awk function strftime and mktime without gawk

[JorisKB]

I found some things and then complete it to create a strftime function that works the same way as the gawk one :

function weeknumber(flag)
{
        local n;
        if (flag == "U") return int((yearday + 5 - (weekday-1)) / 7);
        if (flag == "W") return int((yearday + 5 - ((weekday>1) ? (weekday-2):6)) / 7);
        n = int((yearday + 8 - (weekday>1 ? (weekday - 2) : 6)) / 7);
        return n ? n : 53;
}

function strftime(fmt,epoc)
{
#calcule de secondes minutes heures jour_mois mois annee jour_an depuis unix time
wipmin = int( epoc / 60 )
second = epoc % 60
wipheure = int( wipmin / 60 )
minute = wipmin % 60
wipjour = int( wipheure / 24 ) + 1
hour = wipheure % 24
year = int( wipjour / 365 ) + 1970
wipjour_an = wipjour % 365
leapmod = 0
for ( an=1970 ; an<year ; an++ )
    { if ( (an % 4 == 0 && an % 100 != 0) || (an % 400 == 0) )
        { leapmod++ } }
if ( leapmod >= wipjour_an ) {
    year = year - 1
    if ( (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0) )
        { wipjour_an = 366 + wipjour_an }
    else
        { wipjour_an = 365 + wipjour_an }
    }
yearday = wipjour_an - leapmod

if ( (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0) )
    { isleap = "Y" }
longmois=31
month=1
wipjour_an2 = yearday
while ( wipjour_an2 > longmois )
    { if ( month == 1 )
        { if ( isleap == "Y" )
            { wipjour_an2 = wipjour_an2 - longmois ; longmois = 29 }
          else
            { wipjour_an2 = wipjour_an2 - longmois ; longmois = 28 }
        }
      if ( month == 2 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      if ( month == 3 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 30 }
      if ( month == 4 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      if ( month == 5 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 30 }
      if ( month == 6 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      if ( month == 7 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      if ( month == 8 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 30 }
      if ( month == 9 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      if ( month == 10 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 30 }
      if ( month == 11 )
        { wipjour_an2 = wipjour_an2 - longmois ; longmois = 31 }
      month++
    }
day = wipjour_an2
#january 1st 1970 was a thursday
weekday = (wipjour + 3) % 7

{ print " epoc "epoc" wipmin "wipmin" second "second" wipheure "wipheure" minute "minute" wipjour "wipjour" hour "hour" year "year" wipjour_an "wipjour_an" yearday "yearday" day "day" month "month" weekday "weekday }

        split("Mon Tue Wed Thu Fri Sat Sun",abdaynames)
        split("Monday Tuesday Wednesday Thursday Friday Saturday Sunday",daynames)
        split("January February March April May June July August September October November December",monthnames)
        split("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec",abmonthnames)

        gsub("%%","\xff",fmt)   # Change %% so we dont lose them
        # We do not support POSIX locales, so %Ex and %Ox are translated to %x.
        gsub("%E|%O","%",fmt)
        # The %c, %x, %X and %r are country-specific abbreviations for other formats:
        gsub("%c","%a %b %e %H:%M:%S %Z %Y",fmt)
        gsub("%x","%m %d %y",fmt)
        gsub("%X","%H:%M:%S",fmt)
        gsub("%r","%I:%M:%S %p",fmt)
        gsub("%D","%m/%d/%y",fmt)
        gsub("%R","%H:%M",fmt)
        gsub("%T","%H:%M:%S",fmt)

        # Now do the format substitutions
        gsub("%a",abdaynames[weekday],fmt)
        gsub("%A",daynames[weekday],fmt)
        gsub("%B",monthnames[month],fmt)
        gsub("%b",abmonthnames[month],fmt)
        gsub("%C",int(year/100),fmt)
        gsub("%d",sprintf("%02d",day),fmt)
        gsub("%e",sprintf("%2d",day),fmt)
        gsub("%h",abmonthnames[month],fmt)
        gsub("%H",sprintf("%02d",hour),fmt)
        gsub("%I",sprintf("%02d",hour % 12 == 0 ? 12 : hour % 12),fmt)
        gsub("%j",sprintf("%03d",yearday),fmt)

        # %k and %l are not in POSIX, but are SunOS compatible?
        gsub("%k",sprintf("%2d",hour),fmt)
        gsub("%l",sprintf("%2d",hour % 12 == 0 ? 12 : hour % 12),fmt)

        gsub("%m",sprintf("%02d",month),fmt)
        gsub("%M",sprintf("%02d",minute),fmt)
        gsub("%n","\n",fmt)
        gsub("%p",hour < 12 ? "AM" : "PM",fmt)
    gsub("%s",int,fmt)
        gsub("%S",sprintf("%02d",second),fmt)
        gsub("%t","\t",fmt)
        # %u is day of week, but assuming 1=Mon, ..., 7=Sun
        gsub("%u",weekday == 1 ? 7 : weekday-1,fmt)
        gsub("%U",sprintf("%02d",weeknumber("U")),fmt)
        gsub("%V",sprintf("%02d",weeknumber("V")),fmt)
        gsub("%w",weekday-1,fmt)
        gsub("%W",sprintf("%02d",weeknumber("W")),fmt)
        gsub("%y",sprintf("%02d",year % 100),fmt)
        gsub("%Y",year,fmt)
        # %Z is time zone name, which is taken from the environment variable.
        # If the TZ environment variable is not set, print nothing.
        gsub("%Z",ENVIRON["TZ"],fmt)  # Time Zone Name

        gsub("\xff","%",fmt)    # Change %% removed above back to %
        return fmt
}

This is an other thing i found on the web for mktime :

http://www.math.utah.edu/docs/info/gawk_16.html#SEC147

# 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
}

function mktime(str,    res1, res2, a, b, i, j, t, diff)
{
    i = split(str, a, " ")    # dont 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] > 61 )
            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 {
# 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
}

Feel free to correct or complete these.

 

[JorisKB]

Oops, i forgot this line that was for debug :

{ print " epoc "epoc" wipmin "wipmin" second "second" wipheure "wipheure" minute "minute" wipjour "wipjour" hour "hour" year "year" wipjour_an "wipjour_an" yearday "yearday" day "day" month "month" weekday "weekday }

Of course you don't want it in the function. (I'm totally newb on this board and dunno how to edit my post)