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504 lines
18 KiB
504 lines
18 KiB
// ---------------------------------------------------------------------------- |
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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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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); |
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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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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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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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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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#if !defined(BOOST_NO_STRING_APPEND) |
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dst.append(src.begin()+beg, src.begin()+end); |
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#else |
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dst += src.substr(beg, end-beg); |
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#endif |
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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( '%'); |
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bool ordered_args=true; |
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int max_argN=-1; |
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// A: find upper_bound on num_items and allocates arrays |
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int num_items = io::detail::upper_bound_from_fstring(buf, arg_mark, fac, exceptions()); |
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make_or_reuse_data(num_items); |
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// B: Now the real parsing of the format string : |
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num_items=0; |
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typename string_type::size_type i0=0, i1=0; |
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typename string_type::const_iterator it; |
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bool special_things=false; |
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int cur_item=0; |
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while( (i1=buf.find(arg_mark,i1)) != string_type::npos ) { |
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string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_; |
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if( buf[i1+1] == buf[i1] ) { // escaped mark, '%%' |
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io::detail::append_string(piece, buf, i0, i1+1); |
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i1+=2; i0=i1; |
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continue; |
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} |
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BOOST_ASSERT( static_cast<unsigned int>(cur_item) < items_.size() || cur_item==0); |
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if(i1!=i0) { |
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io::detail::append_string(piece, buf, i0, i1); |
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i0=i1; |
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} |
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++i1; |
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it = buf.begin()+i1; |
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bool parse_ok = io::detail::parse_printf_directive( |
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it, buf.end(), &items_[cur_item], fac, i1, exceptions()); |
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i1 = it - buf.begin(); |
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if( ! parse_ok ) // the directive will be printed verbatim |
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continue; |
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i0=i1; |
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items_[cur_item].compute_states(); // process complex options, like zeropad, into params |
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int argN=items_[cur_item].argN_; |
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if(argN == format_item_t::argN_ignored) |
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continue; |
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if(argN ==format_item_t::argN_no_posit) |
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ordered_args=false; |
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else if(argN == format_item_t::argN_tabulation) special_things=true; |
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else if(argN > max_argN) max_argN = argN; |
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++num_items; |
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++cur_item; |
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} // loop on %'s |
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BOOST_ASSERT(cur_item == num_items); |
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// store the final piece of string |
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{ |
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string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_; |
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io::detail::append_string(piece, buf, i0, buf.size()); |
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} |
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if( !ordered_args) { |
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if(max_argN >= 0 ) { // dont mix positional with non-positionnal directives |
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if(exceptions() & io::bad_format_string_bit) |
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boost::throw_exception(io::bad_format_string(max_argN, 0)); |
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// else do nothing. => positionnal arguments are processed as non-positionnal |
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} |
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// set things like it would have been with positional directives : |
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int non_ordered_items = 0; |
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for(int i=0; i< num_items; ++i) |
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if(items_[i].argN_ == format_item_t::argN_no_posit) { |
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items_[i].argN_ = non_ordered_items; |
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++non_ordered_items; |
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} |
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max_argN = non_ordered_items-1; |
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} |
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// C: set some member data : |
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items_.resize(num_items, format_item_t(io::detail::const_or_not(fac).widen( ' ')) ); |
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if(special_things) style_ |= special_needs; |
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num_args_ = max_argN + 1; |
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if(ordered_args) style_ |= ordered; |
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else style_ &= ~ordered; |
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return *this; |
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} |
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} // namespace boost |
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#endif // BOOST_FORMAT_PARSING_HPP
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