506 lines
19 KiB
C++
506 lines
19 KiB
C++
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// ----------------------------------------------------------------------------
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// parsing.hpp : implementation of the parsing member functions
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// ( parse, parse_printf_directive)
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// ----------------------------------------------------------------------------
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// Copyright Samuel Krempp 2003. Use, modification, and distribution are
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// subject to the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// see http://www.boost.org/libs/format for library home page
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// ----------------------------------------------------------------------------
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#ifndef BOOST_FORMAT_PARSING_HPP
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#define BOOST_FORMAT_PARSING_HPP
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#include <boost/format/format_class.hpp>
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#include <boost/format/exceptions.hpp>
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#include <boost/throw_exception.hpp>
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#include <boost/assert.hpp>
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#include <boost/config.hpp>
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namespace boost {
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namespace io {
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namespace detail {
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#if defined(BOOST_NO_STD_LOCALE)
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// streams will be used for narrow / widen. but these methods are not const
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template<class T>
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T& const_or_not(const T& x) {
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return const_cast<T&> (x);
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}
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#else
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template<class T>
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const T& const_or_not(const T& x) {
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return x;
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}
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#endif
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template<class Ch, class Facet> inline
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char wrap_narrow(const Facet& fac, Ch c, char deflt) {
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return const_or_not(fac).narrow(c, deflt);
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}
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template<class Ch, class Facet> inline
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bool wrap_isdigit(const Facet& fac, Ch c) {
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#if ! defined( BOOST_NO_LOCALE_ISDIGIT )
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return fac.is(std::ctype<Ch>::digit, c);
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# else
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(void) fac; // remove "unused parameter" warning
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using namespace std;
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return isdigit(c) != 0;
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#endif
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}
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template<class Iter, class Facet>
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Iter wrap_scan_notdigit(const Facet & fac, Iter beg, Iter end) {
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using namespace std;
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for( ; beg!=end && wrap_isdigit(fac, *beg); ++beg) ;
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return beg;
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}
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// Input : [start, last) iterators range and a
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// a Facet to use its widen/narrow member function
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// Effects : read sequence and convert digits into integral n, of type Res
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// Returns : n
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template<class Res, class Iter, class Facet>
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Iter str2int (const Iter & start, const Iter & last, Res & res,
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const Facet& fac)
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{
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using namespace std;
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Iter it;
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res=0;
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for(it=start; it != last && wrap_isdigit(fac, *it); ++it ) {
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char cur_ch = wrap_narrow(fac, *it, 0); // cant fail.
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res *= 10;
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res += cur_ch - '0'; // 22.2.1.1.2.13 of the C++ standard
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}
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return it;
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}
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// skip printf's "asterisk-fields" directives in the format-string buf
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// Input : char string, with starting index *pos_p
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// a Facet merely to use its widen/narrow member function
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// Effects : advance *pos_p by skipping printf's asterisk fields.
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// Returns : nothing
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template<class Iter, class Facet>
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Iter skip_asterisk(Iter start, Iter last, const Facet& fac)
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{
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using namespace std;
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++ start;
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start = wrap_scan_notdigit(fac, start, last);
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if(start!=last && *start== const_or_not(fac).widen( '$') )
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++start;
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return start;
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}
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// auxiliary func called by parse_printf_directive
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// for centralising error handling
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// it either throws if user sets the corresponding flag, or does nothing.
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inline void maybe_throw_exception(unsigned char exceptions,
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std::size_t pos, std::size_t size)
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{
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if(exceptions & io::bad_format_string_bit)
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boost::throw_exception(io::bad_format_string(pos, size) );
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}
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// Input: the position of a printf-directive in the format-string
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// a basic_ios& merely to use its widen/narrow member function
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// a bitset'exceptions' telling whether to throw exceptions on errors.
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// Returns:
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// true if parse succeeded (ignore some errors if exceptions disabled)
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// false if it failed so bad that the directive should be printed verbatim
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// Effects:
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// start is incremented so that *start is the first char after
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// this directive
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// *fpar is set with the parameters read in the directive
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template<class Ch, class Tr, class Alloc, class Iter, class Facet>
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bool parse_printf_directive(Iter & start, const Iter& last,
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detail::format_item<Ch, Tr, Alloc> * fpar,
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const Facet& fac,
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std::size_t offset, unsigned char exceptions)
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{
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typedef typename basic_format<Ch, Tr, Alloc>::format_item_t format_item_t;
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fpar->argN_ = format_item_t::argN_no_posit; // if no positional-directive
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bool precision_set = false;
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bool in_brackets=false;
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Iter start0 = start;
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std::size_t fstring_size = last-start0+offset;
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if(start>= last) { // empty directive : this is a trailing %
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maybe_throw_exception(exceptions, start-start0 + offset, fstring_size);
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return false;
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}
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if(*start== const_or_not(fac).widen( '|')) {
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in_brackets=true;
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if( ++start >= last ) {
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maybe_throw_exception(exceptions, start-start0 + offset, fstring_size);
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return false;
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}
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}
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// the flag '0' would be picked as a digit for argument order, but here it's a flag :
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if(*start== const_or_not(fac).widen( '0'))
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goto parse_flags;
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// handle argument order (%2$d) or possibly width specification: %2d
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if(wrap_isdigit(fac, *start)) {
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int n;
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start = str2int(start, last, n, fac);
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if( start >= last ) {
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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return false;
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}
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// %N% case : this is already the end of the directive
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if( *start == const_or_not(fac).widen( '%') ) {
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fpar->argN_ = n-1;
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++start;
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if( in_brackets)
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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// but don't return. maybe "%" was used in lieu of '$', so we go on.
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else
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return true;
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}
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if ( *start== const_or_not(fac).widen( '$') ) {
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fpar->argN_ = n-1;
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++start;
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}
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else {
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// non-positionnal directive
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fpar->fmtstate_.width_ = n;
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fpar->argN_ = format_item_t::argN_no_posit;
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goto parse_precision;
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}
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}
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parse_flags:
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// handle flags
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while ( start != last) { // as long as char is one of + - = _ # 0 l h or ' '
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// misc switches
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switch ( wrap_narrow(fac, *start, 0)) {
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case '\'' : break; // no effect yet. (painful to implement)
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case 'l':
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case 'h': // short/long modifier : for printf-comaptibility (no action needed)
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break;
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case '-':
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fpar->fmtstate_.flags_ |= std::ios_base::left;
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break;
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case '=':
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fpar->pad_scheme_ |= format_item_t::centered;
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break;
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case '_':
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fpar->fmtstate_.flags_ |= std::ios_base::internal;
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break;
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case ' ':
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fpar->pad_scheme_ |= format_item_t::spacepad;
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break;
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case '+':
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fpar->fmtstate_.flags_ |= std::ios_base::showpos;
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break;
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case '0':
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fpar->pad_scheme_ |= format_item_t::zeropad;
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// need to know alignment before really setting flags,
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// so just add 'zeropad' flag for now, it will be processed later.
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break;
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case '#':
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fpar->fmtstate_.flags_ |= std::ios_base::showpoint | std::ios_base::showbase;
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break;
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default:
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goto parse_width;
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}
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++start;
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} // loop on flag.
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if( start>=last) {
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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return true;
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}
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parse_width:
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// handle width spec
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// first skip 'asterisk fields' : *, or *N$
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if(*start == const_or_not(fac).widen( '*') )
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start = skip_asterisk(start, last, fac);
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if(start!=last && wrap_isdigit(fac, *start))
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start = str2int(start, last, fpar->fmtstate_.width_, fac);
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parse_precision:
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if( start>= last) {
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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return true;
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}
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// handle precision spec
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if (*start== const_or_not(fac).widen( '.')) {
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++start;
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if(start != last && *start == const_or_not(fac).widen( '*') )
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start = skip_asterisk(start, last, fac);
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if(start != last && wrap_isdigit(fac, *start)) {
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start = str2int(start, last, fpar->fmtstate_.precision_, fac);
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precision_set = true;
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}
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else
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fpar->fmtstate_.precision_ =0;
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}
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// handle formatting-type flags :
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while( start != last && ( *start== const_or_not(fac).widen( 'l')
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|| *start== const_or_not(fac).widen( 'L')
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|| *start== const_or_not(fac).widen( 'h')) )
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++start;
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if( start>=last) {
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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return true;
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}
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if( in_brackets && *start== const_or_not(fac).widen( '|') ) {
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++start;
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return true;
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}
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switch ( wrap_narrow(fac, *start, 0) ) {
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case 'X':
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fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
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BOOST_FALLTHROUGH;
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case 'p': // pointer => set hex.
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case 'x':
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fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
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fpar->fmtstate_.flags_ |= std::ios_base::hex;
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break;
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case 'o':
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fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
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fpar->fmtstate_.flags_ |= std::ios_base::oct;
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break;
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case 'E':
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fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
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BOOST_FALLTHROUGH;
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case 'e':
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fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
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fpar->fmtstate_.flags_ |= std::ios_base::scientific;
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fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
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fpar->fmtstate_.flags_ |= std::ios_base::dec;
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break;
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case 'f':
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fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
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fpar->fmtstate_.flags_ |= std::ios_base::fixed;
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BOOST_FALLTHROUGH;
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case 'u':
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case 'd':
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case 'i':
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fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
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fpar->fmtstate_.flags_ |= std::ios_base::dec;
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break;
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case 'T':
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++start;
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if( start >= last)
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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else
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fpar->fmtstate_.fill_ = *start;
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fpar->pad_scheme_ |= format_item_t::tabulation;
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fpar->argN_ = format_item_t::argN_tabulation;
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break;
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case 't':
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fpar->fmtstate_.fill_ = const_or_not(fac).widen( ' ');
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fpar->pad_scheme_ |= format_item_t::tabulation;
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fpar->argN_ = format_item_t::argN_tabulation;
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break;
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case 'G':
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fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
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break;
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case 'g': // 'g' conversion is default for floats.
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fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
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fpar->fmtstate_.flags_ |= std::ios_base::dec;
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// CLEAR all floatield flags, so stream will CHOOSE
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fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
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break;
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case 'C':
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case 'c':
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fpar->truncate_ = 1;
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break;
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case 'S':
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case 's':
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if(precision_set) // handle truncation manually, with own parameter.
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fpar->truncate_ = fpar->fmtstate_.precision_;
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fpar->fmtstate_.precision_ = 6; // default stream precision.
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break;
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case 'n' :
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fpar->argN_ = format_item_t::argN_ignored;
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break;
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default:
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maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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}
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++start;
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if( in_brackets ) {
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if( start != last && *start== const_or_not(fac).widen( '|') ) {
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++start;
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return true;
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}
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else maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
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}
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return true;
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}
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// -end parse_printf_directive()
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template<class String, class Facet>
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int upper_bound_from_fstring(const String& buf,
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const typename String::value_type arg_mark,
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const Facet& fac,
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unsigned char exceptions)
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{
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// quick-parsing of the format-string to count arguments mark (arg_mark, '%')
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// returns : upper bound on the number of format items in the format strings
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using namespace boost::io;
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typename String::size_type i1=0;
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int num_items=0;
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while( (i1=buf.find(arg_mark,i1)) != String::npos ) {
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if( i1+1 >= buf.size() ) {
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if(exceptions & bad_format_string_bit)
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boost::throw_exception(bad_format_string(i1, buf.size() )); // must not end in ".. %"
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else {
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++num_items;
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break;
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}
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}
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if(buf[i1+1] == buf[i1] ) {// escaped "%%"
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i1+=2; continue;
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}
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++i1;
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// in case of %N% directives, dont count it double (wastes allocations..) :
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i1 = detail::wrap_scan_notdigit(fac, buf.begin()+i1, buf.end()) - buf.begin();
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if( i1 < buf.size() && buf[i1] == arg_mark )
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++i1;
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++num_items;
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}
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return num_items;
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}
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template<class String> inline
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void append_string(String& dst, const String& src,
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const typename String::size_type beg,
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const typename String::size_type end) {
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dst.append(src.begin()+beg, src.begin()+end);
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}
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} // detail namespace
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} // io namespace
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// -----------------------------------------------
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// format :: parse(..)
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template<class Ch, class Tr, class Alloc>
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basic_format<Ch, Tr, Alloc>& basic_format<Ch, Tr, Alloc>::
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parse (const string_type& buf) {
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// parse the format-string
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using namespace std;
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#if !defined(BOOST_NO_STD_LOCALE)
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const std::ctype<Ch> & fac = BOOST_USE_FACET( std::ctype<Ch>, getloc());
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#else
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io::basic_oaltstringstream<Ch, Tr, Alloc> fac;
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//has widen and narrow even on compilers without locale
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#endif
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const Ch arg_mark = io::detail::const_or_not(fac).widen( '%');
|
||
|
bool ordered_args=true;
|
||
|
int max_argN=-1;
|
||
|
|
||
|
// A: find upper_bound on num_items and allocates arrays
|
||
|
int num_items = io::detail::upper_bound_from_fstring(buf, arg_mark, fac, exceptions());
|
||
|
make_or_reuse_data(num_items);
|
||
|
|
||
|
// B: Now the real parsing of the format string :
|
||
|
num_items=0;
|
||
|
typename string_type::size_type i0=0, i1=0;
|
||
|
typename string_type::const_iterator it;
|
||
|
bool special_things=false;
|
||
|
int cur_item=0;
|
||
|
while( (i1=buf.find(arg_mark,i1)) != string_type::npos ) {
|
||
|
string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
|
||
|
if( buf[i1+1] == buf[i1] ) { // escaped mark, '%%'
|
||
|
io::detail::append_string(piece, buf, i0, i1+1);
|
||
|
i1+=2; i0=i1;
|
||
|
continue;
|
||
|
}
|
||
|
BOOST_ASSERT( static_cast<unsigned int>(cur_item) < items_.size() || cur_item==0);
|
||
|
|
||
|
if(i1!=i0) {
|
||
|
io::detail::append_string(piece, buf, i0, i1);
|
||
|
i0=i1;
|
||
|
}
|
||
|
++i1;
|
||
|
it = buf.begin()+i1;
|
||
|
bool parse_ok = io::detail::parse_printf_directive(
|
||
|
it, buf.end(), &items_[cur_item], fac, i1, exceptions());
|
||
|
i1 = it - buf.begin();
|
||
|
if( ! parse_ok ) // the directive will be printed verbatim
|
||
|
continue;
|
||
|
i0=i1;
|
||
|
items_[cur_item].compute_states(); // process complex options, like zeropad, into params
|
||
|
|
||
|
int argN=items_[cur_item].argN_;
|
||
|
if(argN == format_item_t::argN_ignored)
|
||
|
continue;
|
||
|
if(argN ==format_item_t::argN_no_posit)
|
||
|
ordered_args=false;
|
||
|
else if(argN == format_item_t::argN_tabulation) special_things=true;
|
||
|
else if(argN > max_argN) max_argN = argN;
|
||
|
++num_items;
|
||
|
++cur_item;
|
||
|
} // loop on %'s
|
||
|
BOOST_ASSERT(cur_item == num_items);
|
||
|
|
||
|
// store the final piece of string
|
||
|
{
|
||
|
string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
|
||
|
io::detail::append_string(piece, buf, i0, buf.size());
|
||
|
}
|
||
|
|
||
|
if( !ordered_args) {
|
||
|
if(max_argN >= 0 ) { // dont mix positional with non-positionnal directives
|
||
|
if(exceptions() & io::bad_format_string_bit)
|
||
|
boost::throw_exception(
|
||
|
io::bad_format_string(static_cast<std::size_t>(max_argN), 0));
|
||
|
// else do nothing. => positionnal arguments are processed as non-positionnal
|
||
|
}
|
||
|
// set things like it would have been with positional directives :
|
||
|
int non_ordered_items = 0;
|
||
|
for(int i=0; i< num_items; ++i)
|
||
|
if(items_[i].argN_ == format_item_t::argN_no_posit) {
|
||
|
items_[i].argN_ = non_ordered_items;
|
||
|
++non_ordered_items;
|
||
|
}
|
||
|
max_argN = non_ordered_items-1;
|
||
|
}
|
||
|
|
||
|
// C: set some member data :
|
||
|
items_.resize(num_items, format_item_t(io::detail::const_or_not(fac).widen( ' ')) );
|
||
|
|
||
|
if(special_things) style_ |= special_needs;
|
||
|
num_args_ = max_argN + 1;
|
||
|
if(ordered_args) style_ |= ordered;
|
||
|
else style_ &= ~ordered;
|
||
|
return *this;
|
||
|
}
|
||
|
|
||
|
} // namespace boost
|
||
|
|
||
|
|
||
|
#endif // BOOST_FORMAT_PARSING_HPP
|