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c Copyright (c) 2003, 2007-8 Matteo Frigo
c Copyright (c) 2003, 2007-8 Massachusetts Institute of Technology
c
c This program is free software; you can redistribute it and/or modify
c it under the terms of the GNU General Public License as published by
c the Free Software Foundation; either version 2 of the License, or
c (at your option) any later version.
c
c This program is distributed in the hope that it will be useful,
c but WITHOUT ANY WARRANTY; without even the implied warranty of
c MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
c GNU General Public License for more details.
c
c You should have received a copy of the GNU General Public License
c along with this program; if not, write to the Free Software
c Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
c
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c
c This is an example implementation of Fortran wisdom export/import
c to/from a Fortran unit (file), exploiting the generic
c dfftw_export_wisdom/dfftw_import_wisdom functions.
c
c We cannot compile this file into the FFTW library itself, lest all
c FFTW-calling programs be required to link to the Fortran I/O
c libraries.
c
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c Strictly speaking, the '$' format specifier, which allows us to
c write a character without a trailing newline, is not standard F77.
c However, it seems to be a nearly universal extension.
subroutine write_char(c, iunit)
character c
integer iunit
write(iunit,321) c
321 format(a,$)
end
subroutine export_wisdom_to_file(iunit)
integer iunit
external write_char
call dfftw_export_wisdom(write_char, iunit)
end
c Fortran 77 does not have any portable way to read an arbitrary
c file one character at a time. The best alternative seems to be to
c read a whole line into a buffer, since for fftw-exported wisdom we
c can bound the line length. (If the file contains longer lines,
c then the lines will be truncated and the wisdom import should
c simply fail.) Ugh.
subroutine read_char(ic, iunit)
integer ic
integer iunit
character*256 buf
save buf
integer ibuf
data ibuf/257/
save ibuf
if (ibuf .lt. 257) then
ic = ichar(buf(ibuf:ibuf))
ibuf = ibuf + 1
return
endif
read(iunit,123,end=666) buf
ic = ichar(buf(1:1))
ibuf = 2
return
666 ic = -1
ibuf = 257
123 format(a256)
end
subroutine import_wisdom_from_file(isuccess, iunit)
integer isuccess
integer iunit
external read_char
call dfftw_import_wisdom(isuccess, read_char, iunit)
end
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