老 base64 for xe8

not recommend ,only for study

procedure TForm1.Button3Click(Sender: TObject);
var
  ssi, sso: TStringStream;
  abt: TBytes;
  s1: string;
begin
  ssi := TStringStream.Create(Edit1.Text);
  sso := TStringStream.Create((''));
  Base64Unit.EncodeStream(ssi, sso);

  sso.Seek(, soFromBeginning);
  SetLength(abt, sso.Size * );
  sso.ReadData(abt, sso.Size * );

  s1 := TEncoding.Unicode.GetString(abt);
  Edit2.Text := s1;
  ssi.Free;
  sso.Free;
end;

procedure TForm1.Button5Click(Sender: TObject);
var
  ssi, sso: TStringStream;
  abt: TBytes;
  s1: string;
begin
  ssi := TStringStream.Create(Edit2.Text);
  sso := TStringStream.Create((''));
  Base64Unit.DecodeStream(ssi, sso);

  sso.Seek(, soFromBeginning);
  SetLength(abt, sso.Size * );
  sso.ReadData(abt, sso.Size * );

  Edit4.Text := sso.DataString;
  ssi.Free;
  sso.Free;

end;

unit Base64Unit;

interface

uses
  Classes, SysUtils;

  function Base64Encryption(const Input:String):String;
  function Base64Decryption(const Input:String):String;

  procedure EncodeStream(InStream, OutStream : TStream);
  procedure DecodeStream(InStream, OutStream : TStream);

implementation

const
  BASE64Table : array[..] of Char = ( #,  #,  #,  #,  #,
         #,  #,  #,  #,  #,  #,  #,  #,  #,  #,
         #,  #,  #,  #,  #,  #,  #,  #,  #,  #,
         #,  #,  #,  #, #, #, #, #, #, #,
        #, #, #, #, #, #, #, #, #, #,
        #, #, #, #, #, #, #,  #,  #,  #,
         #,  #,  #,  #,  #,  #,  #,  #,  #);

const
  BASE64DeTable : array[..] of Byte = ($3E, $7F, $7F, $7F, $3F, $,
      $, $, $, $, $, $3A, $3B, $3C, $3D, $7F, $7F, $7F, $7F,
      $7F, $7F, $7F, $, $, $, $, $, $, $, $, $, $,
      $0A, $0B, $0C, $0D, $0E, $0F, $, $, $, $, $, $, $,
      $, $, $, $7F, $7F, $7F, $7F, $7F, $7F, $1A, $1B, $1C, $1D,
      $1E, $1F, $, $, $, $, $, $, $, $, $, $, $2A,
      $2B, $2C, $2D, $2E, $2F, $, $, $, $);

//BASE64算法流加密
procedure EncodeStream(InStream, OutStream : TStream);
var
  I, O, Count : Integer;
  InBuf  : array[..] of Byte;
  OutBuf : array[..] of Char;     //Char
  Temp : Byte;
  abt:TBytes;
begin
  FillChar(OutBuf, Sizeof(OutBuf), #);

  repeat
    Count := InStream.Read(InBuf, SizeOf(InBuf));
    if Count =  then Break;
    I := ;
    O := ;
    while I <= (Count-) do begin
      { 编码第一个字节 }
      Temp := (InBuf[I] shr );
      OutBuf[O] := Char(BASE64Table[Temp and $3F]);

      { 编码第二个字节 }
      Temp := (InBuf[I] shl ) or (InBuf[I+] shr );
      OutBuf[O+] := Char(BASE64Table[Temp and $3F]);

      { 编码第三个字节 }
      Temp := (InBuf[I+] shl ) or (InBuf[I+] shr );
      OutBuf[O+] := Char(BASE64Table[Temp and $3F]);

      { 编码第四个字节 }
      Temp := (InBuf[I+] and $3F);
      OutBuf[O+] := Char(BASE64Table[Temp]);

      Inc(I, );
      Inc(O, );
    end;

    if (I <= Count) then begin
      Temp := (InBuf[I] shr );
      OutBuf[O] := Char(BASE64Table[Temp and $3F]);

      { 一个奇数字节 }
      if I = Count then begin
        Temp := (InBuf[I] shl ) and $;
        OutBuf[O+] := Char(BASE64Table[Temp and $3F]);
        OutBuf[O+] := '=';
      { 两个基数字节 }
      end else begin
        Temp := ((InBuf[I] shl ) and $) or ((InBuf[I+] shr ) and $0F);
        OutBuf[O+] := Char(BASE64Table[Temp and $3F]);
        Temp := (InBuf[I+] shl ) and $3C;
        OutBuf[O+] := Char(BASE64Table[Temp and $3F]);
      end;
      { 增加= }
      OutBuf[O+] := '=';
      Inc(O, );
    end;

    { 把编码好的块写到流中 }
    OutStream.Write(OutBuf, O*); // Modified by for xe8 2015-07-30 15:36:51 o > o*2
  until Count < SizeOf(InBuf);
end;

//BASE64算法流解密
procedure DecodeStream(InStream, OutStream : TStream);
var
  I, O, Count, c1, c2, c3 : Byte;
  InBuf  : array[..] of Byte;
  OutBuf : array[..] of Byte;
begin
  repeat
    O := ;
    I := ;

    Count := InStream.Read(InBuf, SizeOf(InBuf));
    if (Count = ) then
      Break;

    { 解密的数据输入到流中 }
    while I < Count do begin
      if (InBuf[I] < ) or (InBuf[I] > ) or
         (InBuf[I+] < ) or (InBuf[I+] > ) or
         (InBuf[I+] < ) or (InBuf[I+] > ) or
         (InBuf[I+] < ) or (InBuf[I+] > ) then
        raise Exception.Create('Invalid Base64 Character');

      c1 := BASE64DeTable[InBuf[I]];
      c2 := BASE64DeTable[InBuf[I+]];
      c3 := BASE64DeTable[InBuf[I+]];
      OutBuf[O] := ((c1 shl ) or (c2 shr ));
      Inc(O);
      if Char(InBuf[I+]) <> '=' then begin
        OutBuf[O] := ((c2 shl ) or (c3 shr ));
        Inc(O);
        if Char(InBuf[I+]) <> '=' then begin
          OutBuf[O] := ((c3 shl ) or BASE64DeTable[InBuf[I+]]);
          Inc(O);
        end;
      end;
      Inc(I, );
    end;
    OutStream.Write(OutBuf, O);
  until Count < SizeOf(InBuf);
end;

//BASE64算法字符串加密
function Base64Encryption(const Input:String):String;
var
  InStream  : TMemoryStream;
  OutStream : TMemoryStream;
begin
  InStream := TMemoryStream.Create;
  OutStream := TMemoryStream.Create;

  InStream.Write(Input[], Length(Input));
  InStream.Position := ;
  EncodeStream(InStream, OutStream);
  OutStream.Position := ;
  SetLength(Result, OutStream.Size);
  OutStream.Read(Result[], OutStream.Size);

  InStream.Free;
  OutStream.Free;
end;

//BASE64算法字符串解密
function Base64Decryption(const Input:String):String;
var
  InStream  : TMemoryStream;
  OutStream : TMemoryStream;
begin
  InStream := TMemoryStream.Create;
  OutStream := TMemoryStream.Create;

  InStream.Write(Input[], Length(Input));
  InStream.Position := ;
  DecodeStream(InStream, OutStream);
  OutStream.Position := ;
  SetLength(Result, OutStream.Size);
  OutStream.Read(Result[], OutStream.Size);

  InStream.Free;
  OutStream.Free;
end;

end.