upgrade ast 8.7.1

1 files changed, 2327 insertions, 0 deletions

diff --git a/ast/tranmap.c b/ast/tranmap.c
new file mode 100644
index 0000000..ab1853d
--- /dev/null
+++ b/ast/tranmap.c
@@ -0,0 +1,2327 @@
+/*
+*class++
+*  Name:
+*     TranMap
+
+*  Purpose:
+*     Mapping with specified forward and inverse transformations.
+
+*  Constructor Function:
+c     astTranMap
+f     AST_TRANMAP
+
+*  Description:
+*     A TranMap is a Mapping which combines the forward transformation of
+*     a supplied Mapping with the inverse transformation of another
+*     supplied Mapping, ignoring the un-used transformation in each
+*     Mapping (indeed the un-used transformation need not exist).
+*
+*     When the forward transformation of the TranMap is referred to, the
+*     transformation actually used is the forward transformation of the
+*     first Mapping supplied when the TranMap was constructed. Likewise,
+*     when the inverse transformation of the TranMap is referred to, the
+*     transformation actually used is the inverse transformation of the
+*     second Mapping supplied when the TranMap was constructed.
+
+*  Inheritance:
+*     The TranMap class inherits from the Mapping class.
+
+*  Attributes:
+*     The TranMap class does not define any new attributes beyond those
+*     which are applicable to all Mappings.
+
+*  Functions:
+c     The TranMap class does not define any new functions beyond those
+f     The TranMap 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:
+*     10-FEB-2004 (DSB):
+*        Original version.
+*     19-JAN-2005 (DSB):
+*        Fix memory leak.
+*     14-FEB-2006 (DSB):
+*        - Over-ride the astDecompose method.
+*        - Fix bug in MapSplit related to use of invert flags.
+*     14-FEB-2006 (DSB):
+*        Override astGetObjSize.
+*     10-MAY-2006 (DSB):
+*        Override astEqual.
+*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 TranMap
+
+/* 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 "channel.h"             /* I/O channels */
+#include "permmap.h"             /* Coordinate permutation Mappings */
+#include "cmpmap.h"              /* Compound Mappings */
+#include "unitmap.h"             /* Unit Mappings */
+#include "tranmap.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 * );
+static int *(* parent_mapsplit)( AstMapping *, int, const int *, AstMapping **, 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(TranMap)
+
+/* Define macros for accessing each item of thread specific global data. */
+#define class_init astGLOBAL(TranMap,Class_Init)
+#define class_vtab astGLOBAL(TranMap,Class_Vtab)
+
+
+#include <pthread.h>
+
+
+#else
+
+
+/* Define the class virtual function table and its initialisation flag
+   as static variables. */
+static AstTranMapVtab 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. */
+AstTranMap *astTranMapId_( void *, 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 *MapSplit( AstMapping *, int, const int *, AstMapping **, int * );
+static int Equal( AstObject *, 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 void Decompose( AstMapping *, AstMapping **, AstMapping **, int *, int *, int *, int * );
+static int GetObjSize( AstObject *, 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 TranMaps are equivalent.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     int Equal( AstObject *this, AstObject *that, int *status )
+
+*  Class Membership:
+*     TranMap 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 TranMaps are equivalent.
+
+*  Parameters:
+*     this
+*        Pointer to the first Object (a TranMap).
+*     that
+*        Pointer to the second Object.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     One if the TranMaps 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: */
+   AstTranMap *that;
+   AstTranMap *this;
+   int nin;
+   int nout;
+   int result;
+   int that_inv1;
+   int that_inv2;
+   int this_inv1;
+   int this_inv2;
+
+/* Initialise. */
+   result = 0;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Obtain pointers to the two TranMap structures. */
+   this = (AstTranMap *) this_object;
+   that = (AstTranMap *) that_object;
+
+/* Check the second object is a TranMap. We know the first is a
+   TranMap since we have arrived at this implementation of the virtual
+   function. */
+   if( astIsATranMap( that ) ) {
+
+/* Get the number of inputs and outputs and check they are the same for both. */
+      nin = astGetNin( this );
+      nout = astGetNout( this );
+      if( astGetNin( that ) == nin && astGetNout( that ) == nout ) {
+
+/* Temporarily re-instate the original Invert flag values. */
+         that_inv1 = astGetInvert( that->map1 );
+         that_inv2 = astGetInvert( that->map2 );
+         this_inv1 = astGetInvert( this->map1 );
+         this_inv2 = astGetInvert( this->map2 );
+
+         astSetInvert( this->map1, this->invert1 );
+         astSetInvert( this->map2, this->invert2 );
+         astSetInvert( that->map1, that->invert1 );
+         astSetInvert( that->map2, that->invert2 );
+
+/* If the Invert flags for the two TranMaps differ, it may still be possible
+   for them to be equivalent. First compare the TranMaps if their Invert
+   flags are the same. In this case all the attributes of the two TranMaps
+   must be identical. */
+         if( astGetInvert( this ) == astGetInvert( that ) ) {
+            if( astEqual( this->map1, that->map1 ) &&
+                astEqual( this->map2, that->map2 ) ) {
+               result = 1;
+            }
+
+/* If the Invert flags for the two TranMaps differ, the attributes of the two
+   TranMaps must be inversely related to each other. */
+         } else {
+
+            astInvert( that->map1 );
+            astInvert( that->map2 );
+
+            if( astEqual( this->map1, that->map2 ) &&
+                astEqual( this->map2, that->map1 ) ) {
+               result = 1;
+            }
+
+         }
+
+/* Restore the original Invert flag values. */
+         astSetInvert( this->map1, this_inv1 );
+         astSetInvert( this->map2, this_inv2 );
+         astSetInvert( that->map1, that_inv1 );
+         astSetInvert( that->map2, that_inv2 );
+      }
+   }
+
+/* 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 "tranmap.h"
+*     int GetObjSize( AstObject *this, int *status )
+
+*  Class Membership:
+*     TranMap member function (over-rides the astGetObjSize protected
+*     method inherited from the parent class).
+
+*  Description:
+*     This function returns the in-memory size of the supplied TranMap,
+*     in bytes.
+
+*  Parameters:
+*     this
+*        Pointer to the TranMap.
+*     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: */
+   AstTranMap *this;         /* Pointer to TranMap structure */
+   int result;                /* Result value to return */
+
+/* Initialise. */
+   result = 0;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Obtain a pointers to the TranMap structure. */
+   this = (AstTranMap *) this_object;
+
+/* Invoke the GetObjSize method inherited from the parent class, and then
+   add on any components of the class structure defined by thsi class
+   which are stored in dynamically allocated memory. */
+   result = (*parent_getobjsize)( this_object, status );
+   result += astGetObjSize( this->map1 );
+   result += astGetObjSize( this->map2 );
+
+/* If an error occurred, clear the result value. */
+   if ( !astOK ) result = 0;
+
+/* Return the result, */
+   return result;
+}
+
+static void Decompose( AstMapping *this_mapping, AstMapping **map1,
+                       AstMapping **map2, int *series, int *invert1,
+                       int *invert2, int *status ) {
+/*
+*
+*  Name:
+*     Decompose
+
+*  Purpose:
+*     Decompose a Mapping into two component Mappings.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     void Decompose( AstMapping *this, AstMapping **map1,
+*                     AstMapping **map2, int *series,
+*                     int *invert1, int *invert2, int *status )
+
+*  Class Membership:
+*     TranMap member function (over-rides the protected astDecompose
+*     method inherited from the Mapping class).
+
+*  Description:
+*     This function returns pointers to the two Mappings encapsulated by
+*     a TranMap.
+
+*  Parameters:
+*     this
+*        Pointer to the Mapping.
+*     map1
+*        Address of a location to receive a pointer to first component
+*        Mapping (the forward Mapping).
+*     map2
+*        Address of a location to receive a pointer to second component
+*        Mapping (the inverse Mapping).
+*     series
+*        Address of a location to receive a value indicating if the
+*        component Mappings are applied in series or parallel. A non-zero
+*        value means that the supplied Mapping is equivalent to applying map1
+*        followed by map2 in series. A zero value means that the supplied
+*        Mapping is equivalent to applying map1 to the lower numbered axes
+*        and map2 to the higher numbered axes, in parallel. Zero is
+*        returned for a TranMap.
+*     invert1
+*        The value of the Invert attribute to be used with map1.
+*     invert2
+*        The value of the Invert attribute to be used with map2.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Notes:
+*     - Any changes made to the component Mappings using the returned
+*     pointers will be reflected in the supplied Mapping.
+
+*-
+*/
+
+
+/* Local Variables: */
+   AstTranMap *this;             /* Pointer to TranMap structure */
+
+/* Check the global error status. */
+   if ( !astOK ) return;
+
+/* Obtain a pointer to the TranMap structure. */
+   this = (AstTranMap *) this_mapping;
+
+/* If the TranMap has been inverted, return the Mappings in reverse
+   order with inverted Invert falgs. */
+   if( astGetInvert( this ) ) {
+      if( map1 ) *map1 = astClone( this->map2 );
+      if( map2 ) *map2 = astClone( this->map1 );
+      if( invert1 ) *invert1 = this->invert2 ? 0 : 1;
+      if( invert2 ) *invert2 = this->invert1 ? 0 : 1;
+
+/* If the TranMap has not been inverted, return the Mappings in their
+   original order with their original Invert flags. */
+   } else {
+      if( map1 ) *map1 = astClone( this->map1 );
+      if( map2 ) *map2 = astClone( this->map2 );
+      if( invert1 ) *invert1 = this->invert1;
+      if( invert2 ) *invert2 = this->invert2;
+   }
+}
+
+void astInitTranMapVtab_(  AstTranMapVtab *vtab, const char *name, int *status ) {
+/*
+*+
+*  Name:
+*     astInitTranMapVtab
+
+*  Purpose:
+*     Initialise a virtual function table for a TranMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     void astInitTranMapVtab( AstTranMapVtab *vtab, const char *name )
+
+*  Class Membership:
+*     TranMap vtab initialiser.
+
+*  Description:
+*     This function initialises the component of a virtual function
+*     table which is used by the TranMap 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 astIsATranMap) 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;
+
+   mapping->RemoveRegions = RemoveRegions;
+
+#if defined(THREAD_SAFE)
+   parent_managelock = object->ManageLock;
+   object->ManageLock = ManageLock;
+#endif
+
+   parent_transform = mapping->Transform;
+   mapping->Transform = Transform;
+
+   parent_mapsplit = mapping->MapSplit;
+   mapping->MapSplit = MapSplit;
+
+/* Store replacement pointers for methods which will be over-ridden by
+   new member functions implemented here. */
+   object->Equal = Equal;
+   mapping->Decompose = Decompose;
+   mapping->MapMerge = MapMerge;
+   mapping->Rate = Rate;
+
+/* Declare the copy constructor, destructor and class dump function. */
+   astSetCopy( vtab, Copy );
+   astSetDelete( vtab, Delete );
+   astSetDump( vtab, Dump, "TranMap", "Compound Transformation 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:
+*     TranMap 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: */
+   AstTranMap *this;       /* Pointer to TranMap structure */
+   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 TranMap structure. */
+   this = (AstTranMap *) 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->map1, mode, extra, fail );
+   if( !result ) result = astManageLock( this->map2, 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 TranMap.
+
+*  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:
+*     TranMap 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 TranMap 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 TranMap 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 TranMap which is to be merged with
+*        its neighbours. This should be a cloned copy of the TranMap
+*        pointer contained in the array element "(*map_list)[where]"
+*        (see below). This pointer will not be annulled, and the
+*        TranMap it identifies will not be modified by this function.
+*     where
+*        Index in the "*map_list" array (below) at which the pointer
+*        to the nominated TranMap 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: */
+   AstCmpMap *cmap;              /* Pointer to compound Mapping */
+   AstMapping *cmap_f;           /* Pointer to compound Mapping */
+   AstMapping *cmap_i;           /* Pointer to compound Mapping */
+   AstMapping *hmap1;            /* Pointer to 1st comp of higher TranMap */
+   AstMapping *hmap2;            /* Pointer to 2nd comp of higher TranMap */
+   AstMapping *hmap_f;           /* Pointer to fwd Mapping of higher TranMap */
+   AstMapping *hmap_i;           /* Pointer to inv Mapping of higher TranMap */
+   AstMapping *map1;             /* Pointer to 1st comp of nominated TranMap */
+   AstMapping *map2;             /* Pointer to 2nd comp of nominated TranMap */
+   AstMapping *map_f;            /* Pointer to fwd Mapping of nominated TranMap */
+   AstMapping *map_i;            /* Pointer to inv Mapping of nominated TranMap */
+   AstMapping *smap;             /* Pointer to simplified Mapping */
+   AstMapping *smap_f;           /* Pointer to simplified Mapping */
+   AstMapping *smap_i;           /* Pointer to simplified Mapping */
+   AstTranMap *hmap;             /* Pointer to higher TranMap */
+   AstTranMap *map;              /* Pointer to this TranMap */
+   AstTranMap *new;              /* Pointer to merged TranMap */
+   int i;                        /* Loop count */
+   int old_hinv1;                /* Original Invert flag for hmap->map1 */
+   int old_hinv2;                /* Original Invert flag for hmap->map2 */
+   int old_inv1;                 /* Original Invert flag for this->map1 */
+   int old_inv2;                 /* Original Invert flag for this->map2 */
+   int result;                   /* The value to return */
+
+/* Initialise.*/
+   result = -1;
+
+/* Check the inherited status. */
+   if ( !astOK ) return result;
+
+/* Get a pointer to this TranMap. */
+   map = (AstTranMap *) this;
+
+/* Get the two component Mappings,and temporarily set their Invert
+   attributes back to the values they had when the TranMap was created,
+   saving their current Invert values so that they can be re-instated later. */
+   map1 = map->map1;
+   old_inv1 = astGetInvert( map1 );
+   astSetInvert( map1, map->invert1 );
+
+   map2 = map->map2;
+   old_inv2 = astGetInvert( map2 );
+   astSetInvert( map2, map->invert2 );
+
+/* Simplify the TranMap on its own. */
+/* ================================ */
+
+/* If the TranMap is inverted, creat an equal TranMap which is not inverted.
+   To do this, invert and swap the component Mappings. */
+   if( ( *invert_list )[ where ] ) {
+      astInvert( map1 );
+      astInvert( map2 );
+      new = astTranMap( map2, map1, "", status );
+      astInvert( map1 );
+      astInvert( map2 );
+
+      (void) astAnnul( ( *map_list )[ where ] );
+      ( *map_list )[ where ] = (AstMapping *) new;
+      ( *invert_list )[ where ] = 0;
+      result = where;
+
+/* Otherwise, try to simplify each of the component Mappings. */
+   } else {
+      smap_f = astSimplify( map1 );
+      smap_i = astSimplify( map2 );
+
+/* Assume some simplification took place if the pointers have changed. */
+      if( smap_f != map1 || smap_i != map2 ) {
+
+/* Construct a new TranMap from these simplifgied Mappings. */
+         (void) astAnnul( ( *map_list )[ where ] );
+         ( *map_list )[ where ] = (AstMapping *) astTranMap( smap_f, smap_i, "", status );
+         result = where;
+
+/* Otherwise, if the both component Mappings are defined in both directions... */
+      } else if( astGetTranForward( map1 ) && astGetTranInverse( map1 ) &&
+                 astGetTranForward( map2 ) && astGetTranInverse( map2 ) ) {
+
+/* Form a series CmpMap from the two component Mappings, with the second
+   Mapping inverted. */
+         astInvert( map2 );
+         cmap = astCmpMap( map1, map2, 1, "", status );
+         astInvert( map2 );
+
+/* If this CmpMap simplifies to a UnitMap, then the two components of the
+   TranMap are equal, and so we can replace the entire TranMap with either
+   of its components. Note, we leave the supplied invert flag unchanged,
+   since the copycreated below refers to the Mapping as it was when the
+   TranMap was created. However, we invert the returned Mapping if
+   necessary. */
+         smap = astSimplify( cmap );
+         if( astIsAUnitMap( smap ) ) {
+            (void) astAnnul( ( *map_list )[ where ] );
+            ( *map_list )[ where ] = astCopy( map1 );
+            if( ( *invert_list )[ where ] ) astInvert( ( *map_list )[ where ] );
+            result = where;
+         }
+
+/* Release resources. */
+         smap = astAnnul( smap );
+         cmap = astAnnul( cmap );
+      }
+
+/* Release resources. */
+      smap_f = astAnnul( smap_f );
+      smap_i = astAnnul( smap_i );
+   }
+
+/* Merge the TranMap with a neighbouring TranMap. */
+/* ============================================== */
+/* Only do this if no change was made above, and we are combining the
+   Mappings in series. */
+   if( result == -1 && series ) {
+
+/* Is the higher neighbour a TranMap? */
+      if( where < ( *nmap - 1 ) &&
+          astIsATranMap( ( *map_list )[ where + 1 ] ) ){
+
+/* Get the two component Mappings of the higher TranMap, and temporarily set
+   their Invert attributes back to the values they had when the TranMap was
+   created, saving their current Invert values so that they can be re-instated
+   later. */
+         hmap = (AstTranMap *) ( *map_list )[ where + 1 ];
+
+         hmap1 = hmap->map1;
+         old_hinv1 = astGetInvert( hmap1 );
+         astSetInvert( hmap1, hmap->invert1 );
+
+         hmap2 = hmap->map2;
+         old_hinv2 = astGetInvert( hmap2 );
+         astSetInvert( hmap2, hmap->invert2 );
+
+/* Get the Mappings which defines the forward and inverse transformation of
+   the lower TranMap ("this"). Then, map_f and map_i are pointers to
+   Mappings which could be used to construct a new TranMap which would be
+   equivalent to "this" with the supplied invert setting. */
+         if( ( *invert_list )[ where ] ) {
+            map_f = map2;
+            map_i = map1;
+            astInvert( map_f );
+            astInvert( map_i );
+         } else {
+            map_f = map1;
+            map_i = map2;
+         }
+
+/* Likewise, get the Mappings which defines the forward and inverse
+   transformation of the higher TranMap. */
+         if( ( *invert_list )[ where + 1 ] ) {
+            hmap_f = hmap2;
+            hmap_i = hmap1;
+            astInvert( hmap_f );
+            astInvert( hmap_i );
+         } else {
+            hmap_f = hmap1;
+            hmap_i = hmap2;
+         }
+
+/* Combine the two forward Mappings together into a series CmpMap, and
+   simplify it. */
+         cmap_f = (AstMapping *) astCmpMap( map_f,  hmap_f, 1, "", status );
+         smap_f = astSimplify( cmap_f );
+
+/* Do the same for the inverse Mappings */
+         cmap_i = (AstMapping *) astCmpMap( map_i,  hmap_i, 1, "", status );
+         smap_i = astSimplify( cmap_i );
+
+/* Was any simplification performed? We assume this is the case if the
+   either of the simplied pointer differs from the original pointer. */
+         if( cmap_f != smap_f || cmap_i != smap_i ) {
+
+/* In which case,construct a new TranMap from the simplified Mappings. */
+            new = astTranMap( smap_f, smap_i, "", status );
+
+         } else {
+            new = NULL;
+         }
+
+/* Free resources.*/
+         cmap_f = astAnnul( cmap_f );
+         smap_f = astAnnul( smap_f );
+         cmap_i = astAnnul( cmap_i );
+         smap_i = astAnnul( smap_i );
+
+/* Re-instate the original Invert values for the component Mappings of
+   the higher TranMap. */
+         astSetInvert( hmap1, old_hinv1 );
+         astSetInvert( hmap2, old_hinv2 );
+
+/* If we have a new TranMap, annul the first of the two Mappings, and replace
+   it with the merged TranMap. Also set the invert flag. */
+         if( new ) {
+            (void) astAnnul( ( *map_list )[ where ] );
+            ( *map_list )[ where ] = (AstMapping *) new;
+            ( *invert_list )[ where ] = 0;
+
+/* Annul the second of the two Mappings, and shuffle down the rest of the
+   list to fill the gap. */
+            (void) astAnnul( ( *map_list )[ where + 1 ] );
+            for ( i = where + 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;
+         }
+      }
+   }
+
+/* Re-instate the original Invert values for the component Mappings. */
+   astSetInvert( map1, old_inv1 );
+   astSetInvert( map2, old_inv2 );
+
+/* If an error occurred, clear the result value. */
+   if ( !astOK ) result = -1;
+
+/* Return the result. */
+   return result;
+}
+
+static int *MapSplit( AstMapping *this_map, int nin, const int *in, AstMapping **map, int *status ){
+/*
+*  Name:
+*     MapSplit
+
+*  Purpose:
+*     Create a Mapping representing a subset of the inputs of an existing
+*     TranMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     int *MapSplit( AstMapping *this, int nin, const int *in, AstMapping **map, int *status )
+
+*  Class Membership:
+*     TranMap method (over-rides the protected astMapSplit method
+*     inherited from the Mapping class).
+
+*  Description:
+*     This function creates a new Mapping by picking specified inputs from
+*     an existing TranMap. This is only possible if the specified inputs
+*     correspond to some subset of the TranMap outputs. That is, there
+*     must exist a subset of the TranMap outputs for which each output
+*     depends only on the selected TranMap inputs, and not on any of the
+*     inputs which have not been selected. If this condition is not met
+*     by the supplied TranMap, then a NULL Mapping is returned.
+
+*  Parameters:
+*     this
+*        Pointer to the TranMap to be split (the TranMap is not actually
+*        modified by this function).
+*     nin
+*        The number of inputs to pick from "this".
+*     in
+*        Pointer to an array of indices (zero based) for the inputs which
+*        are to be picked. This array should have "nin" elements. If "Nin"
+*        is the number of inputs of the supplied TranMap, then each element
+*        should have a value in the range zero to Nin-1.
+*     map
+*        Address of a location at which to return a pointer to the new
+*        Mapping. This Mapping will have "nin" inputs (the number of
+*        outputs may be different to "nin"). A NULL pointer will be
+*        returned if the supplied TranMap has no subset of outputs which
+*        depend only on the selected inputs.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     A pointer to a dynamically allocated array of ints. The number of
+*     elements in this array will equal the number of outputs for the
+*     returned Mapping. Each element will hold the index of the
+*     corresponding output in the supplied TranMap. The array should be
+*     freed using astFree when no longer needed. A NULL pointer will
+*     be returned if no output Mapping can be created.
+
+*  Notes:
+*     - If this function is invoked with the global error status set,
+*     or if it should fail for any reason, then NULL values will be
+*     returned as the function value and for the "map" pointer.
+*/
+
+/* Local Variables: */
+   AstMapping *fmap;          /* Pointer to forward Mapping in supplied TranMap */
+   AstMapping *imap;          /* Pointer to inverse Mapping in supplied TranMap */
+   AstMapping *rfmap;         /* Pointer to split forward Mapping */
+   AstMapping *rimap;         /* Pointer to split inverse Mapping */
+   AstTranMap *this;          /* Pointer to TranMap structure */
+   int *ires;                 /* I/ps of inv Mapping dependent on selected o/ps */
+   int *out;                  /* O/ps of fwd Mapping dependent on selected i/ps */
+   int *result;               /* Pointer to returned array */
+   int finv;                  /* Invert flag to use with fmap */
+   int i;                     /* Loop count */
+   int iinv;                  /* Invert flag to use with imap */
+   int nout;                  /* No. of outputs dependent on selected inputs */
+   int ok;                    /* Can required Mapping be created? */
+   int old_finv;              /* Original Invert flag for fmap */
+   int old_iinv;              /* Original Invert flag for imap */
+
+/* Initialise */
+   result = NULL;
+   *map = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Invoke the parent astMapSplit method to see if it can do the job. */
+   result = (*parent_mapsplit)( this_map, nin, in, map, status );
+
+/* If not, we provide a special implementation here. */
+   if( !result ) {
+
+/* Get a pointer to the TranMap structure. */
+      this = (AstTranMap *) this_map;
+
+/* Get pointers to the forward and inverse Mappings, taking into account
+   whether the TranMap has been inverted. */
+      if( !astGetInvert( this ) ) {
+         fmap = this->map1;
+         finv = this->invert1;
+         imap = this->map2;
+         iinv = this->invert2;
+      } else {
+         imap = this->map1;
+         iinv = !( this->invert1 );
+         fmap = this->map2;
+         finv = !( this->invert2 );
+      }
+
+/* Temporarily set the Invert flag of both Mappings back to their
+   original values. */
+      old_finv = astGetInvert( fmap );
+      astSetInvert( fmap, finv );
+      old_iinv = astGetInvert( imap );
+      astSetInvert( imap, iinv );
+
+/* Try to split the forward Mapping. */
+      out = astMapSplit( fmap, nin, in, &rfmap );
+
+/* Check the split could be done. */
+      if( out ) {
+
+/* Get the number of outputs which are fed by the selected inputs. */
+         nout = astGetNout( rfmap );
+
+/* See if the inverse Mapping can be split using these outputs as inputs. */
+         astInvert( imap );
+         ires = astMapSplit( imap, nout, out, &rimap );
+         astInvert( imap );
+         if( ires ) {
+            astInvert( rimap );
+
+/* Check that the resulting inputs are the same as the supplied inputs. */
+            if( astGetNin( rimap ) == nin ) {
+               ok = 1;
+               for( i = 0; i < nin; i++ ) {
+                  if( in[ i ] != ires[ i ] ) {
+                     ok = 0;
+                     break;
+                  }
+               }
+
+/* If so create the required new TranMap. */
+               if( ok ) {
+                  *map = (AstMapping *) astTranMap( rfmap, rimap, "", status );
+                  result = out;
+               }
+            }
+
+/* Free resources. */
+            ires = astFree( ires );
+            rimap = astAnnul( rimap );
+         }
+
+         if( !result ) out = astFree( out );
+         rfmap = astAnnul( rfmap );
+      }
+
+/* Re-instate the Invert flags of the component Mappings. */
+      astSetInvert( fmap, old_finv );
+      astSetInvert( imap, old_iinv );
+   }
+
+/* Free returned resources if an error has occurred. */
+   if( !astOK ) {
+      result = astFree( result );
+      *map = astAnnul( *map );
+   }
+
+/* Return the list of output indices. */
+   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 "tranmap.h"
+*     result = Rate( AstMapping *this, double *at, int ax1, int ax2, int *status )
+
+*  Class Membership:
+*     TranMap 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: */
+   AstTranMap *map;
+   AstMapping *cmap;
+   double result;
+   int cinv;
+   int old_inv;
+
+/* Check inherited status */
+   if( !astOK ) return AST__BAD;
+
+/* Get a pointer to the TranMap structure. */
+   map = (AstTranMap *) this;
+
+/* Choose the component Mapping to use, and get its original Invert
+   value. Invert this if the TranMap itself has been inverted (this is
+   because the astRate function has no "invert" argument so we need to
+   invert the Mapping before calling astRate). */
+   if( astGetInvert( this ) ) {
+      cmap = map->map2;
+      cinv = !(map->invert2);
+   } else {
+      cmap = map->map1;
+      cinv = map->invert1;
+   }
+
+/* Temporarily set the Invert flag of the component Mapping back to its
+   original value. */
+   old_inv = astGetInvert( cmap );
+   astSetInvert( cmap, cinv );
+
+/* Use the astRate method of the component Mapping. */
+   result = astRate( cmap, at, ax1, ax2 );
+
+/* Re-instate the Invert flag of the component Mapping. */
+   astSetInvert( cmap, old_inv );
+
+/* 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 "tranmap.h"
+*     AstMapping *RemoveRegions( AstMapping *this, int *status )
+
+*  Class Membership:
+*     TranMap 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 TranMap) 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 TranMap), then it is replaced with an equivalent UnitMap
+*     in the returned Mapping.
+*
+*     The implementation provided by the TranMap class invokes the
+*     astRemoveRegions method on the two component Mappings, and joins
+*     the results together into a new TranMap.
+
+*  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: */
+   AstTranMap *new;              /* Pointer to new TranMap */
+   AstTranMap *this;             /* Pointer to TranMap structure */
+   AstMapping *newmap1;          /* New first component Mapping */
+   AstMapping *newmap2;          /* New second component Mapping */
+   AstMapping *result;           /* Result pointer to return */
+   int nax;                      /* Number of Frame axes */
+   int unit1;                    /* Is new first Mapping a UnitMap? */
+   int unit2;                    /* Is new second Mapping a UnitMap? */
+
+/* Initialise. */
+   result = NULL;
+
+/* Check the global error status. */
+   if ( !astOK ) return result;
+
+/* Get a pointer to the TranMap. */
+   this = (AstTranMap *) this_mapping;
+
+/* Invoke the astRemoveRegions method on the two component Mappings. */
+   newmap1 = astRemoveRegions( this->map1 );
+   newmap2 = astRemoveRegions( this->map2 );
+
+/* If neither component was modified, just return a clone of the supplied
+   pointer. */
+   if( this->map1 == newmap1 && this->map2 == newmap2 ) {
+      result = astClone( this );
+
+/* Otherwise, we need to create a new Mapping to return. */
+   } else {
+
+/* 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 either of these new Mappings is
+   a Frame, replace it with an equivalent UnitMap. Also, get flags
+   indicating if either Mapping is a UnitMap.*/
+      if( astIsAFrame( newmap1 ) ) {
+         nax = astGetNin( newmap1 );
+         (void) astAnnul( newmap1 );
+         newmap1 = (AstMapping *) astUnitMap( nax, " ", status );
+         unit1 = 1;
+      } else {
+         unit1 = astIsAUnitMap( newmap1 );
+      }
+
+      if( astIsAFrame( newmap2 ) ) {
+         nax = astGetNin( newmap2 );
+         (void) astAnnul( newmap2 );
+         newmap2 = (AstMapping *) astUnitMap( nax, " ", status );
+         unit2 = 1;
+      } else {
+         unit2 = astIsAUnitMap( newmap2 );
+      }
+
+/* If both new Mappings are UnitMaps, return an equivalent UnitMap. */
+      if( unit1 && unit2 ) {
+         result = (AstMapping *) astUnitMap( astGetNin( newmap1 ) +
+                                             astGetNin( newmap2 ), " ",
+                                             status );
+
+/* Otherwise, return a new TranMap containing the two new Mappings. */
+      } else {
+         new = astCopy( this );
+         (void) astAnnul( new->map1 );
+         (void) astAnnul( new->map2 );
+         new->map1 = astClone( newmap1 );
+         new->map2 = astClone( newmap2 );
+         result = (AstMapping *) new;
+      }
+   }
+
+/* Free resources. */
+   newmap1 = astAnnul( newmap1 );
+   newmap2 = astAnnul( newmap2 );
+
+/* Annul the returned Mapping if an error has occurred. */
+   if( !astOK ) result = astAnnul( result );
+
+/* Return the result. */
+   return result;
+}
+
+static AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+                               int forward, AstPointSet *out, int *status ) {
+/*
+*  Name:
+*     Transform
+
+*  Purpose:
+*     Apply a TranMap to transform a set of points.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+*                             int forward, AstPointSet *out, int *status )
+
+*  Class Membership:
+*     TranMap member function (over-rides the astTransform method inherited
+*     from the Mapping class).
+
+*  Description:
+*     This function takes a TranMap 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 TranMap's component Mappings in turn,
+*     either in series or in parallel.
+
+*  Parameters:
+*     this
+*        Pointer to the TranMap.
+*     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 TranMap 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 *cmap;             /* Mapping which defines the required transformation */
+   AstPointSet *result;          /* Pointer to output PointSet */
+   AstTranMap *map;              /* Pointer to TranMap to be applied */
+   int cinv;                     /* Invert flag when TranMap was created */
+   int old_inv;                  /* Invert flag on entry to this function */
+
+/* Check the global error status. */
+   if ( !astOK ) return NULL;
+
+/* Obtain a pointer to the TranMap. */
+   map = (AstTranMap *) 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 TranMap to generate the output coordinate values. */
+
+/* Determine whether to apply the forward or inverse Mapping, according to the
+   direction specified and whether the Mapping has been inverted. */
+   if ( astGetInvert( map ) ) forward = !forward;
+
+/* Choose the component Mapping to use, and get its original Invert value. */
+   if( forward ) {
+      cmap = map->map1;
+      cinv = map->invert1;
+   }else {
+      cmap = map->map2;
+      cinv = map->invert2;
+   }
+
+/* Temporarily set the Invert flag of the component Mapping back to its
+   original value. */
+   old_inv = astGetInvert( cmap );
+   astSetInvert( cmap, cinv );
+
+/* Use the Transform method of the component Mapping. */
+   result = astTransform( cmap, in, forward, out );
+
+/* Re-instate the Invert flag of the component Mapping. */
+   astSetInvert( cmap, old_inv );
+
+/* 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 TranMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Copy( const AstObject *objin, AstObject *objout, int *status )
+
+*  Description:
+*     This function implements the copy constructor for TranMap 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 TranMap.
+*/
+
+/* Local Variables: */
+   AstTranMap *in;                /* Pointer to input TranMap */
+   AstTranMap *out;               /* Pointer to output TranMap */
+
+/* Check the global error status. */
+   if ( !astOK ) return;
+
+/* Obtain pointers to the input and output TranMaps. */
+   in = (AstTranMap *) objin;
+   out = (AstTranMap *) objout;
+
+/* For safety, start by clearing any references to the input component
+   Mappings from the output TranMap. */
+   out->map1 = NULL;
+   out->map2 = NULL;
+
+/* Make copies of these Mappings and store pointers to them in the output
+   TranMap structure. */
+   out->map1 = astCopy( in->map1 );
+   out->map2 = astCopy( in->map2 );
+}
+
+/* Destructor. */
+/* ----------- */
+static void Delete( AstObject *obj, int *status ) {
+/*
+*  Name:
+*     Delete
+
+*  Purpose:
+*     Destructor for TranMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Delete( AstObject *obj, int *status )
+
+*  Description:
+*     This function implements the destructor for TranMap 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: */
+   AstTranMap *this;              /* Pointer to TranMap */
+
+/* Obtain a pointer to the TranMap structure. */
+   this = (AstTranMap *) obj;
+
+/* Annul the pointers to the component Mappings. */
+   this->map1 = astAnnul( this->map1 );
+   this->map2 = astAnnul( this->map2 );
+
+/* Clear the remaining TranMap variables. */
+   this->invert1 = 0;
+   this->invert2 = 0;
+}
+
+/* Dump function. */
+/* -------------- */
+static void Dump( AstObject *this_object, AstChannel *channel, int *status ) {
+/*
+*  Name:
+*     Dump
+
+*  Purpose:
+*     Dump function for TranMap 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 TranMap class to an output Channel.
+
+*  Parameters:
+*     this
+*        Pointer to the TranMap 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: */
+   AstTranMap *this;              /* Pointer to the TranMap structure */
+   int ival;                     /* Integer value */
+   int set;                      /* Attribute value set? */
+
+/* Check the global error status. */
+   if ( !astOK ) return;
+
+/* Obtain a pointer to the TranMap structure. */
+   this = (AstTranMap *) this_object;
+
+/* Write out values representing the instance variables for the TranMap
+   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. */
+
+/* First Invert flag. */
+/* ------------------ */
+   ival = this->invert1;
+   set = ( ival != 0 );
+   astWriteInt( channel, "InvA", set, 0, ival,
+                ival ? "First Mapping used in inverse direction" :
+                       "First Mapping used in forward direction" );
+
+/* Second Invert flag. */
+/* ------------------- */
+   ival = this->invert2;
+   set = ( ival != 0 );
+   astWriteInt( channel, "InvB", set, 0, ival,
+                ival ? "Second Mapping used in inverse direction" :
+                       "Second Mapping used in forward direction" );
+
+/* First Mapping. */
+/* -------------- */
+   astWriteObject( channel, "MapA", 1, 1, this->map1,
+                   "Mapping for forward transformation" );
+
+/* Second Mapping. */
+/* --------------- */
+   astWriteObject( channel, "MapB", 1, 1, this->map2,
+                   "Mapping for inverse transformation" );
+}
+
+/* Standard class functions. */
+/* ========================= */
+/* Implement the astIsATranMap and astCheckTranMap functions using the
+   macros defined for this purpose in the "object.h" header file. */
+astMAKE_ISA(TranMap,Mapping)
+astMAKE_CHECK(TranMap)
+
+AstTranMap *astTranMap_( void *map1_void, void *map2_void, const char *options, int *status, ...) {
+/*
+*+
+*  Name:
+*     astTranMap
+
+*  Purpose:
+*     Create a TranMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     AstTranMap *astTranMap( AstMapping *map1, AstMapping *map2, const char *options, int *status, ... )
+
+*  Class Membership:
+*     TranMap constructor.
+
+*  Description:
+*     This function creates a new TranMap and optionally initialises its
+*     attributes.
+
+*  Parameters:
+*     map1
+*        Pointer to the first Mapping (which deinfes the forward
+*        transformation).
+*     map2
+*        Pointer to the second Mapping (which deinfes the inverse
+*        transformation).
+*     options
+*        Pointer to a null terminated string containing an optional
+*        comma-separated list of attribute assignments to be used for
+*        initialising the new TranMap. The syntax used is the same as for the
+*        astSet method and may include "printf" format specifiers identified
+*        by "%" symbols in the normal way.
+*     status
+*        Pointer to the inherited status variable.
+*     ...
+*        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 TranMap.
+
+*  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 TranMap constructor which is
+*     available via the protected interface to the TranMap class.  A
+*     public interface is provided by the astTranMapId_ 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 */
+   AstTranMap *new;              /* Pointer to new TranMap */
+   AstMapping *map1;             /* Pointer to first Mapping structure */
+   AstMapping *map2;             /* Pointer to second Mapping structure */
+   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;
+
+/* Obtain and validate pointers to the Mapping structures provided. */
+   map1 = astCheckMapping( map1_void );
+   map2 = astCheckMapping( map2_void );
+   if ( astOK ) {
+
+/* Initialise the TranMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+      new = astInitTranMap( NULL, sizeof( AstTranMap ), !class_init, &class_vtab,
+                           "TranMap", map1, map2 );
+
+/* 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 TranMap'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 );
+      }
+   }
+
+/* Return a pointer to the new TranMap. */
+   return new;
+}
+
+AstTranMap *astTranMapId_( void *map1_void, void *map2_void,
+                           const char *options, ... ) {
+/*
+*++
+*  Name:
+c     astTranMap
+f     AST_TRANMAP
+
+*  Purpose:
+*     Create a TranMap.
+
+*  Type:
+*     Public function.
+
+*  Synopsis:
+c     #include "tranmap.h"
+c     AstTranMap *astTranMap( AstMapping *map1, AstMapping *map2,
+c                           const char *options, ... )
+f     RESULT = AST_TRANMAP( MAP1, MAP2, OPTIONS, STATUS )
+
+*  Class Membership:
+*     TranMap constructor.
+
+*  Description:
+*     This function creates a new TranMap and optionally initialises
+*     its attributes.
+*
+*     A TranMap is a Mapping which combines the forward transformation of
+*     a supplied Mapping with the inverse transformation of another
+*     supplied Mapping, ignoring the un-used transformation in each
+*     Mapping (indeed the un-used transformation need not exist).
+*
+*     When the forward transformation of the TranMap is referred to, the
+*     transformation actually used is the forward transformation of the
+*     first Mapping supplied when the TranMap was constructed. Likewise,
+*     when the inverse transformation of the TranMap is referred to, the
+*     transformation actually used is the inverse transformation of the
+*     second Mapping supplied when the TranMap was constructed.
+
+*  Parameters:
+c     map1
+f     MAP1 = INTEGER (Given)
+*        Pointer to the first component Mapping, which defines the
+*        forward transformation.
+c     map2
+f     MAP2 = INTEGER (Given)
+*        Pointer to the second component Mapping, which defines the
+*        inverse transformation.
+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 TranMap. 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 TranMap. 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     astTranMap()
+f     AST_TRANMAP = INTEGER
+*        A pointer to the new TranMap.
+
+*  Notes:
+*     - The number of output coordinates generated by the two Mappings
+*     (their Nout attribute) must be equal, as must the number of input
+*     coordinates accepted by each Mapping (their Nin attribute).
+*     - The forward transformation of the first Mapping must exist.
+*     - The inverse transformation of the second Mapping must exist.
+c     - Note that the component Mappings supplied are not copied by
+c     astTranMap (the new TranMap simply retains a reference to
+c     them). They may continue to be used for other purposes, but
+c     should not be deleted. If a TranMap containing a copy of its
+c     component Mappings is required, then a copy of the TranMap should
+c     be made using astCopy.
+f     - Note that the component Mappings supplied are not copied by
+f     AST_TRANMAP (the new TranMap simply retains a reference to
+f     them). They may continue to be used for other purposes, but
+f     should not be deleted. If a TranMap containing a copy of its
+f     component Mappings is required, then a copy of the TranMap 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.
+
+*  Status Handling:
+*     The protected interface to this function includes an extra
+*     parameter at the end of the parameter list descirbed above. This
+*     parameter is a pointer to the integer inherited status
+*     variable: "int *status".
+
+*--
+
+*  Implementation Notes:
+*     - This function implements the external (public) interface to
+*     the astTranMap constructor function. It returns an ID value
+*     (instead of a true C pointer) to external users, and must be
+*     provided because astTranMap_ 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 astTranMap_ 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 */
+   AstTranMap *new;               /* Pointer to new TranMap */
+   AstMapping *map1;             /* Pointer to first Mapping structure */
+   AstMapping *map2;             /* Pointer to second Mapping structure */
+   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;
+
+/* Obtain the Mapping pointers from the ID's supplied and validate the
+   pointers to ensure they identify valid Mappings. */
+   map1 = astVerifyMapping( astMakePointer( map1_void ) );
+   map2 = astVerifyMapping( astMakePointer( map2_void ) );
+   if ( astOK ) {
+
+/* Initialise the TranMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+      new = astInitTranMap( NULL, sizeof( AstTranMap ), !class_init, &class_vtab,
+                           "TranMap", map1, map2 );
+
+/* 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 TranMap'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 );
+      }
+   }
+
+/* Return an ID value for the new TranMap. */
+   return astMakeId( new );
+}
+
+AstTranMap *astInitTranMap_( void *mem, size_t size, int init,
+                           AstTranMapVtab *vtab, const char *name,
+                           AstMapping *map1, AstMapping *map2, int *status ) {
+/*
+*+
+*  Name:
+*     astInitTranMap
+
+*  Purpose:
+*     Initialise a TranMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     AstTranMap *astInitTranMap( void *mem, size_t size, int init,
+*                               AstTranMapVtab *vtab, const char *name,
+*                               AstMapping *map1, AstMapping *map2 )
+
+*  Class Membership:
+*     TranMap initialiser.
+
+*  Description:
+*     This function is provided for use by class implementations to initialise
+*     a new TranMap object. It allocates memory (if necessary) to
+*     accommodate the TranMap plus any additional data associated with the
+*     derived class. It then initialises a TranMap 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 TranMap at the start of
+*     the memory passed via the "vtab" parameter.
+
+*  Parameters:
+*     mem
+*        A pointer to the memory in which the TranMap is to be initialised.
+*        This must be of sufficient size to accommodate the TranMap data
+*        (sizeof(TranMap)) 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 TranMap (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
+*        TranMap structure, so a valid value must be supplied even if not
+*        required for allocating memory.
+*     init
+*        A logical flag indicating if the TranMap'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 TranMap.
+*     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).
+*     map1
+*        Pointer to the first Mapping.
+*     map2
+*        Pointer to the second Mapping.
+
+*  Returned Value:
+*     A pointer to the new TranMap.
+
+*  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: */
+   AstTranMap *new;               /* Pointer to new TranMap */
+   int nin;                      /* No. input coordinates for TranMap */
+   int nout;                     /* No. output coordinates for TranMap */
+
+/* Check the global status. */
+   if ( !astOK ) return NULL;
+
+/* If necessary, initialise the virtual function table. */
+   if ( init ) astInitTranMapVtab( vtab, name );
+
+/* Initialise. */
+   new = NULL;
+
+/* Report an error if map1 has no forward transformation. */
+   if( !astGetTranForward( map1 ) && astOK ) {
+      astError( AST__INTRD, "astInitTranMap(%s): The first supplied Mapping "
+              "is not able to transform coordinates in the forward direction.", status,
+              name );
+   }
+
+/* Report an error if map2 has no inverse transformation. */
+   if( !astGetTranInverse( map2 ) && astOK ) {
+      astError( AST__INTRD, "astInitTranMap(%s): The second supplied Mapping "
+              "is not able to transform coordinates in the inverse direction.", status,
+              name );
+   }
+
+/* Check that the number of coordinates are compatible and report an error if
+   they are not. */
+   nout = astGetNout( map1 );
+   if ( astGetNout( map2 ) != nout && astOK ) {
+      astError( AST__INNCO, "astInitTranMap(%s): The number of output "
+                      "coordinates per point (%d) for the first Mapping "
+                      "supplied does not match the number of output "
+                      "coordinates (%d) for the second Mapping.", status, name, nout,
+                      astGetNout( map2 ) );
+   }
+
+   nin = astGetNin( map1 );
+   if ( astGetNin( map2 ) != nin && astOK ) {
+      astError( AST__INNCO, "astInitTranMap(%s): The number of input "
+                      "coordinates per point (%d) for the first Mapping "
+                      "supplied does not match the number of input "
+                      "coordinates (%d) for the second Mapping.", status, name, nin,
+                      astGetNin( map2 ) );
+   }
+
+/* Initialise a Mapping structure (the parent class) as the first component
+   within the TranMap 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 = (AstTranMap *) astInitMapping( mem, size, 0,
+                                          (AstMappingVtab *) vtab, name,
+                                          nin, nout, 1, 1 );
+
+      if ( astOK ) {
+
+/* Initialise the TranMap data. */
+/* --------------------------- */
+/* Store pointers to the component Mappings. */
+         new->map1 = astClone( map1 );
+         new->map2 = astClone( map2 );
+
+/* Save the initial values of the inversion flags for these Mappings. */
+         new->invert1 = astGetInvert( map1 );
+         new->invert2 = astGetInvert( map2 );
+
+/* If an error occurred, clean up by annulling the Mapping pointers and
+   deleting the new object. */
+         if ( !astOK ) {
+            new->map1 = astAnnul( new->map1 );
+            new->map2 = astAnnul( new->map2 );
+            new = astDelete( new );
+         }
+      }
+   }
+
+/* Return a pointer to the new object. */
+   return new;
+}
+
+AstTranMap *astLoadTranMap_( void *mem, size_t size,
+                           AstTranMapVtab *vtab, const char *name,
+                           AstChannel *channel, int *status ) {
+/*
+*+
+*  Name:
+*     astLoadTranMap
+
+*  Purpose:
+*     Load a TranMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "tranmap.h"
+*     AstTranMap *astLoadTranMap( void *mem, size_t size,
+*                               AstTranMapVtab *vtab, const char *name,
+*                               AstChannel *channel )
+
+*  Class Membership:
+*     TranMap loader.
+
+*  Description:
+*     This function is provided to load a new TranMap 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
+*     TranMap 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 TranMap at the start of the memory
+*     passed via the "vtab" parameter.
+
+
+*  Parameters:
+*     mem
+*        A pointer to the memory into which the TranMap is to be
+*        loaded.  This must be of sufficient size to accommodate the
+*        TranMap data (sizeof(TranMap)) 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 TranMap (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 TranMap 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(AstTranMap) is used instead.
+*     vtab
+*        Pointer to the start of the virtual function table to be
+*        associated with the new TranMap. If this is NULL, a pointer to
+*        the (static) virtual function table for the TranMap 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 "TranMap" is used instead.
+
+*  Returned Value:
+*     A pointer to the new TranMap.
+
+*  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 */
+   AstTranMap *new;               /* Pointer to the new TranMap */
+
+/* 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 TranMap. In this case the
+   TranMap belongs to this class, so supply appropriate values to be
+   passed to the parent class loader (and its parent, etc.). */
+   if ( !vtab ) {
+      size = sizeof( AstTranMap );
+      vtab = &class_vtab;
+      name = "TranMap";
+
+/* If required, initialise the virtual function table for this class. */
+      if ( !class_init ) {
+         astInitTranMapVtab( 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 TranMap. */
+   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, "TranMap" );
+
+/* 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. */
+
+/* First Invert flag. */
+/* ------------------ */
+      new->invert1 = astReadInt( channel, "inva", 0 );
+      new->invert1 = ( new->invert1 != 0 );
+
+/* Second Invert flag. */
+/* ------------------- */
+      new->invert2 = astReadInt( channel, "invb", 0 );
+      new->invert2 = ( new->invert2 != 0 );
+
+/* First Mapping. */
+/* -------------- */
+      new->map1 = astReadObject( channel, "mapa", NULL );
+
+/* Second Mapping. */
+/* --------------- */
+      new->map2 = astReadObject( channel, "mapb", NULL );
+
+/* If an error occurred, clean up by deleting the new TranMap. */
+      if ( !astOK ) new = astDelete( new );
+   }
+
+/* Return the new TranMap 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. */
+
+
+
+