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// -*- C++ -*-
// Boost general library 'format' ---------------------------
// See http://www.boost.org for updates, documentation, and revision history.
// (C) Samuel Krempp 2001
// krempp@crans.ens-cachan.fr
// Permission to copy, use, modify, sell and
// distribute this software is granted provided this copyright notice appears
// in all copies. This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
// ideas taken from Rüdiger Loos's format class
// and Karl Nelson's ofstream
// ----------------------------------------------------------------------------
// internals.hpp : internal structs. included by format.hpp
// stream_format_state, and format_item
// ----------------------------------------------------------------------------
#ifndef BOOST_FORMAT_INTERNALS_HPP
#define BOOST_FORMAT_INTERNALS_HPP
#include <string>
#include <sstream>
namespace boost {
namespace io {
namespace detail {
// --------------
// set of params that define the format state of a stream
struct stream_format_state
{
typedef std::ios basic_ios;
std::streamsize width_;
std::streamsize precision_;
char fill_;
std::ios::fmtflags flags_;
stream_format_state() : width_(-1), precision_(-1), fill_(0), flags_(std::ios::dec) {}
stream_format_state(basic_ios& os) {set_by_stream(os); }
void apply_on(basic_ios & os) const; //- applies format_state to the stream
template<class T> void apply_manip(T manipulator) //- modifies state by applying manipulator.
{ apply_manip_body<T>( *this, manipulator) ; }
void reset(); //- sets to default state.
void set_by_stream(const basic_ios& os); //- sets to os's state.
};
// --------------
// format_item : stores all parameters that can be defined by directives in the format-string
struct format_item
{
enum pad_values { zeropad = 1, spacepad =2, centered=4, tabulation = 8 };
enum arg_values { argN_no_posit = -1, // non-positional directive. argN will be set later.
argN_tabulation = -2, // tabulation directive. (no argument read)
argN_ignored = -3 // ignored directive. (no argument read)
};
typedef BOOST_IO_STD ios basic_ios;
typedef detail::stream_format_state stream_format_state;
typedef std::string string_t;
typedef BOOST_IO_STD ostringstream internal_stream_t;
int argN_; //- argument number (starts at 0, eg : %1 => argN=0)
// negative values are used for items that don't process
// an argument
string_t res_; //- result of the formatting of this item
string_t appendix_; //- piece of string between this item and the next
stream_format_state ref_state_;// set by parsing the format_string, is only affected by modify_item
stream_format_state state_; // always same as ref_state, _unless_ modified by manipulators 'group(..)'
// non-stream format-state parameters
signed int truncate_; //- is >=0 for directives like %.5s (take 5 chars from the string)
unsigned int pad_scheme_; //- several possible padding schemes can mix. see pad_values
format_item() : argN_(argN_no_posit), truncate_(-1), pad_scheme_(0) {}
void compute_states(); // sets states according to truncate and pad_scheme.
};
// -----------------------------------------------------------
// Definitions
// -----------------------------------------------------------
// --- stream_format_state:: -------------------------------------------
inline
void stream_format_state::apply_on(basic_ios & os) 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_);
}
inline
void stream_format_state::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();
}
template<class T> inline
void apply_manip_body( stream_format_state& self,
T manipulator)
// modify our params according to the manipulator
{
BOOST_IO_STD stringstream ss;
self.apply_on( ss );
ss << manipulator;
self.set_by_stream( ss );
}
inline
void stream_format_state::reset()
// set our params to standard's default state
{
width_=-1; precision_=-1; fill_=0;
flags_ = std::ios::dec;
}
// --- format_items:: -------------------------------------------
inline
void format_item::compute_states()
// reflect pad_scheme_ on state_ and ref_state_
// because some pad_schemes has complex consequences on several state params.
{
if(pad_scheme_ & zeropad)
{
if(ref_state_.flags_ & std::ios::left)
{
pad_scheme_ = pad_scheme_ & (~zeropad); // ignore zeropad in left alignment
}
else
{
ref_state_.fill_='0';
ref_state_.flags_ |= std::ios::internal;
}
}
state_ = ref_state_;
}
} } } // namespaces boost :: io :: detail
#endif // BOOST_FORMAT_INTERNALS_HPP
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