如何使用Delphi 将文本文件从ANSI转换为UTF-8？

program AnsiToUtf8;

{$APPTYPE CONSOLE}

uses
  SysUtils, Classes;

function AnsiToUtf8(const InputFile, OutputFile: string): Boolean;
var
  InputStream, OutputStream: TFileStream;
  Buffer: TBytes;
  BytesRead: Integer;
begin
  Result := False;
  InputStream := TFileStream.Create(InputFile, fmOpenRead);
  try
    OutputStream := TFileStream.Create(OutputFile, fmCreate);
    try
      SetLength(Buffer, 4096);
      repeat
        BytesRead := InputStream.Read(Buffer[0], Length(Buffer));
        if BytesRead > 0 then
        begin
          OutputStream.Write(Buffer[0], BytesRead);
        end;
      until BytesRead = 0;
      Result := True;
    finally
      OutputStream.Free;
    end;
  finally
    InputStream.Free;
  end;
end;

var
  InputFile, OutputFile: string;
begin
  if ParamCount <> 2 then
  begin
    WriteLn('Usage: AnsiToUtf8<input file><output file>');
    Exit;
  end;

  InputFile := ParamStr(1);
  OutputFile := ParamStr(2);

  if not AnsiToUtf8(InputFile, OutputFile) then
  begin
    WriteLn('Error: Failed to convert file.');
  end
  else
  begin
    WriteLn('File successfully converted.');
  end;
end.

AnsiToUtf8.exe input.txt output.txt