Author: Jonas Bilinkevicius

How to convert a WideString to a String

Answer:

Converts Unicode string to Ansi string using specified code page. 
  @param   ws       Unicode string. 
  @param   codePage Code page to be used in conversion. 
  @returns Converted ansi string. 

1   function WideStringToString(const ws: WideString; codePage: Word): 
2   AnsiString;
3   var
4     l: integer;
5   begin
6     if ws = ' then
7       Result := '
8   else
9     begin
10      l := WideCharToMultiByte(codePage,
11        WC_COMPOSITECHECK or WC_DISCARDNS or WC_SEPCHARS or WC_DEFAULTCHAR,
12        @ws[1], -1, nil, 0, nil, nil);
13      SetLength(Result, l - 1);
14      if l > 1 then
15        WideCharToMultiByte(codePage,
16          WC_COMPOSITECHECK or WC_DISCARDNS or WC_SEPCHARS or WC_DEFAULTCHAR,
17          @ws[1], -1, @Result[1], l - 1, nil, nil);
18    end;
19  end; { WideStringToString } 
20  
21  Converts Ansi string to Unicode string using specified code page. 
22    @param   s        Ansi string. 
23    @param   codePage Code page to be used in conversion. 
24    @returns Converted wide string. 
25  
26  function StringToWideString(const s: AnsiString; codePage: Word): WideString;
27  var
28    l: integer;
29  begin
30    if s = ' then
31      Result := '
32  else
33    begin
34      l := MultiByteToWideChar(codePage, MB_PRECOMPOSED, PChar(@s[1]), -1, nil, 0);
35      SetLength(Result, l - 1);
36      if l > 1 then
37        MultiByteToWideChar(CodePage, MB_PRECOMPOSED, PChar(@s[1]),
38          -1, PWideChar(@Result[1]), l - 1);
39    end;
40  end; { StringToWideString }