ref: f99b9cae6a3dc5775a83b264d6041be8d5d416d6
dir: /sys/src/cmd/upas/imap4d/date.c/
#include "imap4d.h"
static char *wdayname[] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static char *monname[] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
/*
* zone : [A-Za-z][A-Za-z][A-Za-z] some time zone names
* | [A-IK-Z] military time; rfc1123 says the rfc822 spec is wrong.
* | "UT" universal time
* | [+-][0-9][0-9][0-9][0-9]
* zones is the rfc-822 list of time zone names
*/
static Namedint zones[] =
{
{"A", -1 * 3600},
{"B", -2 * 3600},
{"C", -3 * 3600},
{"CDT", -5 * 3600},
{"CST", -6 * 3600},
{"D", -4 * 3600},
{"E", -5 * 3600},
{"EDT", -4 * 3600},
{"EST", -5 * 3600},
{"F", -6 * 3600},
{"G", -7 * 3600},
{"GMT", 0},
{"H", -8 * 3600},
{"I", -9 * 3600},
{"K", -10 * 3600},
{"L", -11 * 3600},
{"M", -12 * 3600},
{"MDT", -6 * 3600},
{"MST", -7 * 3600},
{"N", +1 * 3600},
{"O", +2 * 3600},
{"P", +3 * 3600},
{"PDT", -7 * 3600},
{"PST", -8 * 3600},
{"Q", +4 * 3600},
{"R", +5 * 3600},
{"S", +6 * 3600},
{"T", +7 * 3600},
{"U", +8 * 3600},
{"UT", 0},
{"V", +9 * 3600},
{"W", +10 * 3600},
{"X", +11 * 3600},
{"Y", +12 * 3600},
{"Z", 0},
};
static void
zone2tm(Tm *tm, char *s)
{
int i;
Tm aux, *atm;
if(*s == '+' || *s == '-'){
i = strtol(s, &s, 10);
tm->tzoff = (i/100)*3600 + i%100;
strncpy(tm->zone, "", 4);
return;
}
/*
* look it up in the standard rfc822 table
*/
strncpy(tm->zone, s, 3);
tm->zone[3] = 0;
tm->tzoff = 0;
for(i = 0; i < nelem(zones); i++){
if(cistrcmp(zones[i].name, s) == 0){
tm->tzoff = zones[i].v;
return;
}
}
/*
* one last try: look it up in the current local timezone
* probe a couple of times to get daylight/standard time change.
*/
aux = *tm;
memset(aux.zone, 0, 4);
aux.hour--;
for(i = 0; i < 2; i++){
atm = localtime(tm2sec(&aux));
if(cistrcmp(tm->zone, atm->zone) == 0){
tm->tzoff = atm->tzoff;
return;
}
aux.hour++;
}
strncpy(tm->zone, "GMT", 4);
tm->tzoff = 0;
}
/*
* hh[:mm[:ss]]
*/
static void
time2tm(Tm *tm, char *s)
{
tm->hour = strtoul(s, &s, 10);
if(*s++ != ':')
return;
tm->min = strtoul(s, &s, 10);
if(*s++ != ':')
return;
tm->sec = strtoul(s, &s, 10);
}
static int
dateindex(char *d, char **tab, int n)
{
int i;
for(i = 0; i < n; i++)
if(cistrcmp(d, tab[i]) == 0)
return i;
return -1;
}
int
imap4date(Tm *tm, char *date)
{
char *flds[4];
if(getfields(date, flds, 3, 0, "-") != 3)
return 0;
tm->mday = strtol(flds[0], nil, 10);
tm->mon = dateindex(flds[1], monname, 12);
tm->year = strtol(flds[2], nil, 10) - 1900;
return 1;
}
/*
* parse imap4 dates
*/
ulong
imap4datetime(char *date)
{
char *flds[4], *sflds[4];
ulong t;
Tm tm;
if(getfields(date, flds, 4, 0, " ") != 3)
return ~0;
if(!imap4date(&tm, flds[0]))
return ~0;
if(getfields(flds[1], sflds, 3, 0, ":") != 3)
return ~0;
tm.hour = strtol(sflds[0], nil, 10);
tm.min = strtol(sflds[1], nil, 10);
tm.sec = strtol(sflds[2], nil, 10);
strcpy(tm.zone, "GMT");
tm.yday = 0;
t = tm2sec(&tm);
zone2tm(&tm, flds[2]);
t -= tm.tzoff;
return t;
}
/*
* parse dates of formats
* [Wkd[,]] DD Mon YYYY HH:MM:SS zone
* [Wkd] Mon ( D|DD) HH:MM:SS zone YYYY
* plus anything similar
* return nil for a failure
*/
Tm*
date2tm(Tm *tm, char *date)
{
char *flds[7], *s, dstr[64];
int n;
Tm gmt, *atm;
/*
* default date is Thu Jan 1 00:00:00 GMT 1970
*/
tm->wday = 4;
tm->mday = 1;
tm->mon = 1;
tm->hour = 0;
tm->min = 0;
tm->sec = 0;
tm->year = 70;
strcpy(tm->zone, "GMT");
tm->tzoff = 0;
strncpy(dstr, date, sizeof dstr);
dstr[sizeof dstr - 1] = 0;
n = tokenize(dstr, flds, 7);
if(n != 6 && n != 5)
return nil;
if(n == 5){
for(n = 5; n >= 1; n--)
flds[n] = flds[n - 1];
n = 5;
}else{
/*
* Wday[,]
*/
s = strchr(flds[0], ',');
if(s != nil)
*s = 0;
tm->wday = dateindex(flds[0], wdayname, 7);
if(tm->wday < 0)
return nil;
}
/*
* check for the two major formats:
* Month first or day first
*/
tm->mon = dateindex(flds[1], monname, 12);
if(tm->mon >= 0){
tm->mday = strtoul(flds[2], nil, 10);
time2tm(tm, flds[3]);
zone2tm(tm, flds[4]);
tm->year = strtoul(flds[5], nil, 10);
if(strlen(flds[5]) > 2)
tm->year -= 1900;
}else{
tm->mday = strtoul(flds[1], nil, 10);
tm->mon = dateindex(flds[2], monname, 12);
tm->year = strtoul(flds[3], nil, 10);
if(strlen(flds[3]) > 2)
tm->year -= 1900;
time2tm(tm, flds[4]);
zone2tm(tm, flds[5]);
}
if(n == 5){
gmt = *tm;
strncpy(gmt.zone, "", 4);
gmt.tzoff = 0;
atm = gmtime(tm2sec(&gmt));
tm->wday = atm->wday;
}else{
/*
* Wday[,]
*/
s = strchr(flds[0], ',');
if(s != nil)
*s = 0;
tm->wday = dateindex(flds[0], wdayname, 7);
if(tm->wday < 0)
return nil;
}
return tm;
}