217 lines
6.2 KiB
C++
217 lines
6.2 KiB
C++
// Copyright (c) 2000 David Abrahams.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// Copyright (c) 1994
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// Hewlett-Packard Company
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//
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// Permission to use, copy, modify, distribute and sell this software
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// and its documentation for any purpose is hereby granted without fee,
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// provided that the above copyright notice appear in all copies and
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// that both that copyright notice and this permission notice appear
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// in supporting documentation. Hewlett-Packard Company makes no
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// representations about the suitability of this software for any
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// purpose. It is provided "as is" without express or implied warranty.
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//
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// Copyright (c) 1996
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// Silicon Graphics Computer Systems, Inc.
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//
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// Permission to use, copy, modify, distribute and sell this software
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// and its documentation for any purpose is hereby granted without fee,
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// provided that the above copyright notice appear in all copies and
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// that both that copyright notice and this permission notice appear
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// in supporting documentation. Silicon Graphics makes no
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// representations about the suitability of this software for any
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// purpose. It is provided "as is" without express or implied warranty.
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//
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#ifndef BINARY_SEARCH_DWA_122600_H_
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# define BINARY_SEARCH_DWA_122600_H_
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# include <boost/detail/iterator.hpp>
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# include <utility>
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namespace boost { namespace detail {
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template <class ForwardIter, class Tp>
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ForwardIter lower_bound(ForwardIter first, ForwardIter last,
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const Tp& val)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (*middle < val) {
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first = middle;
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++first;
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len = len - half - 1;
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}
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else
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len = half;
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}
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return first;
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}
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template <class ForwardIter, class Tp, class Compare>
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ForwardIter lower_bound(ForwardIter first, ForwardIter last,
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const Tp& val, Compare comp)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (comp(*middle, val)) {
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first = middle;
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++first;
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len = len - half - 1;
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}
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else
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len = half;
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}
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return first;
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}
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template <class ForwardIter, class Tp>
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ForwardIter upper_bound(ForwardIter first, ForwardIter last,
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const Tp& val)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (val < *middle)
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len = half;
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else {
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first = middle;
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++first;
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len = len - half - 1;
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}
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}
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return first;
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}
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template <class ForwardIter, class Tp, class Compare>
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ForwardIter upper_bound(ForwardIter first, ForwardIter last,
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const Tp& val, Compare comp)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (comp(val, *middle))
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len = half;
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else {
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first = middle;
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++first;
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len = len - half - 1;
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}
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}
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return first;
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}
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template <class ForwardIter, class Tp>
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std::pair<ForwardIter, ForwardIter>
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equal_range(ForwardIter first, ForwardIter last, const Tp& val)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle, left, right;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (*middle < val) {
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first = middle;
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++first;
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len = len - half - 1;
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}
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else if (val < *middle)
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len = half;
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else {
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left = boost::detail::lower_bound(first, middle, val);
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std::advance(first, len);
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right = boost::detail::upper_bound(++middle, first, val);
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return std::pair<ForwardIter, ForwardIter>(left, right);
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}
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}
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return std::pair<ForwardIter, ForwardIter>(first, first);
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}
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template <class ForwardIter, class Tp, class Compare>
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std::pair<ForwardIter, ForwardIter>
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equal_range(ForwardIter first, ForwardIter last, const Tp& val,
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Compare comp)
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{
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typedef detail::iterator_traits<ForwardIter> traits;
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typename traits::difference_type len = boost::detail::distance(first, last);
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typename traits::difference_type half;
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ForwardIter middle, left, right;
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while (len > 0) {
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half = len >> 1;
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middle = first;
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std::advance(middle, half);
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if (comp(*middle, val)) {
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first = middle;
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++first;
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len = len - half - 1;
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}
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else if (comp(val, *middle))
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len = half;
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else {
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left = boost::detail::lower_bound(first, middle, val, comp);
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std::advance(first, len);
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right = boost::detail::upper_bound(++middle, first, val, comp);
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return std::pair<ForwardIter, ForwardIter>(left, right);
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}
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}
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return std::pair<ForwardIter, ForwardIter>(first, first);
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}
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template <class ForwardIter, class Tp>
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bool binary_search(ForwardIter first, ForwardIter last,
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const Tp& val) {
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ForwardIter i = boost::detail::lower_bound(first, last, val);
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return i != last && !(val < *i);
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}
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template <class ForwardIter, class Tp, class Compare>
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bool binary_search(ForwardIter first, ForwardIter last,
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const Tp& val,
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Compare comp) {
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ForwardIter i = boost::detail::lower_bound(first, last, val, comp);
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return i != last && !comp(val, *i);
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}
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}} // namespace boost::detail
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#endif // BINARY_SEARCH_DWA_122600_H_
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