C+
C NAME:
C	smei_frm_c3mask_active
C PURPOSE:
C	Check whether camera 3 mask is active at specified time
C CATEGORY:
C	gen/for/lib/frm
C CALLING SEQUENCE:
	integer function smei_frm_c3mask_active(ipatt,tframe,flat_enabled,cmask,fudge)
C INPUTS:
C	ipatt		integer		0: use exact range of "bad-pixel" mask periods
C					1: use extended range of "bad-pixel" mask periods
C					   for use by smei_cal
C	tframe		character*(*)	SMEI frame time in format YYYY_DOY_hhmmss
C	flat_enabled	integer		nint(hdr(SMEI__HDR_FLAT_ENABLED)) or -1
C					if set to -1 this argument is ignored
C					if set to the "flat_enabled" flag from a
C					SMEI frame then this flag is tested in
C					addition to the time.
C OUTPUTS:
C	smei_frm_c3mask_active
C			integer		1: bad pixel mask in use for specified time
C					0: no bad pixel mask in use for specified time
C	cmask		character*(*)	mask time in format YYYY_DOY_hhmmss
C					This is used in the construction of the file
C					name for the mask.
C	fudge		real		fudge factor for mask
C INCLUDE:
	include		'smei_frm_layout.h'
C PROCEDURE:
C	A camera 3 "bad pixel" mask is in effect onboard during specific
C	periods, and since it is applied as a "flatfield" it is only
C	used if the "flatfield-enabled" flag is set in a SMEI frame.
C	The time periods are hardcoded in this routine.
C
C	If flat_enabled = -1 then only the time 'tframe' is checked:
C	if the time is inside one of the time periods then
C	smei_frm_c3mask_active = 1 is returned. Otherwise 0 is returned.
C	(this is used in href=smei_cal=).
C
C	If flat_enabled = 0 or 1 then the flatfield flag is tested also:
C
C	If flat_enabled = 0 then always smei_frm_c3mask_active=0 is
C	returned (the mask is present, but is not applied)
C
C	If flat_enabled = 1 then smei_frm_c3mask_active is 1 only if the
C	time 'tframe' is inside one of the "bad pixel mask" periods
C	(the mask is present and is applied).
C
C	If a new mask is added to this routine than all SMEI Fortran
C	programs need to be recompiled. This includes smei_base,
C	smei_cal, smei_orb and smei_skyd.
C
C	Modification 2008/10/09: transitions between masks was changed
C	considerably. A number of patterns were recreated:
C		2006_038_085451         removed "mask-in" pattern
C		2006_053_044615                 ,,
C		2006_134_114227                 ,,
C		2006_256_042123                 ,,
C		2007_101_044631         different mask for "mask-in" pattern
C		==================================
C		2007_136_044747 - 2007_250_044827
C		total of 17 patterns:   removed "mask-in" pattern
C		==================================
C		2008_044_044547         removed "mask-in" pattern
C		2008_051_034355         removed "mask-in" pattern
C		==================================
C		2008_156_040215 - 2008_240_043351
C		total of 13 patterns:   removed "mask-in" pattern
C MODIFICATION HISTORY:
C	MAR-2007, Paul Hick (UCSD/CASS)
C	APR-2007, Paul Hick (UCSD/CASS)
C	    Added argument ipatt.
C	NOV-2007, Paul Hick (UCSD/CASS)
C	    Added mask 2007_237
C	JUL-2008, Paul Hick (UCSD/CASS)
C	    Added mask 2008_023
C	OCT-2008, Paul Hick (UCSD/CASS; pphick@ucsd.edu)
C	    Added mask 2008_226
C-
	    integer		ipatt
	    character*(*)	tframe
	    integer		flat_enabled
	    character*(*)	cmask
	    real		fudge

	! Number of time periods where a "bad pixel" mask was in effect
	! Note that there seven different masks; the first two time periods
	! use the same mask 2005_342.

	parameter	(NT = 8)

	! tmask(5,*): name of mask
	! tmask(1,*) - tmask(2,*): time period where the mask is in
	!       effects, i.e. frames in this time period with the onboard-flat-
	!       field flag enabled are using the mask
	! tmask(3,*) - tmask(4,*): only used by smei_cal. For calibration
	!	patterns inside this time range, a pattern is made with the
	!	mask in effect. The time of the first frame used for pattern
	!	construction is used to decided whether or not to add the
	!	the "masked" calibration pattern. In most cases
	!	tmask(3,*) = tmask(1,*) and tmask(4,*) = tmask(2,*)
	! 	(see explanation below)

	! If possible only calibrations inside the time range tmask(1,*) to
	! tmask(2,*) should be used to process the "mask-in" frames in the same
	! time range. For the beginning of a "bad-mask" period this usually means
	! that a couple of days of data need to be processed with smei_base using
	! a calibration pattern LATER than the frame times (by default the
	! preceeding pattern is used). Unless the "bad-mask" periods starts with
	! a calibration pattern, this requires a special run with smei_base
	! explicitly specifying the pattern and setting the c3mask argument to one.
	! (see script c3base). In addition a special run with smei_orb needs
	! to be setup with the minimum pattern set close to the pattern actually
	! used by smei_base (see script c3orb). For these cases
	! tmask(3,*) = tmask(1,*) and tmask(4,*) = tmask(2,*)

	! If there is no adequate calibration pattern available near the
	! beginning or end of the "bad-mask" period tmask(1,*) - tmask(2,*)
	! then a pattern outside this range needs to be selected. This is
	! for instance the case for the 1-day test period for the first mask.
	! For these cases tmask(3,*) is set to the beginning of the
	! calibration preceeding tmask(1,*); and tmask(4,*) is set to the end
	! of the calibration following tmask(2,*). If it is necessary to
	! to use a pattern later than tmask(3,*) to process the end of a 
	! "bad-mask" period than special runs of smei_base and smei_orb
	! need to be set up for the corresponding period as explained
	! above.

	! Note that it is imperative that the special runs of smei_base and
	! and smei_orb need to be consistent with the time periods in this
	! file. If it is done incorrectly than smei_sky may not find the
	! correct pattern (and bail) or use a "mask-out" pattern for
	! "mask-in" pattern (leading to a invalid skymap).

	character	tmask(5,NT)*(SMEI__UT_FORMAT_LEN)

	! The first "bad pixel" mask was tested from 2006_033_00 - 2006_034_00
	! The preceeding calibration 2006_032_034719 is used by smei_base and smei_orb
	! so we need a "mask-in" pattern for that calibration.

	! Start time        End time           Previous cal      Next cal           Mask name
     &	/'2006_033_000000','2006_033_235959', '2006_032_034718','2006_033_235959', '2005_342_000000', ! Test period

	! 2nd "bad-pixel" mask period (using the same mask 2005_342) starts
	! at 2006_053_234500 (with the first frames with onboard flatfield
	! enabled starting 2006_054_000000), and ends with the breakdown of
	! DHU-A around 2006_090_09000. There are no data until 2006_125_200000.
	! The time period 2006_053_234500 - 2006_060_043111 is processed by
	! smei_base using calibration pattern 2006_060_043111 (see script
	! c3base), and smei_orb uses a minimumum orbit close to the
	! calibration (see script c3orb), so we don't need a "mask-in" pattern
	! for the preceeding calibration.

     &	 '2006_053_234500','2006_091_000000', '2006_053_234500','2006_091_000000', '2005_342_000000', ! Ends when DHU-A fails

	! DHU-B picks up around 2006_125_20000. The 2nd mask is uploaded
	! around 2006_260, and becomes active on 2006_261_203602 (after a
	! 2-day data gap).
	! Between 2006_125_200000 and 2006_261_203602 the flatfield is "off"
	! except for one orbit on doy 134 (mode 0) and on doy 150 and 151
	! (mode 1) during which the pre-launch flatfield is used.
	! The time period 2006_261_195846 - 2006_263_035731 is processed by
	! smei_base using calibration c3cal_2006_263_035731 (see script
	! c3base), and smei_orb uses a minimum orbit close to the calibration
	! (see script c3orb), so we don't need a "mask-in" pattern for the
	! preceeding calibration.

     &	 '2006_261_195846','2006_333_235959', '2006_261_195846','2006_333_235959', '2006_215_000000',

	! Transition from 2nd to 3th mask is at 2006_334 with a calibration
	! starting at 2006_334_000000
	! Calibration at beginning of 2006_333 is done with 3th mask
	! Calibration at beginning of 2006_334 is done with 4th mask

     &	 '2006_334_000000','2007_099_150000', '2006_334_000000','2007_099_150000', '2006_334_000000',

	! Transition from 3rd to 4th mask is set to 2007_099_150000 in a data
	! gap between 2007_099_124708 and 2007_099_160819 (when the upload
	! was done).

	! The time period 2007_099_150000 - 2007_101_04463 is processed by
	! smei_base using calibration c3cal_2007_101_044631 (see script
	! c3base), and smei_orb uses a minimum orbit close to the calibration
	! (see script c3orb), so we don't need a "mask-in" pattern for the
	! preceeding calibration.

     &	 '2007_099_150000','2007_136_000000', '2007_099_150000','2007_136_000000', '2007_083_000000',

	! Transition from 4th to 5th mask is at 2007_255_000000 (actually the
	! onboard flatfield is "off" between 2007_136_000000 and
	! 2007_255_000000). There is a calibration at the beginning of 2007_255.
	! The 5th mask ends at 2008_039_140000 with a failed upload of the
	! 6th mask.

     &	 '2007_255_000000','2008_039_140000', '2007_255_000000','2008_039_140000', '2007_237_000000',

	! The first attempt at uploading the 6th mask on 2008_039 failed.
	! The second upload on 2008_049 succeeded. In between the science
	! mode data with flatfield enabled (2008_040_153000 - 2008_042_174500)
	! are no good (these frames have been flagged as bad). The 6th mask
	! was first used between 2008_051_051647 and 2008_051_052451 (mode 0)
	! and starting 2008_053_175208 for mode 1.

	! The pattern c3cal_2008_051_034355 includes a "mask-in" pattern
	! to be able to process the brief mode 0 data with flatfield enabled
	! starting at 2008_051_051647.

	! The time period 2008_053_175208 - 2008_058_040855 is processed by
	! smei_base using calibration c3cal_2008_058_040855 (see script
	! c3base), and smei_orb uses a minimum orbit close to the calibration
	! (see script c3orb), so we don't need a "mask-in" pattern for the
	! preceeding calibration.

     &	 '2008_051_051646','2008_156_000000', '2008_051_034158','2008_156_000000', '2008_023_000000',

	! Transition from 6th to 7th mask is at 2008_247_000000. The flatfield
	! is "off" between 2008_156_000000 and 2008_247_025149 (except for a
	! brief period of mode 0 frames between 2008_242_182147 and
	! 2008_242_182955). The first new "mask-in" frame is at 2008_247_025153
	! (15 minutes before calibration c3cal_2008_247_041127).

	! The time period 2008_247_025153 - 2008_247_041127 is processed by
	! smei_base using calibration c3cal_2008_247_041127  (see script
	! c3base), and smei_orb uses a minimum orbit close to the calibration
	! (see script c3orb), so we don't need a "mask-in" pattern
	! for the preceeding calibration.

     &	 '2008_247_025152','2050_000_000000', '2008_247_025152','2050_000_000000', '2008_226_000000'/

	! The 1.08 for mask 2008_226 has been copied from the preceeding mask
	! and still needs to be confirmed (pph@2008/10/08)

	real		fmask(NT)       /1.02,1.02,1.05,1.057,1.021,1.09,1.08,1.08/

	if (flat_enabled .eq. 0) then

	    smei_frm_c3mask_active = 0
	    cmask = ' '
	    fudge = 1.0

	else

	    ! Loop over the time periods where a "bad pixel" mask was in effect.

	    j = 1+2*ipatt
	    i = 1
	    do while (i .le. NT .and. .not. (tmask(j,i) .le. tframe .and. tframe .le. tmask(j+1,i)))
		i = i+1
	    end do

	    if (i .le. NT) then			! "Bad pixel" mask active
		smei_frm_c3mask_active = 1
		cmask = tmask(5,i)
		fudge = 1.0/fmask(i)
	    else				! No "bad pixel mask active
		smei_frm_c3mask_active = 0
		cmask = ' '
		fudge = 1.0
	    end if

	end if

	return
	end