summaryrefslogtreecommitdiff
path: root/include/o3tl/range.hxx
blob: 1a28784a41bdd5146d400204649ea6c2bd8c8ac1 (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
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#ifndef INCLUDED_O3TL_RANGE_HXX
#define INCLUDED_O3TL_RANGE_HXX


#include <cstring>
#include <boost/assert.hpp>



namespace o3tl
{
/** Represents a range of integer or iterator values.

    @tpl T
    Has to be assignable, add- and subtractable. That is:
    either it is
        - an integral type
        - or a random access iterator.
*/
template <class T>
class range
{
  public:
    typedef T           element_type;       /// Provided for generic programming.
    typedef range<T>    self;

  // LIFECYCLE
                        range(
                            T                   i_inclusiveLowerBorder,
                            T                   i_exclusiveUpperBorder );
                        ~range();
  // INQUIRY
    T                   begin() const;
    T                   end() const;
    std::size_t         size() const;

    bool                contains(
                            T                   i_value ) const;
    bool                contains(
                            const self &        i_other ) const;
    bool                overlaps(
                            const self &        i_other ) const;
    /// @return i_other.begin() - this->end()
    long                distance_to(
                            const self &        i_other ) const;
  private:
  // DATA
    T                   nBegin;
    T                   nEnd;
};


template <class T>
inline range<T>
make_range(T i1, T i2)
{
    return range<T>(i1, i2);
}

template <class T>
inline range<typename T::const_iterator>
range_of(const T & i_container)
{
    return make_range( i_container.begin(),
                       i_container.end()
                     );
}

template <class T>
inline range<typename T::iterator>
range_of(T & io_container)
{
    return make_range( io_container.begin(),
                       io_container.end()
                     );
}





// IMPLEMENTATION

template <class T>
range<T>::range( T i_inclusiveLowerBorder,
                 T i_exclusiveUpperBorder )
    :   nBegin(i_inclusiveLowerBorder),
        nEnd(i_exclusiveUpperBorder)
{
    BOOST_ASSERT(   nBegin <= nEnd
                 && "Invalid parameters for range<> constructor.");
}

template <class T>
range<T>::~range()
{
}

template <class T>
inline T
range<T>::begin() const
{
    return nBegin;
}

template <class T>
inline T
range<T>::end() const
{
    return nEnd;
}

template <class T>
inline std::size_t
range<T>::size() const
{
    BOOST_ASSERT(   nBegin <= nEnd
                 && "Invalid range limits in range<>::size().");
    return static_cast<std::size_t>( end() - begin() );
}

template <class T>
bool
range<T>::contains(T i_value ) const
{
    return      begin() <= i_value
            &&  i_value < end();
}

template <class T>
bool
range<T>::contains(const self & i_other) const
{
    // This is subtle, because this would be wrong:
    //      begin() <= i_other.begin()
    //      &&  i_other.end() <= end();
    // An empty range that begins and starts at my end()
    // must not be contained.

    return      contains(i_other.begin())
            &&  i_other.end() <= end();
}

template <class T>
bool
range<T>::overlaps(const self & i_other) const
{
    return      contains(i_other.begin())
            ||  i_other.contains(begin());
}

template <class T>
long
range<T>::distance_to(const self & i_other) const
{
    return i_other.begin() - end();
}



}   // namespace o3tl
#endif

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */