ceph/src/boost/libs/format/include/boost/format/parsing.hpp

   1 // ----------------------------------------------------------------------------
   2 // parsing.hpp :  implementation of the parsing member functions
   3 //                      ( parse, parse_printf_directive)
   4 // ----------------------------------------------------------------------------
   5
   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)
   9
  10 // see http://www.boost.org/libs/format for library home page
  11
  12 // ----------------------------------------------------------------------------
  13
  14 #ifndef BOOST_FORMAT_PARSING_HPP
  15 #define BOOST_FORMAT_PARSING_HPP
  16
  17
  18 #include <boost/format/format_class.hpp>
  19 #include <boost/format/exceptions.hpp>
  20 #include <boost/throw_exception.hpp>
  21 #include <boost/assert.hpp>
  22 #include <boost/config.hpp>
  23
  24
  25 namespace boost {
  26 namespace io {
  27 namespace detail {
  28
  29 #if defined(BOOST_NO_STD_LOCALE)
  30     // streams will be used for narrow / widen. but these methods are not const
  31     template<class T>
  32     T& const_or_not(const T& x) {
  33         return const_cast<T&> (x);
  34     }
  35 #else
  36     template<class T>
  37     const T& const_or_not(const T& x) {
  38         return x;
  39     }
  40 #endif
  41
  42     template<class Ch, class Facet> inline
  43     char wrap_narrow(const Facet& fac, Ch c, char deflt) {
  44         return const_or_not(fac).narrow(c, deflt);
  45     }
  46
  47     template<class Ch, class Facet> inline
  48     bool wrap_isdigit(const Facet& fac, Ch c) {
  49 #if ! defined( BOOST_NO_LOCALE_ISDIGIT )
  50         return fac.is(std::ctype<Ch>::digit, c);
  51 # else
  52         (void) fac;     // remove "unused parameter" warning
  53         using namespace std;
  54         return isdigit(c) != 0;
  55 #endif
  56     }
  57
  58     template<class Iter, class Facet>
  59     Iter wrap_scan_notdigit(const Facet & fac, Iter beg, Iter end) {
  60         using namespace std;
  61         for( ; beg!=end && wrap_isdigit(fac, *beg); ++beg) ;
  62         return beg;
  63     }
  64
  65
  66     // Input : [start, last) iterators range and a
  67     //          a Facet to use its widen/narrow member function
  68     // Effects : read sequence and convert digits into integral n, of type Res
  69     // Returns : n
  70     template<class Res, class Iter, class Facet>
  71     Iter str2int (const Iter & start, const Iter & last, Res & res,
  72                  const Facet& fac)
  73     {
  74         using namespace std;
  75         Iter it;
  76         res=0;
  77         for(it=start; it != last && wrap_isdigit(fac, *it); ++it ) {
  78             char cur_ch = wrap_narrow(fac, *it, 0); // cant fail.
  79             res *= 10;
  80             res += cur_ch - '0'; // 22.2.1.1.2.13 of the C++ standard
  81         }
  82         return it;
  83     }
  84
  85     // skip printf's "asterisk-fields" directives in the format-string buf
  86     // Input : char string, with starting index *pos_p
  87     //         a Facet merely to use its widen/narrow member function
  88     // Effects : advance *pos_p by skipping printf's asterisk fields.
  89     // Returns : nothing
  90     template<class Iter, class Facet>
  91     Iter skip_asterisk(Iter start, Iter last, const Facet& fac)
  92     {
  93         using namespace std;
  94         ++ start;
  95         start = wrap_scan_notdigit(fac, start, last);
  96         if(start!=last && *start== const_or_not(fac).widen( '$') )
  97             ++start;
  98         return start;
  99     }
 100
 101
 102     // auxiliary func called by parse_printf_directive
 103     // for centralising error handling
 104     // it either throws if user sets the corresponding flag, or does nothing.
 105     inline void maybe_throw_exception(unsigned char exceptions,
 106                                       std::size_t pos, std::size_t size)
 107     {
 108         if(exceptions & io::bad_format_string_bit)
 109             boost::throw_exception(io::bad_format_string(pos, size) );
 110     }
 111
 112
 113     // Input: the position of a printf-directive in the format-string
 114     //    a basic_ios& merely to use its widen/narrow member function
 115     //    a bitset'exceptions' telling whether to throw exceptions on errors.
 116     // Returns:
 117     //  true if parse succeeded (ignore some errors if exceptions disabled)
 118     //  false if it failed so bad that the directive should be printed verbatim
 119     // Effects:
 120     //  start is incremented so that *start is the first char after
 121     //     this directive
 122     //  *fpar is set with the parameters read in the directive
 123     template<class Ch, class Tr, class Alloc, class Iter, class Facet>
 124     bool parse_printf_directive(Iter & start, const Iter& last,
 125                                 detail::format_item<Ch, Tr, Alloc> * fpar,
 126                                 const Facet& fac,
 127                                 std::size_t offset, unsigned char exceptions)
 128     {
 129         typedef typename basic_format<Ch, Tr, Alloc>::format_item_t format_item_t;
 130
 131         fpar->argN_ = format_item_t::argN_no_posit;  // if no positional-directive
 132         bool precision_set = false;
 133         bool in_brackets=false;
 134         Iter start0 = start;
 135         std::size_t fstring_size = last-start0+offset;
 136
 137         if(start>= last) { // empty directive : this is a trailing %
 138                 maybe_throw_exception(exceptions, start-start0 + offset, fstring_size);
 139                 return false;
 140         }
 141
 142         if(*start== const_or_not(fac).widen( '|')) {
 143             in_brackets=true;
 144             if( ++start >= last ) {
 145                 maybe_throw_exception(exceptions, start-start0 + offset, fstring_size);
 146                 return false;
 147             }
 148         }
 149
 150         // the flag '0' would be picked as a digit for argument order, but here it's a flag :
 151         if(*start== const_or_not(fac).widen( '0'))
 152             goto parse_flags;
 153
 154         // handle argument order (%2$d)  or possibly width specification: %2d
 155         if(wrap_isdigit(fac, *start)) {
 156             int n;
 157             start = str2int(start, last, n, fac);
 158             if( start >= last ) {
 159                 maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 160                 return false;
 161             }
 162
 163             // %N% case : this is already the end of the directive
 164             if( *start ==  const_or_not(fac).widen( '%') ) {
 165                 fpar->argN_ = n-1;
 166                 ++start;
 167                 if( in_brackets)
 168                     maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 169                 // but don't return.  maybe "%" was used in lieu of '$', so we go on.
 170                 else
 171                     return true;
 172             }
 173
 174             if ( *start== const_or_not(fac).widen( '$') ) {
 175                 fpar->argN_ = n-1;
 176                 ++start;
 177             }
 178             else {
 179                 // non-positionnal directive
 180                 fpar->fmtstate_.width_ = n;
 181                 fpar->argN_  = format_item_t::argN_no_posit;
 182                 goto parse_precision;
 183             }
 184         }
 185
 186       parse_flags:
 187         // handle flags
 188         while ( start != last) { // as long as char is one of + - = _ # 0 l h   or ' '
 189             // misc switches
 190             switch ( wrap_narrow(fac, *start, 0)) {
 191             case '\'' : break; // no effect yet. (painful to implement)
 192             case 'l':
 193             case 'h':  // short/long modifier : for printf-comaptibility (no action needed)
 194                 break;
 195             case '-':
 196                 fpar->fmtstate_.flags_ |= std::ios_base::left;
 197                 break;
 198             case '=':
 199                 fpar->pad_scheme_ |= format_item_t::centered;
 200                 break;
 201             case '_':
 202                 fpar->fmtstate_.flags_ |= std::ios_base::internal;
 203                 break;
 204             case ' ':
 205                 fpar->pad_scheme_ |= format_item_t::spacepad;
 206                 break;
 207             case '+':
 208                 fpar->fmtstate_.flags_ |= std::ios_base::showpos;
 209                 break;
 210             case '0':
 211                 fpar->pad_scheme_ |= format_item_t::zeropad;
 212                 // need to know alignment before really setting flags,
 213                 // so just add 'zeropad' flag for now, it will be processed later.
 214                 break;
 215             case '#':
 216                 fpar->fmtstate_.flags_ |= std::ios_base::showpoint | std::ios_base::showbase;
 217                 break;
 218             default:
 219                 goto parse_width;
 220             }
 221             ++start;
 222         } // loop on flag.
 223
 224         if( start>=last) {
 225             maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 226             return true;
 227         }
 228       parse_width:
 229         // handle width spec
 230         // first skip 'asterisk fields' :  *, or *N$
 231         if(*start == const_or_not(fac).widen( '*') )
 232             start = skip_asterisk(start, last, fac);
 233         if(start!=last && wrap_isdigit(fac, *start))
 234             start = str2int(start, last, fpar->fmtstate_.width_, fac);
 235
 236       parse_precision:
 237         if( start>= last) {
 238             maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 239             return true;
 240         }
 241         // handle precision spec
 242         if (*start== const_or_not(fac).widen( '.')) {
 243             ++start;
 244             if(start != last && *start == const_or_not(fac).widen( '*') )
 245                 start = skip_asterisk(start, last, fac);
 246             if(start != last && wrap_isdigit(fac, *start)) {
 247                 start = str2int(start, last, fpar->fmtstate_.precision_, fac);
 248                 precision_set = true;
 249             }
 250             else
 251                 fpar->fmtstate_.precision_ =0;
 252         }
 253
 254         // handle  formatting-type flags :
 255         while( start != last && ( *start== const_or_not(fac).widen( 'l')
 256                                   || *start== const_or_not(fac).widen( 'L')
 257                                   || *start== const_or_not(fac).widen( 'h')) )
 258             ++start;
 259         if( start>=last) {
 260             maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 261             return true;
 262         }
 263
 264         if( in_brackets && *start== const_or_not(fac).widen( '|') ) {
 265             ++start;
 266             return true;
 267         }
 268         switch ( wrap_narrow(fac, *start, 0) ) {
 269         case 'X':
 270             fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
 271             BOOST_FALLTHROUGH;
 272         case 'p': // pointer => set hex.
 273         case 'x':
 274             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
 275             fpar->fmtstate_.flags_ |= std::ios_base::hex;
 276             break;
 277
 278         case 'o':
 279             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
 280             fpar->fmtstate_.flags_ |=  std::ios_base::oct;
 281             break;
 282
 283         case 'E':
 284             fpar->fmtstate_.flags_ |=  std::ios_base::uppercase;
 285             BOOST_FALLTHROUGH;
 286         case 'e':
 287             fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
 288             fpar->fmtstate_.flags_ |=  std::ios_base::scientific;
 289
 290             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
 291             fpar->fmtstate_.flags_ |=  std::ios_base::dec;
 292             break;
 293
 294         case 'f':
 295             fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
 296             fpar->fmtstate_.flags_ |=  std::ios_base::fixed;
 297             BOOST_FALLTHROUGH;
 298         case 'u':
 299         case 'd':
 300         case 'i':
 301             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
 302             fpar->fmtstate_.flags_ |=  std::ios_base::dec;
 303             break;
 304
 305         case 'T':
 306             ++start;
 307             if( start >= last)
 308                 maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 309             else
 310                 fpar->fmtstate_.fill_ = *start;
 311             fpar->pad_scheme_ |= format_item_t::tabulation;
 312             fpar->argN_ = format_item_t::argN_tabulation;
 313             break;
 314         case 't':
 315             fpar->fmtstate_.fill_ = const_or_not(fac).widen( ' ');
 316             fpar->pad_scheme_ |= format_item_t::tabulation;
 317             fpar->argN_ = format_item_t::argN_tabulation;
 318             break;
 319
 320         case 'G':
 321             fpar->fmtstate_.flags_ |= std::ios_base::uppercase;
 322             break;
 323         case 'g': // 'g' conversion is default for floats.
 324             fpar->fmtstate_.flags_ &= ~std::ios_base::basefield;
 325             fpar->fmtstate_.flags_ |=  std::ios_base::dec;
 326
 327             // CLEAR all floatield flags, so stream will CHOOSE
 328             fpar->fmtstate_.flags_ &= ~std::ios_base::floatfield;
 329             break;
 330
 331         case 'C':
 332         case 'c':
 333             fpar->truncate_ = 1;
 334             break;
 335         case 'S':
 336         case 's':
 337             if(precision_set) // handle truncation manually, with own parameter.
 338                 fpar->truncate_ = fpar->fmtstate_.precision_;
 339             fpar->fmtstate_.precision_ = 6; // default stream precision.
 340             break;
 341         case 'n' :
 342             fpar->argN_ = format_item_t::argN_ignored;
 343             break;
 344         default:
 345             maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 346         }
 347         ++start;
 348
 349         if( in_brackets ) {
 350             if( start != last && *start== const_or_not(fac).widen( '|') ) {
 351                 ++start;
 352                 return true;
 353             }
 354             else  maybe_throw_exception(exceptions, start-start0+offset, fstring_size);
 355         }
 356         return true;
 357     }
 358     // -end parse_printf_directive()
 359
 360     template<class String, class Facet>
 361     int upper_bound_from_fstring(const String& buf,
 362                                  const typename String::value_type arg_mark,
 363                                  const Facet& fac,
 364                                  unsigned char exceptions)
 365     {
 366         // quick-parsing of the format-string to count arguments mark (arg_mark, '%')
 367         // returns : upper bound on the number of format items in the format strings
 368         using namespace boost::io;
 369         typename String::size_type i1=0;
 370         int num_items=0;
 371         while( (i1=buf.find(arg_mark,i1)) != String::npos ) {
 372             if( i1+1 >= buf.size() ) {
 373                 if(exceptions & bad_format_string_bit)
 374                     boost::throw_exception(bad_format_string(i1, buf.size() )); // must not end in ".. %"
 375                 else {
 376                   ++num_items;
 377                   break;
 378                 }
 379             }
 380             if(buf[i1+1] == buf[i1] ) {// escaped "%%"
 381                 i1+=2; continue;
 382             }
 383
 384             ++i1;
 385             // in case of %N% directives, dont count it double (wastes allocations..) :
 386             i1 = detail::wrap_scan_notdigit(fac, buf.begin()+i1, buf.end()) - buf.begin();
 387             if( i1 < buf.size() && buf[i1] == arg_mark )
 388                 ++i1;
 389             ++num_items;
 390         }
 391         return num_items;
 392     }
 393     template<class String> inline
 394     void append_string(String& dst, const String& src,
 395                        const typename String::size_type beg,
 396                        const typename String::size_type end) {
 397         dst.append(src.begin()+beg, src.begin()+end);
 398     }
 399
 400 } // detail namespace
 401 } // io namespace
 402
 403
 404
 405 // -----------------------------------------------
 406 //  format :: parse(..)
 407
 408     template<class Ch, class Tr, class Alloc>
 409     basic_format<Ch, Tr, Alloc>& basic_format<Ch, Tr, Alloc>::
 410     parse (const string_type& buf) {
 411         // parse the format-string
 412         using namespace std;
 413 #if !defined(BOOST_NO_STD_LOCALE)
 414         const std::ctype<Ch> & fac = BOOST_USE_FACET( std::ctype<Ch>, getloc());
 415 #else
 416         io::basic_oaltstringstream<Ch, Tr, Alloc> fac;
 417         //has widen and narrow even on compilers without locale
 418 #endif
 419
 420         const Ch arg_mark = io::detail::const_or_not(fac).widen( '%');
 421         bool ordered_args=true;
 422         int max_argN=-1;
 423
 424         // A: find upper_bound on num_items and allocates arrays
 425         int num_items = io::detail::upper_bound_from_fstring(buf, arg_mark, fac, exceptions());
 426         make_or_reuse_data(num_items);
 427
 428         // B: Now the real parsing of the format string :
 429         num_items=0;
 430         typename string_type::size_type i0=0, i1=0;
 431         typename string_type::const_iterator it;
 432         bool special_things=false;
 433         int cur_item=0;
 434         while( (i1=buf.find(arg_mark,i1)) != string_type::npos ) {
 435             string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
 436             if( buf[i1+1] == buf[i1] ) { // escaped mark, '%%'
 437                 io::detail::append_string(piece, buf, i0, i1+1);
 438                 i1+=2; i0=i1;
 439                 continue;
 440             }
 441             BOOST_ASSERT(  static_cast<unsigned int>(cur_item) < items_.size() || cur_item==0);
 442
 443             if(i1!=i0) {
 444                 io::detail::append_string(piece, buf, i0, i1);
 445                 i0=i1;
 446             }
 447             ++i1;
 448             it = buf.begin()+i1;
 449             bool parse_ok = io::detail::parse_printf_directive(
 450                 it, buf.end(), &items_[cur_item], fac, i1, exceptions());
 451             i1 = it - buf.begin();
 452             if( ! parse_ok ) // the directive will be printed verbatim
 453                 continue;
 454             i0=i1;
 455             items_[cur_item].compute_states(); // process complex options, like zeropad, into params
 456
 457             int argN=items_[cur_item].argN_;
 458             if(argN == format_item_t::argN_ignored)
 459                 continue;
 460             if(argN ==format_item_t::argN_no_posit)
 461                 ordered_args=false;
 462             else if(argN == format_item_t::argN_tabulation) special_things=true;
 463             else if(argN > max_argN) max_argN = argN;
 464             ++num_items;
 465             ++cur_item;
 466         } // loop on %'s
 467         BOOST_ASSERT(cur_item == num_items);
 468
 469         // store the final piece of string
 470         {
 471             string_type & piece = (cur_item==0) ? prefix_ : items_[cur_item-1].appendix_;
 472             io::detail::append_string(piece, buf, i0, buf.size());
 473         }
 474
 475         if( !ordered_args) {
 476             if(max_argN >= 0 ) {  // dont mix positional with non-positionnal directives
 477                 if(exceptions() & io::bad_format_string_bit)
 478                     boost::throw_exception(
 479                         io::bad_format_string(static_cast<std::size_t>(max_argN), 0));
 480                 // else do nothing. => positionnal arguments are processed as non-positionnal
 481             }
 482             // set things like it would have been with positional directives :
 483             int non_ordered_items = 0;
 484             for(int i=0; i< num_items; ++i)
 485                 if(items_[i].argN_ == format_item_t::argN_no_posit) {
 486                     items_[i].argN_ = non_ordered_items;
 487                     ++non_ordered_items;
 488                 }
 489             max_argN = non_ordered_items-1;
 490         }
 491
 492         // C: set some member data :
 493         items_.resize(num_items, format_item_t(io::detail::const_or_not(fac).widen( ' ')) );
 494
 495         if(special_things) style_ |= special_needs;
 496         num_args_ = max_argN + 1;
 497         if(ordered_args) style_ |=  ordered;
 498         else style_ &= ~ordered;
 499         return *this;
 500     }
 501
 502 } // namespace boost
 503
 504
 505 #endif //  BOOST_FORMAT_PARSING_HPP