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+/*
+*class++
+* Name:
+* ShiftMap
+
+* Purpose:
+* Add a constant value to each coordinate.
+
+* Constructor Function:
+c astShiftMap
+f AST_SHIFTMAP
+
+* Description:
+* A ShiftMap is a linear Mapping which shifts each axis by a
+* specified constant value.
+
+* Inheritance:
+* The ShiftMap class inherits from the Mapping class.
+
+* Attributes:
+* The ShiftMap class does not define any new attributes beyond those
+* which are applicable to all Mappings.
+
+* Functions:
+c The ShiftMap class does not define any new functions beyond those
+f The ShiftMap 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 Berry (Starlink)
+
+* History:
+* 15-AUG-2003 (DSB):
+* Original version.
+* 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 ShiftMap
+
+/* Include files. */
+/* ============== */
+/* Interface definitions. */
+/* ---------------------- */
+
+#include "globals.h" /* Thread-safe global data access */
+#include "error.h" /* Error reporting facilities */
+#include "memory.h" /* Memory management facilities */
+#include "object.h" /* Base Object class */
+#include "pointset.h" /* Sets of points/coordinates */
+#include "matrixmap.h" /* Linear mappings */
+#include "unitmap.h" /* Unit mappings */
+#include "zoommap.h" /* Zoom mappings */
+#include "permmap.h" /* Axis permutations */
+#include "mapping.h" /* Coordinate mappings (parent class) */
+#include "channel.h" /* I/O channels */
+#include "winmap.h" /* Window mappings */
+#include "shiftmap.h" /* Interface definition for this class */
+
+/* Error code definitions. */
+/* ----------------------- */
+#include "ast_err.h" /* AST error codes */
+
+/* C header files. */
+/* --------------- */
+#include <float.h>
+#include <math.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.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 * );
+
+
+#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(ShiftMap)
+
+/* Define macros for accessing each item of thread specific global data. */
+#define class_init astGLOBAL(ShiftMap,Class_Init)
+#define class_vtab astGLOBAL(ShiftMap,Class_Vtab)
+
+
+#include <pthread.h>
+
+
+#else
+
+
+/* Define the class virtual function table and its initialisation flag
+ as static variables. */
+static AstShiftMapVtab 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. */
+AstShiftMap *astShiftMapId_( int, const double [], const char *, ... );
+
+/* Prototypes for Private Member Functions. */
+/* ======================================== */
+
+static AstPointSet *Transform( AstMapping *, AstPointSet *, int, AstPointSet *, int * );
+static int GetObjSize( AstObject *, int * );
+static double Rate( AstMapping *, double *, int, int, 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 int Equal( AstObject *, AstObject *, int * );
+static int GetIsLinear( AstMapping *, int * );
+static int *MapSplit( AstMapping *, int, const int *, AstMapping **, int * );
+
+/* Member functions. */
+/* ================= */
+
+static int Equal( AstObject *this_object, AstObject *that_object, int *status ) {
+/*
+* Name:
+* Equal
+
+* Purpose:
+* Test if two ShiftMaps are equivalent.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* int Equal( AstObject *this, AstObject *that, int *status )
+
+* Class Membership:
+* ShiftMap 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 ShiftMaps are equivalent.
+
+* Parameters:
+* this
+* Pointer to the first Object (a ShiftMap).
+* that
+* Pointer to the second Object.
+* status
+* Pointer to the inherited status variable.
+
+* Returned Value:
+* One if the ShiftMaps 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: */
+ AstShiftMap *that;
+ AstShiftMap *this;
+ int i;
+ int nin;
+ int nout;
+ int result;
+
+/* Initialise. */
+ result = 0;
+
+/* Check the global error status. */
+ if ( !astOK ) return result;
+
+/* Obtain pointers to the two ShiftMap structures. */
+ this = (AstShiftMap *) this_object;
+ that = (AstShiftMap *) that_object;
+
+/* Check the second object is a ShiftMap. We know the first is a
+ ShiftMap since we have arrived at this implementation of the virtual
+ function. */
+ if( astIsAShiftMap( 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 ) {
+
+/* If the Invert flags for the two ShiftMaps differ, it may still be possible
+ for them to be equivalent. First compare the ShiftMaps if their Invert
+ flags are the same. In this case all the attributes of the two ShiftMaps
+ must be identical. */
+ if( astGetInvert( this ) == astGetInvert( that ) ) {
+ result = 1;
+ for( i = 0; i < nin; i++ ) {
+ if( !astEQUAL( this->shift[ i ], that->shift[ i ] ) ) {
+ result = 0;
+ break;
+ }
+ }
+
+/* If the Invert flags for the two ShiftMaps differ, the attributes of the two
+ ShiftMaps must be inversely related to each other. */
+ } else {
+
+ result = 1;
+ for( i = 0; i < nin; i++ ) {
+ if( !astEQUAL( this->shift[ i ], -(that->shift[ i ] ) ) ) {
+ result = 0;
+ break;
+ }
+ }
+
+ }
+ }
+ }
+
+/* If an error occurred, clear the result value. */
+ if ( !astOK ) result = 0;
+
+/* Return the result, */
+ return result;
+}
+
+static int GetIsLinear( AstMapping *this_mapping, int *status ){
+/*
+* Name:
+* GetIsLinear
+
+* Purpose:
+* Return the value of the IsLinear attribute for a ShiftMap.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "mapping.h"
+* void GetIsLinear( AstMapping *this, int *status )
+
+* Class Membership:
+* ShiftMap member function (over-rides the protected astGetIsLinear
+* method inherited from the Mapping class).
+
+* Description:
+* This function returns the value of the IsLinear attribute for a
+* Frame, which is always one.
+
+* Parameters:
+* this
+* Pointer to the ShiftMap.
+* status
+* Pointer to the inherited status variable.
+*/
+ return 1;
+}
+
+static int GetObjSize( AstObject *this_object, int *status ) {
+/*
+* Name:
+* GetObjSize
+
+* Purpose:
+* Return the in-memory size of an Object.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* int GetObjSize( AstObject *this, int *status )
+
+* Class Membership:
+* ShiftMap member function (over-rides the astGetObjSize protected
+* method inherited from the parent class).
+
+* Description:
+* This function returns the in-memory size of the supplied ShiftMap,
+* in bytes.
+
+* Parameters:
+* this
+* Pointer to the ShiftMap.
+* 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: */
+ AstShiftMap *this; /* Pointer to ShiftMap structure */
+ int result; /* Result value to return */
+
+/* Initialise. */
+ result = 0;
+
+/* Check the global error status. */
+ if ( !astOK ) return result;
+
+/* Obtain a pointers to the ShiftMap structure. */
+ this = (AstShiftMap *) 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 += astTSizeOf( this->shift );
+
+/* If an error occurred, clear the result value. */
+ if ( !astOK ) result = 0;
+
+/* Return the result, */
+ return result;
+}
+
+void astInitShiftMapVtab_( AstShiftMapVtab *vtab, const char *name, int *status ) {
+/*
+*+
+* Name:
+* astInitShiftMapVtab
+
+* Purpose:
+* Initialise a virtual function table for a ShiftMap.
+
+* Type:
+* Protected function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* void astInitShiftMapVtab( AstShiftMapVtab *vtab, const char *name )
+
+* Class Membership:
+* ShiftMap vtab initialiser.
+
+* Description:
+* This function initialises the component of a virtual function
+* table which is used by the ShiftMap 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 astIsAShiftMap) 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. */
+
+/* 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;
+
+ 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->MapSplit = MapSplit;
+ mapping->GetIsLinear = GetIsLinear;
+
+/* Declare the class dump, copy and delete functions.*/
+ astSetDump( vtab, Dump, "ShiftMap", "Shift each coordinate axis" );
+ astSetCopy( (AstObjectVtab *) vtab, Copy );
+ astSetDelete( (AstObjectVtab *) vtab, Delete );
+
+/* 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) );
+ }
+}
+
+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 ShiftMap.
+
+* 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:
+* ShiftMap 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 ShiftMap 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 ShiftMap with a Mapping 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 ShiftMap which is to be merged with
+* its neighbours. This should be a cloned copy of the ShiftMap
+* pointer contained in the array element "(*map_list)[where]"
+* (see below). This pointer will not be annulled, and the
+* ShiftMap it identifies will not be modified by this function.
+* where
+* Index in the "*map_list" array (below) at which the pointer
+* to the nominated ShiftMap 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: */
+ AstWinMap *w1; /* Pointer to replacement Mapping */
+ AstShiftMap *sm; /* Pointer to this ShiftMap */
+ double *aa; /* Pointer to shift terms for new WinMap */
+ double *bb; /* Pointer to scale terms for new WinMap */
+ int i; /* Axis count */
+ int nin; /* Number of axes */
+ int result; /* Returned value */
+
+/* Initialise. */
+ result = -1;
+
+/* Check the global error status. */
+ if ( !astOK ) return result;
+
+/* A ShiftMap is equivalent to a WinMap with unit scaling. The policy on
+ simplifying a ShiftMap is to convert it to the equivalent WinMap and let
+ the WinMap class do the simplifying. Create the returned WinMap, initially
+ with undefined corners. */
+ nin = astGetNin( this );
+ w1 = astWinMap( nin, NULL, NULL, NULL, NULL, "", status );
+
+/* If succesful, store the scale and shift terms in the WinMap. The scale
+ terms are unity. */
+ if( astOK ){
+ sm = (AstShiftMap *) this;
+
+ bb = w1->b;
+ aa = w1->a;
+ for( i = 0; i < nin; i++ ) {
+ *(bb++) = 1.0;
+ *(aa++) = ( *invert_list )[ where ] ? -(sm->shift)[ i ] : (sm->shift)[ i ];
+ }
+
+/* Replace the supplied ShiftMap with the new WinMap and reset the invert
+ flag. */
+ (void) astAnnul( ( *map_list )[ where ] );
+ ( *map_list )[ where ] = (AstMapping *) w1;
+ ( *invert_list )[ where ] = 0;
+
+/* Return the index of the first modified element. */
+ result = where;
+ }
+
+/* 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
+* ShiftMap.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* int *MapSplit( AstMapping *this, int nin, const int *in, AstMapping **map, int *status )
+
+* Class Membership:
+* ShiftMap 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 ShiftMap. This is only possible if the specified inputs
+* correspond to some subset of the ShiftMap outputs. That is, there
+* must exist a subset of the ShiftMap outputs for which each output
+* depends only on the selected ShiftMap inputs, and not on any of the
+* inputs which have not been selected. If this condition is not met
+* by the supplied ShiftMap, then a NULL Mapping is returned.
+
+* Parameters:
+* this
+* Pointer to the ShiftMap to be split (the ShiftMap 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 ShiftMap, 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 ShiftMap 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 ShiftMap. 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: */
+ AstShiftMap *newsm; /* Pointer to returned ShiftMap */
+ AstShiftMap *this; /* Pointer to ShiftMap structure */
+ int *result; /* Pointer to returned array */
+ int i; /* Loop count */
+ int iin; /* Mapping input index */
+ int mnin; /* No. of Mapping inputs */
+ int ok; /* Are input indices OK? */
+
+/* Initialise */
+ result = NULL;
+ *map = NULL;
+
+/* Check the global error status. */
+ if ( !astOK ) return result;
+
+/* Get a pointer to the ShiftMap structure. */
+ this = (AstShiftMap *) this_map;
+
+/* Allocate memory for the returned array and create a ShiftMap with the
+ required number of axes and initially unsorted shifts. */
+ result = astMalloc( sizeof( int )*(size_t) nin );
+ newsm = astShiftMap( nin, this->shift, "", status );
+ *map = (AstMapping *) newsm;
+
+/* Check pointers can be used safely. */
+ if( astOK ) {
+
+/* Store the required shifts in the new ShiftMap. At the same time check
+ that each axis is valid. */
+ mnin = astGetNin( this );
+ ok = 1;
+ for( i = 0; i < nin; i++ ) {
+ iin = in[ i ];
+ if( iin >= 0 && iin < mnin ) {
+ (newsm->shift)[ i ] = (this->shift)[ iin ];
+ result[ i ] = iin;
+ } else {
+ ok = 0;
+ break;
+ }
+ }
+
+/* If the "in" array contained any invalid values, free the returned
+ resources. */
+ if( !ok ) {
+ result = astFree( result );
+ *map = astAnnul( *map );
+
+/* If the indices are good, invert the returned ShiftMap if the supplied
+ ShiftMap is inverted. */
+ } else {
+ if( astGetInvert( this ) ) astInvert( *map );
+ }
+ }
+
+/* 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 "shiftmap.h"
+* result = Rate( AstMapping *this, double *at, int ax1, int ax2, int *status )
+
+* Class Membership:
+* ShiftMap 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.
+
+* 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.
+
+*/
+
+ return ( ax1 == ax2 ) ? 1.0 : 0.0;
+}
+
+static AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+ int forward, AstPointSet *out, int *status ) {
+/*
+* Name:
+* Transform
+
+* Purpose:
+* Apply a ShiftMap to transform a set of points.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+* int forward, AstPointSet *out, int *status )
+
+* Class Membership:
+* ShiftMap member function (over-rides the astTransform protected
+* method inherited from the Mapping class).
+
+* Description:
+* This function takes a ShiftMap and a set of points encapsulated in a
+* PointSet and transforms the points so as to map them into the
+* required window.
+
+* Parameters:
+* this
+* Pointer to the ShiftMap.
+* in
+* Pointer to the PointSet holding the input coordinate data.
+* 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 ShiftMap 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: */
+ AstPointSet *result; /* Pointer to output PointSet */
+ AstShiftMap *map; /* Pointer to ShiftMap to be applied */
+ const char *class; /* Object class */
+ double **ptr_in; /* Pointer to input coordinate data */
+ double **ptr_out; /* Pointer to output coordinate data */
+ double *axin; /* Pointer to next input axis value */
+ double *axout; /* Pointer to next output axis value */
+ double a; /* Shift for current axis */
+ int coord; /* Loop counter for coordinates */
+ int ncoord; /* Number of coordinates per point */
+ int npoint; /* Number of points */
+ int point; /* Loop counter for points */
+
+/* Check the global error status. */
+ if ( !astOK ) return NULL;
+
+/* Obtain a pointer to the ShiftMap. */
+ map = (AstShiftMap *) 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 will now extend the parent astTransform method by performing the
+ calculations needed to generate the output coordinate values. */
+
+/* Determine the numbers of points and coordinates per point from the input
+ PointSet and obtain pointers for accessing the input and output coordinate
+ values. */
+ ncoord = astGetNcoord( in );
+ npoint = astGetNpoint( in );
+ ptr_in = astGetPoints( in );
+ ptr_out = astGetPoints( result );
+
+/* 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;
+
+/* Report an error if the ShiftMap does not contain any shifts. */
+ if( !map->shift && astOK ){
+ class = astGetClass( this );
+ astError( AST__BADSM, "astTransform(%s): The supplied %s does not "
+ "contain any shift information.", status, class, class );
+ }
+
+/* Perform coordinate arithmetic. */
+/* ------------------------------ */
+ if( astOK ){
+
+/* Apply the mapping to each axis. */
+ for( coord = 0; coord < ncoord; coord++ ){
+
+/* Store pointers to the first input and output values on this axis. */
+ axin = ptr_in[ coord ];
+ axout = ptr_out[ coord ];
+
+/* Get the value to add to each axis value. */
+ a = (map->shift)[ coord ];
+
+/* If the shift is bad store bad output values. */
+ if( a == AST__BAD ){
+ for( point = 0; point < npoint; point++ ) *(axout++) = AST__BAD;
+
+/* Otherwise, shift this axis, taking account of whether the mapping is
+ inverted or not. */
+ } else {
+ if( !forward ) a = -a;
+
+ for( point = 0; point < npoint; point++ ){
+ if( *axin != AST__BAD ){
+ *(axout++) = (*axin) + a;
+ } else {
+ *(axout++) = AST__BAD;
+ }
+ axin++;
+ }
+ }
+ }
+ }
+
+/* Return a pointer to the output PointSet. */
+ return result;
+}
+
+/* Functions which access class attributes. */
+/* ---------------------------------------- */
+/* Implement member functions to access the attributes associated with
+ this class using the macros defined for this purpose in the
+ "object.h" file. For a description of each attribute, see the class
+ interface (in the associated .h file). */
+
+/* Copy constructor. */
+/* ----------------- */
+static void Copy( const AstObject *objin, AstObject *objout, int *status ) {
+/*
+* Name:
+* Copy
+
+* Purpose:
+* Copy constructor for ShiftMap objects.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* void Copy( const AstObject *objin, AstObject *objout, int *status )
+
+* Description:
+* This function implements the copy constructor for ShiftMap objects.
+
+* Parameters:
+* objin
+* Pointer to the ShiftMap to be copied.
+* objout
+* Pointer to the ShiftMap being constructed.
+* status
+* Pointer to the inherited status variable.
+
+*/
+
+/* Local Variables: */
+ AstShiftMap *out; /* Pointer to output ShiftMap */
+ AstShiftMap *in; /* Pointer to input ShiftMap */
+ int ncoord; /* No. of axes for the mapping */
+
+/* Check the global error status. */
+ if ( !astOK ) return;
+
+/* Obtain a pointer to the input and output ShiftMaps. */
+ in= (AstShiftMap *) objin;
+ out = (AstShiftMap *) objout;
+
+/* Get the number of coordinates mapped by the ShiftMap. */
+ ncoord = astGetNin( in );
+
+/* Allocate memory holding copies of the shifts defining the mapping. */
+ out->shift = (double *) astStore( NULL, (void *) in->shift,
+ sizeof(double)*(size_t)ncoord );
+
+/* If an error occurred, free any allocated memory. */
+ if ( !astOK ) {
+ out->shift = (double *) astFree( (void *) out->shift );
+ }
+
+}
+
+/* Destructor. */
+/* ----------- */
+static void Delete( AstObject *obj, int *status ) {
+/*
+* Name:
+* Delete
+
+* Purpose:
+* Destructor for ShiftMap objects.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* void Delete( AstObject *obj, int *status )
+
+* Description:
+* This function implements the destructor for ShiftMap objects.
+
+* Parameters:
+* obj
+* Pointer to the ShiftMap to be deleted.
+* status
+* Pointer to the inherited status variable.
+
+* Notes:
+* - This destructor does nothing and exists only to maintain a
+* one-to-one correspondence between destructors and copy
+* constructors.
+*/
+
+/* Local Variables: */
+ AstShiftMap *this; /* Pointer to ShiftMap */
+
+/* Obtain a pointer to the ShiftMap structure. */
+ this = (AstShiftMap *) obj;
+
+/* Free the memory holding the shifts. */
+ this->shift = (double *) astFree( (void *) this->shift );
+
+}
+
+/* Dump function. */
+/* -------------- */
+static void Dump( AstObject *this_object, AstChannel *channel, int *status ) {
+/*
+* Name:
+* Dump
+
+* Purpose:
+* Dump function for ShiftMap 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 ShiftMap class to an output Channel.
+
+* Parameters:
+* this
+* Pointer to the ShiftMap 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 Constants: */
+#define COMMENT_LEN 50 /* Maximum length of a comment string */
+#define KEY_LEN 50 /* Maximum length of a keyword */
+
+/* Local Variables: */
+ AstShiftMap *this; /* Pointer to the ShiftMap structure */
+ char buff[ KEY_LEN + 1 ]; /* Buffer for keyword string */
+ char comment[ COMMENT_LEN + 1 ]; /* Buffer for comment string */
+ int axis; /* Axis index */
+ int ncoord; /* No. of axes for mapping */
+
+/* Check the global error status. */
+ if ( !astOK ) return;
+
+/* Obtain a pointer to the ShiftMap structure. */
+ this = (AstShiftMap *) this_object;
+
+/* Get the number of coordinates to be mapped. */
+ ncoord = astGetNin( this );
+
+/* Write out values representing the instance variables for the
+ ShiftMap class. Accompany these with appropriate comment strings,
+ possibly depending on the values being written.*/
+
+/* The shifts. */
+ for( axis = 0; axis < ncoord; axis++ ){
+ (void) sprintf( buff, "Sft%d", axis + 1 );
+ (void) sprintf( comment, "Shift for axis %d", axis + 1 );
+ astWriteDouble( channel, buff, (this->shift)[ axis ] != 0.0, 0,
+ (this->shift)[ axis ], comment );
+ }
+
+/* Undefine macros local to this function. */
+#undef COMMENT_LEN
+#undef KEY_LEN
+}
+
+/* Standard class functions. */
+/* ========================= */
+/* Implement the astIsAShiftMap and astCheckShiftMap functions using the macros
+ defined for this purpose in the "object.h" header file. */
+astMAKE_ISA(ShiftMap,Mapping)
+astMAKE_CHECK(ShiftMap)
+
+AstShiftMap *astShiftMap_( int ncoord, const double shift[], const char *options, int *status, ...) {
+/*
+*++
+* Name:
+c astShiftMap
+f AST_SHIFTMAP
+
+* Purpose:
+* Create a ShiftMap.
+
+* Type:
+* Public function.
+
+* Synopsis:
+c #include "shiftmap.h"
+c AstShiftMap *astShiftMap( int ncoord, const double shift[],
+c const char *options, ... )
+f RESULT = AST_SHIFTMAP( NCOORD, SHIFT, OPTIONS, STATUS )
+
+* Class Membership:
+* ShiftMap constructor.
+
+* Description:
+* This function creates a new ShiftMap and optionally initialises its
+* attributes.
+*
+* A ShiftMap is a linear Mapping which shifts each axis by a
+* specified constant value.
+
+* Parameters:
+c ncoord
+f NCOORD = INTEGER (Given)
+* The number of coordinate values for each point to be
+* transformed (i.e. the number of dimensions of the space in
+* which the points will reside). The same number is applicable
+* to both input and output points.
+c shift
+f SHIFT( NCOORD ) = DOUBLE PRECISION (Given)
+* An array containing the values to be added on to the input
+* coordinates in order to create the output coordinates. A separate
+* value should be supplied for each coordinate.
+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 ShiftMap. 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 ShiftMap. 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 astShiftMap()
+f AST_SHIFTMAP = INTEGER
+* A pointer to the new ShiftMap.
+
+* Notes:
+* - 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".
+
+*--
+*/
+
+/* Local Variables: */
+ astDECLARE_GLOBALS /* Pointer to thread-specific global data */
+ AstShiftMap *new; /* Pointer to new ShiftMap */
+ va_list args; /* Variable argument list */
+
+/* Get a pointer to the thread specific global data structure. */
+ astGET_GLOBALS(NULL);
+
+/* Check the global status. */
+ if ( !astOK ) return NULL;
+
+/* Initialise the ShiftMap, allocating memory and initialising the
+ virtual function table as well if necessary. */
+ new = astInitShiftMap( NULL, sizeof( AstShiftMap ), !class_init, &class_vtab,
+ "ShiftMap", ncoord, shift );
+
+/* 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 ShiftMap'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 ShiftMap. */
+ return new;
+}
+
+AstShiftMap *astShiftMapId_( int ncoord, const double shift[],
+ const char *options, ... ) {
+/*
+* Name:
+* astShiftMapId_
+
+* Purpose:
+* Create a ShiftMap.
+
+* Type:
+* Private function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* AstShiftMap *astShiftMapId_( int ncoord, const double shift[],
+* const char *options, ... )
+
+* Class Membership:
+* ShiftMap constructor.
+
+* Description:
+* This function implements the external (public) interface to the
+* astShiftMap constructor function. It returns an ID value (instead
+* of a true C pointer) to external users, and must be provided
+* because astShiftMap_ has a variable argument list which cannot be
+* encapsulated in a macro (where this conversion would otherwise
+* occur).
+*
+* The variable argument list also prevents this function from
+* invoking astShiftMap_ directly, so it must be a re-implementation
+* of it in all respects, except for the final conversion of the
+* result to an ID value.
+
+* Parameters:
+* As for astShiftMap_.
+
+* Returned Value:
+* The ID value associated with the new ShiftMap.
+*/
+
+/* Local Variables: */
+ astDECLARE_GLOBALS /* Pointer to thread-specific global data */
+ AstShiftMap *new; /* Pointer to new ShiftMap */
+ va_list args; /* Variable argument list */
+
+ int *status; /* Pointer to inherited status value */
+
+/* Get a pointer to the inherited status value. */
+ status = astGetStatusPtr;
+
+/* Get a pointer to the thread specific global data structure. */
+ astGET_GLOBALS(NULL);
+
+/* Check the global status. */
+ if ( !astOK ) return NULL;
+
+/* Initialise the ShiftMap, allocating memory and initialising the
+ virtual function table as well if necessary. */
+ new = astInitShiftMap( NULL, sizeof( AstShiftMap ), !class_init, &class_vtab,
+ "ShiftMap", ncoord, shift );
+
+/* 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 ShiftMap'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 ShiftMap. */
+ return astMakeId( new );
+}
+
+AstShiftMap *astInitShiftMap_( void *mem, size_t size, int init,
+ AstShiftMapVtab *vtab, const char *name,
+ int ncoord, const double *shift, int *status ) {
+/*
+*+
+* Name:
+* astInitShiftMap
+
+* Purpose:
+* Initialise a ShiftMap.
+
+* Type:
+* Protected function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* AstShiftMap *astInitShiftMap( void *mem, size_t size, int init,
+* AstShiftMapVtab *vtab, const char *name,
+* int ncoord, const double *shift )
+
+* Class Membership:
+* ShiftMap initialiser.
+
+* Description:
+* This function is provided for use by class implementations to initialise
+* a new ShiftMap object. It allocates memory (if necessary) to accommodate
+* the ShiftMap plus any additional data associated with the derived class.
+* It then initialises a ShiftMap 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 ShiftMap at the start of the memory passed via the
+* "vtab" parameter.
+
+* Parameters:
+* mem
+* A pointer to the memory in which the ShiftMap is to be initialised.
+* This must be of sufficient size to accommodate the ShiftMap data
+* (sizeof(ShiftMap)) 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 ShiftMap (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 ShiftMap
+* structure, so a valid value must be supplied even if not required for
+* allocating memory.
+* init
+* A logical flag indicating if the ShiftMap'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 ShiftMap.
+* 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).
+* ncoord
+* The number of coordinate values per point.
+* shift
+* Pointer to an array of shifts, one for each coordinate.
+
+* Returned Value:
+* A pointer to the new ShiftMap.
+
+* 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: */
+ AstShiftMap *new; /* Pointer to new ShiftMap */
+ int axis; /* Axis index */
+
+/* Check the global status. */
+ if ( !astOK ) return NULL;
+
+/* If necessary, initialise the virtual function table. */
+ if ( init ) astInitShiftMapVtab( vtab, name );
+
+/* Initialise. */
+ new = NULL;
+
+/* Initialise a Mapping structure (the parent class) as the first component
+ within the ShiftMap structure, allocating memory if necessary. Specify that
+ the Mapping should be defined in both the forward and inverse directions. */
+ new = (AstShiftMap *) astInitMapping( mem, size, 0,
+ (AstMappingVtab *) vtab, name,
+ ncoord, ncoord, 1, 1 );
+
+ if ( astOK ) {
+
+/* Initialise the ShiftMap data. */
+/* ---------------------------- */
+/* Allocate memory to hold the shift for each axis. */
+ new->shift = (double *) astMalloc( sizeof(double)*(size_t)ncoord );
+
+/* Check the pointers can be used */
+ if( astOK ){
+
+/* Store the shift and scale for each axis. */
+ for( axis = 0; axis < ncoord; axis++ ){
+ (new->shift)[ axis ] = shift ? shift[ axis ] : AST__BAD;
+ }
+
+ }
+
+/* If an error occurred, clean up by deleting the new ShiftMap. */
+ if ( !astOK ) new = astDelete( new );
+ }
+
+/* Return a pointer to the new ShiftMap. */
+ return new;
+}
+
+AstShiftMap *astLoadShiftMap_( void *mem, size_t size,
+ AstShiftMapVtab *vtab, const char *name,
+ AstChannel *channel, int *status ) {
+/*
+*+
+* Name:
+* astLoadShiftMap
+
+* Purpose:
+* Load a ShiftMap.
+
+* Type:
+* Protected function.
+
+* Synopsis:
+* #include "shiftmap.h"
+* AstShiftMap *astLoadShiftMap( void *mem, size_t size,
+* AstShiftMapVtab *vtab, const char *name,
+* AstChannel *channel )
+
+* Class Membership:
+* ShiftMap loader.
+
+* Description:
+* This function is provided to load a new ShiftMap 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
+* ShiftMap 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 ShiftMap at the start of the memory
+* passed via the "vtab" parameter.
+
+
+* Parameters:
+* mem
+* A pointer to the memory into which the ShiftMap is to be
+* loaded. This must be of sufficient size to accommodate the
+* ShiftMap data (sizeof(ShiftMap)) 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 ShiftMap (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 ShiftMap 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(AstShiftMap) is used instead.
+* vtab
+* Pointer to the start of the virtual function table to be
+* associated with the new ShiftMap. If this is NULL, a pointer
+* to the (static) virtual function table for the ShiftMap 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 "ShiftMap" is used instead.
+
+* Returned Value:
+* A pointer to the new ShiftMap.
+
+* 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 Constants. */
+ astDECLARE_GLOBALS /* Pointer to thread-specific global data */
+#define KEY_LEN 50 /* Maximum length of a keyword */
+
+/* Local Variables: */
+ AstShiftMap *new; /* Pointer to the new ShiftMap */
+ char buff[ KEY_LEN + 1 ]; /* Buffer for keyword string */
+ int axis; /* Axis index */
+ int ncoord; /* The number of coordinate axes */
+
+/* Get a pointer to the thread specific global data structure. */
+ astGET_GLOBALS(channel);
+
+/* Initialise. */
+ new = NULL;
+
+/* Check the global error status. */
+ if ( !astOK ) return new;
+
+/* If a NULL virtual function table has been supplied, then this is
+ the first loader to be invoked for this ShiftMap. In this case the
+ ShiftMap belongs to this class, so supply appropriate values to be
+ passed to the parent class loader (and its parent, etc.). */
+ if ( !vtab ) {
+ size = sizeof( AstShiftMap );
+ vtab = &class_vtab;
+ name = "ShiftMap";
+
+/* If required, initialise the virtual function table for this class. */
+ if ( !class_init ) {
+ astInitShiftMapVtab( 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 ShiftMap. */
+ new = astLoadMapping( mem, size, (AstMappingVtab *) vtab, name,
+ channel );
+
+ if ( astOK ) {
+
+/* Get the number of axis for the mapping. */
+ ncoord = astGetNin( (AstMapping *) new );
+
+/* Allocate memory to hold the shifts. */
+ new->shift = (double *) astMalloc( sizeof(double)*(size_t)ncoord );
+
+/* Read input data. */
+/* ================ */
+/* Request the input Channel to read all the input data appropriate to
+ this class into the internal "values list". */
+ astReadClassData( channel, "ShiftMap" );
+
+/* Now read each individual data item from this list and use it to
+ initialise the appropriate instance variable(s) for this class. */
+
+/* The shifts. */
+ for( axis = 0; axis < ncoord; axis++ ){
+ (void) sprintf( buff, "sft%d", axis + 1 );
+ (new->shift)[ axis ] = astReadDouble( channel, buff, 0.0 );
+ }
+ }
+
+/* If an error occurred, clean up by deleting the new ShiftMap. */
+ if ( !astOK ) new = astDelete( new );
+
+/* Return the new ShiftMap pointer. */
+ return new;
+
+/* Undefine macros local to this function. */
+#undef KEY_LEN
+}
+
+/* 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. */
+
+
+
+
+