1 // ----------------------------------------------------------------------------
2 // feed_args.hpp : functions for processing each argument
3 // (feed, feed_manip, and distribute)
4 // ----------------------------------------------------------------------------
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)
10 // See http://www.boost.org/libs/format for library home page
12 // ----------------------------------------------------------------------------
14 #ifndef BOOST_FORMAT_FEED_ARGS_HPP
15 #define BOOST_FORMAT_FEED_ARGS_HPP
17 #include <boost/config.hpp>
18 #include <boost/assert.hpp>
19 #include <boost/throw_exception.hpp>
21 #include <boost/format/format_class.hpp>
22 #include <boost/format/group.hpp>
23 #include <boost/format/detail/msvc_disambiguater.hpp>
29 template<class Ch, class Tr, class Alloc>
30 void mk_str( std::basic_string<Ch,Tr, Alloc> & res,
32 typename std::basic_string<Ch,Tr,Alloc>::size_type size,
35 std::ios_base::fmtflags f,
36 const Ch prefix_space, // 0 if no space-padding
38 // applies centered/left/right padding to the string [beg, beg+size[
39 // Effects : the result is placed in res.
41 typedef typename std::basic_string<Ch,Tr,Alloc>::size_type size_type;
43 if(w<=0 || static_cast<size_type>(w) <=size) {
45 res.reserve(size + !!prefix_space);
47 res.append(1, prefix_space);
49 res.append(beg, size);
52 std::streamsize n=static_cast<std::streamsize>(w-size-!!prefix_space);
53 std::streamsize n_after = 0, n_before = 0;
54 res.reserve(static_cast<size_type>(w)); // allocate once for the 2 inserts
56 n_after = n/2, n_before = n - n_after;
58 if(f & std::ios_base::left)
62 // now make the res string :
63 if(n_before) res.append(static_cast<size_type>(n_before), fill_char);
65 res.append(1, prefix_space);
67 res.append(beg, size);
68 if(n_after) res.append(static_cast<size_type>(n_after), fill_char);
73 #if BOOST_WORKAROUND(__DECCXX_VER, BOOST_TESTED_AT(60590042))
74 // __DECCXX needs to be tricked to disambiguate this simple overload..
75 // the trick is in "boost/format/msvc_disambiguater.hpp"
77 template< class Ch, class Tr, class T> inline
78 void put_head (BOOST_IO_STD basic_ostream<Ch, Tr> & os, const T& x ) {
79 disambiguater<Ch, Tr, T>::put_head(os, x, 1L);
81 template< class Ch, class Tr, class T> inline
82 void put_last (BOOST_IO_STD basic_ostream<Ch, Tr> & os, const T& x ) {
83 disambiguater<Ch, Tr, T>::put_last(os, x, 1L);
88 template< class Ch, class Tr, class T> inline
89 void put_head (BOOST_IO_STD basic_ostream<Ch, Tr> &, const T& ) {
92 template< class Ch, class Tr, class T> inline
93 void put_head( BOOST_IO_STD basic_ostream<Ch, Tr> & os, const group1<T>& x ) {
94 os << group_head(x.a1_); // send the first N-1 items, not the last
97 template< class Ch, class Tr, class T> inline
98 void put_last( BOOST_IO_STD basic_ostream<Ch, Tr> & os, const T& x ) {
102 template< class Ch, class Tr, class T> inline
103 void put_last( BOOST_IO_STD basic_ostream<Ch, Tr> & os, const group1<T>& x ) {
104 os << group_last(x.a1_); // this selects the last element
107 #ifndef BOOST_NO_OVERLOAD_FOR_NON_CONST
108 template< class Ch, class Tr, class T> inline
109 void put_head( BOOST_IO_STD basic_ostream<Ch, Tr> &, T& ) {
112 template< class Ch, class Tr, class T> inline
113 void put_last( BOOST_IO_STD basic_ostream<Ch, Tr> & os, T& x) {
117 #endif // -__DECCXX workaround
119 template< class Ch, class Tr, class T>
120 void call_put_head(BOOST_IO_STD basic_ostream<Ch, Tr> & os, const void* x) {
121 put_head(os, *(typename ::boost::remove_reference<T>::type*)x);
124 template< class Ch, class Tr, class T>
125 void call_put_last(BOOST_IO_STD basic_ostream<Ch, Tr> & os, const void* x) {
126 put_last(os, *(T*)x);
129 template< class Ch, class Tr>
134 put_head(&call_put_head<Ch, Tr, T>),
135 put_last(&call_put_last<Ch, Tr, T>)
138 void (*put_head)(BOOST_IO_STD basic_ostream<Ch, Tr> & os, const void* x);
139 void (*put_last)(BOOST_IO_STD basic_ostream<Ch, Tr> & os, const void* x);
142 template< class Ch, class Tr> inline
143 void put_head( BOOST_IO_STD basic_ostream<Ch, Tr> & os, const put_holder<Ch, Tr>& t) {
144 t.put_head(os, t.arg);
147 template< class Ch, class Tr> inline
148 void put_last( BOOST_IO_STD basic_ostream<Ch, Tr> & os, const put_holder<Ch, Tr>& t) {
149 t.put_last(os, t.arg);
153 template< class Ch, class Tr, class Alloc, class T>
155 const format_item<Ch, Tr, Alloc>& specs,
156 typename basic_format<Ch, Tr, Alloc>::string_type& res,
157 typename basic_format<Ch, Tr, Alloc>::internal_streambuf_t & buf,
158 io::detail::locale_t *loc_p = NULL)
161 // If std::min<unsigned> or std::max<unsigned> are already instantiated
162 // at this point then we get a blizzard of warning messages when we call
163 // those templates with std::size_t as arguments. Weird and very annoyning...
164 #pragma warning(push)
165 #pragma warning(disable:4267)
167 // does the actual conversion of x, with given params, into a string
168 // using the supplied stringbuf.
170 typedef typename basic_format<Ch, Tr, Alloc>::string_type string_type;
171 typedef typename basic_format<Ch, Tr, Alloc>::format_item_t format_item_t;
172 typedef typename string_type::size_type size_type;
174 basic_oaltstringstream<Ch, Tr, Alloc> oss( &buf);
175 specs.fmtstate_.apply_on(oss, loc_p);
177 // the stream format state can be modified by manipulators in the argument :
179 // in case x is a group, apply the manip part of it,
180 // in order to find width
182 const std::ios_base::fmtflags fl=oss.flags();
183 const bool internal = (fl & std::ios_base::internal) != 0;
184 const std::streamsize w = oss.width();
185 const bool two_stepped_padding= internal && (w!=0);
188 if(! two_stepped_padding) {
189 if(w>0) // handle padding via mk_str, not natively in stream
192 const Ch * res_beg = buf.pbase();
194 if(specs.pad_scheme_ & format_item_t::spacepad)
195 if(buf.pcount()== 0 ||
196 (res_beg[0] !=oss.widen('+') && res_beg[0] !=oss.widen('-') ))
197 prefix_space = oss.widen(' ');
198 size_type res_size = (std::min)(
199 static_cast<size_type>(specs.truncate_ - !!prefix_space),
201 mk_str(res, res_beg, res_size, w, oss.fill(), fl,
202 prefix_space, (specs.pad_scheme_ & format_item_t::centered) !=0 );
204 else { // 2-stepped padding
205 // internal can be implied by zeropad, or user-set.
206 // left, right, and centered alignment overrule internal,
207 // but spacepad or truncate might be mixed with internal (using manipulator)
208 put_last( oss, x); // may pad
209 const Ch * res_beg = buf.pbase();
210 size_type res_size = buf.pcount();
211 bool prefix_space=false;
212 if(specs.pad_scheme_ & format_item_t::spacepad)
213 if(buf.pcount()== 0 ||
214 (res_beg[0] !=oss.widen('+') && res_beg[0] !=oss.widen('-') ))
216 if(res_size == static_cast<size_type>(w) && w<=specs.truncate_ && !prefix_space) {
217 // okay, only one thing was printed and padded, so res is fine
218 res.assign(res_beg, res_size);
220 else { // length w exceeded
221 // either it was multi-output with first output padding up all width..
222 // either it was one big arg and we are fine.
223 // Note that res_size<w is possible (in case of bad user-defined formatting)
224 res.assign(res_beg, res_size);
225 res_beg=NULL; // invalidate pointers.
227 // make a new stream, to start re-formatting from scratch :
229 basic_oaltstringstream<Ch, Tr, Alloc> oss2( &buf);
230 specs.fmtstate_.apply_on(oss2, loc_p);
237 if(buf.pcount()==0 && specs.pad_scheme_ & format_item_t::spacepad) {
241 // we now have the minimal-length output
242 const Ch * tmp_beg = buf.pbase();
243 size_type tmp_size = (std::min)(static_cast<size_type>(specs.truncate_),
247 if(static_cast<size_type>(w) <= tmp_size) {
248 // minimal length is already >= w, so no padding (cool!)
249 res.assign(tmp_beg, tmp_size);
251 else { // hum.. we need to pad (multi_output, or spacepad present)
252 //find where we should pad
253 size_type sz = (std::min)(res_size + (prefix_space ? 1 : 0), tmp_size);
254 size_type i = prefix_space;
255 for(; i<sz && tmp_beg[i] == res[i - (prefix_space ? 1 : 0)]; ++i) {}
256 if(i>=tmp_size) i=prefix_space;
257 res.assign(tmp_beg, i);
258 std::streamsize d = w - static_cast<std::streamsize>(tmp_size);
260 res.append(static_cast<size_type>( d ), oss2.fill());
261 res.append(tmp_beg+i, tmp_size-i);
262 BOOST_ASSERT(i+(tmp_size-i)+(std::max)(d,(std::streamsize)0)
263 == static_cast<size_type>(w));
264 BOOST_ASSERT(res.size() == static_cast<size_type>(w));
275 template< class Ch, class Tr, class Alloc, class T>
276 void distribute (basic_format<Ch,Tr, Alloc>& self, T x) {
277 // call put(x, ..) on every occurrence of the current argument :
278 if(self.cur_arg_ >= self.num_args_) {
279 if( self.exceptions() & too_many_args_bit )
280 boost::throw_exception(too_many_args(self.cur_arg_, self.num_args_));
283 for(unsigned long i=0; i < self.items_.size(); ++i) {
284 if(self.items_[i].argN_ == self.cur_arg_) {
285 put<Ch, Tr, Alloc, T> (x, self.items_[i], self.items_[i].res_,
286 self.buf_, boost::get_pointer(self.loc_) );
291 template<class Ch, class Tr, class Alloc, class T>
292 basic_format<Ch, Tr, Alloc>&
293 feed_impl (basic_format<Ch,Tr, Alloc>& self, T x) {
294 if(self.dumped_) self.clear();
295 distribute<Ch, Tr, Alloc, T> (self, x);
297 if(self.bound_.size() != 0) {
298 while( self.cur_arg_ < self.num_args_ && self.bound_[self.cur_arg_] )
304 template<class Ch, class Tr, class Alloc, class T> inline
305 basic_format<Ch, Tr, Alloc>&
306 feed (basic_format<Ch,Tr, Alloc>& self, T x) {
307 return feed_impl<Ch, Tr, Alloc, const put_holder<Ch, Tr>&>(self, put_holder<Ch, Tr>(x));
310 } // namespace detail
315 #endif // BOOST_FORMAT_FEED_ARGS_HPP