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+// ----------------------------------------------------------------------------
+// internals.hpp : internal structs : stream_format_state, format_item.
+// included by format.hpp
+// ----------------------------------------------------------------------------
+
+// Copyright Samuel Krempp 2003. Use, modification, and distribution are
+// subject to the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+// See http://www.boost.org/libs/format for library home page
+
+// ----------------------------------------------------------------------------
+
+#ifndef BOOST_FORMAT_INTERNALS_HPP
+#define BOOST_FORMAT_INTERNALS_HPP
+
+
+#include <string>
+#include <boost/assert.hpp>
+#include <boost/optional.hpp>
+#include <boost/limits.hpp>
+#include <boost/format/detail/compat_workarounds.hpp>
+#include <boost/format/alt_sstream.hpp> // used as a dummy stream
+
+namespace boost {
+namespace io {
+namespace detail {
+
+
+//---- stream_format_state --------------------------------------------------//
+
+// set of params that define the format state of a stream
+ template<class Ch, class Tr>
+ struct stream_format_state
+ {
+ typedef BOOST_IO_STD basic_ios<Ch, Tr> basic_ios;
+
+ stream_format_state(Ch fill) { reset(fill); }
+// stream_format_state(const basic_ios& os) { set_by_stream(os); }
+
+ void reset(Ch fill); //- sets to default state.
+ void set_by_stream(const basic_ios& os); //- sets to os's state.
+ void apply_on(basic_ios & os, //- applies format_state to the stream
+ boost::io::detail::locale_t * loc_default = 0) const;
+ template<class T>
+ void apply_manip(T manipulator) //- modifies state by applying manipulator
+ { apply_manip_body<Ch, Tr, T>( *this, manipulator) ; }
+
+ // --- data ---
+ std::streamsize width_;
+ std::streamsize precision_;
+ Ch fill_;
+ std::ios_base::fmtflags flags_;
+ std::ios_base::iostate rdstate_;
+ std::ios_base::iostate exceptions_;
+ boost::optional<boost::io::detail::locale_t> loc_;
+ };
+
+
+//---- format_item ---------------------------------------------------------//
+
+// stores all parameters that can be specified in format strings
+ template<class Ch, class Tr, class Alloc>
+ struct format_item
+ {
+ enum pad_values { zeropad = 1, spacepad =2, centered=4, tabulation = 8 };
+ // 1. if zeropad is set, all other bits are not,
+ // 2. if tabulation is set, all others are not.
+ // centered and spacepad can be mixed freely.
+ enum arg_values { argN_no_posit = -1, // non-positional directive. will set argN later
+ argN_tabulation = -2, // tabulation directive. (no argument read)
+ argN_ignored = -3 // ignored directive. (no argument read)
+ };
+ typedef BOOST_IO_STD basic_ios<Ch, Tr> basic_ios;
+ typedef detail::stream_format_state<Ch, Tr> stream_format_state;
+ typedef ::std::basic_string<Ch, Tr, Alloc> string_type;
+
+ format_item(Ch fill) :argN_(argN_no_posit), fmtstate_(fill),
+ truncate_(max_streamsize()), pad_scheme_(0) {}
+ void reset(Ch fill);
+ void compute_states(); // sets states according to truncate and pad_scheme.
+
+ static std::streamsize max_streamsize() {
+ return (std::numeric_limits<std::streamsize>::max)();
+ }
+
+ // --- data ---
+ int argN_; //- argument number (starts at 0, eg : %1 => argN=0)
+ // negative values for items that don't process an argument
+ string_type res_; //- result of the formatting of this item
+ string_type appendix_; //- piece of string between this item and the next
+
+ stream_format_state fmtstate_;// set by parsing, is only affected by modify_item
+
+ std::streamsize truncate_;//- is set for directives like %.5s that ask truncation
+ unsigned int pad_scheme_;//- several possible padding schemes can mix. see pad_values
+ };
+
+
+
+//--- Definitions ------------------------------------------------------------
+
+// - stream_format_state:: -------------------------------------------------
+ template<class Ch, class Tr>
+ void stream_format_state<Ch,Tr>:: apply_on (basic_ios & os,
+ boost::io::detail::locale_t * loc_default) const {
+ // set the state of this stream according to our params
+ if(width_ != -1)
+ os.width(width_);
+ if(precision_ != -1)
+ os.precision(precision_);
+ if(fill_ != 0)
+ os.fill(fill_);
+ os.flags(flags_);
+ os.clear(rdstate_);
+ os.exceptions(exceptions_);
+#if !defined(BOOST_NO_STD_LOCALE)
+ if(loc_)
+ os.imbue(loc_.get());
+ else if(loc_default)
+ os.imbue(*loc_default);
+#else
+ (void) loc_default; // keep compiler quiet if we don't support locales
+#endif
+ }
+
+ template<class Ch, class Tr>
+ void stream_format_state<Ch,Tr>:: set_by_stream(const basic_ios& os) {
+ // set our params according to the state of this stream
+ flags_ = os.flags();
+ width_ = os.width();
+ precision_ = os.precision();
+ fill_ = os.fill();
+ rdstate_ = os.rdstate();
+ exceptions_ = os.exceptions();
+ }
+
+
+ template<class Ch, class Tr, class T>
+ void apply_manip_body( stream_format_state<Ch, Tr>& self,
+ T manipulator) {
+ // modify our params according to the manipulator
+ basic_oaltstringstream<Ch, Tr> ss;
+ self.apply_on( ss );
+ ss << manipulator;
+ self.set_by_stream( ss );
+ }
+
+ template<class Ch, class Tr> inline
+ void stream_format_state<Ch,Tr>:: reset(Ch fill) {
+ // set our params to standard's default state. cf 27.4.4.1 of the C++ norm
+ width_=0; precision_=6;
+ fill_=fill; // default is widen(' '), but we cant compute it without the locale
+ flags_ = std::ios_base::dec | std::ios_base::skipws;
+ // the adjust_field part is left equal to 0, which means right.
+ exceptions_ = std::ios_base::goodbit;
+ rdstate_ = std::ios_base::goodbit;
+ }
+
+
+// --- format_item:: --------------------------------------------------------
+
+ template<class Ch, class Tr, class Alloc>
+ void format_item<Ch, Tr, Alloc>::
+ reset (Ch fill) {
+ argN_=argN_no_posit; truncate_ = max_streamsize(); pad_scheme_ =0;
+ res_.resize(0); appendix_.resize(0);
+ fmtstate_.reset(fill);
+ }
+
+ template<class Ch, class Tr, class Alloc>
+ void format_item<Ch, Tr, Alloc>::
+ compute_states() {
+ // reflect pad_scheme_ on fmt_state_
+ // because some pad_schemes has complex consequences on several state params.
+ if(pad_scheme_ & zeropad) {
+ // ignore zeropad in left alignment :
+ if(fmtstate_.flags_ & std::ios_base::left) {
+ BOOST_ASSERT(!(fmtstate_.flags_ &(std::ios_base::adjustfield ^std::ios_base::left)));
+ // only left bit might be set. (not right, nor internal)
+ pad_scheme_ = pad_scheme_ & (~zeropad);
+ }
+ else {
+ pad_scheme_ &= ~spacepad; // printf ignores spacepad when zeropadding
+ fmtstate_.fill_='0';
+ fmtstate_.flags_ = (fmtstate_.flags_ & ~std::ios_base::adjustfield)
+ | std::ios_base::internal;
+ // removes all adjustfield bits, and adds internal.
+ }
+ }
+ if(pad_scheme_ & spacepad) {
+ if(fmtstate_.flags_ & std::ios_base::showpos)
+ pad_scheme_ &= ~spacepad;
+ }
+ }
+
+
+} } } // namespaces boost :: io :: detail
+
+
+#endif // BOOST_FORMAT_INTERNALS_HPP