[delphizip] Re: Code Pages
- From: "R.Peters" <russellpeters@xxxxxxxxxxx>
- To: <delphizip@xxxxxxxxxxxxx>
- Date: Thu, 11 Aug 2005 19:59:49 +1000
Part of your problem, with little doubt, is that it is not really
manipulating codepages!
What it is (or is supposed to do) is compensate for early dos zips being
stored OEM but only for certain versions.
We have updated the function a bit, hopefully also fixing the brackets (not
easy for c programmers) but I don't think that the names of the consts are
actually correct (values are) - they represent the versions of the programs
that converted depending upon operating system.
I did find a reasonable description somewhere in the InfoZip source code but
it is obscure (at least in my foggy memory).
function TZMWorker.ConvertOEM(const Source: String;
Direction: CodePageDirection): String;
const
FS_FAT: Integer = 0;
FS_HPFS: Integer = 6;
FS_NTFS: Integer = 11;
var
buf: String;
begin
Result := Source;
if ((FCodePage = cpAuto) and (FVersionMadeBy1 = FS_FAT) or
(FVersionMadeBy1 =
FS_HPFS) or ((FVersionMadeBy1 = FS_NTFS) and
(FVersionMadeBy0 = 50))) or
(FCodePage =
cpOEM) then
begin
SetLength(buf, 2 * Length(Source) + 1);
// allow worst case - all double
if (Direction = cpdOEM2ISO) then
OemToChar(Pchar(Source), Pchar(buf))
else
CharToOem(Pchar(Source), Pchar(buf));
Result := Pchar(buf);
end;
end;
May have to watch this in the future if converting to Unicode which (at
present) may be 4* length.
- Russell Peters
-----Original Message-----
From: delphizip-bounce@xxxxxxxxxxxxx [mailto:delphizip-bounce@xxxxxxxxxxxxx]
On Behalf Of James Turner
Sent: Thursday, August 11, 2005 7:42 PM
To: delphizip@xxxxxxxxxxxxx
Subject: [delphizip] Code Pages
I've been looking at the issue of code pages.
My copy of DelphiZip is pretty ancient , so this may have been addressed but
it appears that the function ConvCodePage is faulty (requiring extra
brackets around the ( ) or ( ) or ( ) I think).
I've always struggled with the whole concept of codepages so I could be
wrong.
The code that I have reads as follows.
function TZipMaster.ConvCodePage( Source: String; Direction:
CodePageDirection ): String;
const
FS_FAT: Integer = 0;
FS_HPFS: Integer = 6;
FS_NTFS: Integer = 11;
var
i: Integer;
begin
SetLength( Result, Length( Source ) );
if ((FCodePage = cpAuto) and (FVersionMadeBy1 = FS_FAT) or
(FVersionMadeBy1 = FS_HPFS)
or ((FVersionMadeBy1 = FS_NTFS) and (FVersionMadeBy0 = 50))) or
(FCodePage = cpOEM) then
begin
for i := 1 to Length( Source ) do
if Char( Source[i] ) < Char( $80 ) then
Result[i] := Source[i]
else
if Direction = cpdOEM2ISO then
OemToCharBuff( @Source[i], @Result[i], 1 )
else
CharToOemBuff( @Source[i], @Result[i], 1 )
end
else
Result := Source;
end;
This function also appears to be very inefficient. To perform the conversion
you could use something like this procedure OEMConvert(var s:string); begin
if s = '' then exit;
UniqueString(s); OEMToChar(pointer(s),pointer(s)); end; (Obviously, this
only performs the conversion one way.)
Alternatively
function OEMConvert(const s:string):string; begin
result := s; if result = '' then exit;
UniqueString(result); OEMToChar(pointer(result),pointer(result));
end;
-- James Turner
-----------
To unsubscribe from this list, send an empty e-mail message to:
delphizip-request@xxxxxxxxxxxxx
and put the word unsubscribe in the subject.
__________ NOD32 1.1191 (20050810) Information __________
This message was checked by NOD32 antivirus system.
http://www.eset.com
-----------
To unsubscribe from this list, send an empty e-mail
message to:
delphizip-request@xxxxxxxxxxxxx
and put the word unsubscribe in the subject.
Other related posts:
