老 base64 for xe8

2024-03-27 22:42:10

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.

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