Line data    Source code

       1             : //# Copyright (C) 2019
       2             : //# Associated Universities, Inc. Washington DC, USA.
       3             : //#
       4             : //# This library is free software; you can redistribute it and/or modify it
       5             : //# under the terms of the GNU Library General Public License as published by
       6             : //# the Free Software Foundation; either version 2 of the License, or (at your
       7             : //# option) any later version.
       8             : //#
       9             : //# This library is distributed in the hope that it will be useful, but WITHOUT
      10             : //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      11             : //# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
      12             : //# License for more details.
      13             : //#
      14             : //# You should have received a copy of the GNU Library General Public License
      15             : //# along with this library; if not, write to the Free Software Foundation,
      16             : //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
      17             : //#
      18             : //# Correspondence concerning AIPS++ should be addressed as follows:
      19             : //#        Internet email: casa-feedback@nrao.edu.
      20             : //#        Postal address: AIPS++ Project Office
      21             : //#                        National Radio Astronomy Observatory
      22             : //#                        520 Edgemont Road
      23             : //#                        Charlottesville, VA 22903-2475 USA
      24             : //#
      25             : 
      26             : #ifndef MS2ASDM_MAPWITHHDEFAULT_H
      27             : #define MS2ASDM_MAPWITHHDEFAULT_H
      28             : 
      29             : #include <map>
      30             : 
      31             : #include <casacore/casa/aips.h>
      32             : 
      33             : namespace casa { //# NAMESPACE CASA - BEGIN
      34             : 
      35             :     // <summary>
      36             :     // MapWithDefault adds a default value to the std::map class. This default value
      37             :     // is used by the [] operator when the key is not already known.
      38             :     // <summary>
      39             :     
      40             :     // <visibility=export>
      41             : 
      42             :     // <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">
      43             :     // </reviewed>
      44             : 
      45             :     // <prerequisite>
      46             :     //   <li> std::map
      47             :     // </prerequisite>
      48             :     // <etymology>
      49             :     // </etymology>
      50             :     //
      51             :     // <synopsis>
      52             :     // </synopsis>
      53             : 
      54             :     template<class K, class V> class MapWithDefault : public std::map<K,V>
      55             :     {
      56             :     public:
      57             :         // creates a std::map with the associated specified defaultt value
      58           0 :         MapWithDefault (const V& defaultValue) : std::map<K,V>(), defaultVal(defaultValue) {;}
      59             :         
      60             :         // creates a map with default from another one; use copy semantics.
      61             :         MapWithDefault (const MapWithDefault<K,V>& other) : std::map<K,V>(other), defaultVal(other.defaultVal) {;}
      62             : 
      63             :         // Removes a map with default.
      64           0 :         ~MapWithDefault () {;}
      65             : 
      66             :         // Assigns this map with default to another one; copy semantics
      67             :         MapWithDefault<K,V>& operator= (const MapWithDefault<K,V>& other);
      68             : 
      69             :         // this is the specialization which uses the default value as necessary.
      70             :         // If the map from the key to a value is not defined a mapping will
      71             :         // be defined from the key to the default value.
      72             :         V &operator[](const K &key);
      73             : 
      74             :     private:
      75             :         V defaultVal;
      76             :     };
      77             : 
      78             :     template<class K, class V> inline MapWithDefault<K,V> &MapWithDefault<K,V>::operator=(const MapWithDefault<K,V> &other) \
      79             :     {
      80             :         if (this != other) {
      81             :             std::map<K,V>::operator=(*other);
      82             :             this->defaultVal = other->defaultVal;
      83             :         }
      84             :         return this;
      85             :     }
      86             : 
      87           0 :     template<class K, class V> inline V &MapWithDefault<K,V>::operator[](const K &key)
      88             :     {
      89           0 :         if (this->count(key) == 0) {
      90           0 :             std::map<K,V>::operator[](key) = this->defaultVal;
      91             :         }
      92           0 :         return this->at(key);
      93             :     }
      94             :     
      95             : } // # NAMESPACE CASA - END
      96             : 
      97             : #endif