On 27.12.2019 0:19, Michael Van Canneyt wrote:
On Thu, 26 Dec 2019, Ondrej Pokorny wrote:
On 26.12.2019 19:29, Michael Van Canneyt wrote:
So no, I don't think these need to be changed/merged. What IMO can
be discussed is
which of these 2 need to be used as the default codepage in other
code. It
should then resolve the problems that appear, I think.
That would be possible as well. But still please reconsider it:
One reason: just from the convention - the default codepage to use
should be TEncoding.Default. That is intuitive.
Second reason: Now we have TEncoding.ANSI = TEncoding.Default. 2
equal properties. And another FPC-only property
TEncoding.SystemEncoding. That means 3 properties for 2 values.
As far as I know, TEncoding.ANSI = CP_ACP.
This is indeed not correct. See
https://wiki.freepascal.org/FPC_Unicode_support :
CP_ACP: this value represents the currently set "default system code
page". See #Code page settings for more information.
The code for it is in sysos.inc:
function TranslatePlaceholderCP(cp: TSystemCodePage): TSystemCodePage;
{$ifdef SYSTEMINLINE}inline;{$endif}
begin
TranslatePlaceholderCP:=cp;
case cp of
CP_OEMCP:
TranslatePlaceholderCP:=GetOEMCP;
CP_ACP:
TranslatePlaceholderCP:=DefaultSystemCodePage;
end;
end;
Whereas TEncoding.ANSI is the WIN-ANSI OS encoding:
class function TEncoding.GetANSI: TEncoding;
// ...
FStandardEncodings[seAnsi] :=
TMBCSEncoding.Create(widestringmanager.GetStandardCodePageProc(scpAnsi))
and
TStandardCodePageEnum = (
scpAnsi, // system Ansi code page (GetACP on windows)
- as you can see the CP_ACP value does not correspond with the GetACP
WinAPI call result. (But this is wanted as documented in
https://wiki.freepascal.org/FPC_Unicode_support ).
Why should this equal TEncoding.Default ?
sysencoding.inc:
class function TEncoding.GetDefault: TEncoding;
begin
Result := GetANSI;
end;
I think TEncoding.Default = CP_UTF8 on linux ?
Yes, in FPC this is correct. Also TEncoding.ANSI =CP_UTF8 on linux in FPC.
The main problem I see is that there is the system (OS) encoding, and the
encoding specified by DefaultSystemCodePage.
These do not necessarily agree. So it makes sense to have 2
TEncodings: one
for the system encoding, one for the DefaultSystemCodePage variable. They
will not be equal.
If they were, then the DefaultSystemCodePage variable makes no sense
whatever.
Yes, indeed. Therefore I suggested
* TEncoding.Default for the DefaultSystemCodePage variable
and
* TEncoding.ANSI for the system encoding.
Currently we have
* TEncoding.SystemEncoding for the DefaultSystemCodePage variable
and
* both TEncoding.ANSI and TEncoding.Default for the system encoding.
(TEncoding.ANSI and TEncoding.Default are equal in FPC.)
Ondrej
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