stdio-common/printf_fphex.c

   1 /* Print floating point number in hexadecimal notation according to ISO C99.
   2    Copyright (C) 1997-2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <ctype.h>
  21 #include <ieee754.h>
  22 #include <math.h>
  23 #include <printf.h>
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <wchar.h>
  28 #include <_itoa.h>
  29 #include <_itowa.h>
  30 #include <locale/localeinfo.h>
  31
  32 /* #define NDEBUG 1*/           /* Undefine this for debugging assertions.  */
  33 #include <assert.h>
  34
  35 /* This defines make it possible to use the same code for GNU C library and
  36    the GNU I/O library.  */
  37 #include <libioP.h>
  38 #define PUT(f, s, n) _IO_sputn (f, s, n)
  39 #define PAD(f, c, n) (wide ? _IO_wpadn (f, c, n) : _IO_padn (f, c, n))
  40 /* We use this file GNU C library and GNU I/O library.  So make
  41    names equal.  */
  42 #undef putc
  43 #define putc(c, f) (wide \
  44                      ? (int)_IO_putwc_unlocked (c, f) : _IO_putc_unlocked (c, f))
  45 #define size_t     _IO_size_t
  46 #define FILE         _IO_FILE
  47 \f
  48 /* Macros for doing the actual output.  */
  49
  50 #define outchar(ch)                                                           \
  51   do                                                                          \
  52     {                                                                         \
  53       register const int outc = (ch);                                         \
  54       if (putc (outc, fp) == EOF)                                             \
  55         return -1;                                                            \
  56       ++done;                                                                 \
  57     } while (0)
  58
  59 #define PRINT(ptr, wptr, len)                                                 \
  60   do                                                                          \
  61     {                                                                         \
  62       register size_t outlen = (len);                                         \
  63       if (wide)                                                               \
  64         while (outlen-- > 0)                                                  \
  65           outchar (*wptr++);                                                  \
  66       else                                                                    \
  67         while (outlen-- > 0)                                                  \
  68           outchar (*ptr++);                                                   \
  69     } while (0)
  70
  71 #define PADN(ch, len)                                                         \
  72   do                                                                          \
  73     {                                                                         \
  74       if (PAD (fp, ch, len) != len)                                           \
  75         return -1;                                                            \
  76       done += len;                                                            \
  77     }                                                                         \
  78   while (0)
  79
  80 #ifndef MIN
  81 # define MIN(a,b) ((a)<(b)?(a):(b))
  82 #endif
  83 \f
  84
  85 int
  86 __printf_fphex (FILE *fp,
  87                 const struct printf_info *info,
  88                 const void *const *args)
  89 {
  90   /* The floating-point value to output.  */
  91   union
  92     {
  93       union ieee754_double dbl;
  94       union ieee854_long_double ldbl;
  95     }
  96   fpnum;
  97
  98   /* Locale-dependent representation of decimal point.  */
  99   const char *decimal;
 100   wchar_t decimalwc;
 101
 102   /* "NaN" or "Inf" for the special cases.  */
 103   const char *special = NULL;
 104   const wchar_t *wspecial = NULL;
 105
 106   /* Buffer for the generated number string for the mantissa.  The
 107      maximal size for the mantissa is 128 bits.  */
 108   char numbuf[32];
 109   char *numstr;
 110   char *numend;
 111   wchar_t wnumbuf[32];
 112   wchar_t *wnumstr;
 113   wchar_t *wnumend;
 114   int negative;
 115
 116   /* The maximal exponent of two in decimal notation has 5 digits.  */
 117   char expbuf[5];
 118   char *expstr;
 119   wchar_t wexpbuf[5];
 120   wchar_t *wexpstr;
 121   int expnegative;
 122   int exponent;
 123
 124   /* Non-zero is mantissa is zero.  */
 125   int zero_mantissa;
 126
 127   /* The leading digit before the decimal point.  */
 128   char leading;
 129
 130   /* Precision.  */
 131   int precision = info->prec;
 132
 133   /* Width.  */
 134   int width = info->width;
 135
 136   /* Number of characters written.  */
 137   int done = 0;
 138
 139   /* Nonzero if this is output on a wide character stream.  */
 140   int wide = info->wide;
 141
 142
 143   /* Figure out the decimal point character.  */
 144   if (info->extra == 0)
 145     {
 146       decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
 147       decimalwc = _NL_CURRENT_WORD (LC_NUMERIC, _NL_NUMERIC_DECIMAL_POINT_WC);
 148     }
 149   else
 150     {
 151       decimal = _NL_CURRENT (LC_MONETARY, MON_DECIMAL_POINT);
 152       decimalwc = _NL_CURRENT_WORD (LC_MONETARY,
 153                                     _NL_MONETARY_DECIMAL_POINT_WC);
 154     }
 155   /* The decimal point character must never be zero.  */
 156   assert (*decimal != '\0' && decimalwc != L'\0');
 157
 158
 159   /* Fetch the argument value.  */
 160 #ifndef __NO_LONG_DOUBLE_MATH
 161   if (info->is_long_double && sizeof (long double) > sizeof (double))
 162     {
 163       fpnum.ldbl.d = *(const long double *) args[0];
 164
 165       /* Check for special values: not a number or infinity.  */
 166       if (__isnanl (fpnum.ldbl.d))
 167         {
 168           negative = fpnum.ldbl.ieee.negative != 0;
 169           if (isupper (info->spec))
 170             {
 171               special = "NAN";
 172               wspecial = L"NAN";
 173             }
 174           else
 175             {
 176               special = "nan";
 177               wspecial = L"nan";
 178             }
 179         }
 180       else
 181         {
 182           int res = __isinfl (fpnum.ldbl.d);
 183           if (res)
 184             {
 185               if (isupper (info->spec))
 186                 {
 187                   special = "INF";
 188                   wspecial = L"INF";
 189                 }
 190               else
 191                 {
 192                   special = "inf";
 193                   wspecial = L"inf";
 194                 }
 195               negative = res < 0;
 196             }
 197           else
 198             negative = signbit (fpnum.ldbl.d);
 199         }
 200     }
 201   else
 202 #endif  /* no long double */
 203     {
 204       fpnum.dbl.d = *(const double *) args[0];
 205
 206       /* Check for special values: not a number or infinity.  */
 207       if (__isnan (fpnum.dbl.d))
 208         {
 209           negative = fpnum.dbl.ieee.negative != 0;
 210           if (isupper (info->spec))
 211             {
 212               special = "NAN";
 213               wspecial = L"NAN";
 214             }
 215           else
 216             {
 217               special = "nan";
 218               wspecial = L"nan";
 219             }
 220         }
 221       else
 222         {
 223           int res = __isinf (fpnum.dbl.d);
 224           if (res)
 225             {
 226               if (isupper (info->spec))
 227                 {
 228                   special = "INF";
 229                   wspecial = L"INF";
 230                 }
 231               else
 232                 {
 233                   special = "inf";
 234                   wspecial = L"inf";
 235                 }
 236               negative = res < 0;
 237             }
 238           else
 239             negative = signbit (fpnum.dbl.d);
 240         }
 241     }
 242
 243   if (special)
 244     {
 245       int width = info->width;
 246
 247       if (negative || info->showsign || info->space)
 248         --width;
 249       width -= 3;
 250
 251       if (!info->left && width > 0)
 252         PADN (' ', width);
 253
 254       if (negative)
 255         outchar ('-');
 256       else if (info->showsign)
 257         outchar ('+');
 258       else if (info->space)
 259         outchar (' ');
 260
 261       PRINT (special, wspecial, 3);
 262
 263       if (info->left && width > 0)
 264         PADN (' ', width);
 265
 266       return done;
 267     }
 268
 269   if (info->is_long_double == 0 || sizeof (double) == sizeof (long double))
 270     {
 271       /* We have 52 bits of mantissa plus one implicit digit.  Since
 272          52 bits are representable without rest using hexadecimal
 273          digits we use only the implicit digits for the number before
 274          the decimal point.  */
 275       unsigned long long int num;
 276
 277       num = (((unsigned long long int) fpnum.dbl.ieee.mantissa0) << 32
 278              | fpnum.dbl.ieee.mantissa1);
 279
 280       zero_mantissa = num == 0;
 281
 282       if (sizeof (unsigned long int) > 6)
 283         {
 284           wnumstr = _itowa_word (num, wnumbuf + (sizeof wnumbuf) / sizeof (wchar_t), 16,
 285                                  info->spec == 'A');
 286           numstr = _itoa_word (num, numbuf + sizeof numbuf, 16,
 287                                info->spec == 'A');
 288         }
 289       else
 290         {
 291           wnumstr = _itowa (num, wnumbuf + sizeof wnumbuf / sizeof (wchar_t), 16,
 292                             info->spec == 'A');
 293           numstr = _itoa (num, numbuf + sizeof numbuf, 16,
 294                           info->spec == 'A');
 295         }
 296
 297       /* Fill with zeroes.  */
 298       while (wnumstr > wnumbuf + (sizeof wnumbuf - 52) / sizeof (wchar_t))
 299         {
 300           *--wnumstr = L'0';
 301           *--numstr = '0';
 302         }
 303
 304       leading = fpnum.dbl.ieee.exponent == 0 ? '0' : '1';
 305
 306       exponent = fpnum.dbl.ieee.exponent;
 307
 308       if (exponent == 0)
 309         {
 310           if (zero_mantissa)
 311             expnegative = 0;
 312           else
 313             {
 314               /* This is a denormalized number.  */
 315               expnegative = 1;
 316               exponent = IEEE754_DOUBLE_BIAS - 1;
 317             }
 318         }
 319       else if (exponent >= IEEE754_DOUBLE_BIAS)
 320         {
 321           expnegative = 0;
 322           exponent -= IEEE754_DOUBLE_BIAS;
 323         }
 324       else
 325         {
 326           expnegative = 1;
 327           exponent = -(exponent - IEEE754_DOUBLE_BIAS);
 328         }
 329     }
 330 #ifdef PRINT_FPHEX_LONG_DOUBLE
 331   else
 332     PRINT_FPHEX_LONG_DOUBLE;
 333 #endif
 334
 335   /* Look for trailing zeroes.  */
 336   if (! zero_mantissa)
 337     {
 338       wnumend = &wnumbuf[sizeof wnumbuf / sizeof wnumbuf[0]];
 339       numend = &numbuf[sizeof numbuf / sizeof numbuf[0]];
 340       while (wnumend[-1] == L'0')
 341         {
 342           --wnumend;
 343           --numend;
 344         }
 345
 346       if (precision == -1)
 347         precision = numend - numstr;
 348       else if (precision < numend - numstr
 349                && (numstr[precision] > '8'
 350                    || (('A' < '0' || 'a' < '0')
 351                        && numstr[precision] < '0')
 352                    || (numstr[precision] == '8'
 353                        && (precision + 1 < numend - numstr
 354                            /* Round to even.  */
 355                            || (precision > 0
 356                                && ((numstr[precision - 1] & 1)
 357                                    ^ (isdigit (numstr[precision - 1]) == 0)))
 358                            || (precision == 0
 359                                && ((leading & 1)
 360                                    ^ (isdigit (leading) == 0)))))))
 361         {
 362           /* Round up.  */
 363           int cnt = precision;
 364           while (--cnt >= 0)
 365             {
 366               char ch = numstr[cnt];
 367               /* We assume that the digits and the letters are ordered
 368                  like in ASCII.  This is true for the rest of GNU, too.  */
 369               if (ch == '9')
 370                 {
 371                   wnumstr[cnt] = (wchar_t) info->spec;
 372                   numstr[cnt] = info->spec;     /* This is tricky,
 373                                                    think about it!  */
 374                   break;
 375                 }
 376               else if (tolower (ch) < 'f')
 377                 {
 378                   ++numstr[cnt];
 379                   ++wnumstr[cnt];
 380                   break;
 381                 }
 382               else
 383                 {
 384                   numstr[cnt] = '0';
 385                   wnumstr[cnt] = L'0';
 386                 }
 387             }
 388           if (cnt < 0)
 389             {
 390               /* The mantissa so far was fff...f  Now increment the
 391                  leading digit.  Here it is again possible that we
 392                  get an overflow.  */
 393               if (leading == '9')
 394                 leading = info->spec;
 395               else if (tolower (leading) < 'f')
 396                 ++leading;
 397               else
 398                 {
 399                   leading = '1';
 400                   if (expnegative)
 401                     {
 402                       exponent -= 4;
 403                       if (exponent <= 0)
 404                         {
 405                           exponent = -exponent;
 406                           expnegative = 0;
 407                         }
 408                     }
 409                   else
 410                     exponent += 4;
 411                 }
 412             }
 413         }
 414     }
 415   else
 416     {
 417       if (precision == -1)
 418         precision = 0;
 419       numend = numstr;
 420       wnumend = wnumstr;
 421     }
 422
 423   /* Now we can compute the exponent string.  */
 424   expstr = _itoa_word (exponent, expbuf + sizeof expbuf, 10, 0);
 425   wexpstr = _itowa_word (exponent,
 426                          wexpbuf + sizeof wexpbuf / sizeof (wchar_t), 10, 0);
 427
 428   /* Now we have all information to compute the size.  */
 429   width -= ((negative || info->showsign || info->space)
 430             /* Sign.  */
 431             + 2    + 1 + 0 + precision + 1 + 1
 432             /* 0x    h   .   hhh         P   ExpoSign.  */
 433             + ((expbuf + sizeof expbuf) - expstr));
 434             /* Exponent.  */
 435
 436   /* Count the decimal point.
 437      A special case when the mantissa or the precision is zero and the `#'
 438      is not given.  In this case we must not print the decimal point.  */
 439   if (precision > 0 || info->alt)
 440     width -= wide ? 1 : strlen (decimal);
 441
 442   if (!info->left && info->pad != '0' && width > 0)
 443     PADN (' ', width);
 444
 445   if (negative)
 446     outchar ('-');
 447   else if (info->showsign)
 448     outchar ('+');
 449   else if (info->space)
 450     outchar (' ');
 451
 452   outchar ('0');
 453   if ('X' - 'A' == 'x' - 'a')
 454     outchar (info->spec + ('x' - 'a'));
 455   else
 456     outchar (info->spec == 'A' ? 'X' : 'x');
 457
 458   if (!info->left && info->pad == '0' && width > 0)
 459     PADN ('0', width);
 460
 461   outchar (leading);
 462
 463   if (precision > 0 || info->alt)
 464     {
 465       const wchar_t *wtmp = &decimalwc;
 466       PRINT (decimal, wtmp, wide ? 1 : strlen (decimal));
 467     }
 468
 469   if (precision > 0)
 470     {
 471       ssize_t tofill = precision - (numend - numstr);
 472       PRINT (numstr, wnumstr, MIN (numend - numstr, precision));
 473       if (tofill > 0)
 474         PADN ('0', tofill);
 475     }
 476
 477   if ('P' - 'A' == 'p' - 'a')
 478     outchar (info->spec + ('p' - 'a'));
 479   else
 480     outchar (info->spec == 'A' ? 'P' : 'p');
 481
 482   outchar (expnegative ? '-' : '+');
 483
 484   PRINT (expstr, wexpstr, (expbuf + sizeof expbuf) - expstr);
 485
 486   if (info->left && info->pad != '0' && width > 0)
 487     PADN (info->pad, width);
 488
 489   return done;
 490 }