stdio-common/printf_fphex.c

   1 /* Print floating point number in hexadecimal notation according to ISO C99.
   2    Copyright (C) 1997-2002,2004,2006 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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <ctype.h>
  22 #include <ieee754.h>
  23 #include <math.h>
  24 #include <printf.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <wchar.h>
  29 #include "_itoa.h"
  30 #include "_itowa.h"
  31 #include <locale/localeinfo.h>
  32
  33 /* #define NDEBUG 1*/           /* Undefine this for debugging assertions.  */
  34 #include <assert.h>
  35
  36 /* This defines make it possible to use the same code for GNU C library and
  37    the GNU I/O library.  */
  38 #ifdef USE_IN_LIBIO
  39 # include <libioP.h>
  40 # define PUT(f, s, n) _IO_sputn (f, s, n)
  41 # define PAD(f, c, n) (wide ? _IO_wpadn (f, c, n) : INTUSE(_IO_padn) (f, c, n))
  42 /* We use this file GNU C library and GNU I/O library.  So make
  43    names equal.  */
  44 # undef putc
  45 # define putc(c, f) (wide \
  46                      ? (int)_IO_putwc_unlocked (c, f) : _IO_putc_unlocked (c, f))
  47 # define size_t     _IO_size_t
  48 # define FILE        _IO_FILE
  49 #else   /* ! USE_IN_LIBIO */
  50 # define PUT(f, s, n) fwrite (s, 1, n, f)
  51 # define PAD(f, c, n) __printf_pad (f, c, n)
  52 ssize_t __printf_pad (FILE *, char pad, int n) __THROW; /* In vfprintf.c.  */
  53 #endif  /* USE_IN_LIBIO */
  54 \f
  55 /* Macros for doing the actual output.  */
  56
  57 #define outchar(ch)                                                           \
  58   do                                                                          \
  59     {                                                                         \
  60       register const int outc = (ch);                                         \
  61       if (putc (outc, fp) == EOF)                                             \
  62         return -1;                                                            \
  63       ++done;                                                                 \
  64     } while (0)
  65
  66 #define PRINT(ptr, wptr, len)                                                 \
  67   do                                                                          \
  68     {                                                                         \
  69       register size_t outlen = (len);                                         \
  70       if (wide)                                                               \
  71         while (outlen-- > 0)                                                  \
  72           outchar (*wptr++);                                                  \
  73       else                                                                    \
  74         while (outlen-- > 0)                                                  \
  75           outchar (*ptr++);                                                   \
  76     } while (0)
  77
  78 #define PADN(ch, len)                                                         \
  79   do                                                                          \
  80     {                                                                         \
  81       if (PAD (fp, ch, len) != len)                                           \
  82         return -1;                                                            \
  83       done += len;                                                            \
  84     }                                                                         \
  85   while (0)
  86
  87 #ifndef MIN
  88 # define MIN(a,b) ((a)<(b)?(a):(b))
  89 #endif
  90 \f
  91
  92 int
  93 __printf_fphex (FILE *fp,
  94                 const struct printf_info *info,
  95                 const void *const *args)
  96 {
  97   /* The floating-point value to output.  */
  98   union
  99     {
 100       union ieee754_double dbl;
 101       union ieee854_long_double ldbl;
 102     }
 103   fpnum;
 104
 105   /* Locale-dependent representation of decimal point.  */
 106   const char *decimal;
 107   wchar_t decimalwc;
 108
 109   /* "NaN" or "Inf" for the special cases.  */
 110   const char *special = NULL;
 111   const wchar_t *wspecial = NULL;
 112
 113   /* Buffer for the generated number string for the mantissa.  The
 114      maximal size for the mantissa is 128 bits.  */
 115   char numbuf[32];
 116   char *numstr;
 117   char *numend;
 118   wchar_t wnumbuf[32];
 119   wchar_t *wnumstr;
 120   wchar_t *wnumend;
 121   int negative;
 122
 123   /* The maximal exponent of two in decimal notation has 5 digits.  */
 124   char expbuf[5];
 125   char *expstr;
 126   wchar_t wexpbuf[5];
 127   wchar_t *wexpstr;
 128   int expnegative;
 129   int exponent;
 130
 131   /* Non-zero is mantissa is zero.  */
 132   int zero_mantissa;
 133
 134   /* The leading digit before the decimal point.  */
 135   char leading;
 136
 137   /* Precision.  */
 138   int precision = info->prec;
 139
 140   /* Width.  */
 141   int width = info->width;
 142
 143   /* Number of characters written.  */
 144   int done = 0;
 145
 146   /* Nonzero if this is output on a wide character stream.  */
 147   int wide = info->wide;
 148
 149
 150   /* Figure out the decimal point character.  */
 151   if (info->extra == 0)
 152     {
 153       decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
 154       decimalwc = _NL_CURRENT_WORD (LC_NUMERIC, _NL_NUMERIC_DECIMAL_POINT_WC);
 155     }
 156   else
 157     {
 158       decimal = _NL_CURRENT (LC_MONETARY, MON_DECIMAL_POINT);
 159       decimalwc = _NL_CURRENT_WORD (LC_MONETARY,
 160                                     _NL_MONETARY_DECIMAL_POINT_WC);
 161     }
 162   /* The decimal point character must never be zero.  */
 163   assert (*decimal != '\0' && decimalwc != L'\0');
 164
 165
 166   /* Fetch the argument value.  */
 167 #ifndef __NO_LONG_DOUBLE_MATH
 168   if (info->is_long_double && sizeof (long double) > sizeof (double))
 169     {
 170       fpnum.ldbl.d = *(const long double *) args[0];
 171
 172       /* Check for special values: not a number or infinity.  */
 173       if (__isnanl (fpnum.ldbl.d))
 174         {
 175           if (isupper (info->spec))
 176             {
 177               special = "NAN";
 178               wspecial = L"NAN";
 179             }
 180           else
 181             {
 182               special = "nan";
 183               wspecial = L"nan";
 184             }
 185           negative = 0;
 186         }
 187       else
 188         {
 189           if (__isinfl (fpnum.ldbl.d))
 190             {
 191               if (isupper (info->spec))
 192                 {
 193                   special = "INF";
 194                   wspecial = L"INF";
 195                 }
 196               else
 197                 {
 198                   special = "inf";
 199                   wspecial = L"inf";
 200                 }
 201             }
 202
 203           negative = signbit (fpnum.ldbl.d);
 204         }
 205     }
 206   else
 207 #endif  /* no long double */
 208     {
 209       fpnum.dbl.d = *(const double *) args[0];
 210
 211       /* Check for special values: not a number or infinity.  */
 212       if (__isnan (fpnum.dbl.d))
 213         {
 214           if (isupper (info->spec))
 215             {
 216               special = "NAN";
 217               wspecial = L"NAN";
 218             }
 219           else
 220             {
 221               special = "nan";
 222               wspecial = L"nan";
 223             }
 224           negative = 0;
 225         }
 226       else
 227         {
 228           if (__isinf (fpnum.dbl.d))
 229             {
 230               if (isupper (info->spec))
 231                 {
 232                   special = "INF";
 233                   wspecial = L"INF";
 234                 }
 235               else
 236                 {
 237                   special = "inf";
 238                   wspecial = L"inf";
 239                 }
 240             }
 241
 242           negative = signbit (fpnum.dbl.d);
 243         }
 244     }
 245
 246   if (special)
 247     {
 248       int width = info->width;
 249
 250       if (negative || info->showsign || info->space)
 251         --width;
 252       width -= 3;
 253
 254       if (!info->left && width > 0)
 255         PADN (' ', width);
 256
 257       if (negative)
 258         outchar ('-');
 259       else if (info->showsign)
 260         outchar ('+');
 261       else if (info->space)
 262         outchar (' ');
 263
 264       PRINT (special, wspecial, 3);
 265
 266       if (info->left && width > 0)
 267         PADN (' ', width);
 268
 269       return done;
 270     }
 271
 272   if (info->is_long_double == 0 || sizeof (double) == sizeof (long double))
 273     {
 274       /* We have 52 bits of mantissa plus one implicit digit.  Since
 275          52 bits are representable without rest using hexadecimal
 276          digits we use only the implicit digits for the number before
 277          the decimal point.  */
 278       unsigned long long int num;
 279
 280       num = (((unsigned long long int) fpnum.dbl.ieee.mantissa0) << 32
 281              | fpnum.dbl.ieee.mantissa1);
 282
 283       zero_mantissa = num == 0;
 284
 285       if (sizeof (unsigned long int) > 6)
 286         {
 287           wnumstr = _itowa_word (num, wnumbuf + (sizeof wnumbuf) / sizeof (wchar_t), 16,
 288                                  info->spec == 'A');
 289           numstr = _itoa_word (num, numbuf + sizeof numbuf, 16,
 290                                info->spec == 'A');
 291         }
 292       else
 293         {
 294           wnumstr = _itowa (num, wnumbuf + sizeof wnumbuf / sizeof (wchar_t), 16,
 295                             info->spec == 'A');
 296           numstr = _itoa (num, numbuf + sizeof numbuf, 16,
 297                           info->spec == 'A');
 298         }
 299
 300       /* Fill with zeroes.  */
 301       while (wnumstr > wnumbuf + (sizeof wnumbuf - 52) / sizeof (wchar_t))
 302         {
 303           *--wnumstr = L'0';
 304           *--numstr = '0';
 305         }
 306
 307       leading = fpnum.dbl.ieee.exponent == 0 ? '0' : '1';
 308
 309       exponent = fpnum.dbl.ieee.exponent;
 310
 311       if (exponent == 0)
 312         {
 313           if (zero_mantissa)
 314             expnegative = 0;
 315           else
 316             {
 317               /* This is a denormalized number.  */
 318               expnegative = 1;
 319               exponent = IEEE754_DOUBLE_BIAS - 1;
 320             }
 321         }
 322       else if (exponent >= IEEE754_DOUBLE_BIAS)
 323         {
 324           expnegative = 0;
 325           exponent -= IEEE754_DOUBLE_BIAS;
 326         }
 327       else
 328         {
 329           expnegative = 1;
 330           exponent = -(exponent - IEEE754_DOUBLE_BIAS);
 331         }
 332     }
 333 #ifdef PRINT_FPHEX_LONG_DOUBLE
 334   else
 335     PRINT_FPHEX_LONG_DOUBLE;
 336 #endif
 337
 338   /* Look for trailing zeroes.  */
 339   if (! zero_mantissa)
 340     {
 341       wnumend = &wnumbuf[sizeof wnumbuf / sizeof wnumbuf[0]];
 342       numend = &numbuf[sizeof numbuf / sizeof numbuf[0]];
 343       while (wnumend[-1] == L'0')
 344         {
 345           --wnumend;
 346           --numend;
 347         }
 348
 349       if (precision == -1)
 350         precision = numend - numstr;
 351       else if (precision < numend - numstr
 352                && (numstr[precision] > '8'
 353                    || (('A' < '0' || 'a' < '0')
 354                        && numstr[precision] < '0')
 355                    || (numstr[precision] == '8'
 356                        && (precision + 1 < numend - numstr
 357                            /* Round to even.  */
 358                            || (precision > 0
 359                                && ((numstr[precision - 1] & 1)
 360                                    ^ (isdigit (numstr[precision - 1]) == 0)))
 361                            || (precision == 0
 362                                && ((leading & 1)
 363                                    ^ (isdigit (leading) == 0)))))))
 364         {
 365           /* Round up.  */
 366           int cnt = precision;
 367           while (--cnt >= 0)
 368             {
 369               char ch = numstr[cnt];
 370               /* We assume that the digits and the letters are ordered
 371                  like in ASCII.  This is true for the rest of GNU, too.  */
 372               if (ch == '9')
 373                 {
 374                   wnumstr[cnt] = (wchar_t) info->spec;
 375                   numstr[cnt] = info->spec;     /* This is tricky,
 376                                                    think about it!  */
 377                   break;
 378                 }
 379               else if (tolower (ch) < 'f')
 380                 {
 381                   ++numstr[cnt];
 382                   ++wnumstr[cnt];
 383                   break;
 384                 }
 385               else
 386                 {
 387                   numstr[cnt] = '0';
 388                   wnumstr[cnt] = L'0';
 389                 }
 390             }
 391           if (cnt < 0)
 392             {
 393               /* The mantissa so far was fff...f  Now increment the
 394                  leading digit.  Here it is again possible that we
 395                  get an overflow.  */
 396               if (leading == '9')
 397                 leading = info->spec;
 398               else if (tolower (leading) < 'f')
 399                 ++leading;
 400               else
 401                 {
 402                   leading = '1';
 403                   if (expnegative)
 404                     {
 405                       exponent -= 4;
 406                       if (exponent <= 0)
 407                         {
 408                           exponent = -exponent;
 409                           expnegative = 0;
 410                         }
 411                     }
 412                   else
 413                     exponent += 4;
 414                 }
 415             }
 416         }
 417     }
 418   else
 419     {
 420       if (precision == -1)
 421         precision = 0;
 422       numend = numstr;
 423       wnumend = wnumstr;
 424     }
 425
 426   /* Now we can compute the exponent string.  */
 427   expstr = _itoa_word (exponent, expbuf + sizeof expbuf, 10, 0);
 428   wexpstr = _itowa_word (exponent,
 429                          wexpbuf + sizeof wexpbuf / sizeof (wchar_t), 10, 0);
 430
 431   /* Now we have all information to compute the size.  */
 432   width -= ((negative || info->showsign || info->space)
 433             /* Sign.  */
 434             + 2    + 1 + 0 + precision + 1 + 1
 435             /* 0x    h   .   hhh         P   ExpoSign.  */
 436             + ((expbuf + sizeof expbuf) - expstr));
 437             /* Exponent.  */
 438
 439   /* Count the decimal point.
 440      A special case when the mantissa or the precision is zero and the `#'
 441      is not given.  In this case we must not print the decimal point.  */
 442   if (precision > 0 || info->alt)
 443     width -= wide ? 1 : strlen (decimal);
 444
 445   if (!info->left && info->pad != '0' && width > 0)
 446     PADN (' ', width);
 447
 448   if (negative)
 449     outchar ('-');
 450   else if (info->showsign)
 451     outchar ('+');
 452   else if (info->space)
 453     outchar (' ');
 454
 455   outchar ('0');
 456   if ('X' - 'A' == 'x' - 'a')
 457     outchar (info->spec + ('x' - 'a'));
 458   else
 459     outchar (info->spec == 'A' ? 'X' : 'x');
 460
 461   if (!info->left && info->pad == '0' && width > 0)
 462     PADN ('0', width);
 463
 464   outchar (leading);
 465
 466   if (precision > 0 || info->alt)
 467     {
 468       const wchar_t *wtmp = &decimalwc;
 469       PRINT (decimal, wtmp, wide ? 1 : strlen (decimal));
 470     }
 471
 472   if (precision > 0)
 473     {
 474       ssize_t tofill = precision - (numend - numstr);
 475       PRINT (numstr, wnumstr, MIN (numend - numstr, precision));
 476       if (tofill > 0)
 477         PADN ('0', tofill);
 478     }
 479
 480   if ('P' - 'A' == 'p' - 'a')
 481     outchar (info->spec + ('p' - 'a'));
 482   else
 483     outchar (info->spec == 'A' ? 'P' : 'p');
 484
 485   outchar (expnegative ? '-' : '+');
 486
 487   PRINT (expstr, wexpstr, (expbuf + sizeof expbuf) - expstr);
 488
 489   if (info->left && info->pad != '0' && width > 0)
 490     PADN (info->pad, width);
 491
 492   return done;
 493 }