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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* 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 COPYING 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. *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* Module Info: This module contains the functionality for setting & querying
* the datatype precision for the H5T interface.
*/
#include "H5Tmodule.h" /* This source code file is part of the H5T module */
#include "H5private.h" /* Generic Functions */
#include "H5Eprivate.h" /* Error handling */
#include "H5Iprivate.h" /* IDs */
#include "H5Tpkg.h" /* Datatypes */
/* Static local functions */
static herr_t H5T__set_precision(const H5T_t *dt, size_t prec);
/*-------------------------------------------------------------------------
* Function: H5Tget_precision
*
* Purpose: Gets the precision of a datatype. The precision is
* the number of significant bits which, unless padding is
* present, is 8 times larger than the value returned by
* H5Tget_size().
*
* Return: Success: Number of significant bits
*
* Failure: 0 (all atomic types have at least one
* significant bit)
*
*-------------------------------------------------------------------------
*/
size_t
H5Tget_precision(hid_t type_id)
{
H5T_t *dt;
size_t ret_value;
FUNC_ENTER_API(0)
H5TRACE1("z", "i", type_id);
/* Check args */
if (NULL == (dt = (H5T_t *)H5I_object_verify(type_id, H5I_DATATYPE)))
HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "not a datatype");
/* Get precision */
if ((ret_value = H5T_get_precision(dt)) == 0)
HGOTO_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, 0, "can't get precision for specified datatype");
done:
FUNC_LEAVE_API(ret_value)
} /* end H5Tget_precision() */
/*-------------------------------------------------------------------------
* Function: H5T_get_precision
*
* Purpose: Gets the precision of a datatype. The precision is
* the number of significant bits which, unless padding is
* present, is 8 times larger than the value returned by
* H5Tget_size().
*
* Return: Success: Number of significant bits
* Failure: 0 (all atomic types have at least one
* significant bit)
*
*-------------------------------------------------------------------------
*/
size_t
H5T_get_precision(const H5T_t *dt)
{
size_t ret_value = 0; /* Return value */
FUNC_ENTER_NOAPI(0)
/* Defer to parent*/
while (dt->shared->parent)
dt = dt->shared->parent;
if (!H5T_IS_ATOMIC(dt->shared))
HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, 0, "operation not defined for specified datatype");
/* Precision */
ret_value = dt->shared->u.atomic.prec;
done:
FUNC_LEAVE_NOAPI(ret_value)
} /* end H5T_get_precision() */
/*-------------------------------------------------------------------------
* Function: H5Tset_precision
*
* Purpose: Sets the precision of a datatype. The precision is
* the number of significant bits which, unless padding is
* present, is 8 times larger than the value returned by
* H5Tget_size().
*
* If the precision is increased then the offset is decreased
* and then the size is increased to insure that significant
* bits do not "hang over" the edge of the datatype.
*
* The precision property of strings is read-only.
*
* When decreasing the precision of a floating point type, set
* the locations and sizes of the sign, mantissa, and exponent
* fields first.
*
* Return: Non-negative on success/Negative on failure
*
*-------------------------------------------------------------------------
*/
herr_t
H5Tset_precision(hid_t type_id, size_t prec)
{
H5T_t *dt = NULL;
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_API(FAIL)
H5TRACE2("e", "iz", type_id, prec);
/* Check args */
if (NULL == (dt = (H5T_t *)H5I_object_verify(type_id, H5I_DATATYPE)))
HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a datatype");
if (H5T_STATE_TRANSIENT != dt->shared->state)
HGOTO_ERROR(H5E_ARGS, H5E_CANTSET, FAIL, "datatype is read-only");
if (NULL != dt->vol_obj)
HGOTO_ERROR(H5E_ARGS, H5E_CANTSET, FAIL, "datatype is committed");
if (prec == 0)
HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "precision must be positive");
if (H5T_ENUM == dt->shared->type && dt->shared->u.enumer.nmembs > 0)
HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "operation not allowed after members are defined");
if (H5T_STRING == dt->shared->type)
HGOTO_ERROR(H5E_ARGS, H5E_UNSUPPORTED, FAIL, "precision for this type is read-only");
if (H5T_COMPOUND == dt->shared->type || H5T_OPAQUE == dt->shared->type)
HGOTO_ERROR(H5E_DATATYPE, H5E_UNSUPPORTED, FAIL, "operation not defined for specified datatype");
/* Do the work */
if (H5T__set_precision(dt, prec) < 0)
HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to set precision");
done:
FUNC_LEAVE_API(ret_value)
}
/*-------------------------------------------------------------------------
* Function: H5T__set_precision
*
* Purpose: Sets the precision of a datatype. The precision is
* the number of significant bits which, unless padding is
* present, is 8 times larger than the value returned by
* H5Tget_size().
*
* If the precision is increased then the offset is decreased
* and then the size is increased to insure that significant
* bits do not "hang over" the edge of the datatype.
*
* The precision property of strings is read-only.
*
* When decreasing the precision of a floating point type, set
* the locations and sizes of the sign, mantissa, and exponent
* fields first.
*
* Return: Non-negative on success/Negative on failure
*
*-------------------------------------------------------------------------
*/
static herr_t
H5T__set_precision(const H5T_t *dt, size_t prec)
{
size_t offset, size;
herr_t ret_value = SUCCEED; /* Return value */
FUNC_ENTER_PACKAGE
/* Check args */
assert(dt);
assert(prec > 0);
assert(H5T_OPAQUE != dt->shared->type);
assert(H5T_COMPOUND != dt->shared->type);
assert(H5T_STRING != dt->shared->type);
assert(!(H5T_ENUM == dt->shared->type && 0 == dt->shared->u.enumer.nmembs));
if (dt->shared->parent) {
if (H5T__set_precision(dt->shared->parent, prec) < 0)
HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to set precision for base type");
/* Adjust size of datatype appropriately */
if (dt->shared->type == H5T_ARRAY)
dt->shared->size = dt->shared->parent->shared->size * dt->shared->u.array.nelem;
else if (dt->shared->type != H5T_VLEN)
dt->shared->size = dt->shared->parent->shared->size;
}
else {
if (H5T_IS_ATOMIC(dt->shared)) {
/* Adjust the offset and size */
offset = dt->shared->u.atomic.offset;
size = dt->shared->size;
if (prec > 8 * size)
offset = 0;
else if (offset + prec > 8 * size)
offset = 8 * size - prec;
if (prec > 8 * size)
size = (prec + 7) / 8;
/* Check that things are still kosher */
switch (dt->shared->type) {
case H5T_INTEGER:
case H5T_TIME:
case H5T_BITFIELD:
/* nothing to check */
break;
case H5T_FLOAT:
/*
* The sign, mantissa, and exponent fields should be adjusted
* first when decreasing the precision of a floating point
* type.
*/
if (dt->shared->u.atomic.u.f.sign >= prec + offset ||
dt->shared->u.atomic.u.f.epos + dt->shared->u.atomic.u.f.esize > prec + offset ||
dt->shared->u.atomic.u.f.mpos + dt->shared->u.atomic.u.f.msize > prec + offset)
HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL,
"adjust sign, mantissa, and exponent fields first");
break;
case H5T_NO_CLASS:
case H5T_STRING:
case H5T_OPAQUE:
case H5T_COMPOUND:
case H5T_REFERENCE:
case H5T_ENUM:
case H5T_VLEN:
case H5T_ARRAY:
case H5T_NCLASSES:
default:
HGOTO_ERROR(H5E_ARGS, H5E_UNSUPPORTED, FAIL, "operation not defined for datatype class");
} /* end switch */
/* Commit */
dt->shared->size = size;
dt->shared->u.atomic.offset = offset;
dt->shared->u.atomic.prec = prec;
} /* end if */
else
HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "operation not defined for specified datatype");
} /* end else */
done:
FUNC_LEAVE_NOAPI(ret_value)
}
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