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(* DynamicPath.mod implements a path for DynamicStrings.
Copyright (C) 2001-2024 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. *)
IMPLEMENTATION MODULE DynamicPath ; (*!m2iso+gm2*)
FROM Storage IMPORT ALLOCATE, DEALLOCATE ;
FROM DynamicStrings IMPORT InitString, ConCat, ConCatChar, char, Dup,
KillString, Length, EqualArray ;
FROM SFIO IMPORT Exists ;
FROM FIO IMPORT StdErr ;
FROM M2Printf IMPORT fprintf0, fprintf1 ;
CONST
Directory = '/' ;
Debugging = FALSE ;
TYPE
PathList = POINTER TO RECORD
tail,
next : PathList ;
entry: String ;
END ;
VAR
FreeList: PathList ;
(*
KillPathList - places list pl onto the freelist.
Postcondition: pl will be NIL.
*)
PROCEDURE KillPathList (VAR pl: PathList) ;
BEGIN
IF pl # NIL
THEN
pl^.tail^.next := FreeList ;
FreeList := pl ;
pl := NIL
END
END KillPathList ;
(*
InitPathList - creates a new empty path list.
It takes a copy of the string.
*)
PROCEDURE InitPathList (str: String) : PathList ;
VAR
pl: PathList ;
BEGIN
NEW (pl) ;
WITH pl^ DO
tail := pl ;
next := NIL ;
entry := Dup (str)
END ;
RETURN pl
END InitPathList ;
(*
Cons - appends str to the end of a path list.
If pl is NIL a new list is created and returned
containing str.
*)
PROCEDURE Cons (pl: PathList; str: String) : PathList ;
BEGIN
IF pl = NIL
THEN
pl := InitPathList (str)
ELSE
pl := ConsList (pl, InitPathList (str))
END ;
RETURN pl
END Cons ;
(*
ConsList - concatenates path list left and right together.
*)
PROCEDURE ConsList (left, right: PathList) : PathList ;
BEGIN
IF right # NIL
THEN
left^.tail^.next := right ;
left^.tail := right^.tail
END ;
RETURN left
END ConsList ;
(*
Stash - returns pl before setting pl to NIL.
*)
PROCEDURE Stash (VAR pl: PathList) : PathList ;
VAR
old: PathList ;
BEGIN
old := pl ;
pl := NIL ;
RETURN old
END Stash ;
(*
AddDir - if str is not empty and does not end with / then add
a directory.
Postcondition: str is returned (with a '/' at the end)
or is empty.
*)
PROCEDURE AddDir (str: String) : String ;
BEGIN
IF Length (str) > 0
THEN
IF char (str, -1) # Directory
THEN
str := ConCatChar (str, Directory)
END
END ;
RETURN str
END AddDir ;
(*
FindFileName - returns NIL if a file cannot be found otherwise
it returns the path including the filename.
*)
PROCEDURE FindFileName (filename: String; pl: PathList) : String ;
VAR
s: String ;
BEGIN
WHILE pl # NIL DO
s := ConCat (AddDir (Dup (pl^.entry)), Dup (filename)) ;
IF Debugging
THEN
fprintf1 (StdErr, "testing for %s: ", s)
END ;
IF Exists (s)
THEN
IF Debugging
THEN
fprintf0 (StdErr, "yes\n")
END ;
RETURN s
END ;
IF Debugging
THEN
fprintf0 (StdErr, "no\n")
END ;
s := KillString (s) ;
pl := pl^.next
END ;
IF Debugging
THEN
fprintf1 (StdErr, "FindFileName did not find: %s in path\n", filename)
END ;
RETURN NIL
END FindFileName ;
(*
DumpPath - debugging dump of the pathlist.
*)
PROCEDURE DumpPath (name: String; pl: PathList) ;
BEGIN
fprintf1 (StdErr, "%s:", name) ;
WHILE pl # NIL DO
fprintf0 (StdErr, " {") ;
fprintf1 (StdErr, "%s", pl^.entry) ;
fprintf0 (StdErr, "}") ;
pl := pl^.next
END ;
fprintf0 (StdErr, "\n")
END DumpPath ;
BEGIN
FreeList := NIL
END DynamicPath.
|
