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19361cb7 | 1 | /* Compatibility functions for floating point formatting, reentrant versions. |
a334319f | 2 | Copyright (C) 1995,96,97,98,99,2000,01,02,04 Free Software Foundation, Inc. |
19361cb7 UD |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
19361cb7 UD |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
19361cb7 | 14 | |
41bdb6e2 AJ |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, write to the Free | |
17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
18 | 02111-1307 USA. */ | |
60478656 RM |
19 | |
20 | #include <errno.h> | |
1420df2c | 21 | #include <float.h> |
60478656 RM |
22 | #include <stdio.h> |
23 | #include <string.h> | |
24 | #include <ctype.h> | |
25 | #include <math.h> | |
1d8dc429 | 26 | #include <stdlib.h> |
da2d1bc5 | 27 | #include <sys/param.h> |
60478656 | 28 | |
2064087b | 29 | #ifndef FLOAT_TYPE |
67994d6f UD |
30 | # define FLOAT_TYPE double |
31 | # define FUNC_PREFIX | |
32 | # define FLOAT_FMT_FLAG | |
33 | # define FLOAT_NAME_EXT | |
ec8c29dc | 34 | # define FLOAT_MIN_10_EXP DBL_MIN_10_EXP |
b113c12c UD |
35 | # if DBL_MANT_DIG == 53 |
36 | # define NDIGIT_MAX 17 | |
f9a2a636 UD |
37 | # elif DBL_MANT_DIG == 24 |
38 | # define NDIGIT_MAX 9 | |
39 | # elif DBL_MANT_DIG == 56 | |
40 | # define NDIGIT_MAX 18 | |
b113c12c | 41 | # else |
f9a2a636 UD |
42 | /* See IEEE 854 5.6, table 2 for this formula. Unfortunately we need a |
43 | compile time constant here, so we cannot use it. */ | |
44 | # error "NDIGIT_MAX must be precomputed" | |
b113c12c UD |
45 | # define NDIGIT_MAX (lrint (ceil (M_LN2 / M_LN10 * DBL_MANT_DIG + 1.0))) |
46 | # endif | |
ec8c29dc UD |
47 | # if DBL_MIN_10_EXP == -37 |
48 | # define FLOAT_MIN_10_NORM 1.0e-37 | |
49 | # elif DBL_MIN_10_EXP == -307 | |
50 | # define FLOAT_MIN_10_NORM 1.0e-307 | |
51 | # elif DBL_MIN_10_EXP == -4931 | |
52 | # define FLOAT_MIN_10_NORM 1.0e-4931 | |
53 | # else | |
54 | /* libc can't depend on libm. */ | |
55 | # error "FLOAT_MIN_10_NORM must be precomputed" | |
56 | # define FLOAT_MIN_10_NORM exp10 (DBL_MIN_10_EXP) | |
57 | # endif | |
2064087b RM |
58 | #endif |
59 | ||
60 | #define APPEND(a, b) APPEND2 (a, b) | |
61 | #define APPEND2(a, b) a##b | |
62 | ||
63 | #define FLOOR APPEND(floor, FLOAT_NAME_EXT) | |
64 | #define FABS APPEND(fabs, FLOAT_NAME_EXT) | |
65 | #define LOG10 APPEND(log10, FLOAT_NAME_EXT) | |
1f205a47 | 66 | #define EXP APPEND(exp, FLOAT_NAME_EXT) |
2064087b RM |
67 | |
68 | ||
60478656 | 69 | int |
a334319f | 70 | APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len) |
2064087b | 71 | FLOAT_TYPE value; |
60478656 RM |
72 | int ndigit, *decpt, *sign; |
73 | char *buf; | |
c2216480 | 74 | size_t len; |
60478656 | 75 | { |
2a068d20 UD |
76 | ssize_t n; |
77 | ssize_t i; | |
1eb687d0 | 78 | int left; |
60478656 RM |
79 | |
80 | if (buf == NULL) | |
81 | { | |
c4029823 | 82 | __set_errno (EINVAL); |
60478656 RM |
83 | return -1; |
84 | } | |
85 | ||
1eb687d0 | 86 | left = 0; |
1f205a47 UD |
87 | if (isfinite (value)) |
88 | { | |
89 | *sign = signbit (value) != 0; | |
90 | if (*sign) | |
91 | value = -value; | |
da2d1bc5 UD |
92 | |
93 | if (ndigit < 0) | |
94 | { | |
95 | /* Rounding to the left of the decimal point. */ | |
1eb687d0 UD |
96 | while (ndigit < 0) |
97 | { | |
98 | FLOAT_TYPE new_value = value * 0.1; | |
99 | ||
100 | if (new_value < 1.0) | |
101 | { | |
102 | ndigit = 0; | |
103 | break; | |
104 | } | |
da2d1bc5 | 105 | |
1eb687d0 UD |
106 | value = new_value; |
107 | ++left; | |
108 | ++ndigit; | |
109 | } | |
da2d1bc5 | 110 | } |
1f205a47 | 111 | } |
07b51ba5 UD |
112 | else |
113 | /* Value is Inf or NaN. */ | |
114 | *sign = 0; | |
115 | ||
67994d6f UD |
116 | n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX), |
117 | value); | |
b9d3d9f7 | 118 | /* Check for a too small buffer. */ |
2a068d20 | 119 | if (n >= (ssize_t) len) |
60478656 RM |
120 | return -1; |
121 | ||
122 | i = 0; | |
123 | while (i < n && isdigit (buf[i])) | |
124 | ++i; | |
125 | *decpt = i; | |
1f205a47 UD |
126 | |
127 | if (i == 0) | |
07b51ba5 UD |
128 | /* Value is Inf or NaN. */ |
129 | return 0; | |
1f205a47 UD |
130 | |
131 | if (i < n) | |
132 | { | |
133 | do | |
134 | ++i; | |
135 | while (i < n && !isdigit (buf[i])); | |
da2d1bc5 | 136 | |
b8ce6e3e | 137 | if (*decpt == 1 && buf[0] == '0' && value != 0.0) |
da2d1bc5 UD |
138 | { |
139 | /* We must not have leading zeroes. Strip them all out and | |
140 | adjust *DECPT if necessary. */ | |
141 | --*decpt; | |
142 | while (i < n && buf[i] == '0') | |
143 | { | |
144 | --*decpt; | |
145 | ++i; | |
146 | } | |
147 | } | |
148 | ||
149 | memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i); | |
150 | buf[n - (i - MAX (*decpt, 0))] = '\0'; | |
1f205a47 | 151 | } |
60478656 | 152 | |
1eb687d0 UD |
153 | if (left) |
154 | { | |
155 | *decpt += left; | |
6dd67bd5 | 156 | if ((ssize_t) --len > n) |
1eb687d0 | 157 | { |
6dd67bd5 | 158 | while (left-- > 0 && n < (ssize_t) len) |
1eb687d0 UD |
159 | buf[n++] = '0'; |
160 | buf[n] = '\0'; | |
161 | } | |
162 | } | |
163 | ||
60478656 RM |
164 | return 0; |
165 | } | |
a334319f | 166 | libc_hidden_def (APPEND (FUNC_PREFIX, fcvt_r)) |
60478656 RM |
167 | |
168 | int | |
a334319f | 169 | APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign, buf, len) |
2064087b | 170 | FLOAT_TYPE value; |
60478656 RM |
171 | int ndigit, *decpt, *sign; |
172 | char *buf; | |
c2216480 | 173 | size_t len; |
60478656 | 174 | { |
1f205a47 | 175 | int exponent = 0; |
0676b5fd | 176 | |
1f205a47 | 177 | if (isfinite (value) && value != 0.0) |
4d585333 | 178 | { |
ff8ac383 UD |
179 | /* Slow code that doesn't require -lm functions. */ |
180 | FLOAT_TYPE d; | |
181 | FLOAT_TYPE f = 1.0; | |
182 | if (value < 0.0) | |
183 | d = -value; | |
1f205a47 | 184 | else |
ff8ac383 | 185 | d = value; |
ec8c29dc UD |
186 | /* For denormalized numbers the d < 1.0 case below won't work, |
187 | as f can overflow to +Inf. */ | |
188 | if (d < FLOAT_MIN_10_NORM) | |
189 | { | |
190 | value /= FLOAT_MIN_10_NORM; | |
191 | if (value < 0.0) | |
192 | d = -value; | |
193 | else | |
194 | d = value; | |
195 | exponent += FLOAT_MIN_10_EXP; | |
196 | } | |
ff8ac383 | 197 | if (d < 1.0) |
1f205a47 | 198 | { |
ff8ac383 | 199 | do |
1f205a47 | 200 | { |
ff8ac383 UD |
201 | f *= 10.0; |
202 | --exponent; | |
1f205a47 | 203 | } |
ff8ac383 UD |
204 | while (d * f < 1.0); |
205 | ||
206 | value *= f; | |
207 | } | |
208 | else if (d >= 10.0) | |
209 | { | |
210 | do | |
1f205a47 | 211 | { |
ff8ac383 UD |
212 | f *= 10; |
213 | ++exponent; | |
1f205a47 | 214 | } |
ff8ac383 UD |
215 | while (d >= f * 10.0); |
216 | ||
217 | value /= f; | |
1f205a47 | 218 | } |
4d585333 | 219 | } |
da2d1bc5 UD |
220 | else if (value == 0.0) |
221 | /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0. | |
222 | This could be changed to -1 if we want to return 0. */ | |
223 | exponent = 0; | |
224 | ||
225 | if (ndigit <= 0 && len > 0) | |
226 | { | |
227 | buf[0] = '\0'; | |
228 | *decpt = 1; | |
229 | *sign = isfinite (value) ? signbit (value) != 0 : 0; | |
230 | } | |
231 | else | |
a334319f UD |
232 | if (APPEND (FUNC_PREFIX, fcvt_r) (value, MIN (ndigit, NDIGIT_MAX) - 1, |
233 | decpt, sign, buf, len)) | |
da2d1bc5 | 234 | return -1; |
4d585333 | 235 | |
1f205a47 UD |
236 | *decpt += exponent; |
237 | return 0; | |
60478656 | 238 | } |
a334319f | 239 | libc_hidden_def (APPEND (FUNC_PREFIX, ecvt_r)) |