Delphi 的 Utf-8 轉換

使用Delphi6以上版本有AnsiToUTF8可用

Delphi5以下可使用

http://blog.teatime.com.tw/1/post/419

 提供的方案轉編碼



unit util_utf8;

interface

uses Windows;

type
  UTF8String = AnsiString;

  function AnsiToWide(const S: AnsiString): WideString;
  function WideToUTF8(const WS: WideString): UTF8String;
  function AnsiToUTF8(const S: AnsiString): UTF8String;
  function UTF8ToWide(const US: UTF8String): WideString;
  function WideToAnsi(const WS: WideString): AnsiString;
  function UTF8ToAnsi(const S: UTF8String): AnsiString;

implementation

function AnsiToWide(const S: AnsiString): WideString;
var len: integer;
    ws: WideString;
begin
Result:='';
if (Length(S) = 0) then
  exit;
len:=MultiByteToWideChar(CP_ACP, 0, PChar(s), -1, nil, 0);
SetLength(ws, len);
MultiByteToWideChar(CP_ACP, 0, PChar(s), -1, PWideChar(ws), len);
Result:=ws;
end;

function WideToUTF8(const WS: WideString): UTF8String;
var len: integer;
    us: UTF8String;
begin
Result:='';
if (Length(WS) = 0) then
  exit;
len:=WideCharToMultiByte(CP_UTF8, 0, PWideChar(WS), -1, nil, 0, nil, nil);
SetLength(us, len);
WideCharToMultiByte(CP_UTF8, 0, PWideChar(WS), -1, PChar(us), len, nil, nil);
Result:=us;
end;

function AnsiToUTF8(const S: AnsiString): UTF8String;
begin
Result:=WideToUTF8(AnsiToWide(S));
end;

function UTF8ToWide(const US: UTF8String): WideString;
var len: integer;
    ws: WideString;
begin
Result:='';
if (Length(US) = 0) then
  exit;
len:=MultiByteToWideChar(CP_UTF8, 0, PChar(US), -1, nil, 0);
SetLength(ws, len);
MultiByteToWideChar(CP_UTF8, 0, PChar(US), -1, PWideChar(ws), len);
Result:=ws;
end;

function WideToAnsi(const WS: WideString): AnsiString;
var len: integer;
    s: AnsiString;
begin
Result:='';
if (Length(WS) = 0) then
  exit;
len:=WideCharToMultiByte(CP_ACP, 0, PWideChar(WS), -1, nil, 0, nil, nil);
SetLength(s, len);
WideCharToMultiByte(CP_ACP, 0, PWideChar(WS), -1, PChar(s), len, nil, nil);
Result:=s;
end;

function UTF8ToAnsi(const S: UTF8String): AnsiString;
begin
Result:=WideToAnsi(UTF8ToWide(S));
end;

end.

該方案有一個小小的bug

就是WideToUTF8 回傳的結果最後會加上一個換行符號

 造成轉碼後的結果可能會跟預期不一樣。

最後可使用 S:= copy(S,0,Length(S)-1);

以修正預期產出之結果。