Skip to content
Snippets Groups Projects
date_utils.F90 11.6 KiB
Newer Older
Guillaume Samson's avatar
Guillaume Samson committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482
MODULE date_utils

   USE toolspar_kind
   IMPLICIT NONE

CONTAINS

   SUBROUTINE add_date(initial_date,hours,final_date)

      ! Add a number of hours to initial_date and return it in final_date

      IMPLICIT NONE


      !! Arguments
      INTEGER,INTENT(in) :: initial_date ! Initial date (YYYYMMDDHH)
      INTEGER,INTENT(in) :: hours        ! Number of hours to add
      INTEGER,INTENT(out) :: final_date  ! Final date (YYYYMMDDHH)

      !! Local variables

      INTEGER :: isec,imin,ihours,iyear,imon,iday ! temporary results
      REAL(dp):: juld

      CALL split_date(initial_date,iyear,imon,iday,ihours)

      CALL greg2jul(0,0,ihours,iday,imon,iyear,juld)

      juld=juld+REAL(hours)/24.0

      CALL jul2greg(isec,imin,ihours,iday,imon,iyear,juld)

      final_date=iyear*1000000+imon*10000+iday*100+ihours

   END SUBROUTINE add_date


   SUBROUTINE add_days_to_date(initial_date,days,final_date)

      ! Add a number of days to initial_date and return it in final_date

      IMPLICIT NONE


      !! Arguments
      INTEGER,INTENT(in) :: initial_date ! Initial date (YYYYMMDD)
      INTEGER,INTENT(in) :: days         ! Number of days to add
      INTEGER,INTENT(out) :: final_date  ! Final date (YYYYMMDD)

      !! Local variables

      INTEGER :: isec,imin,ihours,iyear,imon,iday ! temporary results
      REAL(dp):: juld

		! Account for lack of hours in date format (initial_date*100)
      CALL split_date(initial_date*100,iyear,imon,iday,ihours)

      CALL greg2jul(0,0,ihours,iday,imon,iyear,juld)

      juld=juld+REAL(days)

      CALL jul2greg(isec,imin,ihours,iday,imon,iyear,juld)

      final_date=(iyear*1000000+imon*10000+iday*100+ihours)/100

   END SUBROUTINE add_days_to_date


   SUBROUTINE split_date(iyyyymmddhh,iyyyy,imm,idd,ihh)

      ! Splits a date in YYYYMMDDHH format into iyyyy, imm, idd, ihh

      IMPLICIT NONE
      INTEGER,INTENT(in) :: iyyyymmddhh
      INTEGER,INTENT(out) :: iyyyy,imm,idd,ihh

      iyyyy=iyyyymmddhh/1000000
      imm=iyyyymmddhh/10000-iyyyy*100
      idd=iyyyymmddhh/100-(iyyyy*10000+imm*100)
      ihh=MOD(iyyyymmddhh,100)

   END SUBROUTINE split_date

   SUBROUTINE jul2greg( ksec, kminut, khour, kday, kmonth, kyear, &
      &                           prelday )

      IMPLICIT NONE
      !!-----------------------------------------------------------------------
      !!
      !!                     ***  ROUTINE jul2greg  ***
      !!
      !! ** Purpose : Take the relative time in days and re-express in terms of
      !!              seconds, minutes, hours, days, month, year.
      !!
      !! ** Method  : Reference date : 19500101
      !!
      !! ** Action  :
      !!
      !! History
      !!      ! 06-04  (A. Vidard) Original
      !!      ! 06-05  (A. Vidard) Reformatted and refdate      
      !!      ! 06-10  (A. Weaver) Cleanup
      !!-----------------------------------------------------------------------

      ! * Arguments
      INTEGER, INTENT(OUT) :: &
         & ksec,   &
         & kminut, &
         & khour,  &
         & kday,   &
         & kmonth, &
         & kyear
      REAL(KIND=dp), INTENT(IN) :: &
         & prelday

      !! * Local declarations
      INTEGER, PARAMETER :: &
         & jpgreg = 2299161, &
         & jporef = 2433283, &
         & jparef = 2415021
      INTEGER :: &
         & ijulian, &
         & ij1,     &
         & ija,     &
         & ijb,     &
         & ijc,     &
         & ijd,     &
         & ije,     &
         & isec,    &
         & imin,    &
         & ihou,    &
         & iday,    &
         & imon,    &
         & iyea,    &
         & iref
      REAL(KIND=wp) :: &
         & zday, &
         & zref

      ! Main computation
      iref = jporef 

      zday = prelday
      ksec = NINT( 86400. * MOD( zday, 1.0_wp ) )

      IF ( ksec < 0. ) ksec = 86400. + ksec

      khour  = ksec / 3600
      kminut = ( ksec - 3600 * khour ) / 60
      ksec   = MOD( ksec , 60 )

      ijulian = iref + INT( zday )
      IF ( zday < 0. ) ijulian = ijulian - 1

      ! If input date after 10/15/1582 :
      IF ( ijulian >= jpgreg ) THEN
         ij1 = INT( ( DBLE( ijulian - 1867216 ) - 0.25 ) / 36524.25 )
         ija = ijulian + 1 + ij1 - INT( ( 0.25 * ij1 ) )
      ELSE
         ija = ijulian
      ENDIF

      ijb = ija + 1524
      ijc = INT( 6680. + ( DBLE ( ijb - 2439870 ) - 122.1 ) / 365.25 )
      ijd = 365 * ijc + INT( 0.25 * ijc )
      ije = INT( ( ijb - ijd ) / 30.6001 )
      kday = ijb - ijd - INT( 30.6001 * ije )
      kmonth = ije - 1
      IF ( kmonth > 12 ) kmonth = kmonth - 12
      kyear = ijc - 4715
      IF ( kmonth > 2 ) kyear = kyear - 1
      IF ( kyear <= 0 ) kyear = kyear - 1

   END SUBROUTINE jul2greg

   SUBROUTINE greg2jul( ksec, kmin, khour, kday, kmonth, kyear, pjulian )

      IMPLICIT NONE
      !!-----------------------------------------------------------------------
      !!
      !!                     ***  ROUTINE greg2jul  ***
      !!
      !! ** Purpose : Produce the time relative to the current date and time.
      !!
      !! ** Method  : The units are days, so hours and minutes transform to
      !!              fractions of a day. 
      !!
      !!              Reference date : 19500101
      !! ** Action  :
      !!
      !! History :
      !!      ! 06-04  (A. Vidard) Original
      !!      ! 06-04  (A. Vidard) Reformatted
      !!      ! 06-10  (A. Weaver) Cleanup
      !!-----------------------------------------------------------------------

      ! * Arguments
      INTEGER, INTENT(IN) :: &
         & ksec,   &
         & kmin,   &
         & khour,  & 
         & kday,   &
         & kmonth, & 
         & kyear
      REAL(KIND=dp), INTENT(OUT) :: &
         & pjulian

      !! * Local declarations
      INTEGER, PARAMETER :: &
         & jpgreg = 15 + 31 * ( 10 + 12 * 1582 ), &  ! Gregorian calendar introduction date
         & jpjref = 2433283                          ! Julian reference date: 19500101
      INTEGER :: &
         & ija,     &
         & ijy,     &
         & ijm,     &
         & ijultmp, &
         & ijyear

      ! Main computation
      ijyear = kyear
      IF ( ijyear < 0 ) ijyear = ijyear + 1
      IF ( kmonth > 2 ) THEN
         ijy = ijyear
         ijm = kmonth + 1
      ELSE
         ijy = ijyear  - 1
         ijm = kmonth + 13
      ENDIF
      ijultmp = INT( 365.25 * ijy ) + INT( 30.6001 * ijm ) + kday + 1720995
      IF ( kday + 31 * ( kmonth + 12 * ijyear ) >= jpgreg ) THEN
         ija = INT( 0.01 * ijy )
         ijultmp = ijultmp + 2 - ija + INT( 0.25 * ija )
      ENDIF
      pjulian = ( ijultmp - jpjref ) + ( ( 60 * khour + kmin ) * 60 + ksec ) / 86400.

   END SUBROUTINE greg2jul


   SUBROUTINE addseconds(iyear,imon,iday,ihour,imin,isec,iaddsec)

      ! Add iaddsecs to the date and return the new date (in place)

      !! Arguments

      INTEGER,intent(inout) :: iyear,imon,iday,ihour,imin,isec,iaddsec

      !! Local variables

      INTEGER :: itotsec,idays,isecs
      INTEGER :: mday(12) = (/31,28,31,30,31,30,31,31,30,31,30,31/) 

      itotsec=iaddsec+ihour*3600*imin*60+isec

      IF (itotsec<0) THEN
         WRITE(*,*)'Negative itotsec in addseconds'
         WRITE(*,*)'This does not work'
         RETURN
      ENDIF

      ihour=0
      imin=0
      isec=0

      idays=itotsec/86400
      isecs=itotsec-idays*86400
      iday=iday+idays

      ! Compute the date
      DO
         ! Leap year 
         mday(2)=28
         IF (MOD(iyear,4).EQ.0) mday(2)=29
         IF (MOD(iyear,100).EQ.0) mday(2)=28
         IF (MOD(iyear,400).EQ.0) mday(2)=29
         IF (MOD(iyear,4000).EQ.0) mday(2)=28

         IF (iday.GT.mday(imon))THEN
            iday=iday-mday(imon)
            imon=imon+1
            IF(imon.GT.12)THEN
               imon=1
               iyear=iyear+1
            ENDIF
         ELSE
            EXIT
         ENDIF

      ENDDO

      ! Set the time
      ihour=isecs/3600
      imin=isecs/60-ihour*60
      isec=isecs-ihour*3600-imin*60

   END SUBROUTINE addseconds

   INTEGER FUNCTION nextdate(idate)

      ! Return next date.
      ! Date format is assumed to be YYYYMMDD

      IMPLICIT NONE

      !! Arguments

      INTEGER :: idate ! Initial date

      !! Local variables

      INTEGER :: year,day,mon
      INTEGER :: mday(12) = (/31,28,31,30,31,30,31,31,30,31,30,31/)


      day=MOD(idate,100)
      mon=MOD((idate-day)/100,100)
      year=idate/10000

      mday(2)=28
      IF (MOD(year,4).EQ.0) mday(2)=29
      IF (MOD(year,100).EQ.0) mday(2)=28
      IF (MOD(year,400).EQ.0) mday(2)= 29
      IF (MOD(year,4000).EQ.0) mday(2) = 28

      day=day+1
      IF (day.GT.mday(mon))THEN
         day=1
         mon=mon+1
         IF(mon.GT.12)THEN
            mon=1
            year=year+1
         ENDIF
      ENDIF
      nextdate=year*10000+mon*100+day
      RETURN

   END FUNCTION nextdate

   INTEGER FUNCTION prevdate(idate)

      ! Return previous date.
      ! Date format is assumed to be YYYYMMDD

      IMPLICIT NONE

      !! Arguments

      INTEGER :: idate ! Initial date

      !! Local variables

      INTEGER :: year,day,mon
      INTEGER :: mday(12) = (/31,28,31,30,31,30,31,31,30,31,30,31/)


      day=MOD(idate,100)
      mon=MOD((idate-day)/100,100)
      year=idate/10000

      mday(2)=28
      IF (MOD(year,4).EQ.0) mday(2)=29
      IF (MOD(year,100).EQ.0) mday(2)=28
      IF (MOD(year,400).EQ.0) mday(2)= 29
      IF (MOD(year,4000).EQ.0) mday(2) = 28

      day=day-1
      IF (day.LT.1)THEN
         mon=mon-1
         IF(mon.LT.1)THEN
            mon=12
            year=year-1
         ENDIF
         day=mday(mon)
      ENDIF
      prevdate=year*10000+mon*100+day
      RETURN

   END FUNCTION prevdate

   INTEGER FUNCTION diffdate(idate1,idate2)

      ! Compute difference in days between dates
      ! Assumes YYYYMMDD format for dates

      IMPLICIT NONE

      !! Argument

      INTEGER :: idate1,idate2    ! Dates to be diffed.

      !! Local variables

      INTEGER :: itdate1,itdate2
      INTEGER :: it

      itdate1=MIN(idate1,idate2)
      itdate2=MAX(idate1,idate2)

      IF (itdate1==itdate2) THEN
         diffdate=0
         RETURN
      ENDIF
      diffdate=0
      it=itdate1
      DO 
         it=nextdate(it)
         diffdate=diffdate+1
         IF (it==itdate2) EXIT
      ENDDO
      RETURN

   END FUNCTION diffdate

   INTEGER FUNCTION difftime(itime1,itime2)

      ! Compute difference in minutes between times
      ! Assumes HHMM or HMM or MM or M format for dates
		!
		! ORDER MATTERS - itime1 is ealier time
		! Result is an integer number of minutes

      IMPLICIT NONE
      INTEGER, INTENT(IN) :: itime1,itime2    ! Times to be diffed.
      INTEGER :: imin1, imin2, ihr1, ihr2

		ihr1 = (itime1/100)
		ihr2 = (itime2/100)
		
		imin1 = (itime1 - ihr1*100) + (60 * ihr1)
		imin2 = (itime2 - ihr2*100) + (60 * ihr2)
		
		! Assume that itime2 is later, so wrap around midnight if necessary.
		IF (imin2 < imin1) THEN
			imin2 = imin2 + 24*60
		END IF
		
		difftime = imin2 - imin1
		
   END FUNCTION difftime


   INTEGER FUNCTION add_mins_to_time(itime1, imin_add)

      ! Add number of minutes onto given time
      ! Assumes time in HHMM or HMM or MM or M format
		!
		! Result is in HHMM format

      IMPLICIT NONE
      INTEGER, INTENT(IN) :: itime1,imin_add
      INTEGER :: imin1, ihr1, imin2, ihr2

		ihr1 = (itime1/100)
		
		! itime1 in minutes from previous midnight
		imin1 = (itime1 - ihr1*100) + (60 * ihr1)
		
		imin1 = imin1 + imin_add
		
		! Add 1day if time went nagative
		IF (imin1 < 0) THEN
			imin1 = imin1 + 24*60
		END IF
		
		! Turn number of minutes back into HHMM
		ihr2 = imin1/60
		imin2 = imin1 - ihr2*60

		DO
			IF (ihr2<0) THEN
				ihr2 = ihr2 + 24
			ELSE IF (ihr2>=24) THEN
				ihr2 = ihr2 - 24
			END IF
			IF ((ihr2>=0).OR.(ihr2<24)) EXIT
		END DO

		add_mins_to_time = ihr2*100 + imin2
	
   END FUNCTION add_mins_to_time


END MODULE date_utils