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subroutine extractmessage174(decoded,msgreceived,ncrcflag)
use iso_c_binding, only: c_loc,c_size_t
use crc
use packjt
character*68 alphabet
character*22 msgreceived
character*87 cbits
integer*1 decoded(87)
integer*1, target:: i1Dec8BitBytes(11)
integer*4 i4Dec6BitWords(12)
alphabet='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-+/?.'
! Write decoded bits into cbits: 75-bit message plus 12-bit CRC
write(cbits,1000) decoded
1000 format(87i1)
read(cbits,1001) i1Dec8BitBytes
1001 format(11b8)
read(cbits,1002) ncrc12 !Received CRC12
1002 format(75x,b12)
i1Dec8BitBytes(10)=iand(i1Dec8BitBytes(10),transfer(128+64+32,0_1))
i1Dec8BitBytes(11)=0
icrc12=crc12(c_loc(i1Dec8BitBytes),11) !CRC12 computed from 75 msg bits
icrc12=xor(icrc12, 42) ! TODO: jsherer - could change the crc here
if(ncrc12.eq.icrc12) then ! .or. sum(decoded(57:87)).eq.0) then !### Kludge ###
! CRC12 checks out --- unpack 72-bit message
do ibyte=1,12
itmp=0
do ibit=1,6
itmp=ishft(itmp,1)+iand(1_1,decoded((ibyte-1)*6+ibit))
enddo
i4Dec6BitWords(ibyte)=itmp
enddo
!call unpackmsg(i4Dec6BitWords,msgreceived,.false.,' ')
msgreceived=' '
do ibyte=1,12
itmp=i4Dec6BitWords(ibyte)
msgreceived(ibyte:ibyte) = alphabet(itmp+1:itmp+1)
enddo
ncrcflag=1
else
msgreceived=' '
ncrcflag=-1
endif
return
end subroutine extractmessage174
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