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BaseTabIter.h
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1//# BaseTabIter.h: Base class for table iterator
2//# Copyright (C) 1994,1995,1996,1997,1999
3//# Associated Universities, Inc. Washington DC, USA.
4//#
5//# This library is free software; you can redistribute it and/or modify it
6//# under the terms of the GNU Library General Public License as published by
7//# the Free Software Foundation; either version 2 of the License, or (at your
8//# option) any later version.
9//#
10//# This library is distributed in the hope that it will be useful, but WITHOUT
11//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13//# License for more details.
14//#
15//# You should have received a copy of the GNU Library General Public License
16//# along with this library; if not, write to the Free Software Foundation,
17//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18//#
19//# Correspondence concerning AIPS++ should be addressed as follows:
20//# Internet email: aips2-request@nrao.edu.
21//# Postal address: AIPS++ Project Office
22//# National Radio Astronomy Observatory
23//# 520 Edgemont Road
24//# Charlottesville, VA 22903-2475 USA
25//#
26//# $Id$
27
28#ifndef TABLES_BASETABITER_H
29#define TABLES_BASETABITER_H
30
31//# Includes
32#include <casacore/casa/aips.h>
33#include <casacore/tables/Tables/Table.h>
34#include <casacore/casa/Utilities/Compare.h>
35#include <casacore/casa/Containers/Block.h>
36
37namespace casacore { //# NAMESPACE CASACORE - BEGIN
38
39//# Forward Declarations
40class TableColumn;
41class RefTable;
42class String;
43
44
45// <summary>
46// Base class for table iterator
47// </summary>
48
49// <use visibility=local>
50
51// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
52// </reviewed>
53
54// <prerequisite>
55//# Classes you should understand before using this one.
56// <li> BaseTable
57// <li> TableIterator
58// </prerequisite>
59
60// <etymology>
61// BaseTableIterator is the base class for the classes doing
62// the actual iterating through a table.
63// </etymology>
64
65// <synopsis>
66// BaseTableIterator is the base class for the table iterators.
67// It is a letter class of the envelope TableIterator.
68// Currently there are no classes derived from BaseTableIterator,
69// since it can do all the work itself. However, in the future
70// this need not to be true anymore.
71//
72// BaseTableIterator iterates by sorting the table in the required
73// order and then creating a RefTable for each step containing the
74// rows for that iteration step. Each iteration step assembles the
75// rows with equal key values.
76// </synopsis>
77
78//# <todo asof="$DATE:$">
79//# A List of bugs, limitations, extensions or planned refinements.
80//# </todo>
81
82
84{
85public:
86
87 // Create the table iterator to iterate through the given
88 // columns in the given order. The given compare objects
89 // will be used for the sort and to compare if values are equal.
90 // If a compare object in cmpObjs is null, the default ObjCompare<T>
91 // will be used.
92 // If cacheIterationBoundaries is set to true then the iteration
93 // boundaries computed at construction time while sorting the table
94 // are used when advancing with next(). Otherwise, for each next()
95 // call the comparison functions are reevaluated again to get the
96 // iteration boundary. This improves performance in general but will
97 // break existing applications that change the comparison objects
98 // (cmpObjs) between iterations.
100 const Block<CountedPtr<BaseCompare> >& cmpObjs,
101 const Block<Int>& orders,
102 int option,
103 bool cacheIterationBoundaries = false);
104
105 // Clone this iterator.
107
109
110 // Reset the iterator (i.e. restart iteration).
111 virtual void reset();
112
113 // Return the next group.
114 virtual BaseTable* next();
115
116 virtual void copyState(const BaseTableIterator &);
117
118 // Report Name of slowest sort column that changed (according to the
119 // comparison function) to terminate the most recent call to next()
120 // Enables clients to sense iteration boundary properties
121 // and organize associated iterations
122 inline const String& keyChangeAtLastNext() const { return keyChangeAtLastNext_p; };
123
124protected:
125 BaseTable* sortTab_p; //# Table sorted in iteration order
126 rownr_t lastRow_p; //# last row used from reftab
127 uInt nrkeys_p; //# nr of columns in group
128 String keyChangeAtLastNext_p; //# name of column that terminated most recent next()
129 PtrBlock<BaseColumn*> colPtr_p; //# pointer to column objects
130 Block<CountedPtr<BaseCompare> > cmpObj_p; //# comparison object per column
131
132 // Copy constructor (to be used by clone)
134
136
137private:
138 // Assignment is not needed, because the assignment operator in
139 // the envelope class TableIterator has reference semantics.
140 // Declaring it private, makes it unusable.
142
143 Block<void*> lastVal_p; //# last value per column
144 Block<void*> curVal_p; //# current value per column
145
146 std::shared_ptr<Vector<rownr_t>> sortIterBoundaries_p;
147 std::shared_ptr<Vector<size_t>> sortIterKeyIdxChange_p;
151};
152
153
154
155} //# NAMESPACE CASACORE - END
156
157#endif
const String & keyChangeAtLastNext() const
Report Name of slowest sort column that changed (according to the comparison function) to terminate t...
BaseTableIterator(const BaseTableIterator &)
Copy constructor (to be used by clone)
std::shared_ptr< Vector< size_t > > sortIterKeyIdxChange_p
Vector< rownr_t >::iterator sortIterBoundariesIt_p
virtual void copyState(const BaseTableIterator &)
virtual BaseTable * next()
Return the next group.
PtrBlock< BaseColumn * > colPtr_p
BaseTableIterator & operator=(const BaseTableIterator &)
Assignment is not needed, because the assignment operator in the envelope class TableIterator has ref...
Vector< size_t >::iterator sortIterKeyIdxChangeIt_p
std::shared_ptr< Vector< rownr_t > > sortIterBoundaries_p
BaseTableIterator * clone() const
Clone this iterator.
BaseTableIterator(BaseTable *, const Block< String > &columnNames, const Block< CountedPtr< BaseCompare > > &cmpObjs, const Block< Int > &orders, int option, bool cacheIterationBoundaries=false)
Create the table iterator to iterate through the given columns in the given order.
Block< CountedPtr< BaseCompare > > cmpObj_p
virtual void reset()
Reset the iterator (i.e.
BaseTable * noCachedIterBoundariesNext()
simple 1-D array
Definition Block.h:200
Referenced counted pointer for constant data.
Definition CountedPtr.h:81
A drop-in replacement for Block<T*>.
Definition Block.h:814
String: the storage and methods of handling collections of characters.
Definition String.h:225
this file contains all the compiler specific defines
Definition mainpage.dox:28
unsigned int uInt
Definition aipstype.h:51
uInt64 rownr_t
Define the type of a row number in a table.
Definition aipsxtype.h:46