summary refs log tree commit diff
path: root/misc/efgcvt_r.c
blob: cd6f4e7628b1fe1eb10d164938def2345c79c2c3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
/* Compatibility functions for floating point formatting, reentrant versions.
   Copyright (C) 1995-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <float.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <stdlib.h>
#include <sys/param.h>
#include <math_ldbl_opt.h>

#ifndef FLOAT_TYPE
# define FLOAT_TYPE double
# define FUNC_PREFIX
# define FLOAT_FMT_FLAG
# define FLOAT_NAME_EXT
# define FLOAT_MIN_10_EXP DBL_MIN_10_EXP
# if DBL_MANT_DIG == 53
#  define NDIGIT_MAX 17
# elif DBL_MANT_DIG == 24
#  define NDIGIT_MAX 9
# elif DBL_MANT_DIG == 56
#  define NDIGIT_MAX 18
# else
/* See IEEE 854 5.6, table 2 for this formula.  Unfortunately we need a
   compile time constant here, so we cannot use it.  */
#  error "NDIGIT_MAX must be precomputed"
#  define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0)))
# endif
# if DBL_MIN_10_EXP == -37
#  define FLOAT_MIN_10_NORM	1.0e-37
# elif DBL_MIN_10_EXP == -307
#  define FLOAT_MIN_10_NORM	1.0e-307
# elif DBL_MIN_10_EXP == -4931
#  define FLOAT_MIN_10_NORM	1.0e-4931
# else
/* libc can't depend on libm.  */
#  error "FLOAT_MIN_10_NORM must be precomputed"
#  define FLOAT_MIN_10_NORM	exp10 (DBL_MIN_10_EXP)
# endif
#else
# define LONG_DOUBLE_CVT
#endif

#define APPEND(a, b) APPEND2 (a, b)
#define APPEND2(a, b) a##b
#define __APPEND(a, b) __APPEND2 (a, b)
#define __APPEND2(a, b) __##a##b

#define FLOOR APPEND(floor, FLOAT_NAME_EXT)
#define FABS APPEND(fabs, FLOAT_NAME_EXT)
#define LOG10 APPEND(log10, FLOAT_NAME_EXT)
#define EXP APPEND(exp, FLOAT_NAME_EXT)


int
__APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len)
     FLOAT_TYPE value;
     int ndigit, *decpt, *sign;
     char *buf;
     size_t len;
{
  ssize_t n;
  ssize_t i;
  int left;

  if (buf == NULL)
    {
      __set_errno (EINVAL);
      return -1;
    }

  left = 0;
  if (isfinite (value))
    {
      *sign = signbit (value) != 0;
      if (*sign)
	value = -value;

      if (ndigit < 0)
	{
	  /* Rounding to the left of the decimal point.  */
	  while (ndigit < 0)
	    {
	      FLOAT_TYPE new_value = value * 0.1;

	      if (new_value < 1.0)
		{
		  ndigit = 0;
		  break;
		}

	      value = new_value;
	      ++left;
	      ++ndigit;
	    }
	}
    }
  else
    /* Value is Inf or NaN.  */
    *sign = 0;

  n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
		  value);
  /* Check for a too small buffer.  */
  if (n >= (ssize_t) len)
    return -1;

  i = 0;
  while (i < n && isdigit (buf[i]))
    ++i;
  *decpt = i;

  if (i == 0)
    /* Value is Inf or NaN.  */
    return 0;

  if (i < n)
    {
      do
	++i;
      while (i < n && !isdigit (buf[i]));

      if (*decpt == 1 && buf[0] == '0' && value != 0.0)
	{
	  /* We must not have leading zeroes.  Strip them all out and
	     adjust *DECPT if necessary.  */
	  --*decpt;
	  while (i < n && buf[i] == '0')
	    {
	      --*decpt;
	      ++i;
	    }
	}

      memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i);
      buf[n - (i - MAX (*decpt, 0))] = '\0';
    }

  if (left)
    {
      *decpt += left;
      if ((ssize_t) --len > n)
	{
	  while (left-- > 0 && n < (ssize_t) len)
	    buf[n++] = '0';
	  buf[n] = '\0';
	}
    }

  return 0;
}

int
__APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len)
     FLOAT_TYPE value;
     int ndigit, *decpt, *sign;
     char *buf;
     size_t len;
{
  int exponent = 0;

  if (isfinite (value) && value != 0.0)
    {
      /* Slow code that doesn't require -lm functions.  */
      FLOAT_TYPE d;
      FLOAT_TYPE f = 1.0;
      if (value < 0.0)
	d = -value;
      else
	d = value;
      /* For denormalized numbers the d < 1.0 case below won't work,
	 as f can overflow to +Inf.  */
      if (d < FLOAT_MIN_10_NORM)
	{
	  value /= FLOAT_MIN_10_NORM;
	  if (value < 0.0)
	    d = -value;
	  else
	    d = value;
	  exponent += FLOAT_MIN_10_EXP;
	}
      if (d < 1.0)
	{
	  do
	    {
	      f *= 10.0;
	      --exponent;
	    }
	  while (d * f < 1.0);

	  value *= f;
	}
      else if (d >= 10.0)
	{
	  do
	    {
	      f *= 10;
	      ++exponent;
	    }
	  while (d >= f * 10.0);

	  value /= f;
	}
    }
  else if (value == 0.0)
    /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0.
       This could be changed to -1 if we want to return 0.  */
    exponent = 0;

  if (ndigit <= 0 && len > 0)
    {
      buf[0] = '\0';
      *decpt = 1;
      *sign = isfinite (value) ? signbit (value) != 0 : 0;
    }
  else
    if (__APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1,
					decpt, sign, buf, len))
      return -1;

  *decpt += exponent;
  return 0;
}

#if LONG_DOUBLE_COMPAT (libc, GLIBC_2_0)
# ifdef LONG_DOUBLE_CVT
#  define cvt_symbol(symbol) \
  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
	      APPEND (FUNC_PREFIX, symbol), GLIBC_2_4)
#  define cvt_symbol_1(lib, local, symbol, version) \
    versioned_symbol (lib, local, symbol, version)
# else
#  define cvt_symbol(symbol) \
  cvt_symbol_1 (libc, __APPEND (FUNC_PREFIX, symbol), \
	      APPEND (q, symbol), GLIBC_2_0); \
  strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
#  define cvt_symbol_1(lib, local, symbol, version) \
  compat_symbol (lib, local, symbol, version)
# endif
#else
# define cvt_symbol(symbol) \
  strong_alias (__APPEND (FUNC_PREFIX, symbol), APPEND (FUNC_PREFIX, symbol))
#endif
cvt_symbol(fcvt_r);
cvt_symbol(ecvt_r);