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1 | /* Copyright (C) 1991, 1992 Free Software Foundation, Inc. |
2 | ||
3 | This program is free software; you can redistribute it and/or modify | |
4 | it under the terms of the GNU General Public License as published by | |
5 | the Free Software Foundation; either version 2, or (at your option) | |
6 | any later version. | |
7 | ||
8 | This program is distributed in the hope that it will be useful, | |
9 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | GNU General Public License for more details. | |
12 | ||
13 | You should have received a copy of the GNU General Public License | |
14 | along with this program; if not, write to the Free Software Foundation, | |
15 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
16 | ||
17 | #if HAVE_CONFIG_H | |
18 | # include <config.h> | |
19 | #endif | |
20 | ||
21 | #ifndef HAVE_STRTOD | |
22 | ||
23 | #include <errno.h> | |
24 | #ifndef errno | |
25 | extern int errno; | |
26 | #endif | |
27 | ||
f73dda09 | 28 | #include <chartypes.h> |
cce855bc JA |
29 | #include <math.h> |
30 | ||
31 | #if HAVE_FLOAT_H | |
32 | # include <float.h> | |
33 | #else | |
34 | # define DBL_MAX 1.7976931348623159e+308 | |
35 | # define DBL_MIN 2.2250738585072010e-308 | |
36 | #endif | |
37 | ||
38 | #include <bashansi.h> | |
39 | ||
40 | #ifndef NULL | |
41 | # define NULL 0 | |
42 | #endif | |
43 | ||
44 | #ifndef HUGE_VAL | |
45 | # define HUGE_VAL HUGE | |
46 | #endif | |
47 | ||
48 | /* Convert NPTR to a double. If ENDPTR is not NULL, a pointer to the | |
49 | character after the last one used in the number is put in *ENDPTR. */ | |
50 | double | |
51 | strtod (nptr, endptr) | |
52 | const char *nptr; | |
53 | char **endptr; | |
54 | { | |
55 | register const char *s; | |
56 | short sign; | |
57 | ||
58 | /* The number so far. */ | |
59 | double num; | |
60 | ||
61 | int got_dot; /* Found a decimal point. */ | |
62 | int got_digit; /* Seen any digits. */ | |
63 | ||
64 | /* The exponent of the number. */ | |
65 | long int exponent; | |
66 | ||
67 | if (nptr == NULL) | |
68 | { | |
69 | errno = EINVAL; | |
70 | goto noconv; | |
71 | } | |
72 | ||
73 | s = nptr; | |
74 | ||
75 | /* Eat whitespace. */ | |
f73dda09 | 76 | while (ISSPACE ((unsigned char)*s)) |
cce855bc JA |
77 | ++s; |
78 | ||
79 | /* Get the sign. */ | |
80 | sign = *s == '-' ? -1 : 1; | |
81 | if (*s == '-' || *s == '+') | |
82 | ++s; | |
83 | ||
84 | num = 0.0; | |
85 | got_dot = 0; | |
86 | got_digit = 0; | |
87 | exponent = 0; | |
88 | for (;; ++s) | |
89 | { | |
f73dda09 | 90 | if (DIGIT (*s)) |
cce855bc JA |
91 | { |
92 | got_digit = 1; | |
93 | ||
94 | /* Make sure that multiplication by 10 will not overflow. */ | |
95 | if (num > DBL_MAX * 0.1) | |
96 | /* The value of the digit doesn't matter, since we have already | |
97 | gotten as many digits as can be represented in a `double'. | |
98 | This doesn't necessarily mean the result will overflow. | |
99 | The exponent may reduce it to within range. | |
100 | ||
101 | We just need to record that there was another | |
102 | digit so that we can multiply by 10 later. */ | |
103 | ++exponent; | |
104 | else | |
105 | num = (num * 10.0) + (*s - '0'); | |
106 | ||
107 | /* Keep track of the number of digits after the decimal point. | |
108 | If we just divided by 10 here, we would lose precision. */ | |
109 | if (got_dot) | |
110 | --exponent; | |
111 | } | |
112 | else if (!got_dot && *s == '.') | |
113 | /* Record that we have found the decimal point. */ | |
114 | got_dot = 1; | |
115 | else | |
116 | /* Any other character terminates the number. */ | |
117 | break; | |
118 | } | |
119 | ||
120 | if (!got_digit) | |
121 | goto noconv; | |
122 | ||
f73dda09 | 123 | if (TOLOWER ((unsigned char)*s) == 'e') |
cce855bc JA |
124 | { |
125 | /* Get the exponent specified after the `e' or `E'. */ | |
126 | int save = errno; | |
127 | char *end; | |
128 | long int exp; | |
129 | ||
130 | errno = 0; | |
131 | ++s; | |
132 | exp = strtol (s, &end, 10); | |
133 | if (errno == ERANGE) | |
134 | { | |
135 | /* The exponent overflowed a `long int'. It is probably a safe | |
136 | assumption that an exponent that cannot be represented by | |
137 | a `long int' exceeds the limits of a `double'. */ | |
138 | if (endptr != NULL) | |
139 | *endptr = end; | |
140 | if (exp < 0) | |
141 | goto underflow; | |
142 | else | |
143 | goto overflow; | |
144 | } | |
145 | else if (end == s) | |
146 | /* There was no exponent. Reset END to point to | |
147 | the 'e' or 'E', so *ENDPTR will be set there. */ | |
148 | end = (char *) s - 1; | |
149 | errno = save; | |
150 | s = end; | |
151 | exponent += exp; | |
152 | } | |
153 | ||
154 | if (endptr != NULL) | |
155 | *endptr = (char *) s; | |
156 | ||
157 | if (num == 0.0) | |
158 | return 0.0; | |
159 | ||
160 | /* Multiply NUM by 10 to the EXPONENT power, | |
161 | checking for overflow and underflow. */ | |
162 | ||
163 | if (exponent < 0) | |
164 | { | |
165 | if (num < DBL_MIN * pow (10.0, (double) -exponent)) | |
166 | goto underflow; | |
167 | } | |
168 | else if (exponent > 0) | |
169 | { | |
170 | if (num > DBL_MAX * pow (10.0, (double) -exponent)) | |
171 | goto overflow; | |
172 | } | |
173 | ||
174 | num *= pow (10.0, (double) exponent); | |
175 | ||
176 | return num * sign; | |
177 | ||
178 | overflow: | |
179 | /* Return an overflow error. */ | |
180 | errno = ERANGE; | |
181 | return HUGE_VAL * sign; | |
182 | ||
183 | underflow: | |
184 | /* Return an underflow error. */ | |
185 | if (endptr != NULL) | |
186 | *endptr = (char *) nptr; | |
187 | errno = ERANGE; | |
188 | return 0.0; | |
189 | ||
190 | noconv: | |
191 | /* There was no number. */ | |
192 | if (endptr != NULL) | |
193 | *endptr = (char *) nptr; | |
194 | return 0.0; | |
195 | } | |
196 | ||
197 | #endif /* !HAVE_STRTOD */ |