Delphi 下的Base64编码和解码

function Base64Encode(s : string) : string;  //base64 编码
var base64 : TIdEncoderMIME;
tmpBytes : TBytes;
begin
base64 := TIdEncoderMIME.Create(nil);
try
base64.FillChar := '=';
tmpBytes := TEncoding.UTF8.GetBytes(s);
Result := base64.EncodeBytes(TIdBytes(tmpBytes));
finally
base64.Free;
end;
end;

function Base64Decode(s : string) : string;  //base64 解码
var base64 : TIdDeCoderMIME;
tmpBytes : TBytes;
begin
Result := s;
base64 := TIdDecoderMIME.Create(nil);
try
base64.FillChar := '=';
tmpBytes := TBytes(base64.DecodeBytes(s));
Result := TEncoding.UTF8.GetString(tmpBytes);
finally
base64.Free;
end;
end;