freebsd-dev/contrib/awk/awklib/eg/lib/mktime.awk
2000-08-15 10:02:07 +00:00

106 lines
2.5 KiB
Awk

# mktime.awk --- convert a canonical date representation
# into a timestamp
# Arnold Robbins, arnold@gnu.org, Public Domain
# May 1993
BEGIN \
{
# Initialize table of month lengths
_tm_months[0,1] = _tm_months[1,1] = 31
_tm_months[0,2] = 28; _tm_months[1,2] = 29
_tm_months[0,3] = _tm_months[1,3] = 31
_tm_months[0,4] = _tm_months[1,4] = 30
_tm_months[0,5] = _tm_months[1,5] = 31
_tm_months[0,6] = _tm_months[1,6] = 30
_tm_months[0,7] = _tm_months[1,7] = 31
_tm_months[0,8] = _tm_months[1,8] = 31
_tm_months[0,9] = _tm_months[1,9] = 30
_tm_months[0,10] = _tm_months[1,10] = 31
_tm_months[0,11] = _tm_months[1,11] = 30
_tm_months[0,12] = _tm_months[1,12] = 31
}
# decide if a year is a leap year
function _tm_isleap(year, ret)
{
ret = (year % 4 == 0 && year % 100 != 0) ||
(year % 400 == 0)
return ret
}
# convert a date into seconds
function _tm_addup(a, total, yearsecs, daysecs,
hoursecs, i, j)
{
hoursecs = 60 * 60
daysecs = 24 * hoursecs
yearsecs = 365 * daysecs
total = (a[1] - 1970) * yearsecs
# extra day for leap years
for (i = 1970; i < a[1]; i++)
if (_tm_isleap(i))
total += daysecs
j = _tm_isleap(a[1])
for (i = 1; i < a[2]; i++)
total += _tm_months[j, i] * daysecs
total += (a[3] - 1) * daysecs
total += a[4] * hoursecs
total += a[5] * 60
total += a[6]
return total
}
# mktime --- convert a date into seconds,
# compensate for time zone
function mktime(str, res1, res2, a, b, i, j, t, diff)
{
i = split(str, a, " ") # don't rely on FS
if (i != 6)
return -1
# force numeric
for (j in a)
a[j] += 0
# validate
if (a[1] < 1970 ||
a[2] < 1 || a[2] > 12 ||
a[3] < 1 || a[3] > 31 ||
a[4] < 0 || a[4] > 23 ||
a[5] < 0 || a[5] > 59 ||
a[6] < 0 || a[6] > 60 )
return -1
res1 = _tm_addup(a)
t = strftime("%Y %m %d %H %M %S", res1)
if (_tm_debug)
printf("(%s) -> (%s)\n", str, t) > "/dev/stderr"
split(t, b, " ")
res2 = _tm_addup(b)
diff = res1 - res2
if (_tm_debug)
printf("diff = %d seconds\n", diff) > "/dev/stderr"
res1 += diff
return res1
}
BEGIN {
if (_tm_test) {
printf "Enter date as yyyy mm dd hh mm ss: "
getline _tm_test_date
t = mktime(_tm_test_date)
r = strftime("%Y %m %d %H %M %S", t)
printf "Got back (%s)\n", r
}
}