Как конвертировать кодовую страницу?

All Systems (Win 95+ and WinNT4+) with MS Internet Explorer 4 and newer have a library named mlang.dll in the Winnt\System32 directory. Usually you can tell Delphi to simply import these COM Libraries. This one however, Delphi did not. I started to convert the "most wanted" interface for myself. The results I present you here.
First I give you the code for the conversion unit, that allows you simply convert any text from code page interpretation into another one. Following I will shortly discuss the code and give you a sample of how to use it.
uCodePageConverter

{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

*

* Unit Name : uCodePageConverter

* Autor : Daniel Wischnewski

* Copyright : Copyright © 2002 by gate(n)etwork. All Right Reserved.

* Urheber : Daniel Wischnewski

*

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}


unit uCodePageConverter;

interface

uses

 Windows;

const

 IID_MLangConvertCharset: TGUID = '{D66D6F98-CDAA-11D0-B822-00C04FC9B31F}';

 CLASS_MLangConvertCharset: TGUID = '{D66D6F99-CDAA-11D0-B822-00C04FC9B31F}';

type

 tagMLCONVCHARF = DWORD;

const

 MLCONVCHARF_AUTODETECT: tagMLCONVCHARF = 1;

 MLCONVCHARF_ENTITIZE: tagMLCONVCHARF = 2;

type

 tagCODEPAGE = UINT;

const

 CODEPAGE_Thai: tagCODEPAGE = 0874;

 CODEPAGE_Japanese: tagCODEPAGE = 0932;

 CODEPAGE_Chinese_PRC: tagCODEPAGE = 0936;

 CODEPAGE_Korean: tagCODEPAGE = 0949;

 CODEPAGE_Chinese_Taiwan: tagCODEPAGE = 0950;

 CODEPAGE_UniCode: tagCODEPAGE = 1200;

 CODEPAGE_Windows_31_EastEurope: tagCODEPAGE = 1250;

 CODEPAGE_Windows_31_Cyrillic: tagCODEPAGE = 1251;

 CODEPAGE_Windows_31_Latin1: tagCODEPAGE = 1252;

 CODEPAGE_Windows_31_Greek: tagCODEPAGE = 1253;

 CODEPAGE_Windows_31_Turkish: tagCODEPAGE = 1254;

 CODEPAGE_Hebrew: tagCODEPAGE = 1255;

 CODEPAGE_Arabic: tagCODEPAGE = 1256;

 CODEPAGE_Baltic: tagCODEPAGE = 1257;

type

 IMLangConvertCharset = interface

  ['{D66D6F98-CDAA-11D0-B822-00C04FC9B31F}']

  function Initialize(

  uiSrcCodePage: tagCODEPAGE; uiDstCodePage: tagCODEPAGE;

  dwProperty: tagMLCONVCHARF

  ): HResult; stdcall;

  function GetSourceCodePage(

  out puiSrcCodePage: tagCODEPAGE

  ): HResult; stdcall;

  function GetDestinationCodePage(

  out puiDstCodePage: tagCODEPAGE

  ): HResult; stdcall;

  function GetProperty(out pdwProperty: tagMLCONVCHARF): HResult; stdcall;

  function DoConversion(

  pSrcStr: PChar; pcSrcSize: PUINT; pDstStr: PChar; pcDstSize: PUINT

  ): HResult; stdcall;

  function DoConversionToUnicode(

  pSrcStr: PChar; pcSrcSize: PUINT; pDstStr: PWChar; pcDstSize: PUINT

  ): HResult; stdcall;

  function DoConversionFromUnicode(

  pSrcStr: PWChar; pcSrcSize: PUINT; pDstStr: PChar; pcDstSize: PUINT

  ): HResult; stdcall;

 end;

 CoMLangConvertCharset = class

  class function Create: IMLangConvertCharset;

  class function CreateRemote(const MachineName: string): IMLangConvertCharset;

 end;

implementation

uses

 ComObj;

{ CoMLangConvertCharset }

class function CoMLangConvertCharset.Create: IMLangConvertCharset;

begin

 Result := CreateComObject(CLASS_MLangConvertCharset) as IMLangConvertCharset;

end;

class function CoMLangConvertCharset.CreateRemote(

 const MachineName: string

 ): IMLangConvertCharset;

begin

 Result := CreateRemoteComObject(

  MachineName, CLASS_MLangConvertCharset

  ) as IMLangConvertCharset;

end;

end.

As you can see, I did translate only one of the many interfaces, however this one is the most efficient (according to Microsoft) and will do the job. Further I added some constants to simplify the task of finding the most important values.
When using this unit to do any code page conersions you must not forget, that the both code pages (source and destination) must be installed and supported on the computer that does the translation. OIn the computer that is going to show the result only the destination code page must be installed and supported.
To test the unit simple create a form with a memo and a button. Add the following code to the buttons OnClick event. (Do not forget to add the conversion unit to the uses clause!)
SAMPLE
procedure TForm1.Button1Click(Sender: TObject);

var

 Conv: IMLangConvertCharset;

 Source: PWChar;

 Dest: PChar;

 SourceSize, DestSize: UINT;

begin

 // connect to MS multi-language lib

 Conv := CoMLangConvertCharset.Create;

 // initialize UniCode Translation to Japanese

 Conv.Initialize(CODEPAGE_UniCode, CODEPAGE_Japanese, MLCONVCHARF_ENTITIZE);

 // load source (from memo)

 Source := PWChar(WideString(Memo1.Text));

 SourceSize := Succ(Length(Memo1.Text));

 // prepare destination

 DestSize := 0;

 // lets calculate size needed

 Conv.DoConversionFromUnicode(Source, @SourceSize, nil, @DestSize);

 // reserve memory

 GetMem(Dest, DestSize);

 try

  // convert

  Conv.DoConversionFromUnicode(Source, @SourceSize, Dest, @DestSize);

  // show

  Memo1.Text := Dest;

 finally

  // free memory

  FreeMem(Dest);

 end;

end;

Взято с Delphi Knowledge Base: http://www.baltsoft.com/

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