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Wrapping several .png files into one file

Hello,
I am trying to take some .png files and put them in one file, which will also specify the position of the start and end of each file in the big file (so that I can recover them afterwards).
The idea is to do something like a zip file.
I'm not very familiar with operating binary files, so any help would be great!
Thanks, Libby

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libbysharf

ASKER

Thanks,What happened was that I answered my question before I got any response... But I'll give you the points for the effort.
I think I did it a bit easier.
This is the code :

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

FileDetails = record
name : array[0..7] of char;
size : integer;
end;

var
Form1: TForm1;
FileDetailsArray : array[0..9] of FileDetails;

implementation

{$R *.DFM}

procedure FileSave;
var
FromF, ToF: file;
NumRead, NumWritten: Integer;
Buffer: array[1..2048] of Byte;
count : integer;
begin
AssignFile(ToF,'AllPng.gnp');
Rewrite(ToF, 1);

seek(ToF,sizeof(FileDetailsArray));
AssignFile(FromF,'91827E42.png');
Reset(FromF, 1);
count:=0;
repeat
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
until (NumRead = 0) or (NumWritten <> NumRead);

FileDetailsArray[0].name:='91827E42';
FileDetailsArray[0].size:=count;

AssignFile(FromF,'91842E42.png');
Reset(FromF, 1);
repeat
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
until (NumRead = 0) or (NumWritten <> NumRead);

FileDetailsArray[1].name:='91842E42';
FileDetailsArray[1].size:=count;

AssignFile(FromF,'91858E42.png');
Reset(FromF, 1);
repeat
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
until (NumRead = 0) or (NumWritten <> NumRead);

FileDetailsArray[2].name:='91858E42';
FileDetailsArray[2].size:=count;

seek(ToF,0);
BlockWrite(ToF, FileDetailsArray, sizeof(FileDetailsArray), NumWritten);

CloseFile(FromF);
CloseFile(ToF);
end;

procedure FileLoad;
var
FromF, ToF: file;
NumRead, NumWritten: Integer;
Buffer: array[1..2048] of Byte;
count : integer;
begin
AssignFile(ToF,'re1.png');
Rewrite(ToF, 1);
AssignFile(FromF,'AllPng.gnp');
Reset(FromF, 1);
BlockRead(FromF,FileDetailsArray , SizeOf(FileDetailsArray), NumRead);

count:=0;
repeat
if (count+SizeOf(Buffer))>FileDetailsArray[0].size then
begin
BlockRead(FromF, Buffer,FileDetailsArray[0].size-count, NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end
else
begin
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end;
until (NumRead = 0) or (NumWritten <> NumRead);

CloseFile(ToF);

AssignFile(ToF,'re2.png');
Rewrite(ToF, 1);
count:=0;
repeat
if (count+SizeOf(Buffer))>(FileDetailsArray[1].size-FileDetailsArray[0].size) then
begin
BlockRead(FromF, Buffer,FileDetailsArray[1].size-FileDetailsArray[0].size-count, NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end
else
begin
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end;
until (NumRead = 0) or (NumWritten <> NumRead);

CloseFile(ToF);

AssignFile(ToF,'re3.png');
Rewrite(ToF, 1);
count:=0;
repeat
if (count+SizeOf(Buffer))>(FileDetailsArray[2].size-FileDetailsArray[1].size) then
begin
BlockRead(FromF, Buffer,FileDetailsArray[2].size-FileDetailsArray[1].size-count, NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end
else
begin
BlockRead(FromF, Buffer, SizeOf(Buffer), NumRead);
BlockWrite(ToF, Buffer, NumRead, NumWritten);
count:=count+NumRead;
end;
until (NumRead = 0) or (NumWritten <> NumRead);

CloseFile(ToF);

CloseFile(FromF);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
FileSave;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
FileLoad;
end;

end.