bc42155199
* Replay 2010[acflm] which had been merged but not recorded. * Merge 2010n. * Reorganize (unsplit) the code to match the upstream layout. * Merge 2022[cdefg]. MFC after: 1 week Sponsored by: Klara, Inc.
109 lines
3.6 KiB
C
109 lines
3.6 KiB
C
/* asctime and asctime_r a la POSIX and ISO C, except pad years before 1000. */
|
|
|
|
/*
|
|
** 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.
|
|
*/
|
|
|
|
/*LINTLIBRARY*/
|
|
|
|
#include "namespace.h"
|
|
#include "private.h"
|
|
#include "un-namespace.h"
|
|
#include <stdio.h>
|
|
|
|
/*
|
|
** 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 and POSIX standards prohibit padding the year,
|
|
** but many implementations pad anyway; most likely the standards are buggy.
|
|
*/
|
|
static char const ASCTIME_FMT[] = "%s %s%3d %.2d:%.2d:%.2d %-4s\n";
|
|
/*
|
|
** 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).
|
|
*/
|
|
static char const ASCTIME_FMT_B[] = "%s %s%3d %.2d:%.2d:%.2d %s\n";
|
|
|
|
enum { 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 NUL byte).
|
|
** The values above are for systems where an int is 32 bits and are provided
|
|
** as an example; the size expression below is a bound for the system at
|
|
** hand.
|
|
*/
|
|
static char buf_asctime[2*3 + 5*INT_STRLEN_MAXIMUM(int) + 7 + 2 + 1 + 1];
|
|
|
|
char *
|
|
asctime_r(register const struct tm *timeptr, char *buf)
|
|
{
|
|
static const char wday_name[][4] = {
|
|
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
|
|
};
|
|
static const char mon_name[][4] = {
|
|
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
|
|
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
|
|
};
|
|
const char * wn;
|
|
const char * mn;
|
|
char year[INT_STRLEN_MAXIMUM(int) + 2];
|
|
char result[sizeof buf_asctime];
|
|
|
|
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".
|
|
*/
|
|
strftime(year, sizeof year, "%Y", timeptr);
|
|
/*
|
|
** We avoid using snprintf since it's not available on all systems.
|
|
*/
|
|
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 {
|
|
errno = EOVERFLOW;
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
char *
|
|
asctime(register const struct tm *timeptr)
|
|
{
|
|
return asctime_r(timeptr, buf_asctime);
|
|
}
|