diff options
Diffstat (limited to 'newlib/libc/time/lcltime_r.c')
-rw-r--r-- | newlib/libc/time/lcltime_r.c | 90 |
1 files changed, 88 insertions, 2 deletions
diff --git a/newlib/libc/time/lcltime_r.c b/newlib/libc/time/lcltime_r.c index cf386719c..1b4269ee1 100644 --- a/newlib/libc/time/lcltime_r.c +++ b/newlib/libc/time/lcltime_r.c @@ -1,18 +1,104 @@ /* * localtime_r.c + * Original Author: Adapted from tzcode maintained by Arthur David Olson. * * Converts the calendar time pointed to by tim_p into a broken-down time * expressed as local time. Returns a pointer to a structure containing the * broken-down time. */ +#include <stdlib.h> #include <time.h> -#include "local.h" + +#define SECSPERMIN 60L +#define MINSPERHOUR 60L +#define HOURSPERDAY 24L +#define SECSPERHOUR (SECSPERMIN * MINSPERHOUR) +#define SECSPERDAY (SECSPERHOUR * HOURSPERDAY) +#define DAYSPERWEEK 7 +#define MONSPERYEAR 12 + +#define YEAR_BASE 1900 +#define EPOCH_YEAR 1970 +#define EPOCH_WDAY 4 + +#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) + +static _CONST int mon_lengths[2][MONSPERYEAR] = { + {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, + {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} +} ; + +static _CONST int year_lengths[2] = { + 365, + 366 +} ; struct tm * _DEFUN (localtime_r, (tim_p, res), _CONST time_t * tim_p _AND struct tm *res) { - return _mktm_r (tim_p, res, 0); + long days, rem; + int y; + int yleap; + _CONST int *ip; + + days = ((long) *tim_p) / SECSPERDAY; + rem = ((long) *tim_p) % SECSPERDAY; + while (rem < 0) + { + rem += SECSPERDAY; + --days; + } + while (rem >= SECSPERDAY) + { + rem -= SECSPERDAY; + ++days; + } + + /* compute hour, min, and sec */ + res->tm_hour = (int) (rem / SECSPERHOUR); + rem %= SECSPERHOUR; + res->tm_min = (int) (rem / SECSPERMIN); + res->tm_sec = (int) (rem % SECSPERMIN); + + /* compute day of week */ + if ((res->tm_wday = ((EPOCH_WDAY + days) % DAYSPERWEEK)) < 0) + res->tm_wday += DAYSPERWEEK; + + /* compute year & day of year */ + y = EPOCH_YEAR; + if (days >= 0) + { + for (;;) + { + yleap = isleap(y); + if (days < year_lengths[yleap]) + break; + y++; + days -= year_lengths[yleap]; + } + } + else + { + do + { + --y; + yleap = isleap(y); + days += year_lengths[yleap]; + } while (days < 0); + } + + res->tm_year = y - YEAR_BASE; + res->tm_yday = days; + ip = mon_lengths[yleap]; + for (res->tm_mon = 0; days >= ip[res->tm_mon]; ++res->tm_mon) + days -= ip[res->tm_mon]; + res->tm_mday = days + 1; + + /* set daylight saving time flag */ + res->tm_isdst = -1; + + return (res); } |