How to rename a file?

How to rename a file?

[Pi]

It may sound stupid, but I didn't find anything.

Is there a way to rename files in Ada?

Other than :
create a new file,
copy every byte into the new one,
delete the old one.

-- 
3,14159265359

Re: How to rename a file?

[tmoran]

>Is there a way to rename files in Ada?
  Often.  Consult your compiler's docs.  Renaming files is usually
impossible in embedded systems, systems living entirely in ROM, etc.

Re: How to rename a file?

[Larry Kilgallen]

In article <WkOs7.54950$L%5.36196502@news1.rdc1.sfba.home.com>, tmoran@acm.org writes:
>>Is there a way to rename files in Ada?
>   Often.  Consult your compiler's docs.  Renaming files is usually
> impossible in embedded systems, systems living entirely in ROM, etc.

And renaming on a general purpose operating system is highly specific
to the operating system in use.  Some things are possible in one
environment but not another.

Re: How to rename a file?

[DuckE]

Here's how I make the OS call on WindowsNT/W2K using ObjectAda or GNAT:

WITH Win32;
WITH Win32.WinBase;
WITH Interfaces.C;
 ...
  PACKAGE WinBase RENAMES Win32.WinBase;
  PACKAGE C RENAMES Interfaces.C;

  USE TYPE Win32.BOOL;
  USE TYPE Win32.DWORD;
...
  PROCEDURE RenameFileDFU( sourceFileNameDFU, destFileNameDFU : STRING;
                           renamedDFU : out BOOLEAN ) IS
    result     : Win32.BOOL;
    sourceName : ALIASED C.Char_Array := C.To_C( sourceFileNameDFU );
    destName   : ALIASED C.Char_Array := C.To_C( destFileNameDFU );
  BEGIN
    result := WinBase.MoveFile( sourceName(0)'UNCHECKED_ACCESS,
                                destName(0)'UNCHECKED_ACCESS );
    renamedDFU := result /= Win32.FALSE;
  END RenameFileDFU;

I hope this helps,
SteveD

"Pi" <pi3_1415926536@yahoo.ca> wrote in message
news:MYKs7.11405$%r.2963162@news20.bellglobal.com...
> It may sound stupid, but I didn't find anything.
>
> Is there a way to rename files in Ada?
>
> Other than :
> create a new file,
> copy every byte into the new one,
> delete the old one.
>
> --
> 3,14159265359
>

Re: How to rename a file?

[Pi]

Thanks buddy,
I'll try it tomorrow :-)

DuckE wrote :

> Here's how I make the OS call on WindowsNT/W2K using ObjectAda or GNAT:
> 
> WITH Win32;
> WITH Win32.WinBase;
> WITH Interfaces.C;
>  ...
>   PACKAGE WinBase RENAMES Win32.WinBase;
>   PACKAGE C RENAMES Interfaces.C;
> 
>   USE TYPE Win32.BOOL;
>   USE TYPE Win32.DWORD;
> ...
>   PROCEDURE RenameFileDFU( sourceFileNameDFU, destFileNameDFU : STRING;
>                            renamedDFU : out BOOLEAN ) IS
>     result     : Win32.BOOL;
>     sourceName : ALIASED C.Char_Array := C.To_C( sourceFileNameDFU );
>     destName   : ALIASED C.Char_Array := C.To_C( destFileNameDFU );
>   BEGIN
>     result := WinBase.MoveFile( sourceName(0)'UNCHECKED_ACCESS,
>                                 destName(0)'UNCHECKED_ACCESS );
>     renamedDFU := result /= Win32.FALSE;
>   END RenameFileDFU;
> 
> I hope this helps,
> SteveD
> 
> "Pi" <pi3_1415926536@yahoo.ca> wrote in message
> news:MYKs7.11405$%r.2963162@news20.bellglobal.com...
> > It may sound stupid, but I didn't find anything.
> >
> > Is there a way to rename files in Ada?
> >
> > Other than :
> > create a new file,
> > copy every byte into the new one,
> > delete the old one.
> >
> > --
> > 3,14159265359
> >
> 
> 

-- 
3,14159265359

Re: How to rename a file?

[David Botton]

On Win32 if you wish to be cross compiler (this also demonstrates why thin
bindings are mostly a waste of time for Ada):

First the ugly method:

   function Rename_File (Old_File, New_File : String) return Boolean
   is
      Old_C : Interfaces.C.Char_Array := Interfaces.C.To_C (Old_File);
      New_C : Interfaces.C.Char_Array := Interfaces.C.To_C (New_File);

      function MoveFile
        (Old_Name : Interfaces.C.Char_Array := Old_C;
         New_Name : Interfaces.C.Char_Array := New_C)
        return Boolean;
      pragma Import (StdCall, MoveFile, "MoveFileA");
   begin
      return MoveFile;
   end Rename_File;

Now the cool method:

   function Rename_File2 (Old_File, New_File : String) return Boolean
   is
      function MoveFile
        (Old_Name : String := Old_File & Character'Val (0);
         New_Name : String := New_File & Character'Val (0))
        return Boolean;
      pragma Import (StdCall, MoveFile, "MoveFileA");
   begin
      return MoveFile;
   end Rename_File2;

Ada arrays are passed as C arrays do to the import so the use of String is
valid, we just need to Zero terminate. Ada record types are also passed as
pointers, which makes life a lot easier. For many more examples look through
the bodies of GWindows code http://www.adapower.com/gwindows


BTW, if you don't care about the result:

   procedure Rename_File3 (Old_File, New_File : String)
   is
      procedure MoveFile
        (Old_Name : String := Old_File & Character'Val (0);
         New_Name : String := New_File & Character'Val (0));
      pragma Import (StdCall, MoveFile, "MoveFileA");
   begin
      MoveFile;
   end Rename_File3;


If you are using a compiler other then GNAT, you may need to insure that
WinBase.lib is linked in (as you would using a Win32 thin binding).

David Botton




----- Original Message -----
From: "DuckE" <nospam_steved94@home.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Thursday, September 27, 2001 10:16 PM
Subject: Re: How to rename a file?


> Here's how I make the OS call on WindowsNT/W2K using ObjectAda or GNAT:
>
> WITH Win32;
> WITH Win32.WinBase;
> WITH Interfaces.C;
>  ...
>   PACKAGE WinBase RENAMES Win32.WinBase;
>   PACKAGE C RENAMES Interfaces.C;
>
>   USE TYPE Win32.BOOL;
>   USE TYPE Win32.DWORD;
> ...
>   PROCEDURE RenameFileDFU( sourceFileNameDFU, destFileNameDFU : STRING;
>                            renamedDFU : out BOOLEAN ) IS
>     result     : Win32.BOOL;
>     sourceName : ALIASED C.Char_Array := C.To_C( sourceFileNameDFU );
>     destName   : ALIASED C.Char_Array := C.To_C( destFileNameDFU );
>   BEGIN
>     result := WinBase.MoveFile( sourceName(0)'UNCHECKED_ACCESS,
>                                 destName(0)'UNCHECKED_ACCESS );
>     renamedDFU := result /= Win32.FALSE;
>   END RenameFileDFU;
>
> I hope this helps,
> SteveD
>
> "Pi" <pi3_1415926536@yahoo.ca> wrote in message
> news:MYKs7.11405$%r.2963162@news20.bellglobal.com...
> > It may sound stupid, but I didn't find anything.
> >
> > Is there a way to rename files in Ada?
> >
> > Other than :
> > create a new file,
> > copy every byte into the new one,
> > delete the old one.
> >
> > --
> > 3,14159265359
> >
>
>
> _______________________________________________
> comp.lang.ada mailing list
> comp.lang.ada@ada.eu.org
> http://ada.eu.org/mailman/listinfo/comp.lang.ada
>

Re: How to rename a file?

[Lutz Donnerhacke]

* David Botton wrote:
>Ada arrays are passed as C arrays do to the import so the use of String is
>valid, we just need to Zero terminate. Ada record types are also passed as
>pointers, which makes life a lot easier.

There is no guarantee AFAIK. Even GCC (not to mention Ada) has different
ways to do this. Therefore I prefer passing Interfaces.C.Strings.char_p over
Interfaces.C.char_array over Standard.String. Especially, if you look how
Standard.String is implemented: As a small struct, passable in registers or
as a pointer to this struct. In the latter case your C-function may assume
the pointer to the memory area containing the string values and the bounds.

       -fpcc-struct-return
              Use the same convention for  returning  struct  and
              union  values  that is used by the usual C compiler
              on your system.  This convention is less  efficient
              for small structures, and on many machines it fails
              to be reentrant; but it has the advantage of allow�
              ing  intercallability between GCC-compiled code and
              PCC-compiled code.

       -freg-struct-return
              Use the convention that struct and union values are
              returned  in registers when possible.  This is more
              efficient     for     small     structures     than
              -fpcc-struct-return.

              If  you  specify  neither  -fpcc-struct-return  nor
              -freg-struct-return, GNU CC defaults  to  whichever
              convention is standard for the target.  If there is
              no  standard  convention,  GNU   CC   defaults   to
              -fpcc-struct-return.

Re: How to rename a file?

[Pascal Obry]

"David Botton" <David@Botton.com> writes:

> On Win32 if you wish to be cross compiler (this also demonstrates why thin
> bindings are mostly a waste of time for Ada):
> 
> First the ugly method:
> 

(code removed)

> 
> Now the cool method:
> 

(code removed)

Now the really cool method :)

  POSIX.Files.Rename ("myoldfile", "whateveristhenewname");

All the ugly binding to the OS has been done by the POSIX bindings
developers... don't waste your time !

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|         http://perso.wanadoo.fr/pascal.obry
--|
--| "The best way to travel is by means of imagination"

Re: How to rename a file?

[Larry Kilgallen]

In article <uofnvnrrz.fsf@wanadoo.fr>, Pascal Obry <p.obry@wanadoo.fr> writes:
> 
> "David Botton" <David@Botton.com> writes:
> 
>> On Win32 if you wish to be cross compiler (this also demonstrates why thin
>> bindings are mostly a waste of time for Ada):
>> 
>> First the ugly method:
>> 
> 
> (code removed)
> 
>> 
>> Now the cool method:
>> 
> 
> (code removed)
> 
> Now the really cool method :)
> 
>   POSIX.Files.Rename ("myoldfile", "whateveristhenewname");
> 
> All the ugly binding to the OS has been done by the POSIX bindings
> developers...

Only if you are satisfied with least-common-denominator semantics,
avoiding OS-specific features.

Re: How to rename a file?

[David Botton]

That's not cool, but certainly an alternative.

The coolness is in that code was that you don't need any "special" bindings
for accessing low level C calls. In fact I think far to much emphasis has
been placed on the need of thin bindings. Concentration should rather be
made on "frameworks" (which POSIX bindings may perhaps also be included, as
cross platform was in mind) and tools that abstract the C interfaces and
work in a more Ada like nature.

David Botton

----- Original Message -----
From: "Pascal Obry" <p.obry@wanadoo.fr>
> Now the really cool method :)
>
>   POSIX.Files.Rename ("myoldfile", "whateveristhenewname");
>
> All the ugly binding to the OS has been done by the POSIX bindings
> developers... don't waste your time !

Re: How to rename a file?

[Pascal Obry]

"David Botton" <David@Botton.com> writes:

> That's not cool, but certainly an alternative.

;)

> The coolness is in that code was that you don't need any "special" bindings
> for accessing low level C calls. In fact I think far to much emphasis has
> been placed on the need of thin bindings. Concentration should rather be

David, really POSIX is *far* from being a thin binding.

Your cool example is way more thin than mine :)

<<
   function Rename_File2 (Old_File, New_File : String) return Boolean
   is
      function MoveFile
        (Old_Name : String := Old_File & Character'Val (0);
         New_Name : String := New_File & Character'Val (0))
        return Boolean;
      pragma Import (StdCall, MoveFile, "MoveFileA");
   begin
      return MoveFile;
   end Rename_File2;
>>

Character'Val (0), Stdcall, pragma Import...

> made on "frameworks" (which POSIX bindings may perhaps also be included, as
> cross platform was in mind) and tools that abstract the C interfaces and
> work in a more Ada like nature.

I won't call POSIX a framework since it is a _binding_ but yet not a
thin one. And yes in cross-platform environemnt it is definitly the 
choice, this is why I do use it!

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|         http://perso.wanadoo.fr/pascal.obry
--|
--| "The best way to travel is by means of imagination"

Re: How to rename a file?

[Florian Weimer]

Pascal Obry <p.obry@wanadoo.fr> writes:

>> made on "frameworks" (which POSIX bindings may perhaps also be included, as
>> cross platform was in mind) and tools that abstract the C interfaces and
>> work in a more Ada like nature.
>
> I won't call POSIX a framework since it is a _binding_ but yet not a
> thin one.

Most POSIX.5 implementations aren't bindings.

> And yes in cross-platform environemnt it is definitly the choice,
> this is why I do use it!

IMHO, the POSIX.5 interface is a horrible mess, combining the
uselessness of POSIX.1 with some additional unfortunate design
decisions.

Re: How to rename a file?

[Pascal Obry]

Florian Weimer <fw@deneb.enyo.de> writes:

> Pascal Obry <p.obry@wanadoo.fr> writes:
> 
> >> made on "frameworks" (which POSIX bindings may perhaps also be included, as
> >> cross platform was in mind) and tools that abstract the C interfaces and
> >> work in a more Ada like nature.
> >
> > I won't call POSIX a framework since it is a _binding_ but yet not a
> > thin one.
> 
> Most POSIX.5 implementations aren't bindings.
> 
> > And yes in cross-platform environemnt it is definitly the choice,
> > this is why I do use it!
> 
> IMHO, the POSIX.5 interface is a horrible mess, combining the
> uselessness of POSIX.1 with some additional unfortunate design
> decisions.

Maybe, maybe not... I'm not a POSIX expert ! But yet I have some large
applications that run without modification on Linux and Windows using a lot
OS routines (Renaming files, running subprocess, waiting for process to
terminate, retrieving environment variable values, retrieving all files on a
specific directory...). I'm not saying that POSIX is in theory a good choice
but it is the best choice I have seen so far... Do you know of other choices ?

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|         http://perso.wanadoo.fr/pascal.obry
--|
--| "The best way to travel is by means of imagination"

Re: How to rename a file?

[DuckE]

I've used both methods.  I don't find thin bindings to be a waste of time,
mainly because it keeps me from having to define constants, structures,
function and procedure prototypes.  Creating these definitions can be
tricky.

Using the thin bindings _usually_ the prototypes are right, it's just a
matter of setting up the arguments correctly.

IMHO
SteveD

"David Botton" <David@Botton.com> wrote in message
news:mailman.1001648485.22108.comp.lang.ada@ada.eu.org...
> On Win32 if you wish to be cross compiler (this also demonstrates why thin
> bindings are mostly a waste of time for Ada):
>
[snip]

Re: How to rename a file?

[David Botton]

> Is there a way to rename files in Ada?

Using GNAT, you would use

GNAT.OS_Lib.Rename_File (Old_Name, New_Name);

Take a look around the GNAT.* packages, you will find many goodies!

David Botton

Re: How to rename a file?

[Jeffrey Carter]

For portability, I would suggest using Posix.Files.Rename. Posix is both
OS and compiler independent. Implementations exist for most platforms.

GNAT.OS_Lib is OS independent but compiler dependent. Putting Win32
calls in your code is probably compiler independent but definitely OS
dependent.

-- 
Jeffrey Carter