PagedArrIter.h

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00001 //# PagedArrIter.h: A concrete iterator for use with PagedArray's.
00002 //# Copyright (C) 1994,1995,1996,1997,1998,1999,2000,2003
00003 //# Associated Universities, Inc. Washington DC, USA.
00004 //#
00005 //# This library is free software; you can redistribute it and/or modify it
00006 //# under the terms of the GNU Library General Public License as published by
00007 //# the Free Software Foundation; either version 2 of the License, or (at your
00008 //# option) any later version.
00009 //#
00010 //# This library is distributed in the hope that it will be useful, but WITHOUT
00011 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00012 //# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
00013 //# License for more details.
00014 //#
00015 //# You should have received a copy of the GNU Library General Public License
00016 //# along with this library; if not, write to the Free Software Foundation,
00017 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
00018 //#
00019 //# Correspondence concerning AIPS++ should be addressed as follows:
00020 //#        Internet email: aips2-request@nrao.edu.
00021 //#        Postal address: AIPS++ Project Office
00022 //#                        National Radio Astronomy Observatory
00023 //#                        520 Edgemont Road
00024 //#                        Charlottesville, VA 22903-2475 USA
00025 //#
00026 //# $Id$
00027 
00028 #ifndef LATTICES_PAGEDARRITER_H
00029 #define LATTICES_PAGEDARRITER_H
00030 
00031 //# Includes
00032 #include <casacore/casa/aips.h>
00033 #include <casacore/lattices/Lattices/LatticeIterInterface.h>
00034 #include <casacore/lattices/Lattices/PagedArray.h>
00035 
00036 
00037 namespace casacore { //# NAMESPACE CASACORE - BEGIN
00038 
00039 // <summary>
00040 // A read/write Lattice iterator for PagedArrays.
00041 // </summary>
00042 
00043 // <use visibility=local>
00044 
00045 // <reviewed reviewer="Peter Barnes" date="1999/10/30" tests="tLatticeIterator.cc" demos="dPagedArray.cc">
00046 // </reviewed>
00047 
00048 // <prerequisite>
00049 //   <li> <linkto class="PagedArray">PagedArray</linkto>
00050 //   <li> <linkto class="LatticeIterator">LatticeIterator</linkto>
00051 //   <li> <linkto class="LatticeIterInterface">LatticeIterInterface
00052 //        </linkto>
00053 //   <li> letter/envelope schemes, eg. Coplien, "Advanced C++", ch 5.5
00054 // </prerequisite>
00055 
00056 // <etymology>
00057 // The PagedArrIter class name is a contraction of Paged Array Iterator 
00058 // and reflects its role as the methods for iterating through Lattices which 
00059 // are resident on disk.
00060 // </etymology>
00061 
00062 // <synopsis>
00063 // This class is not meant for general use. Instead class
00064 // <linkto class="LatticeIterator">LatticeIterator</linkto> should be used
00065 // to iterate through a <src>PagedArray</src> or any other
00066 // <linkto class="Lattice">Lattice</linkto> object
00067 // (like a <linkto class="ArrayLattice">ArrayLattice</linkto>).
00068 // <p>
00069 // PagedArrIter is derived from LatticeIterInterface and implements
00070 // the iterator for a <linkto class=PagedArray>PagedArray</linkto>
00071 // object. This iterator is somewhat special because it sets the
00072 // PagedArray cache size at the start of an iteration.
00073 // </synopsis>
00074 
00075 // <motivation>
00076 // For for each derivation of Lattice to make as efficient an iterator as
00077 // possible.
00078 // The letter/envelope scheme allowed us to hide the special bits in
00079 // classes like the one you see here.
00080 // </motivation>
00081 
00082 // <templating arg=T>
00083 //  <li> Restricted to the type of the PagedArray argument in the 
00084 //   constructors
00085 // </templating>
00086 
00087 //# <todo asof="1997/01/31">
00088 //#   <li>
00089 //# </todo>
00090 
00091 
00092 template <class T> class PagedArrIter : public LatticeIterInterface<T>
00093 {
00094 friend class PagedArray<T>;
00095 
00096   //# Make members of parent class known.
00097 protected:
00098   using LatticeIterInterface<T>::rewriteData;
00099   using LatticeIterInterface<T>::itsNavPtr;
00100 
00101 protected:
00102   // Construct the Iterator with the supplied data, and iteration strategy
00103   PagedArrIter (const PagedArray<T>& data, const LatticeNavigator& method,
00104                 Bool useRef);
00105 
00106   // The copy constructor uses reference sematics for the PagedArray and
00107   // copy semantics for the cursor and Navigator. This way the newly
00108   // constructed PagedArrIter can independently iterate through the same
00109   // data set. (with the same cursor shape etc.)
00110   PagedArrIter (const PagedArrIter<T>& other);
00111 
00112   // Destructor (cleans up dangling references and releases cursor memory)
00113   virtual ~PagedArrIter();
00114   
00115   // The assignment operator uses reference sematics for the PagedArray and
00116   // copy semantics for the cursor and Navigator. This way the
00117   // PagedArrIter objects share the same data set but independently iterate
00118   // with cursors of the same size.
00119   PagedArrIter<T>& operator= (const PagedArrIter<T>& other);
00120 
00121   // Clone the object.
00122   virtual LatticeIterInterface<T>* clone() const;
00123 
00124 private:
00125   // Setup the cache in the tiled storage manager.
00126   void setupTileCache();
00127 
00128 
00129   // reference to the PagedArray
00130   PagedArray<T> itsData;
00131 };
00132 
00133 
00134 
00135 } //# NAMESPACE CASACORE - END
00136 
00137 #ifndef CASACORE_NO_AUTO_TEMPLATES
00138 #include <casacore/lattices/Lattices/PagedArrIter.tcc>
00139 #endif //# CASACORE_NO_AUTO_TEMPLATES
00140 #endif
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