Hello,
I have overloaded the function with different parameters as there was
already some different overloaded versions of it but as you guessed forgot
to mark the changes. Here it is:
procedure ZlibCompressStreamEx(InStream, OutStream: TStream;
NumLevel: Integer; StreamType : TZStreamType; offset : int64;
length : int64); // May 3, 2011 Fastream.com
const
//64 KB buffer
BufSize = 65536;
var
strm : z_stream;
InBuf, OutBuf : PAnsiChar;
UseInBuf, UseOutBuf : boolean;
LastOutCount : integer;
Finished : boolean;
Cancel: boolean;
Totcount: int64;
toRead: integer; // May 3, 2011 Fastream.com
exitLoop: boolean; // May 3, 2011 Fastream.com
procedure WriteOut;
begin
if UseOutBuf then
begin
if LastOutCount > 0 then OutStream.Write(OutBuf^, LastOutCount -
strm.avail_out);
strm.avail_out := BufSize;
strm.next_out := OutBuf;
end
else
begin
if (strm.avail_out = 0) then ExpandStream(OutStream, OutStream.Size +
BufSize);
OutStream.Seek(LastOutCount - strm.avail_out, soFromCurrent);
strm.next_out := DMAOfStream(OutStream, strm.avail_out);
//because we can't really know how much resize is increasing!
end;
LastOutCount := strm.avail_out;
end;
begin
FillChar(strm, sizeof(strm), 0);
InBuf := nil;
OutBuf := nil;
LastOutCount := 0;
Totcount := 0;
exitLoop := false;
InStream.Seek(offset, soFromBeginning);
strm.next_in := DMAOfStream(InStream, strm.avail_in);
UseInBuf := strm.next_in = nil;
if UseInBuf then
GetMem(InBuf, BufSize);
UseOutBuf := not (CanResizeDMAStream(OutStream));
if UseOutBuf then GetMem(OutBuf, BufSize);
ZlibCCheck(deflateInitEx(strm, NumLevel, StreamType)); { V6.01 }
try
repeat
if strm.avail_in = 0 then
begin
if UseInBuf then
begin
toRead := BufSize; // May 3, 2011 Fastream.com
if totCount + BufSize > length then // May 3, 2011 Fastream.com
begin
toRead := length - totCount;
exitLoop := true;
end;
strm.avail_in := InStream.Read(InBuf^, toRead);
strm.next_in := InBuf;
end;
if strm.avail_in = 0 then break;
if exitLoop then break;
end;
if strm.avail_out = 0 then WriteOut;
ZlibCCheck(deflate(strm, Z_NO_FLUSH));
inc(Totcount, strm.avail_in); { V6.01 keep track of data read } //
May 3, 2011 Fastream.com
until false;
repeat
if strm.avail_out = 0 then WriteOut;
Finished := ZlibCCheck(deflate(strm, Z_FINISH)) = Z_STREAM_END;
WriteOut;
until Finished;
if not UseOutBuf then
begin
//truncate when using direct output
OutStream.Size := OutStream.Position;
end;
//adjust position of the input stream
if UseInBuf then
//seek back when unused data
InStream.Seek(-strm.avail_in, soFromCurrent)
else
//simple seek
InStream.Seek(strm.total_in, soFromCurrent);
ZlibCCheck(deflateEnd(strm));
finally
if InBuf <> nil then FreeMem(InBuf);
if OutBuf <> nil then FreeMem(OutBuf);
end;
end;
Regards,
SZ
On Tue, May 3, 2011 at 14:13, Angus Robertson - Magenta Systems Ltd <
[email protected]> wrote:
> > Here is a function I
> > wrote for ICSZlibHigh which takes that into consideration:
> >
> > procedure ZlibCompressStreamEx
>
> There is already a procedure of exactly that name in OverbyteIcsZlibHigh,
> although you appeared to have copied an old version or hacked it, so why
> do need to add it again?
>
> Or are you saying you have modified it in some way, without identifying
> the changes?
>
> Angus
>
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