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
|
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
|
