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3185942a JA |
1 | /* strtod.c - convert string to double-precision floating-point value. */ |
2 | ||
cce855bc JA |
3 | /* Copyright (C) 1991, 1992 Free Software Foundation, Inc. |
4 | ||
3185942a JA |
5 | This file is part of GNU Bash, the Bourne Again SHell. |
6 | ||
7 | Bash is free software: you can redistribute it and/or modify | |
cce855bc | 8 | it under the terms of the GNU General Public License as published by |
3185942a JA |
9 | the Free Software Foundation, either version 3 of the License, or |
10 | (at your option) any later version. | |
cce855bc | 11 | |
3185942a | 12 | Bash is distributed in the hope that it will be useful, |
cce855bc JA |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
3185942a JA |
18 | along with Bash. If not, see <http://www.gnu.org/licenses/>. |
19 | */ | |
cce855bc JA |
20 | |
21 | #if HAVE_CONFIG_H | |
22 | # include <config.h> | |
23 | #endif | |
24 | ||
25 | #ifndef HAVE_STRTOD | |
26 | ||
27 | #include <errno.h> | |
28 | #ifndef errno | |
29 | extern int errno; | |
30 | #endif | |
31 | ||
f73dda09 | 32 | #include <chartypes.h> |
cce855bc JA |
33 | #include <math.h> |
34 | ||
35 | #if HAVE_FLOAT_H | |
36 | # include <float.h> | |
37 | #else | |
38 | # define DBL_MAX 1.7976931348623159e+308 | |
39 | # define DBL_MIN 2.2250738585072010e-308 | |
40 | #endif | |
41 | ||
42 | #include <bashansi.h> | |
43 | ||
44 | #ifndef NULL | |
45 | # define NULL 0 | |
46 | #endif | |
47 | ||
48 | #ifndef HUGE_VAL | |
49 | # define HUGE_VAL HUGE | |
50 | #endif | |
51 | ||
8868edaf CR |
52 | #ifndef locale_decpoint |
53 | extern int locale_decpoint PARAMS((void)); | |
54 | #endif | |
55 | ||
cce855bc JA |
56 | /* Convert NPTR to a double. If ENDPTR is not NULL, a pointer to the |
57 | character after the last one used in the number is put in *ENDPTR. */ | |
58 | double | |
59 | strtod (nptr, endptr) | |
60 | const char *nptr; | |
61 | char **endptr; | |
62 | { | |
63 | register const char *s; | |
64 | short sign; | |
65 | ||
66 | /* The number so far. */ | |
67 | double num; | |
68 | ||
8868edaf | 69 | int radixchar; |
cce855bc JA |
70 | int got_dot; /* Found a decimal point. */ |
71 | int got_digit; /* Seen any digits. */ | |
72 | ||
73 | /* The exponent of the number. */ | |
74 | long int exponent; | |
75 | ||
76 | if (nptr == NULL) | |
77 | { | |
78 | errno = EINVAL; | |
79 | goto noconv; | |
80 | } | |
81 | ||
82 | s = nptr; | |
83 | ||
84 | /* Eat whitespace. */ | |
f73dda09 | 85 | while (ISSPACE ((unsigned char)*s)) |
cce855bc JA |
86 | ++s; |
87 | ||
88 | /* Get the sign. */ | |
89 | sign = *s == '-' ? -1 : 1; | |
90 | if (*s == '-' || *s == '+') | |
91 | ++s; | |
92 | ||
8868edaf | 93 | radixchar = locale_decpoint (); |
cce855bc JA |
94 | num = 0.0; |
95 | got_dot = 0; | |
96 | got_digit = 0; | |
97 | exponent = 0; | |
98 | for (;; ++s) | |
99 | { | |
f73dda09 | 100 | if (DIGIT (*s)) |
cce855bc JA |
101 | { |
102 | got_digit = 1; | |
103 | ||
104 | /* Make sure that multiplication by 10 will not overflow. */ | |
105 | if (num > DBL_MAX * 0.1) | |
106 | /* The value of the digit doesn't matter, since we have already | |
107 | gotten as many digits as can be represented in a `double'. | |
108 | This doesn't necessarily mean the result will overflow. | |
109 | The exponent may reduce it to within range. | |
110 | ||
111 | We just need to record that there was another | |
112 | digit so that we can multiply by 10 later. */ | |
113 | ++exponent; | |
114 | else | |
115 | num = (num * 10.0) + (*s - '0'); | |
116 | ||
117 | /* Keep track of the number of digits after the decimal point. | |
118 | If we just divided by 10 here, we would lose precision. */ | |
119 | if (got_dot) | |
120 | --exponent; | |
121 | } | |
8868edaf | 122 | else if (!got_dot && *s == radixchar) |
cce855bc JA |
123 | /* Record that we have found the decimal point. */ |
124 | got_dot = 1; | |
125 | else | |
126 | /* Any other character terminates the number. */ | |
127 | break; | |
128 | } | |
129 | ||
130 | if (!got_digit) | |
131 | goto noconv; | |
132 | ||
f73dda09 | 133 | if (TOLOWER ((unsigned char)*s) == 'e') |
cce855bc JA |
134 | { |
135 | /* Get the exponent specified after the `e' or `E'. */ | |
136 | int save = errno; | |
137 | char *end; | |
138 | long int exp; | |
139 | ||
140 | errno = 0; | |
141 | ++s; | |
142 | exp = strtol (s, &end, 10); | |
143 | if (errno == ERANGE) | |
144 | { | |
145 | /* The exponent overflowed a `long int'. It is probably a safe | |
146 | assumption that an exponent that cannot be represented by | |
147 | a `long int' exceeds the limits of a `double'. */ | |
148 | if (endptr != NULL) | |
149 | *endptr = end; | |
150 | if (exp < 0) | |
151 | goto underflow; | |
152 | else | |
153 | goto overflow; | |
154 | } | |
155 | else if (end == s) | |
156 | /* There was no exponent. Reset END to point to | |
157 | the 'e' or 'E', so *ENDPTR will be set there. */ | |
158 | end = (char *) s - 1; | |
159 | errno = save; | |
160 | s = end; | |
161 | exponent += exp; | |
162 | } | |
163 | ||
164 | if (endptr != NULL) | |
165 | *endptr = (char *) s; | |
166 | ||
167 | if (num == 0.0) | |
168 | return 0.0; | |
169 | ||
170 | /* Multiply NUM by 10 to the EXPONENT power, | |
171 | checking for overflow and underflow. */ | |
172 | ||
173 | if (exponent < 0) | |
174 | { | |
175 | if (num < DBL_MIN * pow (10.0, (double) -exponent)) | |
176 | goto underflow; | |
177 | } | |
178 | else if (exponent > 0) | |
179 | { | |
180 | if (num > DBL_MAX * pow (10.0, (double) -exponent)) | |
181 | goto overflow; | |
182 | } | |
183 | ||
184 | num *= pow (10.0, (double) exponent); | |
185 | ||
186 | return num * sign; | |
187 | ||
188 | overflow: | |
189 | /* Return an overflow error. */ | |
190 | errno = ERANGE; | |
191 | return HUGE_VAL * sign; | |
192 | ||
193 | underflow: | |
194 | /* Return an underflow error. */ | |
195 | if (endptr != NULL) | |
196 | *endptr = (char *) nptr; | |
197 | errno = ERANGE; | |
198 | return 0.0; | |
199 | ||
200 | noconv: | |
201 | /* There was no number. */ | |
202 | if (endptr != NULL) | |
203 | *endptr = (char *) nptr; | |
204 | return 0.0; | |
205 | } | |
206 | ||
207 | #endif /* !HAVE_STRTOD */ |