cannam@127: c     Copyright (c) 2003, 2007-14 Matteo Frigo
cannam@127: c     Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
cannam@127: c     
cannam@127: c     This program is free software; you can redistribute it and/or modify
cannam@127: c     it under the terms of the GNU General Public License as published by
cannam@127: c     the Free Software Foundation; either version 2 of the License, or
cannam@127: c     (at your option) any later version.
cannam@127: c     
cannam@127: c     This program is distributed in the hope that it will be useful,
cannam@127: c     but WITHOUT ANY WARRANTY; without even the implied warranty of
cannam@127: c     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
cannam@127: c     GNU General Public License for more details.
cannam@127: c     
cannam@127: c     You should have received a copy of the GNU General Public License
cannam@127: c     along with this program; if not, write to the Free Software
cannam@127: c     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
cannam@127: c
cannam@127: cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
cannam@127: c     
cannam@127: c     This is an example implementation of Fortran wisdom export/import
cannam@127: c     to/from a Fortran unit (file), exploiting the generic
cannam@127: c     dfftw_export_wisdom/dfftw_import_wisdom functions.
cannam@127: c     
cannam@127: c     We cannot compile this file into the FFTW library itself, lest all
cannam@127: c     FFTW-calling programs be required to link to the Fortran I/O
cannam@127: c     libraries.
cannam@127: c     
cannam@127: cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
cannam@127: 
cannam@127: c     Strictly speaking, the '$' format specifier, which allows us to
cannam@127: c     write a character without a trailing newline, is not standard F77.
cannam@127: c     However, it seems to be a nearly universal extension.
cannam@127:       subroutine write_char(c, iunit)
cannam@127:       character c
cannam@127:       integer iunit
cannam@127:       write(iunit,321) c
cannam@127:  321  format(a,$)
cannam@127:       end      
cannam@127: 
cannam@127:       subroutine export_wisdom_to_file(iunit)
cannam@127:       integer iunit
cannam@127:       external write_char
cannam@127:       call dfftw_export_wisdom(write_char, iunit)
cannam@127:       end
cannam@127: 
cannam@127: c     Fortran 77 does not have any portable way to read an arbitrary
cannam@127: c     file one character at a time.  The best alternative seems to be to
cannam@127: c     read a whole line into a buffer, since for fftw-exported wisdom we
cannam@127: c     can bound the line length.  (If the file contains longer lines,
cannam@127: c     then the lines will be truncated and the wisdom import should
cannam@127: c     simply fail.)  Ugh.
cannam@127:       subroutine read_char(ic, iunit)
cannam@127:       integer ic
cannam@127:       integer iunit
cannam@127:       character*256 buf
cannam@127:       save buf
cannam@127:       integer ibuf
cannam@127:       data ibuf/257/
cannam@127:       save ibuf
cannam@127:       if (ibuf .lt. 257) then
cannam@127:          ic = ichar(buf(ibuf:ibuf))
cannam@127:          ibuf = ibuf + 1
cannam@127:          return
cannam@127:       endif
cannam@127:       read(iunit,123,end=666) buf
cannam@127:       ic = ichar(buf(1:1))
cannam@127:       ibuf = 2
cannam@127:       return
cannam@127:  666  ic = -1
cannam@127:       ibuf = 257
cannam@127:  123  format(a256)
cannam@127:       end
cannam@127:       
cannam@127:       subroutine import_wisdom_from_file(isuccess, iunit)
cannam@127:       integer isuccess
cannam@127:       integer iunit
cannam@127:       external read_char
cannam@127:       call dfftw_import_wisdom(isuccess, read_char, iunit)
cannam@127:       end