60 lines
1.9 KiB
C
60 lines
1.9 KiB
C
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/* C++ implementation of a binary search.
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Copyright (C) 2019-2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef GDBSUPPORT_GDB_BINARY_SEARCH_H
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#define GDBSUPPORT_GDB_BINARY_SEARCH_H
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#include <algorithm>
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namespace gdb {
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/* Implements a binary search using C++ iterators.
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This differs from std::binary_search in that it returns an iterator for
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the found element and in that the type of EL can be different from the
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type of the elements in the container.
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COMP is a C-style comparison function with signature:
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int comp(const value_type& a, const T& b);
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It should return -1, 0 or 1 if a is less than, equal to, or greater than
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b, respectively.
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[first, last) must be sorted.
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The return value is an iterator pointing to the found element, or LAST if
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no element was found. */
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template<typename It, typename T, typename Comp>
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It binary_search (It first, It last, T el, Comp comp)
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{
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auto lt = [&] (const typename std::iterator_traits<It>::value_type &a,
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const T &b)
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{ return comp (a, b) < 0; };
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auto lb = std::lower_bound (first, last, el, lt);
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if (lb != last)
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{
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if (comp (*lb, el) == 0)
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return lb;
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}
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return last;
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}
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} /* namespace gdb */
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#endif /* GDBSUPPORT_GDB_BINARY_SEARCH_H */
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