So - second attempt at implementing it... same sad result - only now
the XPM fails as well...
This is my now somewhat improved code... am I missing something
extremely obvious here ?
Function DecodeB64(S : String) : String;
Procedure doNothing;
Begin
end;
var
b64decoder: TBase64DecodingStream;
S1 : TSTringStream;
S2 : TStringStream;
begin
S1 := TStringStream.Create(S);
S2 := TStringStream.Create('');
b64decoder := TBase64DecodingStream.Create(S1);
With B64Decoder Do
Begin
try
S2.CopyFrom(B64Decoder,B64Decoder.Size);
Except
DoNothing;
end;
end;
Result := S2.DataString;
S1.Free;
S2.Free;
b64decoder.Free;
end;
I'm stumped as to what it is I am doing wrong...
Any ideas ?
A.J.
On 5/16/07, A.J. Venter <[EMAIL PROTECTED]> wrote:
A small update -
Don't ask me WHY - but get this - I take the exact same unchanged
code, and insert an XPM image.
It works perfectly.
I try a jpg or a png - and it fails.
All I can imagine is that my b64decode function is broken - and that
the breakage is ONLY affecting true binary sources, XPM (like my test
program) is actually an ASCII format - so it survives the process
intact - while png etc. fails.
So - I guess I start hacking my b64decode function.
A.J.
On 5/16/07, A.J. Venter <[EMAIL PROTECTED]> wrote:
> Hi again all
> Based on everyone's advice, I chose to go with base64 encoding - and
> started coding.
>
> Right now I am quite successfully:
> 1) Reading the image
> 2) Encoding it to base64 (using the encodeb64 function from the examples)
> 3) Storing the result in the database (I THINK it's storing right)
>
> Later I then select it, run it through decodeb64 (my own function
> based on the above, code below) and then save this string to a file -
> a file that has the right extension (the reason for this is actually
> good - remote DB access, and I want to cache the images and only
> download if they changed)
> Finally - a simple TImage.Picture.LoadFromFile is meant to handle the
> last bit... only it doesn't - somewhere along the way my data is
> corrupted - the files being dumped differ from the orriginals - yet
> oddly they are the exact same size.
> I know we're not supposed to include attachments on the list, so for
> now I didn't but if I may, I would like to add (assuming anybody says
> it would be usefull:
> 1) An orriginal image
> 2) A post database process filedump of the same image
> 3) The (apparently) base64 encoded database entry for said image
>
> I can say that I tested my b64encode/b64decode functions with a simple
> program that lets me enter string, encodes it, writes that, decodes
> THAT and writes it back (which should match the orriginal input) -
> that at least seems to work fine.
>
> Any idea where the corruption is coming from ? All help, as always,
> greatly appreciated.
>
> Relevant code snippets:
> Function DecodeB64(S : String) : String;
> Procedure doNothing;
> Begin
> end;
> var
> b64decoder: TBase64DecodingStream;
> S1 : TSTringStream;
> S2 : String;
> InputStream: TStream;
> IsEnd: Boolean;
>
> begin
> S1 := TStringStream.Create(S);
> S2 := '';
> b64decoder := TBase64DecodingStream.Create(S1);
> While not B64Decoder.EOF do
> Begin
> try
> S2 := S2+(CHR(B64Decoder.ReadByte));
> except
> doNothing;
> end;
> end;
>
> Result := S2;
> b64decoder.Free;
> end;
>
> Image Saving:
> Procedure SaveBTNClick(Sender:TObject); //Snipped
> Var B64 : String;
> S :TStringList;
> Begin
> S := TStringList.Create;
> S.LoadFromFile(ImgFileName);
> B64 := EncodeB64(S.Text);
> Ad.SaveData(add_desc.text,b64);
> end;
>
>
> Procedure TZC_Advertising.SaveData(Description,Data:String);
> Var Q : String;
> Begin
> Q := 'UPDATE advertising SET data='+QS(Data)+'
> timestamp='+QS('NOW')+' WHERE description = '+QS(Description)+' ;';
> FResult := ZC_DBQuery(Q);
> //Notes: FResult is a PPGResult, ZC_DBQuery is a very well tested
> wrapper function
> //QS = QuoteString - it wraps the input in ''
> end;
>
> Image Loading:
> Function TZC_Advertising.GetData(Description:String):String;
> Var
> S : String;
> Begin
> FResult := ZC_DBQuery('SELECT data FROM advertising WHERE description
> = '+QS(Description)+';');
> If PqNTuples(Fresult) >= 0 then
> begin
> S := PQGetValue(FResult,0,0);
> GetData:=DecodeB64(S);
> end else
> GetData := '';
> end;
>
> //In the app:
> IName := GetTempDir+Ad.GetTimeStamp(add_desc.text)+Ad.GetExt(add_desc.text);
> Data := TStringList.Create;
> Data.Add(Ad.GetData(add_desc.text));
> Data.SaveToFile(Iname);
> ad_Img.Picture.LoadFromFile(Iname);
> Data.Free;
>
> --
> A.J. Venter
> CEO - OutKast Solutions C.C.
> http://www.outkastsolutions.co.za
> Cell: +27 83 455 9978
> Fax: +27 21 413 2800
> Office: +27 21 591 6766
>
--
A.J. Venter
CEO - OutKast Solutions C.C.
http://www.outkastsolutions.co.za
Cell: +27 83 455 9978
Fax: +27 21 413 2800
Office: +27 21 591 6766
--
A.J. Venter
CEO - OutKast Solutions C.C.
http://www.outkastsolutions.co.za
Cell: +27 83 455 9978
Fax: +27 21 413 2800
Office: +27 21 591 6766
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