diff options
Diffstat (limited to 'intl/icu/source/tools/tzcode/asctime.c')
| -rw-r--r-- | intl/icu/source/tools/tzcode/asctime.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/intl/icu/source/tools/tzcode/asctime.c b/intl/icu/source/tools/tzcode/asctime.c new file mode 100644 index 000000000..152b0db4e --- /dev/null +++ b/intl/icu/source/tools/tzcode/asctime.c @@ -0,0 +1,132 @@ +/* +** 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 "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(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(register const struct tm *timeptr) +{ + return asctime_r(timeptr, buf_asctime); +} |