讀取ASNI/UTF8/UNICODE/UNICODE Big格式檔案的通用函數

函數在Delphi2007和Delphi6中測試通過。

 

function LoadTextFile(Filename: String): String;<br />var<br /> Stream:TMemoryStream;<br /> Flag: String;<br /> WS: WideString;<br /> CodeType: Byte; //0:ANSI,1:UTF-8,2:Unicode,3:Unicode big<br /> procedure ProcessUnicodeBig;<br /> var<br /> i: integer;<br /> n: Word;<br /> begin<br /> for i := 1 to Length(WS) do begin<br /> n := Word(WS[i]);<br /> asm<br /> mov ax, n<br /> xchg ah, al<br /> mov n, ax<br /> end;<br /> WS[i] := WideChar(n);<br /> end;<br /> end;<br />begin<br /> Result := '';<br /> CodeType := 0;<br /> Stream := TMemoryStream.Create;<br /> try<br /> Stream.LoadFromFile(Filename);<br /> SetLength(Flag,3);<br /> Stream.Read(Flag[1],3);<br /> if Flag=#EF#BB#BF then CodeType := 1<br /> else if (Flag[1]=#FF) and (Flag[2]=#FE) then CodeType := 2<br /> else if (Flag[1]=#FE) and (Flag[2]=#FF) then CodeType := 3;<br /> case CodeType of<br /> 2,3: begin<br /> Stream.Seek(2, soFromBeginning);<br /> SetLength(WS,(Stream.Size-2) div 2);<br /> Stream.Read(WS[1],Stream.Size-2);<br /> if CodeType = 3 then ProcessUnicodeBig;<br /> Result := AnsiString(WS);<br /> end;<br /> 0: begin<br /> Stream.Seek(0, soFromBeginning);<br /> SetLength(Result, Stream.Size);<br /> Stream.Read(Result[1], Stream.Size);<br /> end;<br /> 1: begin<br /> Stream.Seek(3, soFromBeginning);<br /> SetLength(Result, Stream.Size-3);<br /> Stream.Read(Result[1], Stream.Size-3);<br /> Result := Utf8ToAnsi(Result);<br /> end;<br /> end;<br /> finally<br /> Stream.Free;<br /> end;<br />end;<br />