1 | // (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 | // Thanks to Gareth Sylvester-Bradley for the Dinkumware versions of the |
9 | // positioning functions. |
10 | |
11 | #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED |
12 | #define BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED |
13 | |
14 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
15 | # pragma once |
16 | #endif |
17 | |
18 | #include <boost/config.hpp> |
19 | #include <boost/cstdint.hpp> |
20 | #include <boost/integer_traits.hpp> |
21 | #include <boost/iostreams/detail/config/codecvt.hpp> // mbstate_t. |
22 | #include <boost/iostreams/detail/config/fpos.hpp> |
23 | #include <boost/iostreams/detail/ios.hpp> // streamoff, streampos. |
24 | |
25 | // Must come last. |
26 | #include <boost/iostreams/detail/config/disable_warnings.hpp> |
27 | |
28 | #ifdef BOOST_NO_STDC_NAMESPACE |
29 | namespace std { using ::fpos_t; } |
30 | #endif |
31 | |
32 | namespace boost { namespace iostreams { |
33 | |
34 | //------------------Definition of stream_offset-------------------------------// |
35 | |
36 | typedef boost::intmax_t stream_offset; |
37 | |
38 | //------------------Definition of stream_offset_to_streamoff------------------// |
39 | |
40 | inline std::streamoff stream_offset_to_streamoff(stream_offset off) |
41 | { return static_cast<stream_offset>(off); } |
42 | |
43 | //------------------Definition of offset_to_position--------------------------// |
44 | |
45 | # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
46 | |
47 | inline std::streampos offset_to_position(stream_offset off) { return off; } |
48 | |
49 | # else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
50 | |
51 | inline std::streampos offset_to_position(stream_offset off) |
52 | { return std::streampos(std::mbstate_t(), off); } |
53 | |
54 | # endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
55 | |
56 | //------------------Definition of position_to_offset--------------------------// |
57 | |
58 | // Hande custom pos_type's |
59 | template<typename PosType> |
60 | inline stream_offset position_to_offset(PosType pos) |
61 | { return std::streamoff(pos); } |
62 | |
63 | # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
64 | |
65 | inline stream_offset position_to_offset(std::streampos pos) { return pos; } |
66 | |
67 | # else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
68 | |
69 | // In the Dinkumware standard library, a std::streampos consists of two stream |
70 | // offsets -- _Fpos, of type std::fpos_t, and _Myoff, of type std::streamoff -- |
71 | // together with a conversion state. A std::streampos is converted to a |
72 | // boost::iostreams::stream_offset by extracting the two stream offsets and |
73 | // summing them. The value of _Fpos can be extracted using the implementation- |
74 | // defined member functions seekpos() or get_fpos_t(), depending on the |
75 | // Dinkumware version. The value of _Myoff cannot be extracted directly, but can |
76 | // be calculated as the difference between the result of converting the |
77 | // std::fpos to a std::streamoff and the result of converting the member _Fpos |
78 | // to a long. The latter operation is accomplished with the macro _FPOSOFF, |
79 | // which works correctly on platforms where std::fpos_t is an integral type and |
80 | // platforms where it is a struct |
81 | |
82 | // Converts a std::fpos_t to a stream_offset |
83 | inline stream_offset fpos_t_to_offset(std::fpos_t pos) |
84 | { |
85 | # if defined(_POSIX_) || (_INTEGRAL_MAX_BITS >= 64) || defined(__IBMCPP__) |
86 | return pos; |
87 | # else |
88 | return _FPOSOFF(pos); |
89 | # endif |
90 | } |
91 | |
92 | // Extracts the member _Fpos from a std::fpos |
93 | inline std::fpos_t streampos_to_fpos_t(std::streampos pos) |
94 | { |
95 | # if defined (_CPPLIB_VER) || defined(__IBMCPP__) |
96 | return pos.seekpos(); |
97 | # else |
98 | return pos.get_fpos_t(); |
99 | # endif |
100 | } |
101 | |
102 | inline stream_offset position_to_offset(std::streampos pos) |
103 | { |
104 | return fpos_t_to_offset(streampos_to_fpos_t(pos)) + |
105 | static_cast<stream_offset>( |
106 | static_cast<std::streamoff>(pos) - |
107 | _FPOSOFF(streampos_to_fpos_t(pos)) |
108 | ); |
109 | } |
110 | |
111 | # endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS |
112 | |
113 | } } // End namespaces iostreams, boost. |
114 | |
115 | #include <boost/iostreams/detail/config/enable_warnings.hpp> |
116 | |
117 | #endif // #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED |
118 | |