| /* 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 "private.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]; |
| |
| /* A similar buffer for ctime. |
| C89 requires that they be the same buffer. |
| This requirement was removed in C99, so support it only if requested, |
| as support is more likely to lead to bugs in badly written programs. */ |
| #if SUPPORT_C89 |
| # define buf_ctime buf_asctime |
| #else |
| static char buf_ctime[sizeof buf_asctime]; |
| #endif |
| |
| char * |
| asctime_r(struct tm const *restrict timeptr, char *restrict 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" |
| }; |
| register const char * wn; |
| register 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. |
| */ |
| snprintf(result, sizeof(result), /* Android change: use snprintf. */ |
| ((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_ctime || 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); |
| } |
| |
| char * |
| ctime_r(const time_t *timep, char *buf) |
| { |
| struct tm mytm; |
| struct tm *tmp = localtime_r(timep, &mytm); |
| return tmp ? asctime_r(tmp, buf) : NULL; |
| } |
| |
| char * |
| ctime(const time_t *timep) |
| { |
| return ctime_r(timep, buf_ctime); |
| } |