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
|
/* fpconv - Floating point conversion routines
*
* Copyright (c) 2011-2012 Mark Pulford <mark@kyne.com.au>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* JSON uses a '.' decimal separator. strtod() / sprintf() under C libraries
* with locale support will break when the decimal separator is a comma.
*
* fpconv_* will around these issues with a translation buffer if required.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include "fpconv.h"
/* Lua CJSON assumes the locale is the same for all threads within a
* process and doesn't change after initialisation.
*
* This avoids the need for per thread storage or expensive checks
* for call. */
static char locale_decimal_point = '.';
/* In theory multibyte decimal_points are possible, but
* Lua CJSON only supports UTF-8 and known locales only have
* single byte decimal points ([.,]).
*
* localconv() may not be thread safe (=>crash), and nl_langinfo() is
* not supported on some platforms. Use sprintf() instead - if the
* locale does change, at least Lua CJSON won't crash. */
static void fpconv_update_locale()
{
char buf[8];
snprintf(buf, sizeof(buf), "%g", 0.5);
/* Failing this test might imply the platform has a buggy dtoa
* implementation or wide characters */
if (buf[0] != '0' || buf[2] != '5' || buf[3] != 0) {
fprintf(stderr, "Error: wide characters found or printf() bug.");
abort();
}
locale_decimal_point = buf[1];
}
/* Check for a valid number character: [-+0-9a-yA-Y.]
* Eg: -0.6e+5, infinity, 0xF0.F0pF0
*
* Used to find the probable end of a number. It doesn't matter if
* invalid characters are counted - strtod() will find the valid
* number if it exists. The risk is that slightly more memory might
* be allocated before a parse error occurs. */
static inline int valid_number_character(char ch)
{
char lower_ch;
if ('0' <= ch && ch <= '9')
return 1;
if (ch == '-' || ch == '+' || ch == '.')
return 1;
/* Hex digits, exponent (e), base (p), "infinity",.. */
lower_ch = ch | 0x20;
if ('a' <= lower_ch && lower_ch <= 'y')
return 1;
return 0;
}
/* Calculate the size of the buffer required for a strtod locale
* conversion. */
static int strtod_buffer_size(const char *s)
{
const char *p = s;
while (valid_number_character(*p))
p++;
return p - s;
}
/* Similar to strtod(), but must be passed the current locale's decimal point
* character. Guaranteed to be called at the start of any valid number in a string */
double fpconv_strtod(const char *nptr, char **endptr)
{
char localbuf[FPCONV_G_FMT_BUFSIZE];
char *buf, *endbuf, *dp;
int buflen;
double value;
/* System strtod() is fine when decimal point is '.' */
if (locale_decimal_point == '.')
return strtod(nptr, endptr);
buflen = strtod_buffer_size(nptr);
if (!buflen) {
/* No valid characters found, standard strtod() return */
*endptr = (char *)nptr;
return 0;
}
/* Duplicate number into buffer */
if (buflen >= FPCONV_G_FMT_BUFSIZE) {
/* Handle unusually large numbers */
buf = malloc(buflen + 1);
if (!buf) {
fprintf(stderr, "Out of memory");
abort();
}
} else {
/* This is the common case.. */
buf = localbuf;
}
memcpy(buf, nptr, buflen);
buf[buflen] = 0;
/* Update decimal point character if found */
dp = strchr(buf, '.');
if (dp)
*dp = locale_decimal_point;
value = strtod(buf, &endbuf);
*endptr = (char *)&nptr[endbuf - buf];
if (buflen >= FPCONV_G_FMT_BUFSIZE)
free(buf);
return value;
}
/* "fmt" must point to a buffer of at least 6 characters */
static void set_number_format(char *fmt, int precision)
{
int d1, d2, i;
assert(1 <= precision && precision <= 14);
/* Create printf format (%.14g) from precision */
d1 = precision / 10;
d2 = precision % 10;
fmt[0] = '%';
fmt[1] = '.';
i = 2;
if (d1) {
fmt[i++] = '0' + d1;
}
fmt[i++] = '0' + d2;
fmt[i++] = 'g';
fmt[i] = 0;
}
/* Assumes there is always at least 32 characters available in the target buffer */
int fpconv_g_fmt(char *str, double num, int precision)
{
char buf[FPCONV_G_FMT_BUFSIZE];
char fmt[6];
int len;
char *b;
set_number_format(fmt, precision);
/* Pass through when decimal point character is dot. */
if (locale_decimal_point == '.')
return snprintf(str, FPCONV_G_FMT_BUFSIZE, fmt, num);
/* snprintf() to a buffer then translate for other decimal point characters */
len = snprintf(buf, FPCONV_G_FMT_BUFSIZE, fmt, num);
/* Copy into target location. Translate decimal point if required */
b = buf;
do {
*str++ = (*b == locale_decimal_point ? '.' : *b);
} while(*b++);
return len;
}
void fpconv_init()
{
fpconv_update_locale();
}
/* vi:ai et sw=4 ts=4:
*/
|
