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
|
/* Convert a floating-point number to string.
Copyright (C) 2016-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* Generic implementation for strfrom functions. The implementation is generic
for several floating-point types (e.g.: float, double), so that each
function, such as strfromf and strfroml, share the same code, thus avoiding
code duplication. */
#include <ctype.h>
#include "../libio/libioP.h"
#include "../libio/strfile.h"
#include <printf.h>
#include <string.h>
#include <locale/localeinfo.h>
#define UCHAR_T char
#define L_(Str) Str
#define ISDIGIT(Ch) isdigit (Ch)
#include "stdio-common/printf-parse.h"
int
STRFROM (char *dest, size_t size, const char *format, FLOAT f)
{
_IO_strnfile sfile;
#ifdef _IO_MTSAFE_IO
sfile.f._sbf._f._lock = NULL;
#endif
int done;
/* Single-precision values need to be stored in a double type, because
__printf_fp_l and __printf_fphex do not accept the float type. */
union {
double flt;
FLOAT value;
} fpnum;
const void *fpptr;
fpptr = &fpnum;
/* Variables to control the output format. */
int precision = -1; /* printf_fp and printf_fphex treat this internally. */
int specifier;
struct printf_info info;
/* Single-precision values need to be converted into double-precision,
because __printf_fp and __printf_fphex only accept double and long double
as the floating-point argument. */
if (__builtin_types_compatible_p (FLOAT, float))
fpnum.flt = f;
else
fpnum.value = f;
/* Check if the first character in the format string is indeed the '%'
character. Otherwise, abort. */
if (*format == '%')
format++;
else
abort ();
/* The optional precision specification always starts with a '.'. If such
character is present, read the precision. */
if (*format == '.')
{
format++;
/* Parse the precision. */
if (ISDIGIT (*format))
precision = read_int (&format);
/* If only the period is specified, the precision is taken as zero, as
described in ISO/IEC 9899:2011, section 7.21.6.1, 4th paragraph, 3rd
item. */
else
precision = 0;
}
/* Now there is only the conversion specifier to be read. */
switch (*format)
{
case 'a':
case 'A':
case 'e':
case 'E':
case 'f':
case 'F':
case 'g':
case 'G':
specifier = *format;
break;
default:
abort ();
}
/* The following code to prepare the virtual file has been adapted from the
function _IO_vsnprintf from libio. */
if (size == 0)
{
/* When size is zero, nothing is written and dest may be a null pointer.
This is specified for snprintf in ISO/IEC 9899:2011, Section 7.21.6.5,
in the second paragraph. Thus, if size is zero, prepare to use the
overflow buffer right from the start. */
dest = sfile.overflow_buf;
size = sizeof (sfile.overflow_buf);
}
/* Prepare the virtual string file. */
_IO_no_init (&sfile.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
_IO_JUMPS (&sfile.f._sbf) = &_IO_strn_jumps;
_IO_str_init_static_internal (&sfile.f, dest, size - 1, dest);
/* Prepare the format specification for printf_fp. */
memset (&info, '\0', sizeof (info));
/* The functions strfromd and strfromf pass a floating-point number with
double precision to printf_fp, whereas strfroml passes a floating-point
number with long double precision. The following line informs printf_fp
which type of floating-point number is being passed. */
info.is_long_double = __builtin_types_compatible_p (FLOAT, long double);
/* Set info according to the format string. */
info.prec = precision;
info.spec = specifier;
if (info.spec != 'a' && info.spec != 'A')
done = __printf_fp_l (&sfile.f._sbf._f, _NL_CURRENT_LOCALE, &info, &fpptr);
else
done = __printf_fphex (&sfile.f._sbf._f, &info, &fpptr);
/* Terminate the string. */
if (sfile.f._sbf._f._IO_buf_base != sfile.overflow_buf)
*sfile.f._sbf._f._IO_write_ptr = '\0';
return done;
}
|
