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