1 | // ---------------------------------------------------------------------------- |
2 | // internals.hpp : internal structs : stream_format_state, format_item. |
3 | // included by format.hpp |
4 | // ---------------------------------------------------------------------------- |
5 | |
6 | // Copyright Samuel Krempp 2003. Use, modification, and distribution are |
7 | // subject to the Boost Software License, Version 1.0. (See accompanying |
8 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
9 | |
10 | // See http://www.boost.org/libs/format for library home page |
11 | |
12 | // ---------------------------------------------------------------------------- |
13 | |
14 | #ifndef BOOST_FORMAT_INTERNALS_HPP |
15 | #define BOOST_FORMAT_INTERNALS_HPP |
16 | |
17 | |
18 | #include <string> |
19 | #include <boost/assert.hpp> |
20 | #include <boost/optional.hpp> |
21 | #include <boost/limits.hpp> |
22 | #include <boost/format/detail/compat_workarounds.hpp> |
23 | #include <boost/format/alt_sstream.hpp> // used as a dummy stream |
24 | |
25 | namespace boost { |
26 | namespace io { |
27 | namespace detail { |
28 | |
29 | |
30 | //---- stream_format_state --------------------------------------------------// |
31 | |
32 | // set of params that define the format state of a stream |
33 | template<class Ch, class Tr> |
34 | struct stream_format_state |
35 | { |
36 | typedef BOOST_IO_STD basic_ios<Ch, Tr> basic_ios; |
37 | |
38 | stream_format_state(Ch fill) { reset(fill); } |
39 | // stream_format_state(const basic_ios& os) { set_by_stream(os); } |
40 | |
41 | void reset(Ch fill); //- sets to default state. |
42 | void set_by_stream(const basic_ios& os); //- sets to os's state. |
43 | void apply_on(basic_ios & os, //- applies format_state to the stream |
44 | boost::io::detail::locale_t * loc_default = 0) const; |
45 | template<class T> |
46 | void apply_manip(T manipulator) //- modifies state by applying manipulator |
47 | { apply_manip_body<Ch, Tr, T>( *this, manipulator) ; } |
48 | |
49 | // --- data --- |
50 | std::streamsize width_; |
51 | std::streamsize precision_; |
52 | Ch fill_; |
53 | std::ios_base::fmtflags flags_; |
54 | std::ios_base::iostate rdstate_; |
55 | std::ios_base::iostate exceptions_; |
56 | boost::optional<boost::io::detail::locale_t> loc_; |
57 | }; |
58 | |
59 | |
60 | //---- format_item ---------------------------------------------------------// |
61 | |
62 | // stores all parameters that can be specified in format strings |
63 | template<class Ch, class Tr, class Alloc> |
64 | struct format_item |
65 | { |
66 | enum pad_values { zeropad = 1, spacepad =2, centered=4, tabulation = 8 }; |
67 | // 1. if zeropad is set, all other bits are not, |
68 | // 2. if tabulation is set, all others are not. |
69 | // centered and spacepad can be mixed freely. |
70 | enum arg_values { argN_no_posit = -1, // non-positional directive. will set argN later |
71 | argN_tabulation = -2, // tabulation directive. (no argument read) |
72 | argN_ignored = -3 // ignored directive. (no argument read) |
73 | }; |
74 | typedef BOOST_IO_STD basic_ios<Ch, Tr> basic_ios; |
75 | typedef detail::stream_format_state<Ch, Tr> stream_format_state; |
76 | typedef ::std::basic_string<Ch, Tr, Alloc> string_type; |
77 | |
78 | format_item(Ch fill) :argN_(argN_no_posit), fmtstate_(fill), |
79 | truncate_(max_streamsize()), pad_scheme_(0) {} |
80 | void reset(Ch fill); |
81 | void compute_states(); // sets states according to truncate and pad_scheme. |
82 | |
83 | static std::streamsize max_streamsize() { |
84 | return (std::numeric_limits<std::streamsize>::max)(); |
85 | } |
86 | |
87 | // --- data --- |
88 | int argN_; //- argument number (starts at 0, eg : %1 => argN=0) |
89 | // negative values for items that don't process an argument |
90 | string_type res_; //- result of the formatting of this item |
91 | string_type appendix_; //- piece of string between this item and the next |
92 | |
93 | stream_format_state fmtstate_;// set by parsing, is only affected by modify_item |
94 | |
95 | std::streamsize truncate_;//- is set for directives like %.5s that ask truncation |
96 | unsigned int pad_scheme_;//- several possible padding schemes can mix. see pad_values |
97 | }; |
98 | |
99 | |
100 | |
101 | //--- Definitions ------------------------------------------------------------ |
102 | |
103 | // - stream_format_state:: ------------------------------------------------- |
104 | template<class Ch, class Tr> |
105 | void stream_format_state<Ch,Tr>:: apply_on (basic_ios & os, |
106 | boost::io::detail::locale_t * loc_default) const { |
107 | // If a locale is available, set it first. "os.fill(fill_);" may chrash otherwise. |
108 | #if !defined(BOOST_NO_STD_LOCALE) |
109 | if(loc_) |
110 | os.imbue(loc_.get()); |
111 | else if(loc_default) |
112 | os.imbue(*loc_default); |
113 | #else |
114 | (void) loc_default; // keep compiler quiet if we don't support locales |
115 | #endif |
116 | // set the state of this stream according to our params |
117 | if(width_ != -1) |
118 | os.width(width_); |
119 | if(precision_ != -1) |
120 | os.precision(precision_); |
121 | if(fill_ != 0) |
122 | os.fill(fill_); |
123 | os.flags(flags_); |
124 | os.clear(rdstate_); |
125 | os.exceptions(exceptions_); |
126 | } |
127 | |
128 | template<class Ch, class Tr> |
129 | void stream_format_state<Ch,Tr>:: set_by_stream(const basic_ios& os) { |
130 | // set our params according to the state of this stream |
131 | flags_ = os.flags(); |
132 | width_ = os.width(); |
133 | precision_ = os.precision(); |
134 | fill_ = os.fill(); |
135 | rdstate_ = os.rdstate(); |
136 | exceptions_ = os.exceptions(); |
137 | } |
138 | |
139 | |
140 | template<class Ch, class Tr, class T> |
141 | void apply_manip_body( stream_format_state<Ch, Tr>& self, |
142 | T manipulator) { |
143 | // modify our params according to the manipulator |
144 | basic_oaltstringstream<Ch, Tr> ss; |
145 | self.apply_on( ss ); |
146 | ss << manipulator; |
147 | self.set_by_stream( ss ); |
148 | } |
149 | |
150 | template<class Ch, class Tr> inline |
151 | void stream_format_state<Ch,Tr>:: reset(Ch fill) { |
152 | // set our params to standard's default state. cf 27.4.4.1 of the C++ norm |
153 | width_=0; precision_=6; |
154 | fill_=fill; // default is widen(' '), but we cant compute it without the locale |
155 | flags_ = std::ios_base::dec | std::ios_base::skipws; |
156 | // the adjust_field part is left equal to 0, which means right. |
157 | exceptions_ = std::ios_base::goodbit; |
158 | rdstate_ = std::ios_base::goodbit; |
159 | } |
160 | |
161 | |
162 | // --- format_item:: -------------------------------------------------------- |
163 | |
164 | template<class Ch, class Tr, class Alloc> |
165 | void format_item<Ch, Tr, Alloc>:: |
166 | reset (Ch fill) { |
167 | argN_=argN_no_posit; truncate_ = max_streamsize(); pad_scheme_ =0; |
168 | res_.resize(0); appendix_.resize(0); |
169 | fmtstate_.reset(fill); |
170 | } |
171 | |
172 | template<class Ch, class Tr, class Alloc> |
173 | void format_item<Ch, Tr, Alloc>:: |
174 | compute_states() { |
175 | // reflect pad_scheme_ on fmt_state_ |
176 | // because some pad_schemes has complex consequences on several state params. |
177 | if(pad_scheme_ & zeropad) { |
178 | // ignore zeropad in left alignment : |
179 | if(fmtstate_.flags_ & std::ios_base::left) { |
180 | BOOST_ASSERT(!(fmtstate_.flags_ &(std::ios_base::adjustfield ^std::ios_base::left))); |
181 | // only left bit might be set. (not right, nor internal) |
182 | pad_scheme_ = pad_scheme_ & (~zeropad); |
183 | } |
184 | else { |
185 | pad_scheme_ &= ~spacepad; // printf ignores spacepad when zeropadding |
186 | fmtstate_.fill_='0'; |
187 | fmtstate_.flags_ = (fmtstate_.flags_ & ~std::ios_base::adjustfield) |
188 | | std::ios_base::internal; |
189 | // removes all adjustfield bits, and adds internal. |
190 | } |
191 | } |
192 | if(pad_scheme_ & spacepad) { |
193 | if(fmtstate_.flags_ & std::ios_base::showpos) |
194 | pad_scheme_ &= ~spacepad; |
195 | } |
196 | } |
197 | |
198 | |
199 | } } } // namespaces boost :: io :: detail |
200 | |
201 | |
202 | #endif // BOOST_FORMAT_INTERNALS_HPP |
203 | |