Fortran で、form="unformatted", access="stream" で wirte されたファイルを read する
前置き
natures flyers: Fortran でのバイナリ (unformatted, binary) の扱いについてのメモ では write しか考えてなかった。なぜなら FIELDVIEW という可視化ソフトで読み込むことだけ考えてたので。でも今ちょっと、書きだしたデータを読み込んで処理したいなと思ってる。なので読み込み方を例によって trial & error で調べてみた。
Reference
参考にしたのはこのページくらい→ streamIO
open
ファイルの open 自体はそんな難しくない。こんな感じ。
open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "read" & & , form = "unformatted" & & , access = "stream" & & , status = "old" & & , position = "rewind" & & )
ちゃんと動くコードはこのエントリ後半に掲載した。
read
これがちょっと面倒。read( ファイル名, pos=現在位置 ) のようにする必要がある。ポイントは「ファイル内での現在位置」を常に把握しておく、ということ。
そのために、loc という変数を用意してみた。これをまず 0 で初期化する。で、ファイルの先頭から読みとりを始めるわけだけど、pos は1から始まる正の整数。そこで、常に pos=loc+1 として、読み取った直後にいま読んだ変数の長さ分 loc にたしてやることにする。
とりあえず int, real(4), real(8) の3パタンだけ短いサブルーチンを作って、モジュールにまとめてみた。
読み取りモジュール
module mod__scan_str implicit none private public :: scan_int_str public :: scan_real_str public :: scan_dble_str integer, parameter :: len_int = 4 integer, parameter :: len_real = 4 integer, parameter :: len_dble = 8 contains subroutine scan_int_str( & & n_file_in & & , loc & & , scanned_int & & ) implicit none integer, intent(in) :: n_file_in integer, intent(inout) :: loc integer, intent(out) :: scanned_int !!------------------------------ read(n_file_in, pos=loc+1) scanned_int loc = loc +len_int return endsubroutine scan_int_str subroutine scan_real_str( & & n_file_in & & , loc & & , scanned_real & & ) implicit none integer, intent(in) :: n_file_in integer, intent(inout) :: loc real(4), intent(out) :: scanned_real !!------------------------------ read(n_file_in, pos=loc+1) scanned_real loc = loc +len_real return endsubroutine scan_real_str subroutine scan_dble_str( & & n_file_in & & , loc & & , scanned_dble & & ) implicit none integer, intent(in) :: n_file_in integer, intent(inout) :: loc real(8), intent(out) :: scanned_dble !!------------------------------ read(n_file_in, pos=loc+1) scanned_dble loc = loc +len_dble return endsubroutine scan_dble_str endmodule mod__scan_str
注意事項
正直、自分は kind 関係のことはよくわかってない。なので len_int とかのとこはたぶん本当は selected_int_kind とかなんとかやるべきなんだろうけど（環境依存性に対処するために？）、 4 とかベタ書きしちゃってる。
テストコード
上のモジュールをテストするためのコード。
include 'mod__open_to_read.f90' include 'mod__open_to_write.f90' include 'mod__scan_str.f90' module mod__sub use mod__open_to_read, only : open_to_read_unform_str use mod__open_to_write, only : open_to_write_unform_str_rewind use mod__scan_str implicit none private public :: main_part contains subroutine main_part implicit none integer, parameter :: n_int = 1 !! テスト用変数の数。任意。以下同様 integer, parameter :: n_real = 2 integer, parameter :: n_dble = 3 integer :: arr_int( n_int) real(4) :: arr_real(n_real) real(8) :: arr_dble(n_dble) !! temporary integer :: i !! 現在位置 integer, save :: loc !! file numbers & names integer, save :: n_file_out integer, save :: n_file_in character(len=72), save :: file_out character(len=72), save :: file_in !! 結果の表示 integer :: scanned_int real(4) :: scanned_real real(8) :: scanned_dble !!------------------- !! set numbers do i=1,n_int arr_int(i) = i enddo do i=1,n_real arr_real(i) = real(i,4) enddo do i=1,n_dble arr_dble(i) = dble(i) enddo !! unformatted, stream で書き出し n_file_out = 30 file_out = 'unformatted_stream.dat' call open_to_write_unform_str_rewind( n_file_out, file_out ) write(n_file_out) (arr_dble(i)*1, i=1,n_dble) write(n_file_out) (arr_real(i)*1, i=1,n_real) write(n_file_out) (arr_int(i) *1, i=1,n_int ) close(n_file_out) !! 上で書き出したものを読み込んで表示し、確認する n_file_in = 40 file_in = file_out call open_to_read_unform_str( n_file_in, file_in ) !! save 属性指定するだけで 0 に初期化されるが、念の為に再度初期化しておく。 loc = 0 !! 以下の読み込み順は write した時に合わせないともちろんダメ !! double do i=1,n_dble call scan_dble_str(n_file_in,loc,scanned_dble) !! intent(in,inout,out) write(*,*) scanned_dble enddo !! real do i=1,n_real call scan_real_str(n_file_in,loc,scanned_real) !! intent(in,inout,out) write(*,*) scanned_real enddo !! integer do i=1,n_int call scan_int_str(n_file_in,loc,scanned_int) !! intent(in,inout,out) write(*,*) scanned_int enddo close(n_file_in) return endsubroutine main_part endmodule mod__sub program test_unform_str use mod__sub, only : main_part implicit none call main_part stop endprogram test_unform_str
ただしここで、以下のファイルオープンモジュール（read用、write用）を使っている。
read用
module mod__open_to_read implicit none private public :: open_to_read__run public :: open_to_read_unform_seq public :: open_to_read_unform_str contains subroutine open_to_read__run( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber !! filenumber to assign character(len=72), intent(in) :: filename_in !! filename as variable (not the actual text file name) integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in !! file open, w/ error handling ! open(filenumber,file=filename_in,status="old",iostat=istat,form="formatted",position="rewind",action="read") open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "read" & & , status = "old" & & , position = "rewind" & & , form = "formatted" & ! & , access = "sequential" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a48,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_read__run subroutine open_to_read_unform_seq( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber !! filenumber to assign character(72), intent(in) :: filename_in !! filename as variable (not the actual text file name) integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in !! file open, w/ error handling open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "read" & & , status = "old" & & , position = "rewind" & & , form = "unformatted" & & , access = "sequential" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a48,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_read_unform_seq subroutine open_to_read_unform_str( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber !! filenumber to assign character(72), intent(in) :: filename_in !! filename as variable (not the actual text file name) integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in !! file open, w/ error handling open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "read" & & , form = "unformatted" & & , access = "stream" & & , status = "old" & & , position = "rewind" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a48,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_read_unform_str endmodule mod__open_to_read
write用
module mod__open_to_write implicit none private public :: open_to_write_form_rewind !! formatted, rewind public :: open_to_write_form_append !! formatted, append public :: open_to_write_unform_seq_rewind !! unformatted, sequential, rewind public :: open_to_write_unform_seq_append !! unformatted, sequential, append public :: open_to_write_unform_str_rewind !! unformatted, stream, rewind contains subroutine open_to_write_form_rewind( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber character(len=72), intent(in) :: filename_in integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "write" & & , form = "formatted" & & , status = "replace" & & , position = "rewind" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a36,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_write_form_rewind subroutine open_to_write_form_append( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber character(len=72), intent(in) :: filename_in integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "write" & & , form = "formatted" & & , status = "old" & & , position = "append" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a36,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_write_form_append subroutine open_to_write_unform_seq_rewind( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber character(len=72), intent(in) :: filename_in integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "write" & & , form = "unformatted" & & , access = "sequential" & & , status = "replace" & & , position = "rewind" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a36,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_write_unform_seq_rewind subroutine open_to_write_unform_seq_append( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber character(len=72), intent(in) :: filename_in integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "write" & & , form = "unformatted" & & , access = "sequential" & & , status = "old" & & , position = "append" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a36,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_write_unform_seq_append subroutine open_to_write_unform_str_rewind( filenumber, filename_in ) implicit none integer, intent(in) :: filenumber character(72), intent(in) :: filename_in integer :: istat=0 !!--------------------- write(*,"(2x,'opening [ ',a48,' ]... ',$)") filename_in open( & & unit = filenumber & & , file = filename_in & & , iostat = istat & & , action = "write" & & , form = "unformatted" & & , access = "stream" & & , status = "replace" & & , position = "rewind" & & ) if( istat == 0 ) then write(*,"('... [ ',a48,' ] was successfully opened.')") filename_in return else write(*,"(/,2x,'Error: The file [ ',a36,' ] ',/,' does not exist (istat =',i2,'). Aborting...',/)") filename_in, istat stop endif return endsubroutine open_to_write_unform_str_rewind endmodule mod__open_to_write
汚いけど、とりあえず公開。あ、こういうのこそ github 使うべきなのか…（いまさら）
実行結果
こんな感じになるはず
$ ./a.exe opening [ unformatted_stream.dat ]... ... [ unformatted_stream.dat ] was successfully opened. opening [ unformatted_stream.dat ]... ... [ unformatted_stream.dat ] was successfully opened. 1.0000000000000000 2.0000000000000000 3.0000000000000000 1.00000000 2.00000000 1
