSE)) == H5T_NO_CLASS)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a valid class")

    if((size =  H5T_get_size(dtype)) == 0)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a valid size")

    switch(h5_class) {
        case H5T_INTEGER:
            {
                H5T_sign_t  sign;       /* Signedness of integer type */

                if((sign =  H5T_get_sign(dtype))==H5T_SGN_ERROR)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a valid signess")

                prec =  dtype->shared->u.atomic.prec;

                if((ret_value = H5T_get_native_integer(prec, sign, direction, struct_align, offset, comp_size))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve integer type")
            }
            break;

        case H5T_FLOAT:
            if((ret_value = H5T_get_native_float(size, direction, struct_align, offset, comp_size))==NULL)
                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve float type")

            break;

        case H5T_STRING:
            if((ret_value=H5T_copy(dtype, H5T_COPY_TRANSIENT))==NULL)
                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve float type")

            if(H5T_IS_VL_STRING(dtype->shared)) {
                /* Update size, offset and compound alignment for parent. */
                if(H5T_cmp_offset(comp_size, offset, sizeof(char *), (size_t)1, H5T_POINTER_COMP_ALIGN_g, struct_align)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")
            } else {
                /* Update size, offset and compound alignment for parent. */
                if(H5T_cmp_offset(comp_size, offset, sizeof(char), size, H5T_NATIVE_SCHAR_COMP_ALIGN_g, struct_align)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")
            }
            break;

        /* These 2 types will be supported in the future.  Simply return "not supported"
         * message for now.*/
        case H5T_TIME:
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "time type is not supported yet")

        case H5T_BITFIELD:
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "bit field type is not supported yet")

        case H5T_OPAQUE:
            if((ret_value=H5T_copy(dtype, H5T_COPY_TRANSIENT))==NULL)
                 HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve float type")

            /* Update size, offset and compound alignment for parent. */
            if(H5T_cmp_offset(comp_size, offset, sizeof(char), size, H5T_NATIVE_SCHAR_COMP_ALIGN_g, struct_align)<0)
                HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")
            break;

        case H5T_REFERENCE:
            {
                size_t align;
                size_t ref_size;
                int    not_equal;

                if((ret_value=H5T_copy(dtype, H5T_COPY_TRANSIENT))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve float type")

                /* Decide if the data type is object or dataset region reference. */
                if(NULL==(dt=H5I_object(H5T_STD_REF_OBJ_g)))
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a data type")
                not_equal = H5T_cmp(ret_value, dt, FALSE);

                /* Update size, offset and compound alignment for parent. */
                if(!not_equal) {
                    align = H5T_HOBJREF_COMP_ALIGN_g;
                    ref_size = sizeof(hobj_ref_t);
                } else {
                    align = H5T_HDSETREGREF_COMP_ALIGN_g;
                    ref_size = sizeof(hdset_reg_ref_t);
                }

                if(H5T_cmp_offset(comp_size, offset, ref_size, (size_t)1, align, struct_align)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")
            }
            break;

        case H5T_COMPOUND:
            {
                H5T_t       *memb_type;     /* Datatype of member */
                H5T_t       **memb_list;    /* List of compound member IDs */
                size_t      *memb_offset;   /* List of member offsets in compound type, including member size and alignment */
                size_t      children_size=0;/* Total size of compound members */
                size_t      children_st_align=0;    /* The max alignment among compound members.  This'll be the compound alignment */
                char        **comp_mname;   /* List of member names in compound type */

                if((snmemb = H5T_get_nmembers(dtype))<=0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "compound data type doesn't have any member")
                H5_ASSIGN_OVERFLOW(nmemb,snmemb,int,unsigned);

                if((memb_list   = (H5T_t**)H5MM_malloc(nmemb*sizeof(H5T_t*)))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")
                if((memb_offset = (size_t*)H5MM_calloc(nmemb*sizeof(size_t)))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")
                if((comp_mname = (char**)H5MM_malloc(nmemb*sizeof(char*)))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")

                /* Construct child compound type and retrieve a list of their IDs, offsets, total size, and alignment for compound type. */
                for(i=0; i<nmemb; i++) {
                    if((memb_type = H5T_get_member_type(dtype, i))==NULL)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "member type retrieval failed")

                    if((comp_mname[i] = H5T_get_member_name(dtype, i))==NULL)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "member type retrieval failed")

                    if((memb_list[i] = H5T_get_native_type(memb_type, direction, &children_st_align, &(memb_offset[i]), &children_size))==NULL)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "member identifier retrieval failed")

                    if(H5T_close(memb_type)<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot close datatype")
                }

                /* The alignment for whole compound type */
                if(children_st_align && children_size % children_st_align)
                    children_size += children_st_align-(children_size % children_st_align);

                /* Construct new compound type based on native type */
                if((new_type=H5T_create(H5T_COMPOUND, children_size))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot create a compound type")

                /* Insert members for the new compound type */
                for(i=0; i<nmemb; i++) {
                    if(H5T_insert(new_type, comp_mname[i], memb_offset[i], memb_list[i])<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot insert member to compound datatype")
                }

                /* Update size, offset and compound alignment for parent. */
                if(offset)
                    *offset = *comp_size;
                if(struct_align && *struct_align < children_st_align)
                    *struct_align = children_st_align;
                *comp_size += children_size;

                /* Close member data type */
                for(i=0; i<nmemb; i++) {
                    if(H5T_close(memb_list[i])<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot close datatype")

                    /* Free member names in list */
                    H5MM_xfree(comp_mname[i]);
                }

                /* Free lists for members */
                H5MM_xfree(memb_list);
                H5MM_xfree(memb_offset);
                H5MM_xfree(comp_mname);

                ret_value = new_type;
            }
            break;

        case H5T_ENUM:
            {
                char        *memb_name;         /* Enum's member name */
                void        *memb_value, *tmp_memb_value;        /* Enum's member value */
                hid_t       super_type_id, nat_super_type_id;

                /* Don't need to do anything special for alignment, offset since the ENUM type usually is integer. */

                /* Retrieve base type for enumerated type */
                if((super_type=H5T_get_super(dtype))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to get base type for enumerate type")
                if((nat_super_type = H5T_get_native_type(super_type, direction, struct_align, offset, comp_size))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "base native type retrieval failed")

                if((super_type_id=H5I_register(H5I_DATATYPE, super_type))<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot register datatype")
                if((nat_super_type_id=H5I_register(H5I_DATATYPE, nat_super_type))<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot register datatype")

                /* Allocate room for the enum values */
                if((tmp_memb_value = H5MM_calloc(H5T_get_size(super_type)))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")
                if((memb_value = H5MM_calloc(H5T_get_size(nat_super_type)))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")

                /* Construct new enum type based on native type */
                if((new_type=H5T_enum_create(nat_super_type))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to create enum type")

                /* Retrieve member info and insert members into new enum type */
                if((snmemb = H5T_get_nmembers(dtype))<=0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "enumerate data type doesn't have any member")
                H5_ASSIGN_OVERFLOW(nmemb,snmemb,int,unsigned);
                for(i=0; i<nmemb; i++) {
                    if((memb_name=H5T_get_member_name(dtype, i))==NULL)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot get member name")
                    if(H5T_get_member_value(dtype, i, tmp_memb_value)<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot get member value")
                    HDmemcpy(memb_value, tmp_memb_value, H5T_get_size(super_type));

                    if(H5Tconvert(super_type_id, nat_super_type_id, (size_t)1, memb_value, NULL, H5P_DEFAULT)<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot get member value")

                    if(H5T_enum_insert(new_type, memb_name, memb_value)<0)
                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot insert member")
                    H5MM_xfree(memb_name);
                }
                H5MM_xfree(memb_value);
                H5MM_xfree(tmp_memb_value);

                /* Close base type */
                if(H5Tclose(nat_super_type_id)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot close datatype")
                 /* Close super type */
                if(H5Tclose(super_type_id)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot close datatype")

                ret_value = new_type;
            }
            break;

        case H5T_ARRAY:
            {
                int         sarray_rank;        /* Array's rank */
                unsigned    array_rank;         /* Array's rank */
                hsize_t     *dims = NULL;       /* Dimension sizes for array */
                hsize_t     nelems = 1;
                size_t      super_offset=0;
                size_t      super_size=0;
                size_t      super_align=0;

                /* Retrieve dimension information for array data type */
                if((sarray_rank = H5T_get_array_ndims(dtype)) <= 0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot get dimension rank")
                H5_ASSIGN_OVERFLOW(array_rank, sarray_rank, int, unsigned);
                if((dims = (hsize_t*)H5MM_malloc(array_rank * sizeof(hsize_t))) == NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot allocate memory")
                if(H5T_get_array_dims(dtype, dims) < 0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot get dimension size")

                /* Retrieve base type for array type */
                if((super_type = H5T_get_super(dtype)) == NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to get parent type for array type")
                if((nat_super_type = H5T_get_native_type(super_type, direction, &super_align,
                                                         &super_offset, &super_size)) == NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "parent native type retrieval failed")

                /* Close super type */
                if(H5T_close(super_type) < 0)
                    HGOTO_ERROR(H5E_ARGS, H5E_CLOSEERROR, NULL, "cannot close datatype")

                /* Create a new array type based on native type */
                if((new_type = H5T_array_create(nat_super_type, array_rank, dims)) == NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to create array type")

                /* Close base type */
                if(H5T_close(nat_super_type) < 0)
                    HGOTO_ERROR(H5E_ARGS, H5E_CLOSEERROR, NULL, "cannot close datatype")

                for(i = 0; i < array_rank; i++)
                    nelems *= dims[i];
                H5_CHECK_OVERFLOW(nelems, hsize_t, size_t);
                if(H5T_cmp_offset(comp_size, offset, super_size, (size_t)nelems, super_align, struct_align) < 0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")

                H5MM_xfree(dims);
                ret_value = new_type;
            }
            break;

        case H5T_VLEN:
            {
                size_t      vl_align = 0;
                size_t      vl_size  = 0;
                size_t      super_size=0;

                /* Retrieve base type for array type */
                if((super_type=H5T_get_super(dtype))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to get parent type for VL type")
                /* Don't need alignment, offset information if this VL isn't a field of compound type.  If it
                 * is, go to a few steps below to compute the information directly. */
                if((nat_super_type = H5T_get_native_type(super_type, direction, NULL, NULL, &super_size))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "parent native type retrieval failed")

                /* Close super type */
                if(H5T_close(super_type)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_CLOSEERROR, NULL, "cannot close datatype")

                /* Create a new array type based on native type */
                if((new_type=H5T_vlen_create(nat_super_type))==NULL)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "unable to create VL type")

                /* Close base type */
                if(H5T_close(nat_super_type)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_CLOSEERROR, NULL, "cannot close datatype")

                /* Update size, offset and compound alignment for parent compound type directly. */
                vl_align = H5T_HVL_COMP_ALIGN_g;
                vl_size  = sizeof(hvl_t);

                if(H5T_cmp_offset(comp_size, offset, vl_size, (size_t)1, vl_align, struct_align)<0)
                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")

                ret_value = new_type;
            }
            break;

        case H5T_NO_CLASS:
        case H5T_NCLASSES:
        default:
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "data type doesn't match any native type")
    }

done:
    /* Error cleanup */
    if(ret_value==NULL) {
        if(new_type)
            if(H5T_close(new_type)<0)
                HDONE_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, NULL, "unable to release datatype")
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:    H5T_get_native_integer
 *
 * Purpose:     Returns the native integer type of a datatype.
 *
 * Return:      Success:        Returns the native data type if successful.
 *
 *              Failure:        negative
 *
 * Programmer:  Raymond Lu
 *              Oct 3, 2002
 *
 * Modifications: Pedro Vicente
 *                Sep 4, 2004
 * Choose the type based on the precision; this is to support cases
 * like the Cray SV1, where the size of short is 8 but precision is 32
 * (e.g an INT (size 8, prec 64) would be converted to a SHORT
 * (size 8, prec 32) if the size was the deciding factor)
 *
 *-------------------------------------------------------------------------
 */
static H5T_t*
H5T_get_native_integer(size_t prec, H5T_sign_t sign, H5T_direction_t direction,
                       size_t *struct_align, size_t *offset, size_t *comp_size)
{
    H5T_t       *dt;            /* Appropriate native datatype to copy */
    hid_t       tid=(-1);       /* Datatype ID of appropriate native datatype */
    size_t      align=0;        /* Alignment necessary for native datatype */
    size_t  native_size=0;      /* Datatype size of the native type */
    enum match_type {           /* The different kinds of integers we can match */
        H5T_NATIVE_INT_MATCH_CHAR,
        H5T_NATIVE_INT_MATCH_SHORT,
        H5T_NATIVE_INT_MATCH_INT,
        H5T_NATIVE_INT_MATCH_LONG,
        H5T_NATIVE_INT_MATCH_LLONG,
        H5T_NATIVE_INT_MATCH_UNKNOWN
    } match=H5T_NATIVE_INT_MATCH_UNKNOWN;
    H5T_t       *ret_value;     /* Return value */

    FUNC_ENTER_NOAPI(H5T_get_native_integer, NULL);

    if(direction == H5T_DIR_DEFAULT || direction == H5T_DIR_ASCEND) {
        if(prec<=H5Tget_precision(H5T_NATIVE_SCHAR)) {
            match=H5T_NATIVE_INT_MATCH_CHAR;
            native_size = sizeof(char);
        } else if(prec<=H5Tget_precision(H5T_NATIVE_SHORT)) {
            match=H5T_NATIVE_INT_MATCH_SHORT;
            native_size = sizeof(short);
        } else if(prec<=H5Tget_precision(H5T_NATIVE_INT)) {
            match=H5T_NATIVE_INT_MATCH_INT;
            native_size = sizeof(int);
        } else if(prec<=H5Tget_precision(H5T_NATIVE_LONG)) {
            match=H5T_NATIVE_INT_MATCH_LONG;
            native_size = sizeof(long);
        } else if(prec<=H5Tget_precision(H5T_NATIVE_LLONG)) {
            match=H5T_NATIVE_INT_MATCH_LLONG;
            native_size = sizeof(long_long);
        } else {  /* If no native type matches the querried datatype, simply choose the type of biggest size. */
            match=H5T_NATIVE_INT_MATCH_LLONG;
            native_size = sizeof(long_long);
        }
    } else if(direction == H5T_DIR_DESCEND) {
        if(prec>=H5Tget_precision(H5T_NATIVE_LLONG)) {
            match=H5T_NATIVE_INT_MATCH_LLONG;
            native_size = sizeof(long_long);
        } else if(prec>=H5Tget_precision(H5T_NATIVE_LONG)) {
            if(prec==H5Tget_precision(H5T_NATIVE_LONG)) {
                match=H5T_NATIVE_INT_MATCH_LONG;
                native_size = sizeof(long);
            } else {
                match=H5T_NATIVE_INT_MATCH_LLONG;
                native_size = sizeof(long_long);
            }
        }
        else if(prec>=H5Tget_precision(H5T_NATIVE_INT)) {
            if(prec==H5Tget_precision(H5T_NATIVE_INT)) {
                match=H5T_NATIVE_INT_MATCH_INT;
                native_size = sizeof(int);
            } else {
                match=H5T_NATIVE_INT_MATCH_LONG;
                native_size = sizeof(long);
            }
        }
        else if(prec>=H5Tget_precision(H5T_NATIVE_SHORT)) {
            if(prec==H5Tget_precision(H5T_NATIVE_SHORT)) {
                match=H5T_NATIVE_INT_MATCH_SHORT;
                native_size = sizeof(short);
            } else {
                match=H5T_NATIVE_INT_MATCH_INT;
                native_size = sizeof(int);
            }
        }
        else if(prec>=H5Tget_precision(H5T_NATIVE_SCHAR)) {
            if(prec==H5Tget_precision(H5T_NATIVE_SCHAR)) {
                match=H5T_NATIVE_INT_MATCH_CHAR;
                native_size = sizeof(char);
            } else {
                match=H5T_NATIVE_INT_MATCH_SHORT;
                native_size = sizeof(short);
            }
        }
        else {  /* If no native type matches the queried datatype, simply choose the type of smallest size. */
            match=H5T_NATIVE_INT_MATCH_CHAR;
            native_size = sizeof(char);
        }
    }

    /* Set the appropriate native datatype information */
    switch(match) {
        case H5T_NATIVE_INT_MATCH_CHAR:
            if(sign==H5T_SGN_2)
                tid = H5T_NATIVE_SCHAR;
            else
                tid = H5T_NATIVE_UCHAR;

            align = H5T_NATIVE_SCHAR_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_INT_MATCH_SHORT:
            if(sign==H5T_SGN_2)
                tid = H5T_NATIVE_SHORT;
            else
                tid = H5T_NATIVE_USHORT;
            align = H5T_NATIVE_SHORT_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_INT_MATCH_INT:
            if(sign==H5T_SGN_2)
                tid = H5T_NATIVE_INT;
            else
                tid = H5T_NATIVE_UINT;

            align = H5T_NATIVE_INT_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_INT_MATCH_LONG:
            if(sign==H5T_SGN_2)
                tid = H5T_NATIVE_LONG;
            else
                tid = H5T_NATIVE_ULONG;

            align = H5T_NATIVE_LONG_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_INT_MATCH_LLONG:
            if(sign==H5T_SGN_2)
                tid = H5T_NATIVE_LLONG;
            else
                tid = H5T_NATIVE_ULLONG;

            align = H5T_NATIVE_LLONG_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_INT_MATCH_UNKNOWN:
        default:
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "Unknown native integer match")
    } /* end switch */

    /* Create new native type */
    assert(tid>=0);
    if(NULL==(dt=H5I_object(tid)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a data type")

    if((ret_value=H5T_copy(dt, H5T_COPY_TRANSIENT))==NULL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot copy type")

    /* compute size and offset of compound type member. */
    if(H5T_cmp_offset(comp_size, offset, native_size, (size_t)1, align, struct_align)<0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}



/*-------------------------------------------------------------------------
 * Function:    H5T_get_native_float
 *
 * Purpose:     Returns the native floatt type of a datatype.
 *
 * Return:      Success:        Returns the native data type if successful.
 *
 *              Failure:        negative
 *
 * Programmer:  Raymond Lu
 *              Oct 3, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static H5T_t*
H5T_get_native_float(size_t size, H5T_direction_t direction, size_t *struct_align, size_t *offset, size_t *comp_size)
{
    H5T_t       *dt=NULL;       /* Appropriate native datatype to copy */
    hid_t       tid=(-1);       /* Datatype ID of appropriate native datatype */
    size_t      align=0;        /* Alignment necessary for native datatype */
    size_t 	native_size=0;  /* Datatype size of the native type */
    enum match_type {           /* The different kinds of floating point types we can match */
        H5T_NATIVE_FLOAT_MATCH_FLOAT,
        H5T_NATIVE_FLOAT_MATCH_DOUBLE,
#if H5_SIZEOF_LONG_DOUBLE !=0
        H5T_NATIVE_FLOAT_MATCH_LDOUBLE,
#endif
        H5T_NATIVE_FLOAT_MATCH_UNKNOWN
    } match=H5T_NATIVE_FLOAT_MATCH_UNKNOWN;
    H5T_t       *ret_value;     /* Return value */

    FUNC_ENTER_NOAPI(H5T_get_native_float, NULL)

    assert(size>0);

    if(direction == H5T_DIR_DEFAULT || direction == H5T_DIR_ASCEND) {
        if(size<=sizeof(float)) {
            match=H5T_NATIVE_FLOAT_MATCH_FLOAT;
	    native_size = sizeof(float);
        }
        else if(size<=sizeof(double)) {
            match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
	    native_size = sizeof(double);
        }
#if H5_SIZEOF_LONG_DOUBLE !=0
        else if(size<=sizeof(long double)) {
            match=H5T_NATIVE_FLOAT_MATCH_LDOUBLE;
	    native_size = sizeof(long double);
        }
#endif
        else {   /* If not match, return the biggest datatype */
#if H5_SIZEOF_LONG_DOUBLE !=0
            match=H5T_NATIVE_FLOAT_MATCH_LDOUBLE;
	    native_size = sizeof(long double);
#else
            match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
            native_size = sizeof(double);
#endif
	}
    } else {
#if H5_SIZEOF_LONG_DOUBLE !=0
        if(size>=sizeof(long double)) {
            match=H5T_NATIVE_FLOAT_MATCH_LDOUBLE;
	    native_size = sizeof(long double);
        }
        else if(size>=sizeof(double)) {
            if(size==sizeof(double)) {
                match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
	    	native_size = sizeof(double);
            } else {
                match=H5T_NATIVE_FLOAT_MATCH_LDOUBLE;
	    	native_size = sizeof(long double);
	    }
        }
        else if(size>=sizeof(float)) {
            if(size==sizeof(float)) {
                match=H5T_NATIVE_FLOAT_MATCH_FLOAT;
	    	native_size = sizeof(float);
            } else {
                match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
	    	native_size = sizeof(double);
	    }
        }
        else {
            match=H5T_NATIVE_FLOAT_MATCH_FLOAT;
	    native_size = sizeof(float);
	}
#else
        if(size>=sizeof(double)) {
            match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
	    native_size = sizeof(double);
        }
        else if(size>=sizeof(float)) {
            if(size==sizeof(float)) {
                match=H5T_NATIVE_FLOAT_MATCH_FLOAT;
	    	native_size = sizeof(float);
            } else {
                match=H5T_NATIVE_FLOAT_MATCH_DOUBLE;
	    	native_size = sizeof(double);
	    }
        }
        else {
            match=H5T_NATIVE_FLOAT_MATCH_FLOAT;
	    native_size = sizeof(float);
	}
#endif
    }

    /* Set the appropriate native floating point information */
    switch(match) {
        case H5T_NATIVE_FLOAT_MATCH_FLOAT:
            tid = H5T_NATIVE_FLOAT;
            align = H5T_NATIVE_FLOAT_COMP_ALIGN_g;
            break;

        case H5T_NATIVE_FLOAT_MATCH_DOUBLE:
            tid = H5T_NATIVE_DOUBLE;
            align = H5T_NATIVE_DOUBLE_COMP_ALIGN_g;
            break;

#if H5_SIZEOF_LONG_DOUBLE !=0
        case H5T_NATIVE_FLOAT_MATCH_LDOUBLE:
            tid = H5T_NATIVE_LDOUBLE;
            align = H5T_NATIVE_LDOUBLE_COMP_ALIGN_g;
            break;
#endif
        case H5T_NATIVE_FLOAT_MATCH_UNKNOWN:
        default:
            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "Unknown native floating-point match")
    } /* end switch */

    /* Create new native type */
    assert(tid>=0);
    if(NULL==(dt=H5I_object(tid)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a data type")
    if((ret_value=H5T_copy(dt, H5T_COPY_TRANSIENT))==NULL)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot retrieve float type")

    /* compute offset of compound type member. */
    if(H5T_cmp_offset(comp_size, offset, native_size, (size_t)1, align, struct_align)<0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "cannot compute compound offset")

done:
    FUNC_LEAVE_NOAPI(ret_value)
}


/*-------------------------------------------------------------------------
 * Function:	H5T_cmp_offset
 *
 * Purpose:	This function is only for convenience.  It computes the
 *              compound type size, offset of the member being considered
 *              and the alignment for the whole compound type.
 *
 * Return:	Success:        Non-negative value.
 *
 *		Failure:        Negative value.
 *
 * Programmer:	Raymond Lu
 *		December  10, 2002
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5T_cmp_offset(size_t *comp_size, size_t *offset, size_t elem_size,
                      size_t nelems, size_t align, size_t *struct_align)
{
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(H5T_cmp_offset, FAIL)

    if(offset && comp_size) {
        if(align>1 && *comp_size%align) {
            /* Add alignment value */
            *offset = *comp_size +  (align - *comp_size%align);
            *comp_size += (align - *comp_size%align);
        } else
            *offset = *comp_size;

        /* compute size of compound type member. */
        *comp_size += nelems*elem_size;
    }

    if(struct_align && *struct_align < align)
        *struct_align = align;

done:
    FUNC_LEAVE_NOAPI(ret_value)
}