-
Notifications
You must be signed in to change notification settings - Fork 0
/
asctime.c
141 lines (129 loc) · 4.37 KB
/
asctime.c
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
/*
** This file is in the public domain, so clarified as of
** 1996-06-05 by Arthur David Olson.
*/
/*
** Avoid the temptation to punt entirely to strftime;
** the output of strftime is supposed to be locale specific
** whereas the output of asctime is supposed to be constant.
*/
#ifndef lint
#ifndef NOID
static char elsieid[] = "@(#)asctime.c 8.5";
#endif /* !defined NOID */
#endif /* !defined lint */
/*LINTLIBRARY*/
#include "private.h"
#include "tzfile.h"
/*
** Some systems only handle "%.2d"; others only handle "%02d";
** "%02.2d" makes (most) everybody happy.
** At least some versions of gcc warn about the %02.2d;
** we conditionalize below to avoid the warning.
*/
/*
** All years associated with 32-bit time_t values are exactly four digits long;
** some years associated with 64-bit time_t values are not.
** Vintage programs are coded for years that are always four digits long
** and may assume that the newline always lands in the same place.
** For years that are less than four digits, we pad the output with
** leading zeroes to get the newline in the traditional place.
** The -4 ensures that we get four characters of output even if
** we call a strftime variant that produces fewer characters for some years.
** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
** but many implementations pad anyway; most likely the standards are buggy.
*/
#ifdef __GNUC__
#define ASCTIME_FMT "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
#else /* !defined __GNUC__ */
#define ASCTIME_FMT "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
#endif /* !defined __GNUC__ */
/*
** For years that are more than four digits we put extra spaces before the year
** so that code trying to overwrite the newline won't end up overwriting
** a digit within a year and truncating the year (operating on the assumption
** that no output is better than wrong output).
*/
#ifdef __GNUC__
#define ASCTIME_FMT_B "%.3s %.3s%3d %2.2d:%2.2d:%2.2d %s\n"
#else /* !defined __GNUC__ */
#define ASCTIME_FMT_B "%.3s %.3s%3d %02.2d:%02.2d:%02.2d %s\n"
#endif /* !defined __GNUC__ */
#define STD_ASCTIME_BUF_SIZE 26
/*
** Big enough for something such as
** ??? ???-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n
** (two three-character abbreviations, five strings denoting integers,
** seven explicit spaces, two explicit colons, a newline,
** and a trailing ASCII nul).
** The values above are for systems where an int is 32 bits and are provided
** as an example; the define below calculates the maximum for the system at
** hand.
*/
#define MAX_ASCTIME_BUF_SIZE (2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)
static char buf_asctime[MAX_ASCTIME_BUF_SIZE];
/*
** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
*/
char *
asctime_r(timeptr, buf)
register const struct tm * timeptr;
char * buf;
{
static const char wday_name[][3] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static const char mon_name[][3] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
register const char * wn;
register const char * mn;
char year[INT_STRLEN_MAXIMUM(int) + 2];
char result[MAX_ASCTIME_BUF_SIZE];
if (timeptr == NULL) {
errno = EINVAL;
return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
}
if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
wn = "???";
else wn = wday_name[timeptr->tm_wday];
if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
mn = "???";
else mn = mon_name[timeptr->tm_mon];
/*
** Use strftime's %Y to generate the year, to avoid overflow problems
** when computing timeptr->tm_year + TM_YEAR_BASE.
** Assume that strftime is unaffected by other out-of-range members
** (e.g., timeptr->tm_mday) when processing "%Y".
*/
(void) strftime(year, sizeof year, "%Y", timeptr);
/*
** We avoid using snprintf since it's not available on all systems.
*/
(void) sprintf(result,
((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
wn, mn,
timeptr->tm_mday, timeptr->tm_hour,
timeptr->tm_min, timeptr->tm_sec,
year);
if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime)
return strcpy(buf, result);
else {
#ifdef EOVERFLOW
errno = EOVERFLOW;
#else /* !defined EOVERFLOW */
errno = EINVAL;
#endif /* !defined EOVERFLOW */
return NULL;
}
}
/*
** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
*/
char *
asctime(timeptr)
register const struct tm * timeptr;
{
return asctime_r(timeptr, buf_asctime);
}