ref: 17b80cbcf1d5a7c6afd74c7432ab64c100dbdc2f
dir: /sys/src/cmd/seconds.c/
/*
* seconds absolute_date ... - convert absolute_date to seconds since epoch
*/
#include <u.h>
#include <libc.h>
#include <ctype.h>
typedef ulong Time;
enum {
AM, PM, HR24,
/* token types */
Month = 1,
Year,
Day,
Timetok,
Tz,
Dtz,
Ignore,
Ampm,
Maxtok = 6, /* only this many chars are stored in datetktbl */
Maxdateflds = 25,
};
/*
* macros for squeezing values into low 7 bits of "value".
* all timezones we care about are divisible by 10, and the largest value
* (780) when divided is 78.
*/
#define TOVAL(tp, v) ((tp)->value = (v) / 10)
#define FROMVAL(tp) ((tp)->value * 10) /* uncompress */
/* keep this struct small since we have an array of them */
typedef struct {
char token[Maxtok];
char type;
schar value;
} Datetok;
int dtok_numparsed;
/* forwards */
Datetok *datetoktype(char *s, int *bigvalp);
static Datetok datetktbl[];
static unsigned szdatetktbl;
/* parse 1- or 2-digit number, advance *cpp past it */
static int
eatnum(char **cpp)
{
int c, x;
char *cp;
cp = *cpp;
c = *cp;
if (!isascii(c) || !isdigit(c))
return -1;
x = c - '0';
c = *++cp;
if (isascii(c) && isdigit(c)) {
x = 10*x + c - '0';
cp++;
}
*cpp = cp;
return x;
}
/* return -1 on failure */
int
parsetime(char *time, Tm *tm)
{
tm->hour = eatnum(&time);
if (tm->hour == -1 || *time++ != ':')
return -1; /* only hour; too short */
tm->min = eatnum(&time);
if (tm->min == -1)
return -1;
if (*time++ != ':') {
tm->sec = 0;
return 0; /* no seconds; okay */
}
tm->sec = eatnum(&time);
if (tm->sec == -1)
return -1;
/* this may be considered too strict. garbage at end of time? */
return *time == '\0' || isascii(*time) && isspace(*time)? 0: -1;
}
/*
* try to parse pre-split timestr in fields as an absolute date
*/
int
tryabsdate(char **fields, int nf, Tm *now, Tm *tm)
{
int i, mer = HR24, bigval = -1;
long flg = 0, ty;
char *p;
char upzone[32];
Datetok *tp;
now = localtime(time(0)); /* default to local time (zone) */
tm->tzoff = now->tzoff;
strncpy(tm->zone, now->zone, sizeof tm->zone);
tm->mday = tm->mon = tm->year = -1; /* mandatory */
tm->hour = tm->min = tm->sec = 0;
dtok_numparsed = 0;
for (i = 0; i < nf; i++) {
if (fields[i][0] == '\0')
continue;
tp = datetoktype(fields[i], &bigval);
ty = (1L << tp->type) & ~(1L << Ignore);
if (flg & ty)
return -1; /* repeated type */
flg |= ty;
switch (tp->type) {
case Year:
tm->year = bigval;
if (tm->year < 1970 || tm->year > 2106)
return -1; /* can't represent in ulong */
/* convert 4-digit year to 1900 origin */
if (tm->year >= 1900)
tm->year -= 1900;
break;
case Day:
tm->mday = bigval;
break;
case Month:
tm->mon = tp->value - 1; /* convert to zero-origin */
break;
case Timetok:
if (parsetime(fields[i], tm) < 0)
return -1;
break;
case Dtz:
case Tz:
tm->tzoff = FROMVAL(tp);
/* tm2sec needs the name in upper case */
strcpy(upzone, fields[i]);
for (p = upzone; *p; p++)
if (isascii(*p) && islower(*p))
*p = toupper(*p);
strncpy(tm->zone, upzone, sizeof tm->zone);
break;
case Ignore:
break;
case Ampm:
mer = tp->value;
break;
default:
return -1; /* bad token type: CANTHAPPEN */
}
}
if (tm->year == -1 || tm->mon == -1 || tm->mday == -1)
return -1; /* missing component */
if (mer == PM)
tm->hour += 12;
return 0;
}
int
prsabsdate(char *timestr, Tm *now, Tm *tm)
{
int nf;
char *fields[Maxdateflds];
static char delims[] = "- \t\n/,";
nf = gettokens(timestr, fields, nelem(fields), delims+1);
if (nf > nelem(fields))
return -1;
if (tryabsdate(fields, nf, now, tm) < 0) {
char *p = timestr;
/*
* could be a DEC-date; glue it all back together, split it
* with dash as a delimiter and try again. Yes, this is a
* hack, but so are DEC-dates.
*/
while (--nf > 0) {
while (*p++ != '\0')
;
p[-1] = ' ';
}
nf = gettokens(timestr, fields, nelem(fields), delims);
if (nf > nelem(fields) || tryabsdate(fields, nf, now, tm) < 0)
return -1;
}
return 0;
}
int
validtm(Tm *tm)
{
if (tm->year < 0 || tm->mon < 0 || tm->mon > 11 ||
tm->mday < 1 || tm->hour < 0 || tm->hour >= 24 ||
tm->min < 0 || tm->min > 59 ||
tm->sec < 0 || tm->sec > 61) /* allow 2 leap seconds */
return 0;
return 1;
}
Time
seconds(char *timestr)
{
Tm date;
memset(&date, 0, sizeof date);
if (prsabsdate(timestr, localtime(time(0)), &date) < 0)
return -1;
return validtm(&date)? tm2sec(&date): -1;
}
int
convert(char *timestr)
{
char *copy;
Time tstime;
copy = strdup(timestr);
if (copy == nil)
sysfatal("out of memory");
tstime = seconds(copy);
free(copy);
if (tstime == -1) {
fprint(2, "%s: `%s' not a valid date\n", argv0, timestr);
return 1;
}
print("%lud\n", tstime);
return 0;
}
static void
usage(void)
{
fprint(2, "usage: %s date-time ...\n", argv0);
exits("usage");
}
void
main(int argc, char **argv)
{
int i, sts;
sts = 0;
ARGBEGIN{
default:
usage();
}ARGEND
if (argc == 0)
usage();
for (i = 0; i < argc; i++)
sts |= convert(argv[i]);
exits(sts != 0? "bad": 0);
}
/*
* Binary search -- from Knuth (6.2.1) Algorithm B. Special case like this
* is WAY faster than the generic bsearch().
*/
Datetok *
datebsearch(char *key, Datetok *base, unsigned nel)
{
int cmp;
Datetok *last = base + nel - 1, *pos;
while (last >= base) {
pos = base + ((last - base) >> 1);
cmp = key[0] - pos->token[0];
if (cmp == 0) {
cmp = strncmp(key, pos->token, Maxtok);
if (cmp == 0)
return pos;
}
if (cmp < 0)
last = pos - 1;
else
base = pos + 1;
}
return 0;
}
Datetok *
datetoktype(char *s, int *bigvalp)
{
char *cp = s;
char c = *cp;
static Datetok t;
Datetok *tp = &t;
if (isascii(c) && isdigit(c)) {
int len = strlen(cp);
if (len > 3 && (cp[1] == ':' || cp[2] == ':'))
tp->type = Timetok;
else {
if (bigvalp != nil)
*bigvalp = atoi(cp); /* won't fit in tp->value */
if (len == 4)
tp->type = Year;
else if (++dtok_numparsed == 1)
tp->type = Day;
else
tp->type = Year;
}
} else if (c == '-' || c == '+') {
int val = atoi(cp + 1);
int hr = val / 100;
int min = val % 100;
val = hr*60 + min;
TOVAL(tp, c == '-'? -val: val);
tp->type = Tz;
} else {
char lowtoken[Maxtok+1];
char *ltp = lowtoken, *endltp = lowtoken+Maxtok;
/* copy to lowtoken to avoid modifying s */
while ((c = *cp++) != '\0' && ltp < endltp)
*ltp++ = (isascii(c) && isupper(c)? tolower(c): c);
*ltp = '\0';
tp = datebsearch(lowtoken, datetktbl, szdatetktbl);
if (tp == nil) {
tp = &t;
tp->type = Ignore;
}
}
return tp;
}
/*
* to keep this table reasonably small, we divide the lexval for Tz and Dtz
* entries by 10 and truncate the text field at MAXTOKLEN characters.
* the text field is not guaranteed to be NUL-terminated.
*/
static Datetok datetktbl[] = {
/* text token lexval */
"acsst", Dtz, 63, /* Cent. Australia */
"acst", Tz, 57, /* Cent. Australia */
"adt", Dtz, -18, /* Atlantic Daylight Time */
"aesst", Dtz, 66, /* E. Australia */
"aest", Tz, 60, /* Australia Eastern Std Time */
"ahst", Tz, 60, /* Alaska-Hawaii Std Time */
"am", Ampm, AM,
"apr", Month, 4,
"april", Month, 4,
"ast", Tz, -24, /* Atlantic Std Time (Canada) */
"at", Ignore, 0, /* "at" (throwaway) */
"aug", Month, 8,
"august", Month, 8,
"awsst", Dtz, 54, /* W. Australia */
"awst", Tz, 48, /* W. Australia */
"bst", Tz, 6, /* British Summer Time */
"bt", Tz, 18, /* Baghdad Time */
"cadt", Dtz, 63, /* Central Australian DST */
"cast", Tz, 57, /* Central Australian ST */
"cat", Tz, -60, /* Central Alaska Time */
"cct", Tz, 48, /* China Coast */
"cdt", Dtz, -30, /* Central Daylight Time */
"cet", Tz, 6, /* Central European Time */
"cetdst", Dtz, 12, /* Central European Dayl.Time */
"cst", Tz, -36, /* Central Standard Time */
"dec", Month, 12,
"decemb", Month, 12,
"dnt", Tz, 6, /* Dansk Normal Tid */
"dst", Ignore, 0,
"east", Tz, -60, /* East Australian Std Time */
"edt", Dtz, -24, /* Eastern Daylight Time */
"eet", Tz, 12, /* East. Europe, USSR Zone 1 */
"eetdst", Dtz, 18, /* Eastern Europe */
"est", Tz, -30, /* Eastern Standard Time */
"feb", Month, 2,
"februa", Month, 2,
"fri", Ignore, 5,
"friday", Ignore, 5,
"fst", Tz, 6, /* French Summer Time */
"fwt", Dtz, 12, /* French Winter Time */
"gmt", Tz, 0, /* Greenwish Mean Time */
"gst", Tz, 60, /* Guam Std Time, USSR Zone 9 */
"hdt", Dtz, -54, /* Hawaii/Alaska */
"hmt", Dtz, 18, /* Hellas ? ? */
"hst", Tz, -60, /* Hawaii Std Time */
"idle", Tz, 72, /* Intl. Date Line, East */
"idlw", Tz, -72, /* Intl. Date Line, West */
"ist", Tz, 12, /* Israel */
"it", Tz, 22, /* Iran Time */
"jan", Month, 1,
"januar", Month, 1,
"jst", Tz, 54, /* Japan Std Time,USSR Zone 8 */
"jt", Tz, 45, /* Java Time */
"jul", Month, 7,
"july", Month, 7,
"jun", Month, 6,
"june", Month, 6,
"kst", Tz, 54, /* Korea Standard Time */
"ligt", Tz, 60, /* From Melbourne, Australia */
"mar", Month, 3,
"march", Month, 3,
"may", Month, 5,
"mdt", Dtz, -36, /* Mountain Daylight Time */
"mest", Dtz, 12, /* Middle Europe Summer Time */
"met", Tz, 6, /* Middle Europe Time */
"metdst", Dtz, 12, /* Middle Europe Daylight Time*/
"mewt", Tz, 6, /* Middle Europe Winter Time */
"mez", Tz, 6, /* Middle Europe Zone */
"mon", Ignore, 1,
"monday", Ignore, 1,
"mst", Tz, -42, /* Mountain Standard Time */
"mt", Tz, 51, /* Moluccas Time */
"ndt", Dtz, -15, /* Nfld. Daylight Time */
"nft", Tz, -21, /* Newfoundland Standard Time */
"nor", Tz, 6, /* Norway Standard Time */
"nov", Month, 11,
"novemb", Month, 11,
"nst", Tz, -21, /* Nfld. Standard Time */
"nt", Tz, -66, /* Nome Time */
"nzdt", Dtz, 78, /* New Zealand Daylight Time */
"nzst", Tz, 72, /* New Zealand Standard Time */
"nzt", Tz, 72, /* New Zealand Time */
"oct", Month, 10,
"octobe", Month, 10,
"on", Ignore, 0, /* "on" (throwaway) */
"pdt", Dtz, -42, /* Pacific Daylight Time */
"pm", Ampm, PM,
"pst", Tz, -48, /* Pacific Standard Time */
"sadt", Dtz, 63, /* S. Australian Dayl. Time */
"sast", Tz, 57, /* South Australian Std Time */
"sat", Ignore, 6,
"saturd", Ignore, 6,
"sep", Month, 9,
"sept", Month, 9,
"septem", Month, 9,
"set", Tz, -6, /* Seychelles Time ?? */
"sst", Dtz, 12, /* Swedish Summer Time */
"sun", Ignore, 0,
"sunday", Ignore, 0,
"swt", Tz, 6, /* Swedish Winter Time */
"thu", Ignore, 4,
"thur", Ignore, 4,
"thurs", Ignore, 4,
"thursd", Ignore, 4,
"tue", Ignore, 2,
"tues", Ignore, 2,
"tuesda", Ignore, 2,
"ut", Tz, 0,
"utc", Tz, 0,
"wadt", Dtz, 48, /* West Australian DST */
"wast", Tz, 42, /* West Australian Std Time */
"wat", Tz, -6, /* West Africa Time */
"wdt", Dtz, 54, /* West Australian DST */
"wed", Ignore, 3,
"wednes", Ignore, 3,
"weds", Ignore, 3,
"wet", Tz, 0, /* Western Europe */
"wetdst", Dtz, 6, /* Western Europe */
"wst", Tz, 48, /* West Australian Std Time */
"ydt", Dtz, -48, /* Yukon Daylight Time */
"yst", Tz, -54, /* Yukon Standard Time */
"zp4", Tz, -24, /* GMT +4 hours. */
"zp5", Tz, -30, /* GMT +5 hours. */
"zp6", Tz, -36, /* GMT +6 hours. */
};
static unsigned szdatetktbl = nelem(datetktbl);