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[glibc.git] / stdio-common / printf_fphex.c
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1 /* Print floating point number in hexadecimal notation according to ISO C99.
2 Copyright (C) 1997-2013 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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.
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.
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/>. */
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 #include <stdbool.h>
32 #include <rounding-mode.h>
34 /* #define NDEBUG 1*/ /* Undefine this for debugging assertions. */
35 #include <assert.h>
37 /* This defines make it possible to use the same code for GNU C library and
38 the GNU I/O library. */
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) : _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
50 /* Macros for doing the actual output. */
52 #define outchar(ch) \
53 do \
54 { \
55 register const int outc = (ch); \
56 if (putc (outc, fp) == EOF) \
57 return -1; \
58 ++done; \
59 } while (0)
61 #define PRINT(ptr, wptr, len) \
62 do \
63 { \
64 register size_t outlen = (len); \
65 if (wide) \
66 while (outlen-- > 0) \
67 outchar (*wptr++); \
68 else \
69 while (outlen-- > 0) \
70 outchar (*ptr++); \
71 } while (0)
73 #define PADN(ch, len) \
74 do \
75 { \
76 if (PAD (fp, ch, len) != len) \
77 return -1; \
78 done += len; \
79 } \
80 while (0)
82 #ifndef MIN
83 # define MIN(a,b) ((a)<(b)?(a):(b))
84 #endif
87 int
88 __printf_fphex (FILE *fp,
89 const struct printf_info *info,
90 const void *const *args)
92 /* The floating-point value to output. */
93 union
95 union ieee754_double dbl;
96 union ieee854_long_double ldbl;
98 fpnum;
100 /* Locale-dependent representation of decimal point. */
101 const char *decimal;
102 wchar_t decimalwc;
104 /* "NaN" or "Inf" for the special cases. */
105 const char *special = NULL;
106 const wchar_t *wspecial = NULL;
108 /* Buffer for the generated number string for the mantissa. The
109 maximal size for the mantissa is 128 bits. */
110 char numbuf[32];
111 char *numstr;
112 char *numend;
113 wchar_t wnumbuf[32];
114 wchar_t *wnumstr;
115 wchar_t *wnumend;
116 int negative;
118 /* The maximal exponent of two in decimal notation has 5 digits. */
119 char expbuf[5];
120 char *expstr;
121 wchar_t wexpbuf[5];
122 wchar_t *wexpstr;
123 int expnegative;
124 int exponent;
126 /* Non-zero is mantissa is zero. */
127 int zero_mantissa;
129 /* The leading digit before the decimal point. */
130 char leading;
132 /* Precision. */
133 int precision = info->prec;
135 /* Width. */
136 int width = info->width;
138 /* Number of characters written. */
139 int done = 0;
141 /* Nonzero if this is output on a wide character stream. */
142 int wide = info->wide;
145 /* Figure out the decimal point character. */
146 if (info->extra == 0)
148 decimal = _NL_CURRENT (LC_NUMERIC, DECIMAL_POINT);
149 decimalwc = _NL_CURRENT_WORD (LC_NUMERIC, _NL_NUMERIC_DECIMAL_POINT_WC);
151 else
153 decimal = _NL_CURRENT (LC_MONETARY, MON_DECIMAL_POINT);
154 decimalwc = _NL_CURRENT_WORD (LC_MONETARY,
155 _NL_MONETARY_DECIMAL_POINT_WC);
157 /* The decimal point character must never be zero. */
158 assert (*decimal != '\0' && decimalwc != L'\0');
161 /* Fetch the argument value. */
162 #ifndef __NO_LONG_DOUBLE_MATH
163 if (info->is_long_double && sizeof (long double) > sizeof (double))
165 fpnum.ldbl.d = *(const long double *) args[0];
167 /* Check for special values: not a number or infinity. */
168 if (__isnanl (fpnum.ldbl.d))
170 negative = fpnum.ldbl.ieee.negative != 0;
171 if (isupper (info->spec))
173 special = "NAN";
174 wspecial = L"NAN";
176 else
178 special = "nan";
179 wspecial = L"nan";
182 else
184 int res = __isinfl (fpnum.ldbl.d);
185 if (res)
187 if (isupper (info->spec))
189 special = "INF";
190 wspecial = L"INF";
192 else
194 special = "inf";
195 wspecial = L"inf";
197 negative = res < 0;
199 else
200 negative = signbit (fpnum.ldbl.d);
203 else
204 #endif /* no long double */
206 fpnum.dbl.d = *(const double *) args[0];
208 /* Check for special values: not a number or infinity. */
209 if (__isnan (fpnum.dbl.d))
211 negative = fpnum.dbl.ieee.negative != 0;
212 if (isupper (info->spec))
214 special = "NAN";
215 wspecial = L"NAN";
217 else
219 special = "nan";
220 wspecial = L"nan";
223 else
225 int res = __isinf (fpnum.dbl.d);
226 if (res)
228 if (isupper (info->spec))
230 special = "INF";
231 wspecial = L"INF";
233 else
235 special = "inf";
236 wspecial = L"inf";
238 negative = res < 0;
240 else
241 negative = signbit (fpnum.dbl.d);
245 if (special)
247 int width = info->width;
249 if (negative || info->showsign || info->space)
250 --width;
251 width -= 3;
253 if (!info->left && width > 0)
254 PADN (' ', width);
256 if (negative)
257 outchar ('-');
258 else if (info->showsign)
259 outchar ('+');
260 else if (info->space)
261 outchar (' ');
263 PRINT (special, wspecial, 3);
265 if (info->left && width > 0)
266 PADN (' ', width);
268 return done;
271 if (info->is_long_double == 0 || sizeof (double) == sizeof (long double))
273 /* We have 52 bits of mantissa plus one implicit digit. Since
274 52 bits are representable without rest using hexadecimal
275 digits we use only the implicit digits for the number before
276 the decimal point. */
277 unsigned long long int num;
279 num = (((unsigned long long int) fpnum.dbl.ieee.mantissa0) << 32
280 | fpnum.dbl.ieee.mantissa1);
282 zero_mantissa = num == 0;
284 if (sizeof (unsigned long int) > 6)
286 wnumstr = _itowa_word (num, wnumbuf + (sizeof wnumbuf) / sizeof (wchar_t), 16,
287 info->spec == 'A');
288 numstr = _itoa_word (num, numbuf + sizeof numbuf, 16,
289 info->spec == 'A');
291 else
293 wnumstr = _itowa (num, wnumbuf + sizeof wnumbuf / sizeof (wchar_t), 16,
294 info->spec == 'A');
295 numstr = _itoa (num, numbuf + sizeof numbuf, 16,
296 info->spec == 'A');
299 /* Fill with zeroes. */
300 while (wnumstr > wnumbuf + (sizeof wnumbuf - 52) / sizeof (wchar_t))
302 *--wnumstr = L'0';
303 *--numstr = '0';
306 leading = fpnum.dbl.ieee.exponent == 0 ? '0' : '1';
308 exponent = fpnum.dbl.ieee.exponent;
310 if (exponent == 0)
312 if (zero_mantissa)
313 expnegative = 0;
314 else
316 /* This is a denormalized number. */
317 expnegative = 1;
318 exponent = IEEE754_DOUBLE_BIAS - 1;
321 else if (exponent >= IEEE754_DOUBLE_BIAS)
323 expnegative = 0;
324 exponent -= IEEE754_DOUBLE_BIAS;
326 else
328 expnegative = 1;
329 exponent = -(exponent - IEEE754_DOUBLE_BIAS);
332 #ifdef PRINT_FPHEX_LONG_DOUBLE
333 else
334 PRINT_FPHEX_LONG_DOUBLE;
335 #endif
337 /* Look for trailing zeroes. */
338 if (! zero_mantissa)
340 wnumend = &wnumbuf[sizeof wnumbuf / sizeof wnumbuf[0]];
341 numend = &numbuf[sizeof numbuf / sizeof numbuf[0]];
342 while (wnumend[-1] == L'0')
344 --wnumend;
345 --numend;
348 bool do_round_away = false;
350 if (precision != -1 && precision < numend - numstr)
352 char last_digit = precision > 0 ? numstr[precision - 1] : leading;
353 char next_digit = numstr[precision];
354 int last_digit_value = (last_digit >= 'A' && last_digit <= 'F'
355 ? last_digit - 'A' + 10
356 : (last_digit >= 'a' && last_digit <= 'f'
357 ? last_digit - 'a' + 10
358 : last_digit - '0'));
359 int next_digit_value = (next_digit >= 'A' && next_digit <= 'F'
360 ? next_digit - 'A' + 10
361 : (next_digit >= 'a' && next_digit <= 'f'
362 ? next_digit - 'a' + 10
363 : next_digit - '0'));
364 bool more_bits = ((next_digit_value & 7) != 0
365 || precision + 1 < numend - numstr);
366 int rounding_mode = get_rounding_mode ();
367 do_round_away = round_away (negative, last_digit_value & 1,
368 next_digit_value >= 8, more_bits,
369 rounding_mode);
372 if (precision == -1)
373 precision = numend - numstr;
374 else if (do_round_away)
376 /* Round up. */
377 int cnt = precision;
378 while (--cnt >= 0)
380 char ch = numstr[cnt];
381 /* We assume that the digits and the letters are ordered
382 like in ASCII. This is true for the rest of GNU, too. */
383 if (ch == '9')
385 wnumstr[cnt] = (wchar_t) info->spec;
386 numstr[cnt] = info->spec; /* This is tricky,
387 think about it! */
388 break;
390 else if (tolower (ch) < 'f')
392 ++numstr[cnt];
393 ++wnumstr[cnt];
394 break;
396 else
398 numstr[cnt] = '0';
399 wnumstr[cnt] = L'0';
402 if (cnt < 0)
404 /* The mantissa so far was fff...f Now increment the
405 leading digit. Here it is again possible that we
406 get an overflow. */
407 if (leading == '9')
408 leading = info->spec;
409 else if (tolower (leading) < 'f')
410 ++leading;
411 else
413 leading = '1';
414 if (expnegative)
416 exponent -= 4;
417 if (exponent <= 0)
419 exponent = -exponent;
420 expnegative = 0;
423 else
424 exponent += 4;
429 else
431 if (precision == -1)
432 precision = 0;
433 numend = numstr;
434 wnumend = wnumstr;
437 /* Now we can compute the exponent string. */
438 expstr = _itoa_word (exponent, expbuf + sizeof expbuf, 10, 0);
439 wexpstr = _itowa_word (exponent,
440 wexpbuf + sizeof wexpbuf / sizeof (wchar_t), 10, 0);
442 /* Now we have all information to compute the size. */
443 width -= ((negative || info->showsign || info->space)
444 /* Sign. */
445 + 2 + 1 + 0 + precision + 1 + 1
446 /* 0x h . hhh P ExpoSign. */
447 + ((expbuf + sizeof expbuf) - expstr));
448 /* Exponent. */
450 /* Count the decimal point.
451 A special case when the mantissa or the precision is zero and the `#'
452 is not given. In this case we must not print the decimal point. */
453 if (precision > 0 || info->alt)
454 width -= wide ? 1 : strlen (decimal);
456 if (!info->left && info->pad != '0' && width > 0)
457 PADN (' ', width);
459 if (negative)
460 outchar ('-');
461 else if (info->showsign)
462 outchar ('+');
463 else if (info->space)
464 outchar (' ');
466 outchar ('0');
467 if ('X' - 'A' == 'x' - 'a')
468 outchar (info->spec + ('x' - 'a'));
469 else
470 outchar (info->spec == 'A' ? 'X' : 'x');
472 if (!info->left && info->pad == '0' && width > 0)
473 PADN ('0', width);
475 outchar (leading);
477 if (precision > 0 || info->alt)
479 const wchar_t *wtmp = &decimalwc;
480 PRINT (decimal, wtmp, wide ? 1 : strlen (decimal));
483 if (precision > 0)
485 ssize_t tofill = precision - (numend - numstr);
486 PRINT (numstr, wnumstr, MIN (numend - numstr, precision));
487 if (tofill > 0)
488 PADN ('0', tofill);
491 if ('P' - 'A' == 'p' - 'a')
492 outchar (info->spec + ('p' - 'a'));
493 else
494 outchar (info->spec == 'A' ? 'P' : 'p');
496 outchar (expnegative ? '-' : '+');
498 PRINT (expstr, wexpstr, (expbuf + sizeof expbuf) - expstr);
500 if (info->left && info->pad != '0' && width > 0)
501 PADN (info->pad, width);
503 return done;