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unit base64;
 
interface
 
uses Windows, SysUtils, Classes;
 
function BinToStr(Binary: PByte; Len: Cardinal): String;
procedure StrToStream(Str: String; Stream: TStream);
 
implementation
 
const
  CRYPT_STRING_BASE64 = 1;
 
function CryptBinaryToString(pbBinary: PByte; cbBinary: DWORD; dwFlags: DWORD;
  pszString: PChar; var pcchString: DWORD): BOOL; stdcall;
  external 'Crypt32.dll' name 'CryptBinaryToStringA';
 
function CryptStringToBinary(pszString: PChar; cchString: DWORD; dwFlags: DWORD;
  pbBinary: PByte; var pcbBinary: DWORD; pdwSkip: PDWORD;
  pdwFlags: PDWORD): BOOL; stdcall;
  external 'Crypt32.dll' name 'CryptStringToBinaryA';
 
function BinToStr(Binary: PByte; Len: Cardinal): String;
var
  Count: DWORD;
begin
  Count:= 0;
  if CryptBinaryToString(Binary,Len,CRYPT_STRING_BASE64,nil,Count) then
  begin
    SetLength(Result,Count);
    if not CryptBinaryToString(Binary,Len,CRYPT_STRING_BASE64,PChar(Result),
      Count) then
      Result:= EmptyStr;
  end;
end;
 
procedure StrToStream(Str: String; Stream: TStream);
var
  Buffer: PByte;
  Count: DWORD;
begin
  Count:= 0;
  if CryptStringToBinary(PChar(Str),Length(Str),CRYPT_STRING_BASE64,nil,Count,
    nil,nil) then
  begin
    GetMem(Buffer,Count);
    try
      if CryptStringToBinary(PChar(Str),Length(Str),CRYPT_STRING_BASE64,Buffer,
        Count,nil,nil) then
        Stream.WriteBuffer(Buffer^,Count);
    finally
      FreeMem(Buffer);
    end;
  end;
end;
 
end.

var
  Stream: TMemoryStream;
  Texto: String;
 
begin
  Stream:= TMemoryStream.Create;
  try
    Stream.LoadFromFile('imagen.jpg');
    Texto:= BinToStr(Stream.Memory,Stream.Size);
  finally
    Stream.Free;
  end;
end.

var
 Stream: TFileStream;
 
begin
  Stream:= TFileStream.Create('imagen.jpg',fmCreate);
  try
    StrToStream(Texto,Stream);
  finally
    Stream.Free;
   end;
end.