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+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois. *
+ * All rights reserved. *
+ * *
+ * This file is part of HDF5. The full HDF5 copyright notice, including *
+ * terms governing use, modification, and redistribution, is contained in *
+ * the files COPYING and Copyright.html. COPYING can be found at the root *
+ * of the source code distribution tree; Copyright.html can be found at the *
+ * root level of an installed copy of the electronic HDF5 document set and *
+ * is linked from the top-level documents page. It can also be found at *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html. If you do not have *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Module Info: This module contains the functionality for setting & querying
+ * the datatype precision for the H5T interface.
+ */
+
+#define H5T_PACKAGE /*suppress error about including H5Tpkg */
+
+#include "H5private.h" /*generic functions */
+#include "H5Eprivate.h" /*error handling */
+#include "H5Iprivate.h" /*ID functions */
+#include "H5Tpkg.h" /*data-type functions */
+
+#define PABLO_MASK H5Tprecis_mask
+
+/* Interface initialization */
+static int interface_initialize_g = 0;
+#define INTERFACE_INIT H5T_init_precis_interface
+static herr_t H5T_init_precis_interface(void);
+
+/* Static local functions */
+static herr_t H5T_set_precision(H5T_t *dt, size_t prec);
+
+
+/*--------------------------------------------------------------------------
+NAME
+ H5T_init_precis_interface -- Initialize interface-specific information
+USAGE
+ herr_t H5T_init_precis_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_precis_interface(void)
+{
+ FUNC_ENTER_NOINIT(H5T_init_precis_interface);
+
+ FUNC_LEAVE_NOAPI(H5T_init_interface());
+} /* H5T_init_precis_interface() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Tget_precision
+ *
+ * Purpose: Gets the precision of a data type. 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)
+ *
+ * Programmer: Robb Matzke
+ * Wednesday, January 7, 1998
+ *
+ * Modifications:
+ * Robb Matzke, 22 Dec 1998
+ * Also works for derived data types.
+ *
+ *-------------------------------------------------------------------------
+ */
+size_t
+H5Tget_precision(hid_t type_id)
+{
+ H5T_t *dt = NULL;
+ size_t ret_value;
+
+ FUNC_ENTER_API(H5Tget_precision, 0);
+ H5TRACE1("z","i",type_id);
+
+ /* Check args */
+ if (NULL == (dt = H5I_object_verify(type_id,H5I_DATATYPE)))
+ HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "not a data type");
+ if (dt->parent)
+ dt = dt->parent; /*defer to parent*/
+ if (H5T_COMPOUND==dt->type || H5T_OPAQUE==dt->type || H5T_ARRAY==dt->type)
+ HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, 0, "operation not defined for specified data type");
+
+ /* Precision */
+ assert(H5T_is_atomic(dt));
+ ret_value = dt->u.atomic.prec;
+
+done:
+ FUNC_LEAVE_API(ret_value);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Tset_precision
+ *
+ * Purpose: Sets the precision of a data type. 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 data type.
+ *
+ * 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
+ *
+ * Programmer: Robb Matzke
+ * Wednesday, January 7, 1998
+ *
+ * Modifications:
+ * Robb Matzke, 22 Dec 1998
+ * Moved real work to a private function.
+ *
+ *-------------------------------------------------------------------------
+ */
+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(H5Tset_precision, FAIL);
+ H5TRACE2("e","iz",type_id,prec);
+
+ /* Check args */
+ if (NULL == (dt = H5I_object_verify(type_id,H5I_DATATYPE)))
+ HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a data type");
+ if (H5T_STATE_TRANSIENT!=dt->state)
+ HGOTO_ERROR(H5E_ARGS, H5E_CANTINIT, FAIL, "data type is read-only");
+ if (prec <= 0)
+ HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "precision must be positive");
+ if (H5T_ENUM==dt->type && dt->u.enumer.nmembs>0)
+ HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "operation not allowed after members are defined");
+
+ /* Do the work */
+ if (H5T_set_precision(dt, prec)<0)
+ HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to set precision");
+
+done:
+ FUNC_LEAVE_API(ret_value);
+}
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5T_set_precision
+ *
+ * Purpose: Sets the precision of a data type. 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 data type.
+ *
+ * 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
+ *
+ * Programmer: Robb Matzke
+ * Wednesday, January 7, 1998
+ *
+ * Modifications:
+ * Robb Matzke, 22 Dec 1998
+ * Also works for derived data types.
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T_set_precision(H5T_t *dt, size_t prec)
+{
+ size_t offset, size;
+ herr_t ret_value=SUCCEED; /* Return value */
+
+ FUNC_ENTER_NOAPI(H5T_set_precision, FAIL);
+
+ /* Check args */
+ assert(dt);
+ assert(prec>0);
+ assert(H5T_ENUM!=dt->type || 0==dt->u.enumer.nmembs);
+
+ if (dt->parent) {
+ if (H5T_set_precision(dt->parent, prec)<0)
+ HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to set precision for base type");
+ dt->size = dt->parent->size;
+ } else {
+ if (H5T_COMPOUND==dt->type || H5T_OPAQUE==dt->type || H5T_ARRAY==dt->type) {
+ HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "operation not defined for specified data type");
+ } else if (H5T_ENUM==dt->type) {
+ /*nothing*/
+ } else if (H5T_is_atomic(dt)) {
+ /* Adjust the offset and size */
+ offset = dt->u.atomic.offset;
+ size = dt->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->type) {
+ case H5T_INTEGER:
+ case H5T_TIME:
+ case H5T_BITFIELD:
+ /* nothing to check */
+ break;
+
+ case H5T_STRING:
+ HGOTO_ERROR(H5E_ARGS, H5E_UNSUPPORTED, FAIL, "precision for this type is read-only");
+
+ case H5T_FLOAT:
+ /*
+ * The sign, mantissa, and exponent fields should be adjusted
+ * first when decreasing the precision of a floating point
+ * type.
+ */
+ if (dt->u.atomic.u.f.sign >= prec ||
+ dt->u.atomic.u.f.epos + dt->u.atomic.u.f.esize > prec ||
+ dt->u.atomic.u.f.mpos + dt->u.atomic.u.f.msize > prec) {
+ HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "adjust sign, mantissa, and exponent fields first");
+ }
+ break;
+
+ default:
+ assert("not implemented yet" && 0);
+ }
+
+ /* Commit */
+ dt->size = size;
+ if (H5T_is_atomic(dt)) {
+ dt->u.atomic.offset = offset;
+ dt->u.atomic.prec = prec;
+ }
+ }
+ }
+
+done:
+ FUNC_LEAVE_NOAPI(ret_value);
+}
+