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e18a3057 | 1 | /* Compatibility functions for floating point formatting, reentrant versions. |
2b778ceb | 2 | Copyright (C) 1995-2021 Free Software Foundation, Inc. |
e18a3057 GG |
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 | |
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. | |
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 | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <errno.h> | |
20 | #include <stdio.h> | |
21 | #include <string.h> | |
22 | #include <ctype.h> | |
23 | #include <math.h> | |
24 | #include <stdlib.h> | |
25 | #include <sys/param.h> | |
26 | #include <math_ldbl_opt.h> | |
27 | ||
3021e781 GG |
28 | #ifndef SNPRINTF |
29 | # define SNPRINTF __snprintf | |
30 | #endif | |
31 | ||
e18a3057 GG |
32 | |
33 | #define APPEND(a, b) APPEND2 (a, b) | |
34 | #define APPEND2(a, b) a##b | |
e18a3057 GG |
35 | |
36 | int | |
dce42534 GG |
37 | __FCVT_R (FLOAT_TYPE value, int ndigit, int *decpt, int *sign, |
38 | char *buf, size_t len) | |
e18a3057 GG |
39 | { |
40 | ssize_t n; | |
41 | ssize_t i; | |
42 | int left; | |
43 | ||
44 | if (buf == NULL) | |
45 | { | |
46 | __set_errno (EINVAL); | |
47 | return -1; | |
48 | } | |
49 | ||
50 | left = 0; | |
51 | if (isfinite (value)) | |
52 | { | |
53 | *sign = signbit (value) != 0; | |
54 | if (*sign) | |
55 | value = -value; | |
56 | ||
57 | if (ndigit < 0) | |
58 | { | |
59 | /* Rounding to the left of the decimal point. */ | |
60 | while (ndigit < 0) | |
61 | { | |
62 | FLOAT_TYPE new_value = value * 0.1; | |
63 | ||
64 | if (new_value < 1.0) | |
65 | { | |
66 | ndigit = 0; | |
67 | break; | |
68 | } | |
69 | ||
70 | value = new_value; | |
71 | ++left; | |
72 | ++ndigit; | |
73 | } | |
74 | } | |
75 | } | |
76 | else | |
77 | /* Value is Inf or NaN. */ | |
78 | *sign = 0; | |
79 | ||
3021e781 | 80 | n = SNPRINTF (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX), |
e18a3057 GG |
81 | value); |
82 | /* Check for a too small buffer. */ | |
83 | if (n >= (ssize_t) len) | |
84 | return -1; | |
85 | ||
86 | i = 0; | |
87 | while (i < n && isdigit (buf[i])) | |
88 | ++i; | |
89 | *decpt = i; | |
90 | ||
91 | if (i == 0) | |
92 | /* Value is Inf or NaN. */ | |
93 | return 0; | |
94 | ||
95 | if (i < n) | |
96 | { | |
97 | do | |
98 | ++i; | |
99 | while (i < n && !isdigit (buf[i])); | |
100 | ||
101 | if (*decpt == 1 && buf[0] == '0' && value != 0.0) | |
102 | { | |
103 | /* We must not have leading zeroes. Strip them all out and | |
104 | adjust *DECPT if necessary. */ | |
105 | --*decpt; | |
106 | while (i < n && buf[i] == '0') | |
107 | { | |
108 | --*decpt; | |
109 | ++i; | |
110 | } | |
111 | } | |
112 | ||
113 | memmove (&buf[MAX (*decpt, 0)], &buf[i], n - i); | |
114 | buf[n - (i - MAX (*decpt, 0))] = '\0'; | |
115 | } | |
116 | ||
117 | if (left) | |
118 | { | |
119 | *decpt += left; | |
120 | if ((ssize_t) --len > n) | |
121 | { | |
122 | while (left-- > 0 && n < (ssize_t) len) | |
123 | buf[n++] = '0'; | |
124 | buf[n] = '\0'; | |
125 | } | |
126 | } | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | int | |
dce42534 GG |
132 | __ECVT_R (FLOAT_TYPE value, int ndigit, int *decpt, int *sign, |
133 | char *buf, size_t len) | |
e18a3057 GG |
134 | { |
135 | int exponent = 0; | |
136 | ||
137 | if (isfinite (value) && value != 0.0) | |
138 | { | |
139 | /* Slow code that doesn't require -lm functions. */ | |
140 | FLOAT_TYPE d; | |
141 | FLOAT_TYPE f = 1.0; | |
142 | if (value < 0.0) | |
143 | d = -value; | |
144 | else | |
145 | d = value; | |
146 | /* For denormalized numbers the d < 1.0 case below won't work, | |
147 | as f can overflow to +Inf. */ | |
148 | if (d < FLOAT_MIN_10_NORM) | |
149 | { | |
150 | value /= FLOAT_MIN_10_NORM; | |
151 | if (value < 0.0) | |
152 | d = -value; | |
153 | else | |
154 | d = value; | |
155 | exponent += FLOAT_MIN_10_EXP; | |
156 | } | |
157 | if (d < 1.0) | |
158 | { | |
159 | do | |
160 | { | |
161 | f *= 10.0; | |
162 | --exponent; | |
163 | } | |
164 | while (d * f < 1.0); | |
165 | ||
166 | value *= f; | |
167 | } | |
168 | else if (d >= 10.0) | |
169 | { | |
170 | do | |
171 | { | |
172 | f *= 10; | |
173 | ++exponent; | |
174 | } | |
175 | while (d >= f * 10.0); | |
176 | ||
177 | value /= f; | |
178 | } | |
179 | } | |
180 | else if (value == 0.0) | |
181 | /* SUSv2 leaves it unspecified whether *DECPT is 0 or 1 for 0.0. | |
182 | This could be changed to -1 if we want to return 0. */ | |
183 | exponent = 0; | |
184 | ||
185 | if (ndigit <= 0 && len > 0) | |
186 | { | |
187 | buf[0] = '\0'; | |
188 | *decpt = 1; | |
189 | *sign = isfinite (value) ? signbit (value) != 0 : 0; | |
190 | } | |
191 | else | |
dce42534 GG |
192 | if (__FCVT_R (value, MIN (ndigit, NDIGIT_MAX) - 1, |
193 | decpt, sign, buf, len)) | |
e18a3057 GG |
194 | return -1; |
195 | ||
196 | *decpt += exponent; | |
197 | return 0; | |
198 | } |