1// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
2// (C) Copyright 2005-2007 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 BOOST_IOSTREAMS_EXAMPLE_CONTAINTER_DEVICE_HPP_INCLUDED
9#define BOOST_IOSTREAMS_EXAMPLE_CONTAINTER_DEVICE_HPP_INCLUDED
10
11#include <algorithm> // copy, min.
12#include <cassert>
13#include <boost/config.hpp> // BOOST_NO_STDC_NAMESPACE.
14#include <boost/iostreams/categories.hpp>
15#include <boost/iostreams/detail/ios.hpp> // failure.
16
17// Must come last.
18#include <boost/iostreams/detail/config/disable_warnings.hpp>
19
20namespace boost { namespace iostreams { namespace example {
21
22//
23// Model of Source which reads from an STL-compatible sequence
24// whose iterators are random-access iterators.
25//
26template<typename Container>
27class container_source {
28public:
29 typedef typename Container::value_type char_type;
30 typedef source_tag category;
31 container_source(Container& container)
32 : container_(container), pos_(0)
33 { }
34 std::streamsize read(char_type* s, std::streamsize n)
35 {
36 using namespace std;
37 std::streamsize amt =
38 static_cast<std::streamsize>(container_.size() - pos_);
39 std::streamsize result = (min)(a: n, b: amt);
40 if (result != 0) {
41 std::copy( container_.begin() + pos_,
42 container_.begin() + pos_ + result,
43 s );
44 pos_ += result;
45 return result;
46 } else {
47 return -1; // EOF
48 }
49 }
50 Container& container() { return container_; }
51private:
52 container_source operator=(const container_source&);
53 typedef typename Container::size_type size_type;
54 Container& container_;
55 size_type pos_;
56};
57
58//
59// Model of Sink which appends to an STL-compatible sequence.
60//
61template<typename Container>
62class container_sink {
63public:
64 typedef typename Container::value_type char_type;
65 typedef sink_tag category;
66 container_sink(Container& container) : container_(container) { }
67 std::streamsize write(const char_type* s, std::streamsize n)
68 {
69 container_.insert(container_.end(), s, s + n);
70 return n;
71 }
72 Container& container() { return container_; }
73private:
74 container_sink operator=(const container_sink&);
75 Container& container_;
76};
77
78//
79// Model of SeekableDevice which accessS an TL-compatible sequence
80// whose iterators are random-access iterators.
81//
82template<typename Container>
83class container_device {
84public:
85 typedef typename Container::value_type char_type;
86 typedef seekable_device_tag category;
87 container_device(Container& container)
88 : container_(container), pos_(0)
89 { }
90
91 std::streamsize read(char_type* s, std::streamsize n)
92 {
93 using namespace std;
94 std::streamsize amt =
95 static_cast<std::streamsize>(container_.size() - pos_);
96 std::streamsize result = (min)(a: n, b: amt);
97 if (result != 0) {
98 std::copy( container_.begin() + pos_,
99 container_.begin() + pos_ + result,
100 s );
101 pos_ += result;
102 return result;
103 } else {
104 return -1; // EOF
105 }
106 }
107 std::streamsize write(const char_type* s, std::streamsize n)
108 {
109 using namespace std;
110 std::streamsize result = 0;
111 if (pos_ != container_.size()) {
112 std::streamsize amt =
113 static_cast<std::streamsize>(container_.size() - pos_);
114 result = (min)(a: n, b: amt);
115 std::copy(s, s + result, container_.begin() + pos_);
116 pos_ += result;
117 }
118 if (result < n) {
119 container_.insert(container_.end(), s, s + n);
120 pos_ = container_.size();
121 }
122 return n;
123 }
124 stream_offset seek(stream_offset off, BOOST_IOS::seekdir way)
125 {
126 using namespace std;
127
128 // Determine new value of pos_
129 stream_offset next;
130 if (way == BOOST_IOS::beg) {
131 next = off;
132 } else if (way == BOOST_IOS::cur) {
133 next = pos_ + off;
134 } else if (way == BOOST_IOS::end) {
135 next = container_.size() + off - 1;
136 } else {
137 throw BOOST_IOSTREAMS_FAILURE("bad seek direction");
138 }
139
140 // Check for errors
141 if (next < 0 || next > static_cast<stream_offset>(container_.size()))
142 throw BOOST_IOSTREAMS_FAILURE("bad seek offset");
143
144 pos_ = next;
145 return pos_;
146 }
147
148 Container& container() { return container_; }
149private:
150 container_device operator=(const container_device&);
151 typedef typename Container::size_type size_type;
152 Container& container_;
153 size_type pos_;
154};
155
156} } } // End namespaces example, iostreams, boost.
157
158#include <boost/iostreams/detail/config/enable_warnings.hpp>
159
160#endif // #ifndef BOOST_IOSTREAMS_EXAMPLE_CONTAINTER_DEVICE_HPP_INCLUDED
161

source code of boost/libs/iostreams/example/container_device.hpp