Merge commit '7fde2daeed593684120d75de07598154f3ddaf2c' as 'ast'

1 files changed, 2875 insertions, 0 deletions

diff --git a/ast/switchmap.c b/ast/switchmap.c
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+/*
+*class++
+*  Name:
+*     SwitchMap
+
+*  Purpose:
+*     A Mapping that encapsulates a set of alternate Mappings.
+
+*  Constructor Function:
+c     astSwitchMap
+f     AST_SWITCHMAP
+
+*  Description:
+*     A SwitchMap is a Mapping which represents a set of alternate
+*     Mappings, each of which is used to transform positions within a
+*     particular region of the input or output coordinate system of the
+*     SwitchMap.
+*
+*     A SwitchMap can encapsulate any number of Mappings, but they must
+*     all have the same number of inputs (Nin attribute value) and the
+*     same number of outputs (Nout attribute value). The SwitchMap itself
+*     inherits these same values for its Nin and Nout attributes. Each of
+*     these Mappings represents a "route" through the switch, and are
+*     referred to as "route" Mappings below. Each route Mapping transforms
+*     positions between the input and output coordinate space of the entire
+*     SwitchMap, but only one Mapping will be used to transform any given
+*     position. The selection of the appropriate route Mapping to use with
+*     any given input position is made by another Mapping, called the
+*     "selector" Mapping. Each SwitchMap encapsulates two selector
+*     Mappings in addition to its route Mappings; one for use with the
+*     SwitchMap's forward transformation (called the "forward selector
+*     Mapping"), and one for use with the SwitchMap's inverse transformation
+*     (called the "inverse selector Mapping"). The forward selector Mapping
+*     must have the same number of inputs as the route Mappings, but
+*     should have only one output. Likewise, the inverse selector Mapping
+*     must have the same number of outputs as the route Mappings, but
+*     should have only one input.
+*
+*     When the SwitchMap is used to transform a position in the forward
+*     direction (from input to output), each supplied input position is
+*     first transformed by the forward transformation of the forward selector
+*     Mapping. This produces a single output value for each input position
+*     referred to as the selector value. The nearest integer to the selector
+*     value is found, and is used to index the array of route Mappings (the
+*     first supplied route Mapping has index 1, the second route Mapping has
+*     index 2, etc). If the nearest integer to the selector value is less
+*     than 1 or greater than the number of route Mappings, then the SwitchMap
+*     output position is set to a value of AST__BAD on every axis. Otherwise,
+*     the forward transformation of the selected route Mapping is used to
+*     transform the supplied input position to produce the SwitchMap output
+*     position.
+*
+*     When the SwitchMap is used to transform a position in the inverse
+*     direction (from "output" to "input"), each supplied "output" position
+*     is first transformed by the inverse transformation of the inverse
+*     selector Mapping. This produces a selector value for each "output"
+*     position. Again, the nearest integer to the selector value is found,
+*     and is used to index the array of route Mappings. If this selector
+*     index value is within the bounds of the array of route Mappings, then
+*     the inverse transformation of the selected route Mapping is used to
+*     transform the supplied "output" position to produce the SwitchMap
+*     "input" position. If the selector index value is outside the bounds
+*     of the array of route Mappings, then the SwitchMap "input" position is
+*     set to a value of AST__BAD on every axis.
+*
+*     In practice, appropriate selector Mappings should be chosen to
+*     associate a different route Mapping with each region of coordinate
+*     space. Note that the SelectorMap class of Mapping is particularly
+*     appropriate for this purpose.
+*
+*     If a compound Mapping contains a SwitchMap in series with its own
+*     inverse, the combination of the two adjacent SwitchMaps will be
+*     replaced by a UnitMap when the compound Mapping is simplified using
+c     astSimplify.
+f     AST_SIMPLIFY.
+
+*  Inheritance:
+*     The SwitchMap class inherits from the Mapping class.
+
+*  Attributes:
+*     The SwitchMap class does not define any new attributes beyond those
+*     which are applicable to all Mappings.
+
+*  Functions:
+c     The SwitchMap class does not define any new functions beyond those
+f     The SwitchMap class does not define any new routines beyond those
+*     which are applicable to all Mappings.
+
+*  Copyright:
+*     Copyright (C) 1997-2006 Council for the Central Laboratory of the Research Councils
+
+*  Licence:
+*     This program is free software: you can redistribute it and/or
+*     modify it under the terms of the GNU Lesser General Public
+*     License as published by the Free Software Foundation, either
+*     version 3 of the License, or (at your option) any later
+*     version.
+*     
+*     This program is distributed in the hope that it will be useful,
+*     but WITHOUT ANY WARRANTY; without even the implied warranty of
+*     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*     GNU Lesser General Public License for more details.
+*     
+*     You should have received a copy of the GNU Lesser General
+*     License along with this program.  If not, see
+*     <http://www.gnu.org/licenses/>.
+
+*  Authors:
+*     DSB: David S. Berry (Starlink)
+
+*  History:
+*     13-MAR-2006 (DSB):
+*        Original version.
+*     17-MAR-2006 (DSB):
+*        Guard against AST__BAD selector values.
+*     9-MAY-2006 (DSB):
+*        Check selector Mapping pointers are not NULL before calling
+*        astEqual in Equal.
+*class--
+*/
+
+/* Module Macros. */
+/* ============== */
+/* Set the name of the class we are implementing. This indicates to
+   the header files that define class interfaces that they should make
+   "protected" symbols available. */
+#define astCLASS SwitchMap
+
+/* Include files. */
+/* ============== */
+/* Interface definitions. */
+/* ---------------------- */
+
+#include "globals.h"             /* Thread-safe global data access */
+#include "error.h"               /* Error reporting facilities */
+#include "memory.h"              /* Memory allocation facilities */
+#include "object.h"              /* Base Object class */
+#include "pointset.h"            /* Sets of points/coordinates */
+#include "mapping.h"             /* Coordinate Mappings (parent class) */
+#include "unitmap.h"             /* Unit Mappings */
+#include "channel.h"             /* I/O channels */
+#include "switchmap.h"           /* Interface definition for this class */
+#include "frame.h"               /* Frames */
+
+/* Error code definitions. */
+/* ----------------------- */
+#include "ast_err.h"             /* AST error codes */
+
+/* C header files. */
+/* --------------- */
+#include <stdarg.h>
+#include <stddef.h>
+#include <string.h>
+#include <stdio.h>
+
+/* Module Variables. */
+/* ================= */
+
+/* Address of this static variable is used as a unique identifier for
+   member of this class. */
+static int class_check;
+
+/* Pointers to parent class methods which are extended by this class. */
+static int (* parent_getobjsize)( AstObject *, int * );
+static AstPointSet *(* parent_transform)( AstMapping *, AstPointSet *, int, AstPointSet *, int * );
+
+#if defined(THREAD_SAFE)
+static int (* parent_managelock)( AstObject *, int, int, AstObject **, int * );
+#endif
+
+
+
+#ifdef THREAD_SAFE
+/* Define how to initialise thread-specific globals. */
+#define GLOBAL_inits \
+   globals->Class_Init = 0;
+
+/* Create the function that initialises global data for this module. */
+astMAKE_INITGLOBALS(SwitchMap)
+
+/* Define macros for accessing each item of thread specific global data. */
+#define class_init astGLOBAL(SwitchMap,Class_Init)
+#define class_vtab astGLOBAL(SwitchMap,Class_Vtab)
+
+
+#include <pthread.h>
+
+
+#else
+
+
+/* Define the class virtual function table and its initialisation flag
+   as static variables. */
+static AstSwitchMapVtab class_vtab;   /* Virtual function table */
+static int class_init = 0;       /* Virtual function table initialised? */
+
+#endif
+
+/* External Interface Function Prototypes. */
+/* ======================================= */
+/* The following functions have public prototypes only (i.e. no
+   protected prototypes), so we must provide local prototypes for use
+   within this module. */
+AstSwitchMap *astSwitchMapId_( void *, void *, int, void **, const char *, ... );
+
+/* Prototypes for Private Member Functions. */
+/* ======================================== */
+static AstMapping *RemoveRegions( AstMapping *, int * );
+static AstPointSet *Transform( AstMapping *, AstPointSet *, int, AstPointSet *, int * );
+static double Rate( AstMapping *, double *, int, int, int * );
+static int Equal( AstObject *, AstObject *, int * );
+static int GetObjSize( AstObject *, int * );
+static int MapMerge( AstMapping *, int, int, int *, AstMapping ***, int **, int * );
+static void Copy( const AstObject *, AstObject *, int * );
+static void Delete( AstObject *, int * );
+static void Dump( AstObject *, AstChannel *, int * );
+static AstMapping *GetSelector( AstSwitchMap *, int, int *, int * );
+static AstMapping *GetRoute( AstSwitchMap *, double, int *, int * );
+
+#if defined(THREAD_SAFE)
+static int ManageLock( AstObject *, int, int, AstObject **, int * );
+#endif
+
+/* Member functions. */
+/* ================= */
+static int Equal( AstObject *this_object, AstObject *that_object, int *status ) {
+/*
+*  Name:
+*     Equal
+
+*  Purpose:
+*     Test if two SwitchMaps are equivalent.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     int Equal( AstObject *this, AstObject *that, int *status )
+
+*  Class Membership:
+*     SwitchMap member function (over-rides the astEqual protected
+*     method inherited from the astMapping class).
+
+*  Description:
+*     This function returns a boolean result (0 or 1) to indicate whether
+*     two SwitchMaps are equivalent.
+
+*  Parameters:
+*     this
+*        Pointer to the first Object (a SwitchMap).
+*     that
+*        Pointer to the second Object.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     One if the SwitchMaps are equivalent, zero otherwise.
+
+*  Notes:
+*     - A value of zero will be returned if this function is invoked
+*     with the global status set, or if it should fail for any reason.
+*/
+
+/* Local Variables: */
+   AstMapping *fsmap1;
+   AstMapping *fsmap2;
+   AstMapping *ismap1;
+   AstMapping *ismap2;
+   AstMapping *rmap1;
+   AstMapping *rmap2;
+   AstSwitchMap *that;
+   AstSwitchMap *this;
+   int fsinv1;
+   int fsinv2;
+   int isinv1;
+   int i;
+   int isinv2;
+   int nroute;
+   int result;
+   int rinv1;
+   int rinv2;
+
+/* Initialise. */
+   result = 0;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Obtain pointers to the two SwitchMap structures. */
+   this = (AstSwitchMap *) this_object;
+   that = (AstSwitchMap *) that_object;
+
+/* Check the second object is a SwitchMap. We know the first is a
+   SwitchMap since we have arrived at this implementation of the virtual
+   function. */
+   if( astIsASwitchMap( that ) ) {
+
+/* Check they have the same number of route mappings. */
+      nroute = this->nroute;
+      if( that->nroute == nroute ) {
+
+/* Get the forward selector Mappings from the two SwitchMaps. */
+         fsmap1 = GetSelector( this, 1, &fsinv1, status );
+         fsmap2 = GetSelector( that, 1, &fsinv2, status );
+
+/* Are they equal? */
+         if( ( !fsmap1 && !fsmap2 ) ||
+             ( fsmap1 && fsmap2 && astEqual( fsmap1, fsmap2 ) ) ) {
+
+/* Get the inverse selector Mappings from the two SwitchMaps. */
+            ismap1 = GetSelector( this, 0, &isinv1, status );
+            ismap2 = GetSelector( that, 0, &isinv2, status );
+
+/* Are they equal? */
+            if( ( !ismap1 && !ismap2 ) ||
+                ( ismap1 && ismap2 && astEqual( ismap1, ismap2 ) ) ) {
+
+/* Loop over the route mappings, breaking as soon as two unequal route
+   Mappings are found. Re-instate the original values for the route
+   Mapping Invert flag after testing the route Mappings for equality. */
+               result = 1;
+               for( i = 0; result && i < nroute; i++ ) {
+                  rmap1 = GetRoute( this, (double) ( i + 1 ), &rinv1, status );
+                  rmap2 = GetRoute( that, (double) ( i + 1 ), &rinv2, status );
+                  if( !astEqual( rmap1, rmap2 ) ) result = 0;
+                  astSetInvert( rmap2, rinv2 );
+                  astSetInvert( rmap1, rinv1 );
+               }
+            }
+
+/* Reinstate the invert flags for the inverse selector Mappings. Ensure
+   this is done in the opposite order to which the selector Mappings were
+   obtained (in case they are in fact the same Mapping). */
+            if( ismap2 ) astSetInvert( ismap2, isinv2 );
+            if( ismap1 ) astSetInvert( ismap1, isinv1 );
+         }
+
+/* Reinstate the invert flags for the forward selector Mappings. Ensure
+   this is done in the oppsote order to which the selector Mappings were
+   obtained (in case they are in fact the same Mapping). */
+         if( fsmap2 ) astSetInvert( fsmap2, fsinv2 );
+         if( fsmap1 ) astSetInvert( fsmap1, fsinv1 );
+      }
+   }
+
+/* If an error occurred, clear the result value. */
+   if ( !astOK ) result = 0;
+
+/* Return the result, */
+   return result;
+}
+
+static int GetObjSize( AstObject *this_object, int *status ) {
+/*
+*  Name:
+*     GetObjSize
+
+*  Purpose:
+*     Return the in-memory size of an Object.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     int GetObjSize( AstObject *this, int *status )
+
+*  Class Membership:
+*     SwitchMap member function (over-rides the astGetObjSize protected
+*     method inherited from the parent class).
+
+*  Description:
+*     This function returns the in-memory size of the supplied SwitchMap,
+*     in bytes.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     The Object size, in bytes.
+
+*  Notes:
+*     - A value of zero will be returned if this function is invoked
+*     with the global status set, or if it should fail for any reason.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *this;
+   int i;
+   int result;
+
+/* Initialise. */
+   result = 0;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Obtain a pointers to the SwitchMap structure. */
+   this = (AstSwitchMap *) this_object;
+
+/* Invoke the GetObjSize method inherited from the parent class, and then
+   add on any components of the class structure defined by this class
+   which are stored in dynamically allocated memory. */
+   result = (*parent_getobjsize)( this_object, status );
+
+   result += astGetObjSize( this->fsmap );
+   result += astGetObjSize( this->ismap );
+
+   for( i = 0; i < this->nroute; i++ ) {
+      result += astGetObjSize( this->routemap[ i ] );
+   }
+
+   result += astGetObjSize( this->routeinv );
+
+/* If an error occurred, clear the result value. */
+   if ( !astOK ) result = 0;
+
+/* Return the result, */
+   return result;
+}
+
+static AstMapping *GetRoute( AstSwitchMap *this, double sel, int *inv, int *status ){
+/*
+*  Name:
+*     GetRoute
+
+*  Purpose:
+*     Return a pointer to a route Mapping, handling all Invert flags.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstMapping *GetRoute( AstSwitchMap *this, double sel, int *inv, int *status )
+
+*  Class Membership:
+*     SwitchMap method.
+
+*  Description:
+*     This function returns a pointer to a route Mapping (specified by a
+*     floating point selector value) for the given SwitchMap, taking account
+*     of the state of the Invert flag of both the route Mapping and the
+*     SwitchMap.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap.
+*     sel
+*        The selector value. The nearest integer value (minus 1) is used
+*        to index the array of route Mappings stored in the SwitchMap. A
+*        NULL pointer is returned if the selector value is out of range.
+*     inv
+*        Pointer to an int in which to return the original value of the
+*        Invert flag of the returned Mapping. The astSetInvert method
+*        should be used to re-instate this value once all use of the Mapping
+*        has been completed.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returns:
+*     A pointer to the route Mapping to use. Note, the returned pointer
+*     should NOT be annulled when no longer needed. NULL is returned
+*     (without error) if the SwitchMap does not have a route Mapping for the
+*     requested selector value. The forward transformation of the
+*     returned Mapping will implenment the forward transformation of the
+*     required route Mapping (and vice-versa).
+
+*/
+
+/* Local Variables: */
+   AstMapping *ret;
+   int rindex;
+
+/* Initialise */
+   ret = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return ret;
+
+/* Check selector value is good. */
+   if( sel != AST__BAD ) {
+
+/* Convert the supplied floating point selector value into an integer
+   index into the array of route Mappings held in the supplied SwitchMap. */
+      rindex = (int)( sel + 0.5 ) - 1;
+
+/* Return the null pointer if the index is out of range. */
+      if( rindex >= 0 && rindex < this->nroute ) {
+
+/* Get the required route Mapping. */
+         ret = ( this->routemap )[ rindex ];
+
+/* Return its original invert flag. */
+         *inv = astGetInvert( ret );
+
+/* Set the Invert flag back to the value it had when the SwitchMap was
+   created. */
+         astSetInvert( ret, this->routeinv[ rindex ] );
+
+/* If the SwitchMap has since been inverted, also invert the returned
+   route Mapping, so that the forward transformation of the returned
+   Mapping implements the forward transformation of the supplied
+   SwitchMap (and vice-versa). */
+         if( astGetInvert( this ) ) astInvert( ret );
+      }
+   }
+
+/* Return the pointer. */
+   return ret;
+
+}
+
+static AstMapping *GetSelector( AstSwitchMap *this, int fwd, int *inv, int *status ){
+/*
+*  Name:
+*     GetSelector
+
+*  Purpose:
+*     Return a pointer to a selector Mapping, handling all Invert flags.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstMapping *GetSelector( AstSwitchMap *this, int fwd, int *inv, int *status )
+
+*  Class Membership:
+*     SwitchMap method.
+
+*  Description:
+*     This function returns a pointer to either the forward or inverse
+*     selector Mapping for the given SwitchMap, taking account of the
+*     state of the Invert flag of bothe the selector Mapping and the
+*     SwitchMap.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap.
+*     fwd
+*        If non-zero, return the forward selector Mapping. Otherwise,
+*        return the inverse selector Mapping.
+*     inv
+*        Pointer to an int in which to return the original value of the
+*        Invert flag of the returned Mapping. The astSetInvert method
+*        should be used to re-instate this value once all use of the Mapping
+*        has been completed.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returns:
+*     A pointer to the selector Mapping to use. Note, the returned pointer
+*     should NOT be annulled when no longer needed. NULL is returned
+*     (without error) if the SwitchMap does not have a Mapping for the
+*     requested selector.
+
+*/
+
+/* Local Variables: */
+   AstMapping *ret;
+   int swinv;
+
+/* Initialise */
+   ret = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return ret;
+
+/* See if the SwitchMap has been inverted. */
+   swinv = astGetInvert( this );
+
+/* If the SwitchMap has been inverted, the forward and inverse selector
+   Mappings should be reversed. */
+   if( ( !swinv && !fwd ) || ( swinv && fwd ) ){
+      ret = this->ismap;
+      if( ret ) {
+         *inv = astGetInvert( ret );
+         astSetInvert( ret, this->isinv );
+      }
+
+   } else {
+      ret = this->fsmap;
+      if( ret ) {
+         *inv = astGetInvert( ret );
+         astSetInvert( ret, this->fsinv );
+      }
+   }
+
+   if( ret && swinv ) astInvert( ret );
+
+/* Return the pointer. */
+   return ret;
+
+}
+
+void astInitSwitchMapVtab_(  AstSwitchMapVtab *vtab, const char *name, int *status ) {
+/*
+*+
+*  Name:
+*     astInitSwitchMapVtab
+
+*  Purpose:
+*     Initialise a virtual function table for a SwitchMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     void astInitSwitchMapVtab( AstSwitchMapVtab *vtab, const char *name )
+
+*  Class Membership:
+*     SwitchMap vtab initialiser.
+
+*  Description:
+*     This function initialises the component of a virtual function
+*     table which is used by the SwitchMap class.
+
+*  Parameters:
+*     vtab
+*        Pointer to the virtual function table. The components used by
+*        all ancestral classes will be initialised if they have not already
+*        been initialised.
+*     name
+*        Pointer to a constant null-terminated character string which contains
+*        the name of the class to which the virtual function table belongs (it
+*        is this pointer value that will subsequently be returned by the Object
+*        astClass function).
+*-
+*/
+
+/* Local Variables: */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   AstObjectVtab *object;        /* Pointer to Object component of Vtab */
+   AstMappingVtab *mapping;      /* Pointer to Mapping component of Vtab */
+
+/* Check the local error status. */
+   if ( !astOK ) return;
+
+/* Get a pointer to the thread specific global data structure. */
+   astGET_GLOBALS(NULL);
+
+/* Initialize the component of the virtual function table used by the
+   parent class. */
+   astInitMappingVtab( (AstMappingVtab *) vtab, name );
+
+/* Store a unique "magic" value in the virtual function table. This
+   will be used (by astIsASwitchMap) to determine if an object belongs to
+   this class.  We can conveniently use the address of the (static)
+   class_check variable to generate this unique value. */
+   vtab->id.check = &class_check;
+   vtab->id.parent = &(((AstMappingVtab *) vtab)->id);
+
+/* Initialise member function pointers. */
+/* ------------------------------------ */
+/* Store pointers to the member functions (implemented here) that
+   provide virtual methods for this class. */
+
+/* None. */
+
+/* Save the inherited pointers to methods that will be extended, and
+   replace them with pointers to the new member functions. */
+   object = (AstObjectVtab *) vtab;
+   mapping = (AstMappingVtab *) vtab;
+   parent_getobjsize = object->GetObjSize;
+   object->GetObjSize = GetObjSize;
+
+#if defined(THREAD_SAFE)
+   parent_managelock = object->ManageLock;
+   object->ManageLock = ManageLock;
+#endif
+
+   parent_transform = mapping->Transform;
+   mapping->Transform = Transform;
+
+/* Store replacement pointers for methods which will be over-ridden by
+   new member functions implemented here. */
+   object->Equal = Equal;
+   mapping->MapMerge = MapMerge;
+   mapping->Rate = Rate;
+   mapping->RemoveRegions = RemoveRegions;
+
+/* Declare the copy constructor, destructor and class dump function. */
+   astSetCopy( vtab, Copy );
+   astSetDelete( vtab, Delete );
+   astSetDump( vtab, Dump, "SwitchMap", "Alternate regionalised Mapping" );
+
+/* If we have just initialised the vtab for the current class, indicate
+   that the vtab is now initialised, and store a pointer to the class
+   identifier in the base "object" level of the vtab. */
+   if( vtab == &class_vtab ) {
+      class_init = 1;
+      astSetVtabClassIdentifier( vtab, &(vtab->id) );
+   }
+}
+
+#if defined(THREAD_SAFE)
+static int ManageLock( AstObject *this_object, int mode, int extra,
+                       AstObject **fail, int *status ) {
+/*
+*  Name:
+*     ManageLock
+
+*  Purpose:
+*     Manage the thread lock on an Object.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "object.h"
+*     AstObject *ManageLock( AstObject *this, int mode, int extra,
+*                            AstObject **fail, int *status )
+
+*  Class Membership:
+*     SwitchMap member function (over-rides the astManageLock protected
+*     method inherited from the parent class).
+
+*  Description:
+*     This function manages the thread lock on the supplied Object. The
+*     lock can be locked, unlocked or checked by this function as
+*     deteremined by parameter "mode". See astLock for details of the way
+*     these locks are used.
+
+*  Parameters:
+*     this
+*        Pointer to the Object.
+*     mode
+*        An integer flag indicating what the function should do:
+*
+*        AST__LOCK: Lock the Object for exclusive use by the calling
+*        thread. The "extra" value indicates what should be done if the
+*        Object is already locked (wait or report an error - see astLock).
+*
+*        AST__UNLOCK: Unlock the Object for use by other threads.
+*
+*        AST__CHECKLOCK: Check that the object is locked for use by the
+*        calling thread (report an error if not).
+*     extra
+*        Extra mode-specific information.
+*     fail
+*        If a non-zero function value is returned, a pointer to the
+*        Object that caused the failure is returned at "*fail". This may
+*        be "this" or it may be an Object contained within "this". Note,
+*        the Object's reference count is not incremented, and so the
+*        returned pointer should not be annulled. A NULL pointer is
+*        returned if this function returns a value of zero.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*    A local status value:
+*        0 - Success
+*        1 - Could not lock or unlock the object because it was already
+*            locked by another thread.
+*        2 - Failed to lock a POSIX mutex
+*        3 - Failed to unlock a POSIX mutex
+*        4 - Bad "mode" value supplied.
+
+*  Notes:
+*     - This function attempts to execute even if an error has already
+*     occurred.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *this;       /* Pointer to SwitchMap structure */
+   int i;                      /* Loop count */
+   int result;                 /* Returned status value */
+
+/* Initialise */
+   result = 0;
+
+/* Check the supplied pointer is not NULL. */
+   if( !this_object ) return result;
+
+/* Obtain a pointers to the SwitchMap structure. */
+   this = (AstSwitchMap *) this_object;
+
+/* Invoke the ManageLock method inherited from the parent class. */
+   if( !result ) result = (*parent_managelock)( this_object, mode, extra,
+                                                fail, status );
+
+/* Invoke the astManageLock method on any Objects contained within
+   the supplied Object. */
+   if( !result ) result = astManageLock( this->fsmap, mode, extra, fail );
+   if( !result ) result = astManageLock( this->ismap, mode, extra, fail );
+   for( i = 0; i < this->nroute; i++ ) {
+      if( !result ) result = astManageLock( this->routemap[ i ], mode,
+                                            extra, fail );
+   }
+
+   return result;
+
+}
+#endif
+
+static int MapMerge( AstMapping *this, int where, int series, int *nmap,
+                     AstMapping ***map_list, int **invert_list, int *status ) {
+/*
+*  Name:
+*     MapMerge
+
+*  Purpose:
+*     Simplify a sequence of Mappings containing a SwitchMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "mapping.h"
+*     int MapMerge( AstMapping *this, int where, int series, int *nmap,
+*                   AstMapping ***map_list, int **invert_list, int *status )
+
+*  Class Membership:
+*     SwitchMap method (over-rides the protected astMapMerge method
+*     inherited from the Mapping class).
+
+*  Description:
+*     This function attempts to simplify a sequence of Mappings by
+*     merging a nominated SwitchMap in the sequence with its neighbours,
+*     so as to shorten the sequence if possible.
+*
+*     In many cases, simplification will not be possible and the
+*     function will return -1 to indicate this, without further
+*     action.
+*
+*     In most cases of interest, however, this function will either
+*     attempt to replace the nominated SwitchMap with one which it
+*     considers simpler, or to merge it with the Mappings which
+*     immediately precede it or follow it in the sequence (both will
+*     normally be considered). This is sufficient to ensure the
+*     eventual simplification of most Mapping sequences by repeated
+*     application of this function.
+*
+*     In some cases, the function may attempt more elaborate
+*     simplification, involving any number of other Mappings in the
+*     sequence. It is not restricted in the type or scope of
+*     simplification it may perform, but will normally only attempt
+*     elaborate simplification in cases where a more straightforward
+*     approach is not adequate.
+
+*  Parameters:
+*     this
+*        Pointer to the nominated SwitchMap which is to be merged with
+*        its neighbours. This should be a cloned copy of the SwitchMap
+*        pointer contained in the array element "(*map_list)[where]"
+*        (see below). This pointer will not be annulled, and the
+*        SwitchMap it identifies will not be modified by this function.
+*     where
+*        Index in the "*map_list" array (below) at which the pointer
+*        to the nominated SwitchMap resides.
+*     series
+*        A non-zero value indicates that the sequence of Mappings to
+*        be simplified will be applied in series (i.e. one after the
+*        other), whereas a zero value indicates that they will be
+*        applied in parallel (i.e. on successive sub-sets of the
+*        input/output coordinates).
+*     nmap
+*        Address of an int which counts the number of Mappings in the
+*        sequence. On entry this should be set to the initial number
+*        of Mappings. On exit it will be updated to record the number
+*        of Mappings remaining after simplification.
+*     map_list
+*        Address of a pointer to a dynamically allocated array of
+*        Mapping pointers (produced, for example, by the astMapList
+*        method) which identifies the sequence of Mappings. On entry,
+*        the initial sequence of Mappings to be simplified should be
+*        supplied.
+*
+*        On exit, the contents of this array will be modified to
+*        reflect any simplification carried out. Any form of
+*        simplification may be performed. This may involve any of: (a)
+*        removing Mappings by annulling any of the pointers supplied,
+*        (b) replacing them with pointers to new Mappings, (c)
+*        inserting additional Mappings and (d) changing their order.
+*
+*        The intention is to reduce the number of Mappings in the
+*        sequence, if possible, and any reduction will be reflected in
+*        the value of "*nmap" returned. However, simplifications which
+*        do not reduce the length of the sequence (but improve its
+*        execution time, for example) may also be performed, and the
+*        sequence might conceivably increase in length (but normally
+*        only in order to split up a Mapping into pieces that can be
+*        more easily merged with their neighbours on subsequent
+*        invocations of this function).
+*
+*        If Mappings are removed from the sequence, any gaps that
+*        remain will be closed up, by moving subsequent Mapping
+*        pointers along in the array, so that vacated elements occur
+*        at the end. If the sequence increases in length, the array
+*        will be extended (and its pointer updated) if necessary to
+*        accommodate any new elements.
+*
+*        Note that any (or all) of the Mapping pointers supplied in
+*        this array may be annulled by this function, but the Mappings
+*        to which they refer are not modified in any way (although
+*        they may, of course, be deleted if the annulled pointer is
+*        the final one).
+*     invert_list
+*        Address of a pointer to a dynamically allocated array which,
+*        on entry, should contain values to be assigned to the Invert
+*        attributes of the Mappings identified in the "*map_list"
+*        array before they are applied (this array might have been
+*        produced, for example, by the astMapList method). These
+*        values will be used by this function instead of the actual
+*        Invert attributes of the Mappings supplied, which are
+*        ignored.
+*
+*        On exit, the contents of this array will be updated to
+*        correspond with the possibly modified contents of the
+*        "*map_list" array.  If the Mapping sequence increases in
+*        length, the "*invert_list" array will be extended (and its
+*        pointer updated) if necessary to accommodate any new
+*        elements.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     If simplification was possible, the function returns the index
+*     in the "map_list" array of the first element which was
+*     modified. Otherwise, it returns -1 (and makes no changes to the
+*     arrays supplied).
+
+*  Notes:
+*     - A value of -1 will be returned if this function is invoked
+*     with the global error status set, or if it should fail for any
+*     reason.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *map;
+   AstMapping *new;
+   int i;
+   int nroute;
+   int result;
+   int fsinv_old;
+   int isinv_old;
+   int *rinv_old;
+   AstMapping *sfsmap;
+   AstMapping *sismap;
+   int simp;
+   AstMapping **srmap;
+   AstSwitchMap *swneb;
+   int ilo;
+   int equal;
+
+/* Initialise.*/
+   result = -1;
+
+/* Check the inherited status. */
+   if ( !astOK ) return result;
+
+/* Get a pointer to this SwitchMap, and note the number of route Mappings. */
+   map = (AstSwitchMap *) this;
+   nroute = map->nroute;
+
+/* Temporarily put the Invert flag of all encapsulated Mappings (both
+   route and selector) back to the values they had when the SwitchMap was
+   created, noting their current values so that they can be re-instated
+   later. If the SwitchMap itself has been inverted, swap all the original
+   invert flags. */
+   if( map->fsmap ) {
+      fsinv_old = astGetInvert( map->fsmap );
+      astSetInvert( map->fsmap, map->fsinv );
+   } else {
+      fsinv_old = 0;
+   }
+
+   if( map->ismap ) {
+      isinv_old = astGetInvert( map->ismap );
+      astSetInvert( map->ismap, map->isinv );
+   } else {
+      isinv_old = 0;
+   }
+
+   rinv_old = astMalloc( sizeof( int )*nroute );
+   if( astOK ) {
+      for( i = 0; i < nroute; i++ ) {
+         rinv_old[ i ] = astGetInvert( map->routemap[ i ] );
+         astSetInvert( map->routemap[ i ], map->routeinv[ i ] );
+      }
+   }
+
+/* If possible, merge the SwitchMap with a neighbouring SwitchMap. */
+/* =============================================================== */
+/* Only do this if we are combining the Mappings in series. */
+   if( series ) {
+
+/* Is the higher neighbour a SwitchMap? If so get a pointer to it, and
+   note the index of the lower of the two adjacent SwitchMaps. */
+      if( where < ( *nmap - 1 ) &&
+          astIsASwitchMap( ( *map_list )[ where + 1 ] ) ){
+         swneb = (AstSwitchMap *) ( *map_list )[ where + 1 ];
+         ilo = where;
+
+/* If not, is the lower neighbour a SwitchMap? If so get a pointer to it, and
+   note the index of the lower of the two adjacent SwitchMaps. */
+      } else if( where > 0 &&
+                 astIsASwitchMap( ( *map_list )[ where - 1 ] ) ){
+         swneb = (AstSwitchMap *) ( *map_list )[ where - 1 ];
+         ilo =  where - 1;
+
+      } else {
+         swneb = NULL;
+      }
+
+/* If a neighbouring SwitchMap was found, we can replace the pair by a
+   UnitMap if the two SwitchMaps are equal but have opposite values for
+   their Invert flags. Temporarily invert the neighbour, then compare
+   the two SwitchMaps for equality, then re-invert the neighbour. */
+      if( swneb ) {
+         astInvert( swneb );
+         equal = astEqual( map, swneb );
+         astInvert( swneb );
+
+/* If the two SwitchMaps are equal but opposite, annul the first of the two
+   Mappings, and replace it with a UnitMap. Also set the invert flag. */
+         if( equal ) {
+            new = (AstMapping *) astUnitMap( astGetNin( ( *map_list )[ ilo ] ), "", status );
+            (void) astAnnul( ( *map_list )[ ilo ] );
+            ( *map_list )[ ilo ] = new;
+            ( *invert_list )[ ilo ] = 0;
+
+/* Annul the second of the two Mappings, and shuffle down the rest of the
+   list to fill the gap. */
+            (void) astAnnul( ( *map_list )[ ilo + 1 ] );
+            for ( i = ilo + 2; i < *nmap; i++ ) {
+               ( *map_list )[ i - 1 ] = ( *map_list )[ i ];
+               ( *invert_list )[ i - 1 ] = ( *invert_list )[ i ];
+            }
+
+/* Clear the vacated element at the end. */
+            ( *map_list )[ *nmap - 1 ] = NULL;
+            ( *invert_list )[ *nmap - 1 ] = 0;
+
+/* Decrement the Mapping count and return the index of the first
+   modified element. */
+            ( *nmap )--;
+            result = where;
+         }
+      }
+   }
+
+/* Attempt to simplify the SwitchMap on its own. */
+/* ============================================= */
+/* Only do this if no change was made above. */
+   if( result == -1 ) {
+
+/* If the SwitchMap is inverted, create an equal SwitchMap which is not
+   inverted. To do this, invert and swap the selector Mappings, and
+   invert all the route Mappings. We use astSetInvert rather than astInvert
+   because two or more more stored pointers may point to the same Mapping
+   in which case that Mapping would be inverted more than once with
+   unpredictable results. */
+      if( ( *invert_list )[ where ] ) {
+         if( map->fsmap ) astSetInvert( map->fsmap, !(map->fsinv) );
+         if( map->ismap ) astSetInvert( map->ismap, !(map->isinv) );
+         for( i = 0; i < nroute; i++ ) {
+            astSetInvert( map->routemap[ i ], !(map->routeinv[ i ]) );
+         }
+
+         new = (AstMapping *) astSwitchMap( map->ismap, map->fsmap, nroute, (void **) map->routemap, "", status );
+
+         (void) astAnnul( ( *map_list )[ where ] );
+         ( *map_list )[ where ] = (AstMapping *) new;
+         ( *invert_list )[ where ] = 0;
+         result = where;
+
+/* Otherwise, try to simplify each of the encapsulated Mappings, noting
+   if any simplification takes place. */
+      } else {
+         sfsmap = ( map->fsmap ) ? astSimplify( map->fsmap ) : NULL;
+         sismap = ( map->ismap ) ? astSimplify( map->ismap ) : NULL;
+         simp = ( sfsmap != map->fsmap ) || ( sismap != map->ismap );
+
+         srmap = astMalloc( sizeof( AstMapping * )*nroute );
+         if( astOK ) {
+            for( i = 0; i < nroute; i++ ) {
+               srmap[ i ] = astSimplify( map->routemap[ i ] );
+               simp = simp || ( srmap[ i ] != map->routemap[ i ] );
+            }
+         }
+
+/* If any simplification took place, construct a new SwitchMap from these
+    simplified Mappings. */
+         if( simp ) {
+            (void) astAnnul( ( *map_list )[ where ] );
+            ( *map_list )[ where ] = (AstMapping *) astSwitchMap( sfsmap, sismap,
+                                                    nroute, (void **) srmap, "", status );
+            result = where;
+         }
+
+/* Release resources. */
+         if( sfsmap ) sfsmap = astAnnul( sfsmap );
+         if( sismap ) sismap = astAnnul( sismap );
+         if( srmap ) {
+            for( i = 0; i < nroute; i++ ) srmap[ i ] = astAnnul( srmap[ i ] );
+            srmap = astFree( srmap );
+         }
+      }
+   }
+
+/* Re-instate the original Invert values for the encapsulated Mappings. */
+   if( map->fsmap ) astSetInvert( map->fsmap, fsinv_old );
+   if( map->ismap ) astSetInvert( map->ismap, isinv_old );
+   if( rinv_old ) {
+      for( i = 0; i < nroute; i++ ) {
+         astSetInvert( map->routemap[ i ], rinv_old[ i ] );
+      }
+      rinv_old = astFree( rinv_old );
+   }
+
+/* If an error occurred, clear the result value. */
+   if ( !astOK ) result = -1;
+
+/* Return the result. */
+   return result;
+}
+
+static double Rate( AstMapping *this, double *at, int ax1, int ax2, int *status ){
+/*
+*  Name:
+*     Rate
+
+*  Purpose:
+*     Calculate the rate of change of a Mapping output.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     result = Rate( AstMapping *this, double *at, int ax1, int ax2, int *status )
+
+*  Class Membership:
+*     SwitchMap member function (overrides the astRate method inherited
+*     from the Mapping class ).
+
+*  Description:
+*     This function returns the rate of change of a specified output of
+*     the supplied Mapping with respect to a specified input, at a
+*     specified input position. Also evaluates the second derivative.
+
+*  Parameters:
+*     this
+*        Pointer to the Mapping to be applied.
+*     at
+*        The address of an array holding the axis values at the position
+*        at which the rate of change is to be evaluated. The number of
+*        elements in this array should equal the number of inputs to the
+*        Mapping.
+*     ax1
+*        The index of the Mapping output for which the rate of change is to
+*        be found (output numbering starts at 0 for the first output).
+*     ax2
+*        The index of the Mapping input which is to be varied in order to
+*        find the rate of change (input numbering starts at 0 for the first
+*        input).
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     The rate of change of Mapping output "ax1" with respect to input
+*     "ax2", evaluated at "at", or AST__BAD if the value cannot be
+*     calculated.
+
+*/
+
+/* Local Variables: */
+   AstSwitchMap *map;
+   AstMapping *smap;
+   AstMapping *rmap;
+   double result;
+   double sel;
+   int fsinv;
+   int rinv;
+   int nin;
+
+/* Initialise. */
+   result = AST__BAD;
+
+/* Check inherited status */
+   if( !astOK ) return result;
+
+/* Get a pointer to the SwitchMap structure. */
+   map = (AstSwitchMap *) this;
+
+/* Get a pointer to the effective foward selector Mapping, and its current
+   invert flag (this takes account of whether the SwtichMap has been
+   inverted or not). This call resets the selector's invert flag temporarily
+   back to the value it had when the SwitchMap was created. */
+   smap = GetSelector( map, 1, &fsinv, status );
+
+/* If the SwitchMap has no forward selector Mapping, return AST__BAD. */
+   if( smap ) {
+
+/* Get the number of inputs */
+      nin = astGetNin( smap );
+
+/* Transform the supplied position using the selector Mapping. The output
+   value is the selector value that indicates which route Mapping to use. */
+      astTranN( smap, 1, nin, 1, at, 1, 1, 1, &sel );
+
+/* Get the index of the route Mapping to use, and check it is valid (if
+   not, return AST__BAD if not). This takes account of whether the
+   SwitchMap has been inverted, and also temporarily re-instates the
+   original value of the route Mapping's Invert flag . */
+      rmap = GetRoute( map, sel, &rinv, status );
+      if( rmap ) {
+
+/* Use the astRate method of the route Mapping. */
+         result = astRate( rmap, at, ax1, ax2 );
+
+/* Reset the Invert flag for the route Mapping. */
+         astSetInvert( rmap, rinv );
+      }
+
+/* Reset the Invert flag for the selector Mapping. */
+      astSetInvert( smap, fsinv );
+   }
+
+/* Return the result. */
+   return result;
+}
+
+static AstMapping *RemoveRegions( AstMapping *this_mapping, int *status ) {
+/*
+*  Name:
+*     RemoveRegions
+
+*  Purpose:
+*     Remove any Regions from a Mapping.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstMapping *RemoveRegions( AstMapping *this, int *status )
+
+*  Class Membership:
+*     SwitchMap method (over-rides the astRemoveRegions method inherited
+*     from the Mapping class).
+
+*  Description:
+*     This function searches the supplied Mapping (which may be a
+*     compound Mapping such as a SwitchMap) for any component Mappings
+*     that are instances of the AST Region class. It then creates a new
+*     Mapping from which all Regions have been removed. If a Region
+*     cannot simply be removed (for instance, if it is a component of a
+*     parallel SwitchMap), then it is replaced with an equivalent UnitMap
+*     in the returned Mapping.
+*
+*     The implementation provided by the SwitchMap class invokes the
+*     astRemoveRegions method on all the component Mappings, and joins
+*     the results together into a new SwitchMap.
+
+*  Parameters:
+*     this
+*        Pointer to the original Region.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     A pointer to the modified mapping.
+
+*  Notes:
+*     - A NULL pointer value will be returned if this function is
+*     invoked with the AST error status set, or if it should fail for
+*     any reason.
+*/
+
+/* Local Variables: */
+   AstMapping **temp;            /* Array of new route Mappings */
+   AstMapping *newfsmap;         /* New forward selector Mapping */
+   AstMapping *newismap;         /* New inverse selector Mapping */
+   AstMapping *result;           /* Result pointer to return */
+   AstSwitchMap *new;            /* Pointer to new SwitchMap */
+   AstSwitchMap *this;           /* Pointer to SwitchMap structure */
+   int changed;                  /* Has any mapping been changed? */
+   int i;                        /* Loop count */
+   int nax;                      /* Number of Frame axes */
+
+/* Initialise. */
+   result = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Get a pointer to the SwitchMap. */
+   this = (AstSwitchMap *) this_mapping;
+
+/* Allocate an array to hold the modified Mapping pointers. */
+   temp = astMalloc( sizeof( AstMapping *)*( this->nroute ) );
+   if( astOK ) {
+
+/* Invoke the astRemoveRegions method on all the component Mappings. */
+      changed = 0;
+      for( i = 0; i < this->nroute; i++ ) {
+         temp[ i ] = astRemoveRegions( this->routemap[ i ] );
+
+/* Note if any Mapping was changed. */
+         if( temp[ i ] != this->routemap[ i ] ) {
+            changed = 1;
+
+/* The implementation of the astRemoveRegions method provided by the
+   Region class returns a Frame rather than a UnitMap. But we need
+   Mappings here, not Frames. So if the new Mapping is a Frame, replace
+   it with an equivalent UnitMap. */
+            if( astIsAFrame( temp[ i ] ) ) {
+               nax = astGetNin( temp[ i ] );
+               (void) astAnnul( temp[ i ] );
+               temp[ i ] = (AstMapping *) astUnitMap( nax, " ", status );
+            }
+         }
+      }
+
+/* And on the other ancillary Mappings */
+      if( this->fsmap ) {
+         newfsmap = astRemoveRegions( this->fsmap );
+         if( newfsmap != this->fsmap ) {
+            changed = 1;
+            if( astIsAFrame( newfsmap ) ) {
+               nax = astGetNin( newfsmap );
+               (void) astAnnul( newfsmap );
+               newfsmap = (AstMapping *) astUnitMap( nax, " ", status );
+            }
+         }
+
+      } else {
+         newfsmap = NULL;
+      }
+
+      if( this->ismap ) {
+         newismap = astRemoveRegions( this->ismap );
+         if( newismap != this->ismap ) {
+            changed = 1;
+            if( astIsAFrame( newismap ) ) {
+               nax = astGetNin( newismap );
+               (void) astAnnul( newismap );
+               newismap = (AstMapping *) astUnitMap( nax, " ", status );
+            }
+         }
+
+      } else {
+         newismap = NULL;
+      }
+
+/* If no component was modified, just return a clone of the supplied
+   pointer. */
+      if( ! changed ) {
+         result = astClone( this );
+
+/* Otherwise, we need to create a new Mapping to return. We take a deep
+   copy of the supplied SwitchMap and then modify the Mappings so that
+   we retain any extra information in the supplied SwitchMap. */
+      } else {
+         new = astCopy( this );
+
+         for( i = 0; i < this->nroute; i++ ) {
+            (void) astAnnul( new->routemap[ i ] );
+            new->routemap[ i ] = astClone( temp[ i ] );
+         }
+
+         if( newfsmap ) {
+            (void) astAnnul( new->fsmap );
+            new->fsmap = astClone( newfsmap );
+         }
+
+         if( newismap ) {
+            (void) astAnnul( new->ismap );
+            new->ismap = astClone( newismap );
+         }
+
+         result = (AstMapping *) new;
+      }
+
+/* Free resources. */
+      for( i = 0; i < this->nroute; i++ ) {
+         temp[ i ] = astAnnul( temp[ i ] );
+      }
+
+      if( newfsmap ) newfsmap = astAnnul( newfsmap );
+      if( newismap ) newismap = astAnnul( newismap );
+   }
+
+   temp = astFree( temp );
+
+/* Annul the returned Mapping if an error has occurred. */
+   if( !astOK ) result = astAnnul( result );
+
+/* Return the result. */
+   return result;
+}
+
+int astSwitchList_( AstSwitchMap *this, int invert, int *nmap,
+                    AstMapping ***map_list, int **invert_list, int *status ) {
+/*
+*+
+*  Name:
+*     astSwitchList
+
+*  Purpose:
+*     Extract the selector and route Mappings from a SwitchMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     int astSwitchList( AstSwitchMap *this, int invert, int *nmap,
+*                        AstMapping ***map_list, int **invert_list )
+
+*  Class Membership:
+*     SwitchMap member function.
+
+*  Description:
+*     This function extracts the route and selector Mappings form a
+*     SwitchMap.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap to be decomposed (it is not actually
+*        modified by this function).
+*     invert
+*        The value to which the SwitchMap's Invert attribute is to be
+*        (notionally) set before performing the decomposition. Normally,
+*        the value supplied here will be the actual Invert value obtained
+*        from the SwitchMap (e.g. using astGetInvert).  Sometimes, however,
+*        when a SwitchMap is encapsulated within another structure, that
+*        structure may retain an Invert value (in order to prevent external
+*        interference) which should be used instead.
+*
+*        Note that the actual Invert value of the SwitchMap supplied is
+*        not used (or modified) by this function.
+*     nmap
+*        The address of an int in which to return a count of the number of
+*        individual Mappings in the decomposition. The supplied value is
+*        ignored.
+*     map_list
+*        Address of a pointer to an array of Mapping pointers. The value
+*        supplied on entry is ignored. On exit, it points at a dynamically
+*        allocated array containing Mapping pointers ("*nmap" in number) that
+*        result from the decomposition requested.
+*
+*        The returned Mapping pointers returned will identify the following
+*        sequence of Mappings; forward selector mapping (or NULL if the
+*        SwitchMap has no forward selector Mapping), inverse selector
+*        mapping (or NULL if the SwitchMap has no inverse selector Mapping),
+*        the route Mappings in the order they were supplied when the
+*        SwitchMap was constructed.
+*
+*        All the Mapping pointers returned by this function should be
+*        annulled by the caller, using astAnnul, when no longer
+*        required. The dynamic array holding these pointers should
+*        also be freed, using astFree.
+*     invert_list
+*        Address of a pointer to an array of int. The value supplied on
+*        entry is ignored. On exit, it points at a dynamically allocated
+*        array containing Invert attribute values ("*nmap" in number) that
+*        result from the decomposition requested.
+*
+*        The returned Invert values returned identify the values which must
+*        be assigned to the Invert attributes of the corresponding
+*        Mappings (whose pointers are in the "*map_list" array) before
+*        they are applied. Note that these values may differ from the
+*        actual Invert attribute values of these Mappings, which are
+*        not relevant.
+*
+*        The dynamic array holding these values should be freed by the
+*        caller, using astFree, when no longer required.
+
+*  Returned Value:
+*     The number of route Mappings stored in the SwitchMap.
+
+*  Notes:
+*     - It is unspecified to what extent the original SwitchMap and the
+*     individual (decomposed) Mappings are inter-dependent. Consequently,
+*     the individual Mappings cannot be modified without risking
+*     modification of the original SwitchMap.
+*     - If this function is invoked with the global error status set,
+*     or if it should fail for any reason, then the *nmap value, the
+*     list of Mapping pointers and the list of Invert values will all
+*     be returned unchanged.
+*-
+*/
+
+/* Local Variables: */
+   AstMapping *map;              /* Pointer to Mapping to return */
+   int inv;                      /* Original Invert flag for Mapping */
+   int i;                        /* Route Mapping index */
+   int oldinv;                   /* Original Invert flag for SwitchMap */
+   int result;                   /* Returned value */
+
+/* Check the global error status. */
+   if ( !astOK ) return 0;
+
+/* Store the numbe of route Mappings */
+   result = this->nroute;
+   *nmap = result + 2;
+
+/* Allocate the required arrays. */
+   *map_list = astMalloc( sizeof( AstMapping * )*(size_t) *nmap );
+   *invert_list = astMalloc( sizeof( int )*(size_t) *nmap );
+
+/* Check the pointers can be used safely. */
+   if( astOK ) {
+
+/* Temporaily set the requested Invert flag for the SwitchMap. */
+      oldinv = astGetInvert( this );
+      astSetInvert( this, invert );
+
+/* Get the forward selector Mapping. */
+      map = GetSelector( this, 1, &inv, status );
+
+/* If the SwitchMap has a forward selector Mapping, return a clone of the
+   Mapping pointer, and the invert flag to be used with it, then
+   re-instate the original invert flag value (which was modified by
+   GetSelector). */
+      if( map ) {
+         ( *map_list )[ 0 ] = astClone( map );
+         ( *invert_list )[ 0 ] = astGetInvert( map );
+         astSetInvert( map, inv );
+
+/* If the SwitchMap does not has a forward selector Mapping, return a
+   NULL pointer. */
+      } else {
+         ( *map_list )[ 0 ] = NULL;
+         ( *invert_list )[ 0 ] = 0;
+      }
+
+/* Likewise, get and return the inverse selector Mapping.*/
+      map = GetSelector( this, 0, &inv, status );
+      if( map ) {
+         ( *map_list )[ 1 ] = astClone( map );
+         ( *invert_list )[ 1 ] = astGetInvert( map );
+         astSetInvert( map, inv );
+      } else {
+         ( *map_list )[ 1 ] = NULL;
+         ( *invert_list )[ 1 ] = 0;
+      }
+
+/* Loop round all route Mappings. */
+      for( i = 0; i < result; i++ ){
+
+/* Get the next route Mapping. */
+         map = GetRoute( this, (double) i + 1.0, &inv, status );
+
+/* If the SwitchMap has a route Mapping for the current selector value,
+   return a clone of the Mapping pointer, and the invert flag to be used
+   with it, then re-instate the original invert flag value (which was
+   modified by GetRoute). */
+         if( map ) {
+            ( *map_list )[ i + 2 ] = astClone( map );
+            ( *invert_list )[ i + 2 ] = astGetInvert( map );
+            astSetInvert( map, inv );
+
+/* If the SwitchMap does not has a route Mapping for the current selector
+   value, return a NULL pointer. */
+         } else {
+            ( *map_list )[ i + 2 ] = NULL;
+            ( *invert_list )[ i + 2 ] = 0;
+         }
+
+      }
+
+/* Re-instate the original Ivert flag for the SwitchMap. */
+      astSetInvert( this, oldinv );
+
+   }
+
+/* If an error has occurred, free the returned arrays. */
+   if( !astOK ) {
+      *map_list = astFree( *map_list );
+      *invert_list= astFree( *invert_list );
+      result= 0;
+      *nmap = 0;
+   }
+
+/* Return the result */
+   return result;
+}
+
+static AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+                               int forward, AstPointSet *out, int *status ) {
+/*
+*  Name:
+*     Transform
+
+*  Purpose:
+*     Apply a SwitchMap to transform a set of points.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+*                             int forward, AstPointSet *out, int *status )
+
+*  Class Membership:
+*     SwitchMap member function (over-rides the astTransform method inherited
+*     from the Mapping class).
+
+*  Description:
+*     This function takes a SwitchMap and a set of points encapsulated in a
+*     PointSet and transforms the points so as to apply the required Mapping.
+*     This implies applying each of the SwitchMap's component Mappings in turn,
+*     either in series or in parallel.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap.
+*     in
+*        Pointer to the PointSet associated with the input coordinate values.
+*     forward
+*        A non-zero value indicates that the forward coordinate transformation
+*        should be applied, while a zero value requests the inverse
+*        transformation.
+*     out
+*        Pointer to a PointSet which will hold the transformed (output)
+*        coordinate values. A NULL value may also be given, in which case a
+*        new PointSet will be created by this function.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     Pointer to the output (possibly new) PointSet.
+
+*  Notes:
+*     -  A null pointer will be returned if this function is invoked with the
+*     global error status set, or if it should fail for any reason.
+*     -  The number of coordinate values per point in the input PointSet must
+*     match the number of coordinates for the SwitchMap being applied.
+*     -  If an output PointSet is supplied, it must have space for sufficient
+*     number of points and coordinate values per point to accommodate the
+*     result. Any excess space will be ignored.
+*/
+
+/* Local Variables: */
+   AstMapping *rmap;
+   AstMapping *selmap;
+   AstPointSet *ps1;
+   AstPointSet *ps1a;
+   AstPointSet *ps2;
+   AstPointSet *ps2a;
+   AstPointSet *result;
+   AstPointSet *selps;
+   AstSwitchMap *map;
+   double **in_ptr;
+   double **out_ptr;
+   double **ptr1;
+   double **ptr2;
+   double **sel_ptr;
+   double *outv;
+   double *sel;
+   int *popmap;
+   int iroute;
+   int ipoint;
+   int j;
+   int k;
+   int maxpop;
+   int ncin;
+   int ncout;
+   int npoint;
+   int nroute;
+   int rindex;
+   int rinv;
+   int selinv;
+   int totpop;
+
+/* Check the global error status. */
+   if ( !astOK ) return NULL;
+
+/* Obtain a pointer to the SwitchMap. */
+   map = (AstSwitchMap *) this;
+
+/* Apply the parent Mapping using the stored pointer to the Transform member
+   function inherited from the parent Mapping class. This function validates
+   all arguments and generates an output PointSet if necessary, but does not
+   actually transform any coordinate values. */
+   result = (*parent_transform)( this, in, forward, out, status );
+
+/* We now extend the parent astTransform method by applying the component
+   Mappings of the SwitchMap to generate the output coordinate values. */
+
+/* Get the number of input and output coords. */
+   if( forward ) {
+      ncin = astGetNin( this );
+      ncout = astGetNout( this );
+   } else {
+      ncin = astGetNout( this );
+      ncout = astGetNin( this );
+   }
+
+/* Get the appropriate selector Mapping. */
+   selmap = GetSelector( map, forward, &selinv, status );
+
+/* Transform the supplied positions using the above selector Mapping. */
+   selps = astTransform( selmap, in, forward, NULL );
+
+/* Get a pointer to the array holding the selector value. */
+   sel_ptr = astGetPoints( selps );
+
+/* Get a pointer to the array holding the input values. */
+   in_ptr = astGetPoints( in );
+
+/* Get a pointer to the array in which to store the results, and the total
+   number of points being transformed. */
+   out_ptr = astGetPoints( result );
+   npoint = astGetNpoint( result );
+
+/* We now count how many positions are to be tranformed by each of the
+   route Mappings. */
+   nroute = map->nroute;
+   popmap = astMalloc( sizeof( int )*nroute );
+   if( astOK ) {
+      for( iroute = 0; iroute < nroute; iroute++ ) popmap[ iroute ] = 0;
+
+      sel = sel_ptr[ 0 ];
+      for( ipoint = 0; ipoint < npoint; ipoint++,sel++ ) {
+         if( *sel != AST__BAD ) {
+            rindex = (int)( *sel + 0.5 ) - 1;
+            if( rindex >= 0 && rindex < nroute ) ( popmap[ rindex ] )++;
+         }
+      }
+
+/* Find the number of points transformed by the most popular route Mapping.
+   Also find the total number of points transformed by any route Mapping. */
+      totpop = 0;
+      maxpop = 0;
+      for( iroute = 0; iroute < nroute; iroute++ ) {
+         if( popmap[ iroute ] > maxpop ) maxpop = popmap[ iroute ];
+         totpop += popmap[ iroute ];
+      }
+      if( maxpop == 0 ) maxpop = 1;
+
+/* If some of the points are not transformed by any route Mapping.
+   Initialise the whole output array to hold AST__BAD at every point. */
+      if( totpop < npoint ) {
+         for( j = 0; j < ncout; j++ ) {
+            outv = out_ptr[ j ];
+            for( ipoint = 0; ipoint < npoint; ipoint++ ) *(outv++) = AST__BAD;
+         }
+      }
+
+/* Create a PointSet large enough to hold all the supplied positions
+   which are to be transformed by the most popular route Mapping. */
+      ps1 = astPointSet( maxpop, ncin, "", status );
+      ptr1 = astGetPoints( ps1 );
+
+/* Create a PointSet large enough to hold all the output positions
+   created by the most popular route Mapping. */
+      ps2 = astPointSet( maxpop, ncout, "", status );
+      ptr2 = astGetPoints( ps2 );
+      if( astOK ) {
+
+/* Loop round each route Mapping which is used by at least 1 point. */
+         for( iroute = 0; iroute < nroute; iroute++ ) {
+            if( popmap[ iroute ] >0 ) {
+               rmap = GetRoute( map, (double)( iroute + 1 ), &rinv, status );
+
+/* Construct two PointSets of the correct size to hold the input and
+   output points to be processed with the current route Mapping. We
+   re-use the memory allocated for the largest route Mapping's PointSet. */
+               if( popmap[ iroute ] != maxpop ) {
+                  ps1a = astPointSet( popmap[ iroute ], ncin, "", status );
+                  astSetPoints( ps1a, ptr1 );
+                  ps2a = astPointSet( popmap[ iroute ], ncout, "", status );
+                  astSetPoints( ps2a, ptr2 );
+               } else {
+                  ps1a = astClone( ps1 );
+                  ps2a = astClone( ps2 );
+               }
+
+/* Fill the input PointSet with the input positions which are to be
+   transformed using the current route Mapping. */
+               sel = sel_ptr[ 0 ];
+               k = 0;
+               for( ipoint = 0; ipoint < npoint; ipoint++,sel++ ) {
+                  if( *sel != AST__BAD ) {
+                     rindex = (int)( *sel + 0.5 ) - 1;
+                     if( rindex == iroute ) {
+                        for( j = 0; j < ncin; j++ ) {
+                           ptr1[ j ][ k ] = in_ptr[ j ][ ipoint ];
+                        }
+                        k++;
+                     }
+                  }
+               }
+
+/* Use the route Mapping to transform this PointSet. */
+               (void) astTransform( rmap, ps1a, forward, ps2a );
+
+/* Copy the axis values from the resulting PointSet back into the results
+   array. */
+               sel = sel_ptr[ 0 ];
+               k = 0;
+               for( ipoint = 0; ipoint < npoint; ipoint++,sel++ ) {
+                  if( *sel != AST__BAD ) {
+                     rindex = (int)( *sel + 0.5 ) - 1;
+                     if( rindex == iroute ) {
+                        for( j = 0; j < ncout; j++ ) {
+                           out_ptr[ j ][ ipoint ] = ptr2[ j ][ k ];
+                        }
+                        k++;
+                     }
+                  }
+               }
+
+/* Free resources. */
+               ps1a = astAnnul( ps1a );
+               ps2a = astAnnul( ps2a );
+
+/* Re-instate the Invert flag for the route Mapping. */
+               astSetInvert( rmap, rinv );
+            }
+         }
+      }
+
+/* Free resources. */
+      ps1 = astAnnul( ps1 );
+      ps2 = astAnnul( ps2 );
+   }
+
+   selps = astAnnul( selps );
+   popmap = astFree( popmap );
+
+/* Re-instate the Invert flag of the selector Mapping. */
+   astSetInvert( selmap, selinv );
+
+/* If an error occurred, clean up by deleting the output PointSet (if
+   allocated by this function) and setting a NULL result pointer. */
+   if ( !astOK ) {
+      if ( !out ) result = astDelete( result );
+      result = NULL;
+   }
+
+/* Return a pointer to the output PointSet. */
+   return result;
+}
+
+/* Copy constructor. */
+/* ----------------- */
+static void Copy( const AstObject *objin, AstObject *objout, int *status ) {
+/*
+*  Name:
+*     Copy
+
+*  Purpose:
+*     Copy constructor for SwitchMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Copy( const AstObject *objin, AstObject *objout, int *status )
+
+*  Description:
+*     This function implements the copy constructor for SwitchMap objects.
+
+*  Parameters:
+*     objin
+*        Pointer to the object to be copied.
+*     objout
+*        Pointer to the object being constructed.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     void
+
+*  Notes:
+*     -  This constructor makes a deep copy, including a copy of the component
+*     Mappings within the SwitchMap.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *in;                /* Pointer to input SwitchMap */
+   AstSwitchMap *out;               /* Pointer to output SwitchMap */
+   int i;                           /* Loop count */
+
+/* Check the global error status. */
+   if ( !astOK ) return;
+
+/* Obtain pointers to the input and output SwitchMaps. */
+   in = (AstSwitchMap *) objin;
+   out = (AstSwitchMap *) objout;
+
+/* For safety, start by clearing any references to the input component
+   Mappings,etc, from the output SwitchMap. */
+   out->fsmap = NULL;
+   out->ismap = NULL;
+   out->routemap = NULL;
+   out->routeinv = NULL;
+
+/* Make copies of these Mappings, etc, and store pointers to them in the output
+   SwitchMap structure. */
+   if( in->fsmap ) out->fsmap = astCopy( in->fsmap );
+   if( in->ismap ) out->ismap = astCopy( in->ismap );
+
+   out->routemap = astMalloc( sizeof( AstMapping * )*( in->nroute ) );
+   out->routeinv = astMalloc( sizeof( int )*( in->nroute ) );
+   if( astOK ) {
+      for( i = 0; i < in->nroute; i++ ) {
+         out->routemap[ i ] = astCopy( in->routemap[ i ] );
+         out->routeinv[ i ] = in->routeinv[ i ];
+      }
+   }
+
+}
+
+/* Destructor. */
+/* ----------- */
+static void Delete( AstObject *obj, int *status ) {
+/*
+*  Name:
+*     Delete
+
+*  Purpose:
+*     Destructor for SwitchMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Delete( AstObject *obj, int *status )
+
+*  Description:
+*     This function implements the destructor for SwitchMap objects.
+
+*  Parameters:
+*     obj
+*        Pointer to the object to be deleted.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     void
+
+*  Notes:
+*     This function attempts to execute even if the global error status is
+*     set.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *this;              /* Pointer to SwitchMap */
+   int i;
+
+/* Obtain a pointer to the SwitchMap structure. */
+   this = (AstSwitchMap *) obj;
+
+/* Free dynamically allocated resources. */
+   if( this->fsmap ) this->fsmap = astAnnul( this->fsmap );
+   if( this->ismap ) this->ismap = astAnnul( this->ismap );
+   for( i = 0; i < this->nroute; i++ ) {
+      this->routemap[ i ] = astAnnul( this->routemap[ i ] );
+   }
+   this->routemap = astFree( this->routemap );
+   this->routeinv = astFree( this->routeinv );
+
+/* Clear the remaining SwitchMap variables. */
+   this->nroute = 0;
+   this->fsinv = 0;
+   this->isinv = 0;
+}
+
+/* Dump function. */
+/* -------------- */
+static void Dump( AstObject *this_object, AstChannel *channel, int *status ) {
+/*
+*  Name:
+*     Dump
+
+*  Purpose:
+*     Dump function for SwitchMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Dump( AstObject *this, AstChannel *channel, int *status )
+
+*  Description:
+*     This function implements the Dump function which writes out data
+*     for the SwitchMap class to an output Channel.
+
+*  Parameters:
+*     this
+*        Pointer to the SwitchMap whose data are being written.
+*     channel
+*        Pointer to the Channel to which the data are being written.
+*     status
+*        Pointer to the inherited status variable.
+*/
+
+/* Local Variables: */
+   AstSwitchMap *this;
+   int ival;
+   int set;
+   int i;
+   char buf[ 20 ];
+
+/* Check the global error status. */
+   if ( !astOK ) return;
+
+/* Obtain a pointer to the SwitchMap structure. */
+   this = (AstSwitchMap *) this_object;
+
+/* Write out values representing the instance variables for the SwitchMap
+   class.  Accompany these with appropriate comment strings, possibly
+   depending on the values being written.*/
+
+/* In the case of attributes, we first use the appropriate (private)
+   Test...  member function to see if they are set. If so, we then use
+   the (private) Get... function to obtain the value to be written
+   out.
+
+   For attributes which are not set, we use the astGet... method to
+   obtain the value instead. This will supply a default value
+   (possibly provided by a derived class which over-rides this method)
+   which is more useful to a human reader as it corresponds to the
+   actual default attribute value.  Since "set" will be zero, these
+   values are for information only and will not be read back. */
+
+/* Forward selector Mapping */
+/* ------------------------ */
+   if( this->fsmap ) {
+      astWriteObject( channel, "FSMap", 1, 1, this->fsmap,
+                      "Forward selector Mapping" );
+
+/* Forward selector Invert flag. */
+/* ----------------------------- */
+      ival = this->fsinv;
+      set = ( ival != 0 );
+      astWriteInt( channel, "FSInv", set, 0, ival,
+                   ival ? "Fwd selector used in inverse direction" :
+                          "Fwd selector used in forward direction" );
+   }
+
+
+/* Inverse selector Mapping */
+/* ------------------------ */
+   if( this->ismap ) {
+      astWriteObject( channel, "ISMap", 1, 1, this->ismap,
+                      "Inverse selector Mapping" );
+
+/* Forward selector Invert flag. */
+/* ----------------------------- */
+      ival = this->isinv;
+      set = ( ival != 0 );
+      astWriteInt( channel, "ISInv", set, 0, ival,
+                   ival ? "Inv selector used in inverse direction" :
+                          "Inv selector used in forward direction" );
+   }
+
+/* Loop to dump each route Mapping and its invert flag. */
+/* ---------------------------------------------------- */
+   for( i = 0; i < this->nroute; i++ ) {
+      sprintf( buf, "RMap%d", i + 1 );
+      astWriteObject( channel, buf, 1, 1, this->routemap[ i ],
+                      "Route Mapping" );
+
+      ival = this->routeinv[ i ];
+      set = ( ival != 0 );
+      sprintf( buf, "RInv%d", i + 1 );
+      astWriteInt( channel, buf, set, 0, ival,
+                   ival ? "Route Mapping used in inverse direction" :
+                          "Route Mapping used in forward direction" );
+   }
+
+}
+
+/* Standard class functions. */
+/* ========================= */
+/* Implement the astIsASwitchMap and astCheckSwitchMap functions using the
+   macros defined for this purpose in the "object.h" header file. */
+astMAKE_ISA(SwitchMap,Mapping)
+astMAKE_CHECK(SwitchMap)
+
+AstSwitchMap *astSwitchMap_( void *fsmap_void, void *ismap_void, int nroute,
+                             void **routemaps_void, const char *options, int *status, ...) {
+/*
+*+
+*  Name:
+*     astSwitchMap
+
+*  Purpose:
+*     Create a SwitchMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstSwitchMap *astSwitchMap( AstMapping *fsmap, AstMapping *ismap,
+*                                 int nroute, AstMapping **routemaps,
+*                                 const char *options, ... )
+
+*  Class Membership:
+*     SwitchMap constructor.
+
+*  Description:
+*     This function creates a new SwitchMap and optionally initialises its
+*     attributes.
+
+*  Parameters:
+*     fsmap
+*        Pointer to the forward selector Mapping
+*     ismap
+*        Pointer to the inverse selector Mapping
+*     nroute
+*        The number of route Mappings.
+*     routemaps
+*        An array of pointers to the route Mappings.
+*     options
+*        Pointer to a null terminated string containing an optional
+*        comma-separated list of attribute assignments to be used for
+*        initialising the new SwitchMap. The syntax used is the same as for the
+*        astSet method and may include "printf" format specifiers identified
+*        by "%" symbols in the normal way.
+*     ...
+*        If the "options" string contains "%" format specifiers, then an
+*        optional list of arguments may follow it in order to supply values to
+*        be substituted for these specifiers. The rules for supplying these
+*        are identical to those for the astSet method (and for the C "printf"
+*        function).
+
+*  Returned Value:
+*     A pointer to the new SwitchMap.
+
+*  Notes:
+*     - A null pointer will be returned if this function is invoked
+*     with the global error status set, or if it should fail for any
+*     reason.
+*-
+
+*  Implementation Notes:
+*     - This function implements the basic SwitchMap constructor which is
+*     available via the protected interface to the SwitchMap class.  A
+*     public interface is provided by the astSwitchMapId_ function.
+*     - Because this function has a variable argument list, it is
+*     invoked by a macro that evaluates to a function pointer (not a
+*     function invocation) and no checking or casting of arguments is
+*     performed before the function is invoked. Because of this, the
+*     "map1" and "map2" parameters are of type (void *) and are
+*     converted and validated within the function itself.
+*/
+
+/* Local Variables: */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   AstSwitchMap *new;            /* Pointer to new SwitchMap */
+   AstMapping *fsmap;            /* Pointer to fwd selector Mapping */
+   AstMapping *ismap;            /* Pointer to inv selector Mapping */
+   AstMapping **routemaps;       /* Array of route Mapping pointers */
+   int i;                        /* Route Mappings index */
+   va_list args;                 /* Variable argument list */
+
+/* Initialise. */
+   new = NULL;
+
+/* Get a pointer to the thread specific global data structure. */
+   astGET_GLOBALS(NULL);
+
+/* Check the global status. */
+   if ( !astOK ) return new;
+
+/* Report an error if no route Mappings have been supplied. */
+   if( nroute <= 0 ) astError( AST__BDPAR, "astSwitchMap(SwitchMap): "
+                               "Bad number of route Mappings (%d) specified.", status,
+                               nroute );
+
+/* Otherwise create an array to hold the route Mapping pointers. */
+   routemaps = astMalloc( sizeof( AstMapping * )*nroute );
+
+/* Obtain and validate pointers to the Mapping structures provided. */
+   if( astOK ) {
+      fsmap = fsmap_void ? astCheckMapping( fsmap_void ) : NULL;
+      ismap = ismap_void ? astCheckMapping( ismap_void ) : NULL;
+      for( i = 0; i < nroute; i++ ) {
+         routemaps[ i ] = astCheckMapping( routemaps_void[ i ] );
+      }
+   }
+
+   if ( astOK ) {
+
+/* Initialise the SwitchMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+      new = astInitSwitchMap( NULL, sizeof( AstSwitchMap ), !class_init, &class_vtab,
+                              "SwitchMap", fsmap, ismap, nroute, routemaps );
+
+/* If successful, note that the virtual function table has been
+   initialised. */
+      if ( astOK ) {
+         class_init = 1;
+
+/* Obtain the variable argument list and pass it along with the
+   options string to the astVSet method to initialise the new SwitchMap's
+   attributes. */
+         va_start( args, status );
+         astVSet( new, options, NULL, args );
+         va_end( args );
+
+/* If an error occurred, clean up by deleting the new object. */
+         if ( !astOK ) new = astDelete( new );
+      }
+   }
+
+/* Free memory used to hold the route Mapping pointers. */
+   routemaps = astFree( routemaps );
+
+/* Return a pointer to the new SwitchMap. */
+   return new;
+}
+
+AstSwitchMap *astSwitchMapId_( void *fsmap_void, void *ismap_void, int nroute,
+                               void **routemaps_void, const char *options, ... ) {
+/*
+*++
+*  Name:
+c     astSwitchMap
+f     AST_SWITCHMAP
+
+*  Purpose:
+*     Create a SwitchMap.
+
+*  Type:
+*     Public function.
+
+*  Synopsis:
+c     #include "switchmap.h"
+c     AstSwitchMap *astSwitchMap( AstMapping *fsmap, AstMapping *ismap,
+c                                 int nroute, AstMapping *routemaps[],
+c                                 const char *options, ... )
+f     RESULT = AST_SWITCHMAP( FSMAP, ISMAP, NROUTE, ROUTEMAPS, OPTIONS,
+f                             STATUS )
+
+*  Class Membership:
+*     SwitchMap constructor.
+
+*  Description:
+*     This function creates a new SwitchMap and optionally initialises
+*     its attributes.
+*
+*     A SwitchMap is a Mapping which represents a set of alternate
+*     Mappings, each of which is used to transform positions within a
+*     particular region of the input or output coordinate system of the
+*     SwitchMap.
+*
+*     A SwitchMap can encapsulate any number of Mappings, but they must
+*     all have the same number of inputs (Nin attribute value) and the
+*     same number of outputs (Nout attribute value). The SwitchMap itself
+*     inherits these same values for its Nin and Nout attributes. Each of
+*     these Mappings represents a "route" through the switch, and are
+*     referred to as "route" Mappings below. Each route Mapping transforms
+*     positions between the input and output coordinate space of the entire
+*     SwitchMap, but only one Mapping will be used to transform any given
+*     position. The selection of the appropriate route Mapping to use with
+*     any given input position is made by another Mapping, called the
+*     "selector" Mapping. Each SwitchMap encapsulates two selector
+*     Mappings in addition to its route Mappings; one for use with the
+*     SwitchMap's forward transformation (called the "forward selector
+*     Mapping"), and one for use with the SwitchMap's inverse transformation
+*     (called the "inverse selector Mapping"). The forward selector Mapping
+*     must have the same number of inputs as the route Mappings, but
+*     should have only one output. Likewise, the inverse selector Mapping
+*     must have the same number of outputs as the route Mappings, but
+*     should have only one input.
+*
+*     When the SwitchMap is used to transform a position in the forward
+*     direction (from input to output), each supplied input position is
+*     first transformed by the forward transformation of the forward selector
+*     Mapping. This produces a single output value for each input position
+*     referred to as the selector value. The nearest integer to the selector
+*     value is found, and is used to index the array of route Mappings (the
+*     first supplied route Mapping has index 1, the second route Mapping has
+*     index 2, etc). If the nearest integer to the selector value is less
+*     than 1 or greater than the number of route Mappings, then the SwitchMap
+*     output position is set to a value of AST__BAD on every axis. Otherwise,
+*     the forward transformation of the selected route Mapping is used to
+*     transform the supplied input position to produce the SwitchMap output
+*     position.
+*
+*     When the SwitchMap is used to transform a position in the inverse
+*     direction (from "output" to "input"), each supplied "output" position
+*     is first transformed by the inverse transformation of the inverse
+*     selector Mapping. This produces a selector value for each "output"
+*     position. Again, the nearest integer to the selector value is found,
+*     and is used to index the array of route Mappings. If this selector
+*     index value is within the bounds of the array of route Mappings, then
+*     the inverse transformation of the selected route Mapping is used to
+*     transform the supplied "output" position to produce the SwitchMap
+*     "input" position. If the selector index value is outside the bounds
+*     of the array of route Mappings, then the SwitchMap "input" position is
+*     set to a value of AST__BAD on every axis.
+*
+*     In practice, appropriate selector Mappings should be chosen to
+*     associate a different route Mapping with each region of coordinate
+*     space. Note that the SelectorMap class of Mapping is particularly
+*     appropriate for this purpose.
+*
+*     If a compound Mapping contains a SwitchMap in series with its own
+*     inverse, the combination of the two adjacent SwitchMaps will be
+*     replaced by a UnitMap when the compound Mapping is simplified using
+c     astSimplify.
+f     AST_SIMPLIFY.
+
+*  Parameters:
+c     fsmap
+f     FSMAP = INTEGER (Given)
+*        Pointer to the forward selector Mapping. This must have a
+*        defined forward transformation, but need not have a defined
+*        inverse transformation. It must have one output, and the number of
+*        inputs must match the number of inputs of each of the supplied
+*        route Mappings.
+c        NULL
+f        AST__NULL
+*        may be supplied, in which case the SwitchMap will have an undefined
+*        forward Mapping.
+c     ismap
+f     ISMAP = INTEGER (Given)
+*        Pointer to the inverse selector Mapping. This must have a
+*        defined inverse transformation, but need not have a defined
+*        forward transformation. It must have one input, and the number of
+*        outputs must match the number of outputs of each of the supplied
+*        route Mappings.
+c        NULL
+f        AST__NULL
+*        may be supplied, in which case the SwitchMap will have an undefined
+*        inverse Mapping.
+c     nroute
+f     NROUTE = INTEGER (Given)
+*        The number of supplied route Mappings.
+c     routemaps
+f     ROUTEMAPS( NROUTE ) = INTEGER (Given)
+*        An array of pointers to the route Mappings. All the supplied
+*        route Mappings must have common values for the Nin and Nout
+*        attributes, and these values define the number of inputs and
+*        outputs of the SwitchMap.
+c     options
+f     OPTIONS = CHARACTER * ( * ) (Given)
+c        Pointer to a null-terminated string containing an optional
+c        comma-separated list of attribute assignments to be used for
+c        initialising the new SwitchMap. The syntax used is identical to
+c        that for the astSet function and may include "printf" format
+c        specifiers identified by "%" symbols in the normal way.
+f        A character string containing an optional comma-separated
+f        list of attribute assignments to be used for initialising the
+f        new SwitchMap. The syntax used is identical to that for the
+f        AST_SET routine.
+c     ...
+c        If the "options" string contains "%" format specifiers, then
+c        an optional list of additional arguments may follow it in
+c        order to supply values to be substituted for these
+c        specifiers. The rules for supplying these are identical to
+c        those for the astSet function (and for the C "printf"
+c        function).
+f     STATUS = INTEGER (Given and Returned)
+f        The global status.
+
+*  Returned Value:
+c     astSwitchMap()
+f     AST_SWITCHMAP = INTEGER
+*        A pointer to the new SwitchMap.
+
+*  Notes:
+c     - Note that the component Mappings supplied are not copied by
+c     astSwitchMap (the new SwitchMap simply retains a reference to
+c     them). They may continue to be used for other purposes, but
+c     should not be deleted. If a SwitchMap containing a copy of its
+c     component Mappings is required, then a copy of the SwitchMap should
+c     be made using astCopy.
+f     - Note that the component Mappings supplied are not copied by
+f     AST_SWITCHMAP (the new SwitchMap simply retains a reference to
+f     them). They may continue to be used for other purposes, but
+f     should not be deleted. If a SwitchMap containing a copy of its
+f     component Mappings is required, then a copy of the SwitchMap should
+f     be made using AST_COPY.
+*     - A null Object pointer (AST__NULL) will be returned if this
+c     function is invoked with the AST error status set, or if it
+f     function is invoked with STATUS set to an error value, or if it
+*     should fail for any reason.
+*--
+
+*  Implementation Notes:
+*     - This function implements the external (public) interface to
+*     the astSwitchMap constructor function. It returns an ID value
+*     (instead of a true C pointer) to external users, and must be
+*     provided because astSwitchMap_ has a variable argument list which
+*     cannot be encapsulated in a macro (where this conversion would
+*     otherwise occur).
+*     - Because no checking or casting of arguments is performed
+*     before the function is invoked, the "map1" and "map2" parameters
+*     are of type (void *) and are converted from an ID value to a
+*     pointer and validated within the function itself.
+*     - The variable argument list also prevents this function from
+*     invoking astSwitchMap_ directly, so it must be a re-implementation
+*     of it in all respects, except for the conversions between IDs
+*     and pointers on input/output of Objects.
+*/
+
+/* Local Variables: */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   AstSwitchMap *new;            /* Pointer to new SwitchMap */
+   AstMapping *fsmap;            /* Pointer to fwd selector Mapping */
+   AstMapping *ismap;            /* Pointer to inv selector Mapping */
+   AstMapping **routemaps;       /* Array of route Mapping pointers */
+   int i;                        /* Route Mappings index */
+   va_list args;                 /* Variable argument list */
+
+   int *status;                  /* Pointer to inherited status value */
+
+/* Get a pointer to the thread specific global data structure. */
+   astGET_GLOBALS(NULL);
+
+/* Initialise. */
+   new = NULL;
+
+/* Get a pointer to the inherited status value. */
+   status = astGetStatusPtr;
+
+/* Check the global status. */
+   if ( !astOK ) return new;
+
+/* Report an error if no route Mappings have been supplied. */
+   if( nroute <= 0 ) astError( AST__BDPAR, "astSwitchMap(SwitchMap): "
+                               " Bad number of route Mappings (%d) specified.", status,
+                               nroute );
+
+/* Otherwise create an array to hold the route Mapping pointers. */
+   routemaps = astMalloc( sizeof( AstMapping * )*nroute );
+
+/* Obtain and validate pointers to the Mapping structures provided. */
+   if( astOK ) {
+      fsmap = fsmap_void ? astCheckMapping( astMakePointer(fsmap_void) ) : NULL;
+      ismap = ismap_void ? astCheckMapping( astMakePointer(ismap_void) ) : NULL;
+      for( i = 0; i < nroute; i++ ) {
+         routemaps[ i ] = astVerifyMapping( astMakePointer(routemaps_void[ i ]) );
+      }
+   }
+
+   if ( astOK ) {
+
+/* Initialise the SwitchMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+      new = astInitSwitchMap( NULL, sizeof( AstSwitchMap ), !class_init, &class_vtab,
+                              "SwitchMap", fsmap, ismap, nroute, routemaps );
+
+/* If successful, note that the virtual function table has been
+   initialised. */
+      if ( astOK ) {
+         class_init = 1;
+
+/* Obtain the variable argument list and pass it along with the
+   options string to the astVSet method to initialise the new SwitchMap's
+   attributes. */
+         va_start( args, options );
+         astVSet( new, options, NULL, args );
+         va_end( args );
+
+/* If an error occurred, clean up by deleting the new object. */
+         if ( !astOK ) new = astDelete( new );
+      }
+   }
+
+/* Free memory used to hold the route Mapping pointers. */
+   routemaps = astFree( routemaps );
+
+/* Return an ID value for the new SwitchMap. */
+   return astMakeId( new );
+}
+
+AstSwitchMap *astInitSwitchMap_( void *mem, size_t size, int init,
+                                 AstSwitchMapVtab *vtab, const char *name,
+                                 AstMapping *fsmap, AstMapping *ismap,
+                                 int nroute, AstMapping **routemaps, int *status ) {
+/*
+*+
+*  Name:
+*     astInitSwitchMap
+
+*  Purpose:
+*     Initialise a SwitchMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstSwitchMap *astInitSwitchMap( void *mem, size_t size, int init,
+*                                     AstSwitchMapVtab *vtab, const char *name,
+*                                     AstMapping *fsmap, AstMapping *ismap,
+*                                     int nroute, AstMapping **routemaps )
+
+*  Class Membership:
+*     SwitchMap initialiser.
+
+*  Description:
+*     This function is provided for use by class implementations to initialise
+*     a new SwitchMap object. It allocates memory (if necessary) to
+*     accommodate the SwitchMap plus any additional data associated with the
+*     derived class. It then initialises a SwitchMap structure at the start
+*     of this memory. If the "init" flag is set, it also initialises the
+*     contents of a virtual function table for a SwitchMap at the start of
+*     the memory passed via the "vtab" parameter.
+
+*  Parameters:
+*     mem
+*        A pointer to the memory in which the SwitchMap is to be initialised.
+*        This must be of sufficient size to accommodate the SwitchMap data
+*        (sizeof(SwitchMap)) plus any data used by the derived class. If a
+*        value of NULL is given, this function will allocate the memory itself
+*        using the "size" parameter to determine its size.
+*     size
+*        The amount of memory used by the SwitchMap (plus derived class
+*        data). This will be used to allocate memory if a value of NULL is
+*        given for the "mem" parameter. This value is also stored in the
+*        SwitchMap structure, so a valid value must be supplied even if not
+*        required for allocating memory.
+*     init
+*        A logical flag indicating if the SwitchMap's virtual function table
+*        is to be initialised. If this value is non-zero, the virtual function
+*        table will be initialised by this function.
+*     vtab
+*        Pointer to the start of the virtual function table to be associated
+*        with the new SwitchMap.
+*     name
+*        Pointer to a constant null-terminated character string which contains
+*        the name of the class to which the new object belongs (it is this
+*        pointer value that will subsequently be returned by the Object
+*        astClass function).
+*     fsmap
+*        Pointer to the forward selector Mapping.
+*     ismap
+*        Pointer to the inverse selector Mapping.
+*     nroute
+*        The number of route Mappings supplied.
+*     routemaps
+*        An array holdiong pointers to the route Mappings.
+
+*  Returned Value:
+*     A pointer to the new SwitchMap.
+
+*  Notes:
+*     -  A null pointer will be returned if this function is invoked with the
+*     global error status set, or if it should fail for any reason.
+*-
+*/
+
+/* Local Variables: */
+   AstSwitchMap *new;            /* Pointer to new SwitchMap */
+   int i;                        /* Loop count */
+   int nin;                      /* No. input coordinates for SwitchMap */
+   int nout;                     /* No. output coordinates for SwitchMap */
+
+/* Check the global status. */
+   if ( !astOK ) return NULL;
+
+/* If necessary, initialise the virtual function table. */
+   if ( init ) astInitSwitchMapVtab( vtab, name );
+
+/* Initialise. */
+   new = NULL;
+
+/* Check that all route Mappings have common values for Nin and Nout.*/
+   nin = astGetNin( routemaps[ 0 ] );
+   nout = astGetNout( routemaps[ 0 ] );
+   for( i = 1; i < nroute; i++ ) {
+      if( nin != astGetNin( routemaps[ i ] ) ){
+         if( astOK ) {
+            astError( AST__BADNI, "astInitSwitchMap(%s): Route Mapping "
+                      "number %d has %d input(s) but the first route "
+                      "Mapping has %d input(s).", status, name, i + 1,
+                      astGetNin( routemaps[ i ] ), nin );
+         }
+
+      } else if( nout != astGetNout( routemaps[ i ] ) ){
+         if( astOK ) {
+            astError( AST__BADNO, "astInitSwitchMap(%s): Route Mapping "
+                      "number %d has %d output(s) but the first route "
+                      "Mapping has %d output(s).", status, name, i + 1,
+                      astGetNin( routemaps[ i ] ), nin );
+         }
+      }
+   }
+
+/* If supplied, report an error if fsmap has no forward transformation,
+   or if it has an incorrect number of inputs or output. */
+   if( fsmap && astOK ) {
+      if( !astGetTranForward( fsmap ) ) {
+         astError( AST__INTRD, "astInitSwitchMap(%s): The forward selector Mapping "
+              "is not able to transform coordinates in the forward direction.", status,
+              name );
+
+      } else if( astGetNin( fsmap ) != nin ){
+         astError( AST__BADNI, "astInitSwitchMap(%s): The forward selector "
+                   "Mapping has %d input(s) but the SwitchMap has %d "
+                   "input(s).", status, name, astGetNin( fsmap ), nin );
+
+      } else if( astGetNout( fsmap ) != 1 ){
+         astError( AST__BADNO, "astInitSwitchMap(%s): The forward selector "
+                   "Mapping has %d outputs but should only have 1.", status, name,
+                   astGetNout( fsmap ) );
+      }
+   }
+
+/* If supplied, report an error if ismap has no inverse transformation,
+   or if it has an incorrect number of inputs or outputs. */
+   if( ismap && astOK ) {
+      if( !astGetTranInverse( ismap ) ) {
+         astError( AST__INTRD, "astInitSwitchMap(%s): The inverse selector Mapping "
+              "is not able to transform coordinates in the inverse direction.", status,
+              name );
+      } else if( nout != astGetNout( ismap ) ){
+         astError( AST__BADNO, "astInitSwitchMap(%s): The inverse selector "
+                   "Mapping has %d output(s) but the SwitchMap has %d "
+                   "output(s).", status, name, astGetNout( ismap ), nout );
+
+      } else if( astGetNin( ismap ) != 1 ){
+         astError( AST__BADNI, "astInitSwitchMap(%s): The inverse selector "
+                   "Mapping has %d inputs but should only have 1.", status, name,
+                   astGetNin( ismap ) );
+
+      }
+   }
+
+/* Report an error if neither ismap nor fsmap were supplied. */
+   if( !fsmap && !ismap && astOK ) {
+      astError( AST__INTRD, "astInitSwitchMap(%s): No selector Mappings "
+                "supplied.", status, name );
+   }
+
+/* Initialise a Mapping structure (the parent class) as the first component
+   within the SwitchMap structure, allocating memory if necessary. Specify
+   the number of input and output coordinates and in which directions the
+   Mapping should be defined. */
+   if ( astOK ) {
+      new = (AstSwitchMap *) astInitMapping( mem, size, 0,
+                                             (AstMappingVtab *) vtab, name,
+                                             nin, nout,
+                                             ( fsmap != NULL ),
+                                             ( ismap != NULL ) );
+      if ( astOK ) {
+
+/* Initialise the SwitchMap data. */
+/* --------------------------- */
+/* Store pointers to the selector Mappings. */
+         new->fsmap = fsmap ? astClone( fsmap ) : NULL;
+         new->ismap = ismap ? astClone( ismap ) : NULL;
+
+/* Save the initial values of the inversion flags for these Mappings. */
+         new->fsinv = fsmap ? astGetInvert( fsmap ) : 0;
+         new->isinv = ismap ? astGetInvert( ismap ) : 0;
+
+/* Create arrays for the route Mappings. */
+         new->routemap = astMalloc( sizeof( AstMapping * )*nroute );
+         new->routeinv = astMalloc( sizeof( int )*nroute );
+
+/* Store pointers to the route Mappings and their invert flags. */
+         if( astOK ) {
+            new->nroute = nroute;
+            for( i = 0; i < nroute; i++ ) {
+               new->routemap[ i ] = astClone( routemaps[ i ] );
+               new->routeinv[ i ] = astGetInvert( routemaps[ i ] );
+            }
+         } else {
+            new->nroute = 0;
+         }
+
+/* If an error occurred, clean up by deleting the new object. */
+         if ( !astOK ) new = astDelete( new );
+      }
+   }
+
+/* Return a pointer to the new object. */
+   return new;
+}
+
+AstSwitchMap *astLoadSwitchMap_( void *mem, size_t size,
+                                 AstSwitchMapVtab *vtab, const char *name,
+                                 AstChannel *channel, int *status ) {
+/*
+*+
+*  Name:
+*     astLoadSwitchMap
+
+*  Purpose:
+*     Load a SwitchMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "switchmap.h"
+*     AstSwitchMap *astLoadSwitchMap( void *mem, size_t size,
+*                                     AstSwitchMapVtab *vtab, const char *name,
+*                                     AstChannel *channel )
+
+*  Class Membership:
+*     SwitchMap loader.
+
+*  Description:
+*     This function is provided to load a new SwitchMap using data read
+*     from a Channel. It first loads the data used by the parent class
+*     (which allocates memory if necessary) and then initialises a
+*     SwitchMap structure in this memory, using data read from the input
+*     Channel.
+*
+*     If the "init" flag is set, it also initialises the contents of a
+*     virtual function table for a SwitchMap at the start of the memory
+*     passed via the "vtab" parameter.
+
+
+*  Parameters:
+*     mem
+*        A pointer to the memory into which the SwitchMap is to be
+*        loaded.  This must be of sufficient size to accommodate the
+*        SwitchMap data (sizeof(SwitchMap)) plus any data used by derived
+*        classes. If a value of NULL is given, this function will
+*        allocate the memory itself using the "size" parameter to
+*        determine its size.
+*     size
+*        The amount of memory used by the SwitchMap (plus derived class
+*        data).  This will be used to allocate memory if a value of
+*        NULL is given for the "mem" parameter. This value is also
+*        stored in the SwitchMap structure, so a valid value must be
+*        supplied even if not required for allocating memory.
+*
+*        If the "vtab" parameter is NULL, the "size" value is ignored
+*        and sizeof(AstSwitchMap) is used instead.
+*     vtab
+*        Pointer to the start of the virtual function table to be
+*        associated with the new SwitchMap. If this is NULL, a pointer to
+*        the (static) virtual function table for the SwitchMap class is
+*        used instead.
+*     name
+*        Pointer to a constant null-terminated character string which
+*        contains the name of the class to which the new object
+*        belongs (it is this pointer value that will subsequently be
+*        returned by the astGetClass method).
+*
+*        If the "vtab" parameter is NULL, the "name" value is ignored
+*        and a pointer to the string "SwitchMap" is used instead.
+
+*  Returned Value:
+*     A pointer to the new SwitchMap.
+
+*  Notes:
+*     - A null pointer will be returned if this function is invoked
+*     with the global error status set, or if it should fail for any
+*     reason.
+*-
+*/
+
+/* Local Variables: */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   AstSwitchMap *new;
+   AstMapping *rmap;
+   int i;
+   char buf[ 20 ];
+
+/* Initialise. */
+   new = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return new;
+
+/* Get a pointer to the thread specific global data structure. */
+   astGET_GLOBALS(channel);
+
+/* If a NULL virtual function table has been supplied, then this is
+   the first loader to be invoked for this SwitchMap. In this case the
+   SwitchMap belongs to this class, so supply appropriate values to be
+   passed to the parent class loader (and its parent, etc.). */
+   if ( !vtab ) {
+      size = sizeof( AstSwitchMap );
+      vtab = &class_vtab;
+      name = "SwitchMap";
+
+/* If required, initialise the virtual function table for this class. */
+      if ( !class_init ) {
+         astInitSwitchMapVtab( vtab, name );
+         class_init = 1;
+      }
+   }
+
+/* Invoke the parent class loader to load data for all the ancestral
+   classes of the current one, returning a pointer to the resulting
+   partly-built SwitchMap. */
+   new = astLoadMapping( mem, size, (AstMappingVtab *) vtab, name,
+                         channel );
+   if ( astOK ) {
+
+/* Read input data. */
+/* ================ */
+/* Request the input Channel to read all the input data appropriate to
+   this class into the internal "values list". */
+      astReadClassData( channel, "SwitchMap" );
+
+/* Now read each individual data item from this list and use it to
+   initialise the appropriate instance variable(s) for this class. */
+
+/* In the case of attributes, we first read the "raw" input value,
+   supplying the "unset" value as the default. If a "set" value is
+   obtained, we then use the appropriate (private) Set... member
+   function to validate and set the value properly. */
+
+/* Forward Selector Mapping and its Invert flag. */
+/* --------------------------------------------- */
+      new->fsmap = astReadObject( channel, "fsmap", NULL );
+      new->fsinv = astReadInt( channel, "fsinv", 0 );
+      new->fsinv = ( new->fsinv != 0 );
+
+/* Inverse Selector Mapping and its Invert flag. */
+/* --------------------------------------------- */
+      new->ismap = astReadObject( channel, "ismap", NULL );
+      new->isinv = astReadInt( channel, "isinv", new->fsinv );
+      new->isinv = ( new->isinv != 0 );
+
+/* Loop to load each route Mapping and its invert flag. */
+/* ---------------------------------------------------- */
+      new->routemap = NULL;
+      new->routeinv = NULL;
+      i = 0;
+      while( astOK ) {
+         sprintf( buf, "rmap%d", i + 1 );
+         rmap = astReadObject( channel, buf, NULL );
+         if( rmap ) {
+            new->routemap = astGrow( new->routemap, i + 1, sizeof( AstMapping *) );
+            new->routeinv = astGrow( new->routeinv, i + 1, sizeof( int ) );
+            if( astOK ) {
+               new->routemap[ i ] = rmap;
+               sprintf( buf, "rinv%d", i + 1 );
+               new->routeinv[ i ] = astReadInt( channel, buf, 0 );
+               new->routeinv[ i ] = ( new->routeinv[ i ] != 0 );
+               i++;
+            }
+         } else {
+            break;
+         }
+      }
+
+/* Number of route Mappings. */
+      new->nroute = i;
+
+/* If an error occurred, clean up by deleting the new SwitchMap. */
+      if ( !astOK ) new = astDelete( new );
+   }
+
+/* Return the new SwitchMap pointer. */
+   return new;
+}
+
+/* Virtual function interfaces. */
+/* ============================ */
+/* These provide the external interface to the virtual functions defined by
+   this class. Each simply checks the global error status and then locates and
+   executes the appropriate member function, using the function pointer stored
+   in the object's virtual function table (this pointer is located using the
+   astMEMBER macro defined in "object.h").
+
+   Note that the member function may not be the one defined here, as it may
+   have been over-ridden by a derived class. However, it should still have the
+   same interface. */
+
+/* None. */
+
+
+
+