/usr/include/casacore/casa/Utilities/LinearSearch.h is in casacore-dev 2.2.0-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 | //# LinearSearch.h: Linear search through linear data structures
//# Copyright (C) 1997,1999
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library 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 Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//# Internet email: aips2-request@nrao.edu.
//# Postal address: AIPS++ Project Office
//# National Radio Astronomy Observatory
//# 520 Edgemont Road
//# Charlottesville, VA 22903-2475 USA
//#
//#
//# $Id$
#ifndef CASA_LINEARSEARCH_H
#define CASA_LINEARSEARCH_H
//# Includes
#include <casacore/casa/aips.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
// <summary>
// Linear search a linear data structure.
// </summary>
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tLinearSearch" demos="">
// </reviewed>
// <synopsis>
// These linear search functions work on linear data structures
// which have operator() or operator[] defined on them (<i>e.g.</i>
// C-array, Vector, IPosition, Block, ScalarColumn, <i>etc.</i>)
// Two versions of the functions are provided, one which uses
// parentheses () for indexing, one which uses square brackets [] (obviously
// the latter one can also be used for ordinary C-style pointers and arrays).
// It is assumed that the container uses zero-based indexing.
//
// The returned index is in the range [0..n-1]. When the value is
// not found, -1 is returned.
// <note role=tip>
// While normally you want to search a container with indices in the range
// <src>[0 ... n-1]</src>, any desired lower bound may be used instead.
// </note>
// <note role=caution>
// Linear searching should only be used for small arrays.
// For larger arrays sort and
// <linkto group=BinarySearch.h#binarysearch>binarySearch</linkto>
// should be used.
// </note>
// </synopsis>
//
// <example>
// <srcblock>
// Vector<Int> vi;
// ... // Sets vi somehow
// Int val;
// Bool found;
// while (cin >> val && val != -999) {
// Int where = linearSearch(found, vi, val, vi.nelements());
// if (found) {
// cout << "Found " << val << " at position " << where << endl;
// } else {
// cout << val << " is not in the vector, but it belongs at " <<
// where << endl;
// }
// }
// </srcblock>
// </example>
//
// <motivation>
// Neil Killeen needed a linear search on a Vector.
// Modelling it after BinarySearch was the logical step to take.
// </motivation>
//
// <templating arg=Container>
// <li> operator(Int) or operator[Int] needs to be defined.
// <li> The index must be zero based.
// <li> The result of that indexing must be an expression that can be
// compared with an object of class ElType. Normally in fact it would
// be a temporary of class ElType.
// <li> Member function nelements() is needed when the shorthand is taken.
// </templating>
// <templating arg=ElType>
// <li> The equal operator (==) need to be defined.
// </templating>
//
// <todo asof="yyyy/mm/dd">
// <li> I suspect that an implementation is possible that only calls
// operator() or [] once during each evaluation of the while loop.
// <li> MACROize implementation so that code isn't repeated twice. Or,
// possibly implement one using the other (e.g. by introducing an adapter
// class that turns (i) into [i].
// </todo>
// <group name=linearsearch>
// Search <i>container</i> for <i>value</i>. There are assumed to be at least
// <i>n</i> elements in the container. The container will be searched for
// indices in the range <src>[lower ... lower + n - 1]</src> Return the index
// of the first element which is greater than or equal to (ascending order) or
// less than or equal to (descending order) the value.
// When not found, -1 is returned and found is set to False.
//# GvD 19971008: The functions need different names, because g++ gives errors
//# when instantiating.
// <group>
// This version of the function is for containers that use () for indexing.
template<class Container, class ElType>
Int linearSearch1 (const Container& container, const ElType& value,
uInt lower = 0);
template<class Container, class ElType>
Int linearSearch (Bool& found, const Container& container,
const ElType& value, uInt n, uInt lower=0);
// This version of the function is for containers that use [] for indexing.
template<class Container, class ElType>
Int linearSearchBrackets1 (const Container& container, const ElType& value,
uInt lower = 0);
template<class Container, class ElType>
Int linearSearchBrackets (Bool& found, const Container& container,
const ElType& value, uInt n, uInt lower=0);
// </group>
// </group>
} //# NAMESPACE CASACORE - END
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/casa/Utilities/LinearSearch.tcc>
#endif //# CASACORE_NO_AUTO_TEMPLATES
#endif
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