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Jeff Thompson86b6d642013-10-17 15:01:56 -07001// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
2// (C) Copyright 2003-2007 Jonathan Turkanis
3// Distributed under the Boost Software License, Version 1.0. (See accompanying
4// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
5
6// See http://www.boost.org/libs/iostreams for documentation.
7
8#ifndef NDNBOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED
9#define NDNBOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED
10
11#if defined(_MSC_VER) && (_MSC_VER >= 1020)
12# pragma once
13#endif
14
15#include <algorithm> // min.
16#include <ndnboost/assert.hpp>
17#include <cstddef> // ptrdiff_t.
18#include <iosfwd> // streamsize, streamoff.
19#include <ndnboost/detail/iterator.hpp> // ndnboost::iterator_traits.
20#include <ndnboost/iostreams/categories.hpp>
21#include <ndnboost/iostreams/detail/error.hpp>
22#include <ndnboost/iostreams/positioning.hpp>
23#include <ndnboost/mpl/if.hpp>
24#include <ndnboost/throw_exception.hpp>
25#include <ndnboost/type_traits/is_convertible.hpp>
26#include <ndnboost/utility/enable_if.hpp>
27
28// Must come last.
29#include <ndnboost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
30
31namespace ndnboost { namespace iostreams { namespace detail {
32
33// Used for simulated tag dispatch.
34template<typename Traversal> struct range_adapter_impl;
35
36//
37// Template name: range_adapter
38// Description: Device based on an instance of ndnboost::iterator_range.
39// Template parameters:
40// Mode - A mode tag.
41// Range - An instance of iterator_range.
42//
43template<typename Mode, typename Range>
44class range_adapter {
45private:
46 typedef typename Range::iterator iterator;
47 typedef ndnboost::detail::iterator_traits<iterator> iter_traits;
48 typedef typename iter_traits::iterator_category iter_cat;
49public:
50 typedef typename Range::value_type char_type;
51 struct category : Mode, device_tag { };
52 typedef typename
53 mpl::if_<
54 is_convertible<
55 iter_cat,
56 std::random_access_iterator_tag
57 >,
58 std::random_access_iterator_tag,
59 std::forward_iterator_tag
60 >::type tag;
61 typedef range_adapter_impl<tag> impl;
62
63 explicit range_adapter(const Range& rng);
64 range_adapter(iterator first, iterator last);
65 std::streamsize read(char_type* s, std::streamsize n);
66 std::streamsize write(const char_type* s, std::streamsize n);
67 std::streampos seek(stream_offset off, NDNBOOST_IOS::seekdir way);
68private:
69 iterator first_, cur_, last_;
70};
71
72//------------------Implementation of range_adapter---------------------------//
73
74template<typename Mode, typename Range>
75range_adapter<Mode, Range>::range_adapter(const Range& rng)
76 : first_(rng.begin()), cur_(rng.begin()), last_(rng.end()) { }
77
78template<typename Mode, typename Range>
79range_adapter<Mode, Range>::range_adapter(iterator first, iterator last)
80 : first_(first), cur_(first), last_(last) { }
81
82template<typename Mode, typename Range>
83inline std::streamsize range_adapter<Mode, Range>::read
84 (char_type* s, std::streamsize n)
85{ return impl::read(cur_, last_, s, n); }
86
87template<typename Mode, typename Range>
88inline std::streamsize range_adapter<Mode, Range>::write
89 (const char_type* s, std::streamsize n)
90{ return impl::write(cur_, last_, s, n); }
91
92
93template<typename Mode, typename Range>
94std::streampos range_adapter<Mode, Range>::seek
95 (stream_offset off, NDNBOOST_IOS::seekdir way)
96{
97 impl::seek(first_, cur_, last_, off, way);
98 return offset_to_position(cur_ - first_);
99}
100
101//------------------Implementation of range_adapter_impl----------------------//
102
103template<>
104struct range_adapter_impl<std::forward_iterator_tag> {
105 template<typename Iter, typename Ch>
106 static std::streamsize read
107 (Iter& cur, Iter& last, Ch* s,std::streamsize n)
108 {
109 std::streamsize rem = n; // No. of chars remaining.
110 while (cur != last && rem-- > 0) *s++ = *cur++;
111 return n - rem != 0 ? n - rem : -1;
112 }
113
114 template<typename Iter, typename Ch>
115 static std::streamsize write
116 (Iter& cur, Iter& last, const Ch* s, std::streamsize n)
117 {
118 while (cur != last && n-- > 0) *cur++ = *s++;
119 if (cur == last && n > 0)
120 ndnboost::throw_exception(write_area_exhausted());
121 return n;
122 }
123};
124
125template<>
126struct range_adapter_impl<std::random_access_iterator_tag> {
127 template<typename Iter, typename Ch>
128 static std::streamsize read
129 (Iter& cur, Iter& last, Ch* s,std::streamsize n)
130 {
131 std::streamsize result =
132 (std::min)(static_cast<std::streamsize>(last - cur), n);
133 if (result)
134 std::copy(cur, cur + result, s);
135 cur += result;
136 return result != 0 ? result : -1;
137 }
138
139 template<typename Iter, typename Ch>
140 static std::streamsize write
141 (Iter& cur, Iter& last, const Ch* s, std::streamsize n)
142 {
143 std::streamsize count =
144 (std::min)(static_cast<std::streamsize>(last - cur), n);
145 std::copy(s, s + count, cur);
146 cur += count;
147 if (count < n)
148 ndnboost::throw_exception(write_area_exhausted());
149 return n;
150 }
151
152 template<typename Iter>
153 static void seek
154 ( Iter& first, Iter& cur, Iter& last, stream_offset off,
155 NDNBOOST_IOS::seekdir way )
156 {
157 using namespace std;
158 switch (way) {
159 case NDNBOOST_IOS::beg:
160 if (off > last - first || off < 0)
161 ndnboost::throw_exception(bad_seek());
162 cur = first + off;
163 break;
164 case NDNBOOST_IOS::cur:
165 {
166 std::ptrdiff_t newoff = cur - first + off;
167 if (newoff > last - first || newoff < 0)
168 ndnboost::throw_exception(bad_seek());
169 cur += off;
170 break;
171 }
172 case NDNBOOST_IOS::end:
173 if (last - first + off < 0 || off > 0)
174 ndnboost::throw_exception(bad_seek());
175 cur = last + off;
176 break;
177 default:
178 NDNBOOST_ASSERT(0);
179 }
180 }
181};
182
183} } } // End namespaces detail, iostreams, boost.
184
185#include <ndnboost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
186
187#endif // #ifndef NDNBOOST_IOSTREAMS_DETAIL_RANGE_ADAPTER_HPP_INCLUDED //---------------//