casacore
ExprRange.h
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1//# ExprRange.h: Select range of a column in an select expression
2//# Copyright (C) 1994,1995,1999
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_EXPRRANGE_H
29#define TABLES_EXPRRANGE_H
30
31//# Includes
32#include <casacore/casa/aips.h>
33#include <casacore/casa/Arrays/Vector.h>
34
35namespace casacore { //# NAMESPACE CASACORE - BEGIN
36
37//# Forward Declarations
38class TableColumn;
39
40
41// <summary>
42// Select range of a column in an select expression
43// </summary>
44
45// <use visibility=local>
46
47// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
48// </reviewed>
49
50// <prerequisite>
51//# Classes you should understand before using this one.
52// <li> TableExprNode
53// </prerequisite>
54
55// <etymology>
56// TableExprRange represents the ranges of a column as specified in
57// a table select expression.
58// </etymology>
59
60// <synopsis>
61// TableExprRange holds the ranges of values for a column as specified
62// in a table select expression.
63// It traverses the expression tree and composes the hull of the values.
64// Only double values are taken into account.
65// It can handle operators &&, ||, ==, >, >=, <, <=, !.
66// It can handle a comparison operator only for a column with a constant.
67// Other operators and expressions are non-convertable.
68//
69// The ranges function in class TableExprNode returns a Block
70// of TableExprRange objects which contains the ranges for each
71// (applicable) column used in the expression.
72// </synopsis>
73
74// <motivation>
75// TableExprRange gives great possibilities in optimizing a table
76// selection. It allows to get a rough estimate of the values needed
77// for a column which can be used to do a fast preselect using an index.
78// </motivation>
79
80// <todo asof="$DATE:$">
81//# A List of bugs, limitations, extensions or planned refinements.
82// <li> Support other data types than double
83// <li> Recognize that 2*COL<3 is equal to COL<3/2
84// </todo>
85
86
88{
89public:
90 // Default constructor (needed for Block<TableExprRange>).
92
93 // Construct from a column and a single constant range.
94 TableExprRange (const TableColumn&, double stval, double endval);
95
96 // Copy constructor.
98
100
101 // Assignment operator (copy semantics).
103
104 // Return the vector of start values.
105 // Together with the equally sized vector of end values, this forms
106 // the ranges for the column (which can be acquired using getColumn).
107 const Vector<double>& start() const;
108
109 // Return the vector of end values.
110 // Together with the equally sized vector of start values, this forms
111 // the ranges for the column (which can be acquired using getColumn).
112 const Vector<double>& end() const;
113
114 // Return the column object.
115 const TableColumn& getColumn() const;
116
117 //*display 4
118 // Mix with another range for an AND expression.
119 void mixAnd (const TableExprRange&);
120
121 //*display 4
122 // Mix with another range for an OR expression.
123 void mixOr (const TableExprRange&);
124
125private:
126 Vector<double> sval_p; //# start values
127 Vector<double> eval_p; //# end values
128 TableColumn* tabColPtr_p; //# pointer to column
129};
130
131
133 { return sval_p; }
135 { return eval_p; }
136
137
138
139} //# NAMESPACE CASACORE - END
140
141#endif
TableExprRange(const TableExprRange &)
Copy constructor.
void mixOr(const TableExprRange &)
TableColumn * tabColPtr_p
Definition: ExprRange.h:128
Vector< double > sval_p
Definition: ExprRange.h:126
const TableColumn & getColumn() const
Return the column object.
TableExprRange()
Default constructor (needed for Block<TableExprRange>).
TableExprRange(const TableColumn &, double stval, double endval)
Construct from a column and a single constant range.
TableExprRange & operator=(const TableExprRange &)
Assignment operator (copy semantics).
Vector< double > eval_p
Definition: ExprRange.h:127
void mixAnd(const TableExprRange &)
const Vector< double > & end() const
Return the vector of end values.
Definition: ExprRange.h:134
const Vector< double > & start() const
Return the vector of start values.
Definition: ExprRange.h:132
this file contains all the compiler specific defines
Definition: mainpage.dox:28