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(* mcStream.mod provides an interface to create a file from fragments.
Copyright (C) 2015-2025 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius@glam.ac.uk>.
This file is part of GNU Modula-2.
GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GNU Modula-2 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Modula-2; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. *)
IMPLEMENTATION MODULE mcStream ;
FROM FIO IMPORT File, OpenToWrite, OpenToRead, EOF, ReadNBytes, WriteNBytes, Close, getFileName, IsNoError ;
FROM libc IMPORT unlink, printf, getpid, exit ;
FROM Indexing IMPORT InitIndex, InBounds, HighIndice, LowIndice, PutIndice, GetIndice, Index, ForeachIndiceInIndexDo ;
FROM DynamicStrings IMPORT String, InitString, InitStringCharStar, string ;
FROM FormatStrings IMPORT Sprintf2 ;
FROM SYSTEM IMPORT ADR ;
FROM Storage IMPORT ALLOCATE ;
IMPORT alists ;
IMPORT SFIO ;
TYPE
ptrToFile = POINTER TO File ;
VAR
listOfFiles: alists.alist ;
frag : Index ;
destFile : File ;
seenDest : BOOLEAN ;
(*
removeLater -
*)
PROCEDURE removeLater (filename: String) : String ;
BEGIN
alists.includeItemIntoList (listOfFiles, filename) ;
RETURN filename
END removeLater ;
(*
removeNow - removes a single file, s.
*)
PROCEDURE removeNow (s: String) ;
BEGIN
IF unlink (string (s)) # 0
THEN
END
END removeNow ;
(*
removeFiles - remove any fragment.
*)
PROCEDURE removeFiles ;
BEGIN
alists.foreachItemInListDo (listOfFiles, removeNow) ;
alists.killList (listOfFiles) ;
listOfFiles := alists.initList ()
END removeFiles ;
(*
createTemporaryFile -
*)
PROCEDURE createTemporaryFile (id: CARDINAL) : File ;
VAR
s: String ;
f: File ;
p: INTEGER ;
BEGIN
s := InitString ('/tmp/frag-%d-%d.frag') ;
p := getpid () ;
s := removeLater (Sprintf2 (s, p, id)) ;
f := SFIO.OpenToWrite (s) ;
RETURN f
END createTemporaryFile ;
(*
openFrag - create and open fragment, id, and return the file.
The file should not be closed by the user.
*)
PROCEDURE openFrag (id: CARDINAL) : File ;
VAR
f: File ;
p: ptrToFile ;
BEGIN
f := createTemporaryFile (id) ;
NEW (p) ;
p^ := f ;
PutIndice (frag, id, p) ;
RETURN f
END openFrag ;
(*
copy - copies contents of f to the destination file.
*)
PROCEDURE copy (p: ptrToFile) ;
CONST
maxBuffer = 4096 ;
VAR
buffer: ARRAY [0..maxBuffer] OF CHAR ;
b : CARDINAL ;
s : String ;
f : File ;
BEGIN
IF p # NIL
THEN
f := p^ ;
s := InitStringCharStar(getFileName (f)) ;
Close (f) ;
f := SFIO.OpenToRead (s) ;
WHILE (NOT EOF (f)) AND IsNoError (f) DO
b := ReadNBytes (f, HIGH (buffer), ADR (buffer)) ;
IF IsNoError (f)
THEN
b := WriteNBytes (destFile, b, ADR (buffer))
ELSIF NOT EOF (f)
THEN
printf ("mcStream.mod:copy: error seen when reading file fragment: %s\n",
string (s)) ;
exit (1)
END
END ;
Close (f)
END
END copy ;
(*
setDest - informs the stream module and all fragments must be copied
info, f.
*)
PROCEDURE setDest (f: File) ;
BEGIN
seenDest := TRUE ;
destFile := f
END setDest ;
(*
combine - closes all fragments and then writes them in
order to the destination file. The dest file
is returned.
*)
PROCEDURE combine () : File ;
BEGIN
IF NOT seenDest
THEN
HALT
END ;
ForeachIndiceInIndexDo (frag, copy) ;
removeFiles ;
RETURN destFile
END combine ;
BEGIN
listOfFiles := alists.initList () ;
seenDest := FALSE ;
frag := InitIndex (1)
END mcStream.
|
