asked on

Splitting a 2mb file into 2 * 1mb and back again

Just say I had a 2mb file. Is there a way (in code, D2) to split this file into 2 seperate files then be able to join them together to make the original file again. The reason being that a file of 2mb won't go on a floppy and i'm toying with the idea to make a little app for myself that will do it. I know I could span disks with pkzip etc but would like to do it myself. Any good suggestions will receive the finished util once finished.
ps I know how to get it back into 1 file with the DOS command COPY File1 File2 /B But how to split it in the first place.

ASKER CERTIFIED SOLUTION

rene100

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viktornet

Here is how.....
-------------
var
inFile, outFile : File;
CopyBuffer : Pointer;
iRecsOK, iRecsWr, iX: Integer;
sFileName : String;
CONST
ChunkSize : LongInt = 1024000;
begin
GetMem(CopyBuffer, ChunkSize);
sFileName := 'C:\windows\desktop\test';
AssignFile(inFile, sFileName + '.ZIP');
Reset(inFile);
iX := 1;
repeat
AssignFile(outFile, sFileName + IntToStr(iX) + '.ZIP');
Rewrite(outFile);
inc(iX);
BlockRead(inFile, CopyBuffer^, ChunkSize, iRecsOK);
BlockWrite(outFile, CopyBuffer^, iRecsOK, iRecsWr);
ClosFile(outFile);
until (iRecsOK < Chunksize);
CloseFile(inFile);
FreeMem(CopyBuffer, Chunksize);
end;
------------
Regards,
Viktor Ivanov

viktornet

There is a mistake...

Do you see where it says ClosFile(outFile); this is supose to be CloseFile(outFile);

Regards,
Viktor Ivanov

joshordan

ASKER

Rene / Viktor,

Many thanks for guiding me.

Rene
I can see that your 2 functions have exactly the required result, but.. :) All is OK until the file changed size from 2mb, ie, it changes from 2mb to 5mb or beyond. Is there a way to make the functions a little more generic as to be able to handle any sized file??

rene100

try this:

procedure TForm1.SplitFile(FileName,NewFile1,NewFile2: string);
var
fStream: TMemoryStream;
dStream1,dStream2: TMemoryStream;
tLength1,tLength2: longint;
begin
fStream:=TMemoryStream.create;
dStream1:=TMemoryStream.create;
dStream2:=TMemoryStream.create;
fStream.LoadFromFile(FileName);
if fStream.size mod 2 =0 then
begin
tLength1:=Trunc(FStream.size/2);
tLength2:=Trunc(FStream.size/2);
end
else
begin;
tLength1:=Trunc(FStream.size/2-0.5);
tLength2:=Trunc(FStream.size/2+0.5);
end;
dStream1.CopyFrom(fStream,tLength1);
dStream1.SaveToFile(NewFile1);
dStream1.free;
fStream.Position:=tLength1;
dStream2.CopyFrom(fStream,tLength2);
dStream2.SaveToFile(Newfile2);
dStream2.free;
fStream.free;
end;

procedure Tform1.ConcatFiles(File1,file2,NewFileName: string);
var
fStream: TMemoryStream;
dStream1,dStream2: TMemoryStream;
begin
fStream:=TMemoryStream.create;
dStream1:=TMemoryStream.create;
dStream2:=TMemoryStream.create;
dStream1.LoadFromFile(File1);
dStream2.LoadFromFile(File2);
fStream.CopyFrom(dStream1,dStream1.size);
fStream.Position:=dStream1.Size;
fStream.CopyFrom(dStream2,dStream2.size);
dStream1.free;
dStream2.free;
fStream.SaveToFile(NewFileName);
fStream.free;
end;