Chris@42: c     Copyright (c) 2003, 2007-14 Matteo Frigo
Chris@42: c     Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
Chris@42: c     
Chris@42: c     This program is free software; you can redistribute it and/or modify
Chris@42: c     it under the terms of the GNU General Public License as published by
Chris@42: c     the Free Software Foundation; either version 2 of the License, or
Chris@42: c     (at your option) any later version.
Chris@42: c     
Chris@42: c     This program is distributed in the hope that it will be useful,
Chris@42: c     but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@42: c     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@42: c     GNU General Public License for more details.
Chris@42: c     
Chris@42: c     You should have received a copy of the GNU General Public License
Chris@42: c     along with this program; if not, write to the Free Software
Chris@42: c     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Chris@42: c
Chris@42: cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
Chris@42: c     
Chris@42: c     This is an example implementation of Fortran wisdom export/import
Chris@42: c     to/from a Fortran unit (file), exploiting the generic
Chris@42: c     dfftw_export_wisdom/dfftw_import_wisdom functions.
Chris@42: c     
Chris@42: c     We cannot compile this file into the FFTW library itself, lest all
Chris@42: c     FFTW-calling programs be required to link to the Fortran I/O
Chris@42: c     libraries.
Chris@42: c     
Chris@42: cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
Chris@42: 
Chris@42: c     Strictly speaking, the '$' format specifier, which allows us to
Chris@42: c     write a character without a trailing newline, is not standard F77.
Chris@42: c     However, it seems to be a nearly universal extension.
Chris@42:       subroutine write_char(c, iunit)
Chris@42:       character c
Chris@42:       integer iunit
Chris@42:       write(iunit,321) c
Chris@42:  321  format(a,$)
Chris@42:       end      
Chris@42: 
Chris@42:       subroutine export_wisdom_to_file(iunit)
Chris@42:       integer iunit
Chris@42:       external write_char
Chris@42:       call dfftw_export_wisdom(write_char, iunit)
Chris@42:       end
Chris@42: 
Chris@42: c     Fortran 77 does not have any portable way to read an arbitrary
Chris@42: c     file one character at a time.  The best alternative seems to be to
Chris@42: c     read a whole line into a buffer, since for fftw-exported wisdom we
Chris@42: c     can bound the line length.  (If the file contains longer lines,
Chris@42: c     then the lines will be truncated and the wisdom import should
Chris@42: c     simply fail.)  Ugh.
Chris@42:       subroutine read_char(ic, iunit)
Chris@42:       integer ic
Chris@42:       integer iunit
Chris@42:       character*256 buf
Chris@42:       save buf
Chris@42:       integer ibuf
Chris@42:       data ibuf/257/
Chris@42:       save ibuf
Chris@42:       if (ibuf .lt. 257) then
Chris@42:          ic = ichar(buf(ibuf:ibuf))
Chris@42:          ibuf = ibuf + 1
Chris@42:          return
Chris@42:       endif
Chris@42:       read(iunit,123,end=666) buf
Chris@42:       ic = ichar(buf(1:1))
Chris@42:       ibuf = 2
Chris@42:       return
Chris@42:  666  ic = -1
Chris@42:       ibuf = 257
Chris@42:  123  format(a256)
Chris@42:       end
Chris@42:       
Chris@42:       subroutine import_wisdom_from_file(isuccess, iunit)
Chris@42:       integer isuccess
Chris@42:       integer iunit
Chris@42:       external read_char
Chris@42:       call dfftw_import_wisdom(isuccess, read_char, iunit)
Chris@42:       end