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authorJoseph Hunkeler <jhunkeler@gmail.com>2015-07-08 20:46:52 -0400
committerJoseph Hunkeler <jhunkeler@gmail.com>2015-07-08 20:46:52 -0400
commitfa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 (patch)
treebdda434976bc09c864f2e4fa6f16ba1952b1e555 /pkg/tbtables/fitsio/ftgcxd.f
downloadiraf-linux-fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4.tar.gz
Initial commit
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diff --git a/pkg/tbtables/fitsio/ftgcxd.f b/pkg/tbtables/fitsio/ftgcxd.f
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+C----------------------------------------------------------------------
+ subroutine ftgcxd(iunit,colnum,frow,nrow,fbit,nbit,
+ & dvalue,status)
+
+C read any consecutive bits from an 'X' or 'B' column as an unsigned
+C n-bit integer
+
+C iunit i fortran unit number
+C colnum i number of the column to read
+C frow i first row to read
+C nrow i number of rows to read
+C fbit i first bit within the row to read
+C nbit i number of bits to read
+C dvalue d returned value(s)
+C status i output error status
+C
+C written by Wm Pence, HEASARC/GSFC, Nov 1994
+
+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 iunit,colnum,fbit,nbit,frow,nrow,status
+ integer i,k,istart,itodo,ntodo,row,ibuff
+ double precision dvalue(*),power,dval
+ logical lray(64)
+
+ if (status .gt. 0)return
+
+ ibuff=bufnum(iunit)
+ if ((fbit+nbit+6)/8 .gt. trept(colnum+tstart(ibuff)))then
+ call ftpmsg('Asked to read more bits than exist in'//
+ & ' the column (ftgcxd)')
+ status=308
+ return
+ end if
+
+ row=frow-1
+ do 30 k=1,nrow
+ row=row+1
+ dval=0.
+ power=1.0D+00
+ istart=fbit+nbit
+ ntodo=nbit
+
+10 itodo=min(ntodo,64)
+ istart=istart-itodo
+
+C read up to 64 bits at a time
+C get the individual bits
+ call ftgcx(iunit,colnum,row,istart,itodo,lray,status)
+ if (status .gt. 0)return
+
+C reconstruct the positive integer value
+ do 20 i=itodo,1,-1
+ if (lray(i))dval=dval+power
+ power=power*2.0D+00
+20 continue
+
+ ntodo=ntodo-itodo
+ if (itodo .gt. 0)go to 10
+ dvalue(k)=dval
+30 continue
+ end