Algorithm Math Delphi

Title: How to convert a WideString to a String
function WideStringToString(const ws: WideString; codePage: Word): AnsiString;
var
l: integer;
begin
if ws = ' then
Result := '
else
begin
l := WideCharToMultiByte(codePage,
WC_COMPOSITECHECK or WC_DISCARDNS or WC_SEPCHARS or WC_DEFAULTCHAR,
@ws[1], - 1, nil, 0, nil, nil);
SetLength(Result, l - 1);
if l 1 then
WideCharToMultiByte(codePage,
WC_COMPOSITECHECK or WC_DISCARDNS or WC_SEPCHARS or WC_DEFAULTCHAR,
@ws[1], - 1, @Result[1], l - 1, nil, nil);
end;
end; { WideStringToString }
{:Converts Ansi string to Unicode string using specified code page.
@param s Ansi string.
@param codePage Code page to be used in conversion.
@returns Converted wide string.
}
function StringToWideString(const s: AnsiString; codePage: Word): WideString;
var
l: integer;
begin
if s = ' then
Result := '
else
begin
l := MultiByteToWideChar(codePage, MB_PRECOMPOSED, PChar(@s[1]), - 1, nil, 0);
SetLength(Result, l - 1);
if l 1 then
MultiByteToWideChar(CodePage, MB_PRECOMPOSED, PChar(@s[1]),
- 1, PWideChar(@Result[1]), l - 1);
end;
end; { StringToWideString }