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C----------------------------------------------------------------------
subroutine ftgcx(iunit,colnum,frow,fbit,nbit,lray,status)
C read an array of logical values from a specified bit or byte
C column of the binary table. A logical .true. value is returned
C if the corresponding bit is 1, and a logical .false. value is
C returned if the bit is 0.
C The binary table column being read from must have datatype 'B'
C or 'X'. This routine ignores any undefined values in the 'B' array.
C iunit i fortran unit number
C colnum i number of the column to read
C frow i first row to read
C fbit i first bit within the row to read
C nbit i number of bits to read
C lray l returned array of logical data values that is read
C status i output error status
C
C written by Wm Pence, HEASARC/GSFC, Mar 1992
integer iunit,colnum,frow,fbit,nbit,status
logical lray(*)
C COMMON BLOCK DEFINITIONS:--------------------------------------------
integer nf,nb,ne
parameter (nb = 20)
parameter (nf = 3000)
parameter (ne = 200)
integer bufnum,chdu,hdutyp,maxhdu,hdstrt,hdend,nxthdr,dtstrt
integer nxtfld
logical wrmode
common/ft0001/bufnum(199),chdu(nb),hdutyp(nb),maxhdu(nb),
& wrmode(nb),hdstrt(nb,ne),hdend(nb),nxthdr(nb),dtstrt(nb),nxtfld
integer tfield,tstart,tbcol,rowlen,tdtype,trept,tnull,scount
integer theap,nxheap
double precision tscale,tzero
common/ft0002/tfield(nb),tstart(nb),tbcol(nf),rowlen(nb),
& tdtype(nf),trept(nf),tscale(nf),tzero(nf),tnull(nf),scount(nb)
& ,theap(nb),nxheap(nb)
C END OF COMMON BLOCK DEFINITIONS-----------------------------------
integer bstart,offset,tcode,fbyte,bitloc,ndone
integer ibuff,i,ntodo,repeat,rstart,estart,buffer
logical descrp,log8(8)
character*1 cbuff
if (status .gt. 0)return
ibuff=bufnum(iunit)
tcode=tdtype(colnum+tstart(ibuff))
C check input parameters
if (nbit .le. 0)then
return
else if (frow .lt. 1)then
C error: illegal first row number
status=307
return
else if (fbit .lt. 1)then
C illegal element number
status=308
return
end if
fbyte=(fbit+7)/8
bitloc=fbit-(fbit-1)/8*8
ndone=0
ntodo=nbit
rstart=frow-1
estart=fbyte-1
if (tcode .eq. 11)then
repeat=trept(colnum+tstart(ibuff))
if (fbyte .gt. repeat)then
C illegal element number
status=308
return
end if
descrp=.false.
C move the i/o pointer to the start of the sequence of pixels
bstart=dtstrt(ibuff)+rstart*rowlen(ibuff)+
& tbcol(colnum+tstart(ibuff))+estart
else if (tcode .eq. -11)then
C this is a variable length descriptor column
descrp=.true.
C read the number of elements and the starting offset:
call ftgdes(iunit,colnum,frow,repeat,
& offset,status)
repeat=(repeat+7)/8
if (repeat .eq. 0)then
C error: null length vector
status=318
return
else if ((fbit+nbit+6)/8 .gt. repeat)then
C error: trying to read beyond end of record
status=319
return
end if
bstart=dtstrt(ibuff)+offset+
& theap(ibuff)+estart
else
C column must be byte or bit data type
status=312
return
end if
C move the i/o pointer to the start of the pixel sequence
call ftmbyt(iunit,bstart,.false.,status)
C get the next byte
20 call ftgcbf(iunit,0,1,cbuff,status)
buffer=ichar(cbuff)
if (buffer .lt. 0)buffer=buffer+256
C decode the bits within the byte into an array of logical values
call ftgbit(buffer,log8)
do 10 i=bitloc,8
ndone=ndone+1
lray(ndone)=log8(i)
if (ndone .eq. ntodo)go to 100
10 continue
C not done, so get the next byte
if (.not. descrp)then
estart=estart+1
if (estart .eq. repeat)then
C move the i/o pointer to the next row of pixels
estart=0
rstart=rstart+1
bstart=dtstrt(ibuff)+rstart*rowlen(ibuff)+
& tbcol(colnum+tstart(ibuff))+estart
call ftmbyt(iunit,bstart,.false.,status)
end if
end if
bitloc=1
go to 20
100 continue
end
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