var/external/bufr/i4dy.f

   1       FUNCTION I4DY(IDATE)
   2
   3 C$$$  SUBPROGRAM DOCUMENTATION BLOCK
   4 C
   5 C SUBPROGRAM:    I4DY
   6 C   PRGMMR: WOOLLEN          ORG: NP20       DATE: 1998-07-08
   7 C
   8 C ABSTRACT: THIS FUNCTION CONVERTS AN EIGHT DIGIT INTEGER DATE
   9 C   (YYMMDDHH) TO TEN DIGITS (YYYYMMDDHH) USING THE Y2K "WINDOWING"
  10 C   TECHNIQUE.  ALL TWO-DIGIT YEARS GREATER THAN "20" ARE ASSUMED TO
  11 C   HAVE A FOUR-DIGIT YEAR BEGINNING WITH "19" (1921-1999) AND ALL TWO-
  12 C   DIGIT YEARS LESS THAN OR EQUAL TO "20" ARE ASSUMED TO HAVE A FOUR-
  13 C   DIGIT YEAR BEGINNING WITH "20" (2000-2020).  IF THE INPUT DATE IS
  14 C   ALREADY TEN DIGITS, THIS ROUTINE JUST RETURNS ITS VALUE.
  15 C
  16 C PROGRAM HISTORY LOG:
  17 C 1998-07-08  J. WOOLLEN -- ORIGINAL AUTHOR
  18 C 1998-11-24  J. WOOLLEN -- MODIFIED TO CONFORM TO THE NCEP 2-DIGIT
  19 C                           YEAR TIME WINDOW OF 1921-2020 (BUT
  20 C                           INADVERTENTLY SET TO 1911-2010)
  21 C 1998-12-14  J. WOOLLEN -- MODIFIED TO USE 20 AS THE 2-DIGIT YEAR FOR
  22 C                           WINDOWING TO A 4-DIGIT YEAR (00-20 ==> ADD
  23 C                           2000; 21-99 ==> ADD 1900), THIS WINDOWING
  24 C                           TECHNIQUE WAS INADVERTENTLY CHANGED TO 10
  25 C                           IN THE PREVIOUS IMPLEMENTATION OF I4DY
  26 C                           (1998-11-24)
  27 C 2003-11-04  S. BENDER  -- ADDED REMARKS/BUFRLIB ROUTINE
  28 C                           INTERDEPENDENCIES
  29 C 2003-11-04  D. KEYSER  -- MODIFIED DATE CALCULATIONS TO NO LONGER USE
  30 C                           FLOATING POINT ARITHMETIC SINCE THIS CAN
  31 C                           LEAD TO ROUND OFF ERROR AND AN IMPROPER
  32 C                           RESULTING DATE ON SOME MACHINES (E.G.,
  33 C                           NCEP IBM FROST/SNOW), INCREASES
  34 C                           PORTABILITY; UNIFIED/PORTABLE FOR WRF;
  35 C                           ADDED DOCUMENTATION (INCLUDING HISTORY)
  36 C
  37 C USAGE:    I4DY (IDATE)
  38 C   INPUT ARGUMENT LIST:
  39 C     IDATE    - INTEGER: DATE (EITHER YYMMDDHH OR YYYYMMDDHH),
  40 C                DEPENDING ON DATELEN() VALUE
  41 C
  42 C   OUTPUT ARGUMENT LIST:
  43 C     I4DY     - INTEGER: DATE (YYYYMMDDHH)
  44 C
  45 C REMARKS:
  46 C    THIS ROUTINE CALLS:        None
  47 C    THIS ROUTINE IS CALLED BY: CKTABA   CMSGINI  DATEBF   DUMPBF
  48 C                               IUPBS01  OPENMB   OPENMG   REWNBF
  49 C                               Also called by application programs.
  50 C
  51 C ATTRIBUTES:
  52 C   LANGUAGE: FORTRAN 77
  53 C   MACHINE:  PORTABLE TO ALL PLATFORMS
  54 C
  55 C$$$
  56
  57       IF(IDATE.LT.10**8) THEN
  58          IY = IDATE/10**6
  59          IF(IY.GT.20) I4DY = IDATE + 19*100000000
  60          IF(IY.LE.20) I4DY = IDATE + 20*100000000
  61       ELSE
  62          I4DY = IDATE
  63       ENDIF
  64
  65       RETURN
  66       END