summaryrefslogtreecommitdiffstats
blob: 3dca9b65092954a3b02d4f64032d8a08b72c6881 (plain)
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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
// Copyright (c)  2000 David Abrahams. 
// Distributed under the Boost Software License, Version 1.0. 
// (See accompanying file LICENSE_1_0.txt or copy at 
// http://www.boost.org/LICENSE_1_0.txt)
// 
// Copyright (c) 1994
// Hewlett-Packard Company
// 
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation.  Hewlett-Packard Company makes no
// representations about the suitability of this software for any
// purpose.  It is provided "as is" without express or implied warranty.
// 
// Copyright (c) 1996
// Silicon Graphics Computer Systems, Inc.
// 
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation.  Silicon Graphics makes no
// representations about the suitability of this software for any
// purpose.  It is provided "as is" without express or implied warranty.
// 
#ifndef BINARY_SEARCH_DWA_122600_H_
# define BINARY_SEARCH_DWA_122600_H_

# include <boost/detail/iterator.hpp>
# include <utility>

namespace boost { namespace detail {

template <class ForwardIter, class Tp>
ForwardIter lower_bound(ForwardIter first, ForwardIter last,
                             const Tp& val) 
{
    typedef detail::iterator_traits<ForwardIter> traits;
    
    typename traits::difference_type len = boost::detail::distance(first, last);
    typename traits::difference_type half;
    ForwardIter middle;

    while (len > 0) {
      half = len >> 1;
      middle = first;
      std::advance(middle, half);
      if (*middle < val) {
        first = middle;
        ++first;
        len = len - half - 1;
      }
      else
        len = half;
    }
    return first;
}

template <class ForwardIter, class Tp, class Compare>
ForwardIter lower_bound(ForwardIter first, ForwardIter last,
                              const Tp& val, Compare comp)
{
  typedef detail::iterator_traits<ForwardIter> traits;

  typename traits::difference_type len = boost::detail::distance(first, last);
  typename traits::difference_type half;
  ForwardIter middle;

  while (len > 0) {
    half = len >> 1;
    middle = first;
    std::advance(middle, half);
    if (comp(*middle, val)) {
      first = middle;
      ++first;
      len = len - half - 1;
    }
    else
      len = half;
  }
  return first;
}

template <class ForwardIter, class Tp>
ForwardIter upper_bound(ForwardIter first, ForwardIter last,
                           const Tp& val)
{
  typedef detail::iterator_traits<ForwardIter> traits;

  typename traits::difference_type len = boost::detail::distance(first, last);
  typename traits::difference_type half;
  ForwardIter middle;

  while (len > 0) {
    half = len >> 1;
    middle = first;
    std::advance(middle, half);
    if (val < *middle)
      len = half;
    else {
      first = middle;
      ++first;
      len = len - half - 1;
    }
  }
  return first;
}

template <class ForwardIter, class Tp, class Compare>
ForwardIter upper_bound(ForwardIter first, ForwardIter last,
                           const Tp& val, Compare comp)
{
  typedef detail::iterator_traits<ForwardIter> traits;

  typename traits::difference_type len = boost::detail::distance(first, last);
  typename traits::difference_type half;
  ForwardIter middle;

  while (len > 0) {
    half = len >> 1;
    middle = first;
    std::advance(middle, half);
    if (comp(val, *middle))
      len = half;
    else {
      first = middle;
      ++first;
      len = len - half - 1;
    }
  }
  return first;
}

template <class ForwardIter, class Tp>
std::pair<ForwardIter, ForwardIter>
equal_range(ForwardIter first, ForwardIter last, const Tp& val)
{
  typedef detail::iterator_traits<ForwardIter> traits;

  typename traits::difference_type len = boost::detail::distance(first, last);
  typename traits::difference_type half;
  ForwardIter middle, left, right;

  while (len > 0) {
    half = len >> 1;
    middle = first;
    std::advance(middle, half);
    if (*middle < val) {
      first = middle;
      ++first;
      len = len - half - 1;
    }
    else if (val < *middle)
      len = half;
    else {
      left = boost::detail::lower_bound(first, middle, val);
      std::advance(first, len);
      right = boost::detail::upper_bound(++middle, first, val);
      return std::pair<ForwardIter, ForwardIter>(left, right);
    }
  }
  return std::pair<ForwardIter, ForwardIter>(first, first);
}

template <class ForwardIter, class Tp, class Compare>
std::pair<ForwardIter, ForwardIter>
equal_range(ForwardIter first, ForwardIter last, const Tp& val,
              Compare comp)
{
  typedef detail::iterator_traits<ForwardIter> traits;

  typename traits::difference_type len = boost::detail::distance(first, last);
  typename traits::difference_type half;
  ForwardIter middle, left, right;

  while (len > 0) {
    half = len >> 1;
    middle = first;
    std::advance(middle, half);
    if (comp(*middle, val)) {
      first = middle;
      ++first;
      len = len - half - 1;
    }
    else if (comp(val, *middle))
      len = half;
    else {
      left = boost::detail::lower_bound(first, middle, val, comp);
      std::advance(first, len);
      right = boost::detail::upper_bound(++middle, first, val, comp);
      return std::pair<ForwardIter, ForwardIter>(left, right);
    }
  }
  return std::pair<ForwardIter, ForwardIter>(first, first);
}           

template <class ForwardIter, class Tp>
bool binary_search(ForwardIter first, ForwardIter last,
                   const Tp& val) {
  ForwardIter i = boost::detail::lower_bound(first, last, val);
  return i != last && !(val < *i);
}

template <class ForwardIter, class Tp, class Compare>
bool binary_search(ForwardIter first, ForwardIter last,
                   const Tp& val,
                   Compare comp) {
  ForwardIter i = boost::detail::lower_bound(first, last, val, comp);
  return i != last && !comp(val, *i);
}

}} // namespace boost::detail

#endif // BINARY_SEARCH_DWA_122600_H_