Add routine to get the relevant identifier

Author: timj

Makefile.am

@@ -91,6 +91,7 @@ C_ROUTINES = \
 	dat1InitHDF5.c \
 	dau1CheckName.c \
 	dau1CheckType.c \
+	dat1RetrieveIdentifier.c \
 	dat1RetrieveContainer.c
 
 DAT_PAR: dat_par_f$(EXEEXT)

dat1.h

@@ -155,6 +155,7 @@ dat1New( const HDSLoc *locator, const char *name_str, const char *type_str,
         int ndim, const hdsdim dims[], int *status);
 
 hid_t dat1RetrieveContainer( const HDSLoc *locator, int * status );
+hid_t dat1RetrieveIdentifier( const HDSLoc * locator, int * status );
 
 HDSLoc * dat1FreeLoc( HDSLoc * locator, int * status );
 

dat1RetrieveIdentifier.c

@@ -0,0 +1,98 @@
+/*
+*+
+*  Name:
+*     dat1RetrieveIdentifier
+
+*  Purpose:
+*     Select the group or dataset ID from the supplied struct
+
+*  Language:
+*     Starlink ANSI C
+
+*  Type of Module:
+*     Library routine
+
+*  Invocation:
+*     hid_t dat1RetrieveIdentifier( const HDSLoc * locator, int * status );
+
+*  Arguments:
+*     locator = const HDSLoc * (Given)
+*        HDS locator.
+*     status = int* (Given and Returned)
+*        Pointer to global status.
+
+*  Description:
+*     In many APIs the system doesn't care whether the locator is associated
+*     with a dataset or group so this routine returns the relevant ID.
+
+*  Authors:
+*     TIMJ: Tim Jenness (Cornell)
+*     {enter_new_authors_here}
+
+*  Notes:
+*     
+
+*  History:
+*     2014-08-26 (TIMJ):
+*        Initial version
+*     {enter_further_changes_here}
+
+*  Copyright:
+*     Copyright (C) 2014 Cornell University
+*     All Rights Reserved.
+
+*  Licence:
+*     Redistribution and use in source and binary forms, with or
+*     without modification, are permitted provided that the following
+*     conditions are met:
+*
+*     - Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*
+*     - Redistributions in binary form must reproduce the above
+*       copyright notice, this list of conditions and the following
+*       disclaimer in the documentation and/or other materials
+*       provided with the distribution.
+*
+*     - Neither the name of the {organization} nor the names of its
+*       contributors may be used to endorse or promote products
+*       derived from this software without specific prior written
+*       permission.
+*
+*     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+*     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+*     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+*     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+*     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+*     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+*     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+*     LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+*     USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+*     AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+*     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+*     IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+*     THE POSSIBILITY OF SUCH DAMAGE.
+
+*  Bugs:
+*     {note_any_bugs_here}
+*-
+*/
+
+#include "hdf5.h"
+
+#include "hds1.h"
+#include "dat1.h"
+#include "hds.h"
+
+#include "sae_par.h"
+
+hid_t dat1RetrieveIdentifier( const HDSLoc * locator, int * status ) {
+
+  if (*status != SAI__OK) return 0;
+  if (!locator) return 0;
+
+  if (locator->group_id > 0) return locator->group_id;
+  if (locator->dataset_id > 0) return locator->dataset_id;
+  return 0;
+
+}