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@@ -0,0 +1,388 @@
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+unit zstream;
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+
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+interface
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+
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+uses Sysutils, Classes,zlib;
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+
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+type
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+ // Error reporting.
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+
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+ EZlibError = class(Exception);
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+ ECompressionError = class(EZlibError);
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+ EDecompressionError = class(EZlibError);
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+
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+ TCustomZlibStream = class(TStream)
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+ private
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+ FStrm: TStream;
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+ FStrmPos: Integer;
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+ FOnProgress: TNotifyEvent;
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+ FZRec: TZStream;
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+ FBuffer: array [Word] of Char;
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+ protected
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+ procedure Progress(Sender: TObject); dynamic;
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+ property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
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+ constructor Create(Strm: TStream);
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+ end;
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+
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+ TCompressionLevel = (clNone, clFastest, clDefault, clMax);
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+
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+ TCompressionStream = class(TCustomZlibStream)
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+ private
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+ function GetCompressionRate: extended;
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+ public
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+ constructor Create(CompressionLevel: TCompressionLevel; Dest: TStream);
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+ destructor Destroy; override;
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+ function CompressionCheck(code: Integer): Integer;
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+ procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;
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+ var OutBuf: Pointer; var OutBytes: Integer);
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+ function Read(var Buffer; Count: Longint): Longint; override;
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+ function Write(const Buffer; Count: Longint): Longint; override;
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+ function Seek(Offset: Longint; Origin: Word): Longint; override;
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+ property CompressionRate: extended read GetCompressionRate;
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+ property OnProgress;
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+ end;
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+
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+ TDecompressionStream = class(TCustomZlibStream)
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+ public
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+ constructor Create(Source: TStream);
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+ destructor Destroy; override;
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+ function DecompressionCheck(code: Integer): Integer;
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+ procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;
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+ OutEstimate: Integer; var OutBuf: Pointer; var OutBytes: Integer);
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+ function Read(var Buffer; Count: Longint): Longint; override;
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+ function Write(const Buffer; Count: Longint): Longint; override;
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+ function Seek(Offset: Longint; Origin: Word): Longint; override;
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+ property OnProgress;
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+ end;
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+
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+
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+implementation
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+
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+Const
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+ ErrorStrings : array [0..6] of string =
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+ ('Unknown error %d','Z_ERRNO','Z_STREAM_ERROR',
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+ 'Z_DATA_ERROR','Z_MEM_ERROR','Z_BUF_ERROR','Z_VERSION_ERROR');
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+
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+Type PLongint = ^Longint;
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+
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+Function DGetmem (Size : Longint) : pointer;
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+begin
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+ Inc(Size,SizeOf(Longint));
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+ GetMem(Result,Size);
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+ If Result<>Nil then
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+ begin
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+ Plongint(Result)^:=Size;
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+ Inc(Result,SizeOf(Integer));
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+ end;
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+end;
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+
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+Procedure DFreeMem(P : Pointer);
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+begin
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+ // Get Stored length
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+ Dec(P,SizeOf(Integer));
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+ FreeMem(P,Plongint(P)^);
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+end;
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+
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+Procedure DReallocMem (var P : Pointer; NewSize : Longint);
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+ // Reallocates memory pointed to by P.
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+Var T : pointer;
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+ OldSize : longint;
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+begin
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+ // Should raise an exception if no memory.
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+ T:=DGetMem(NewSize);
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+ OldSize:=PLongint(P-SizeOf(Integer))^;
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+ If oldSize<NewSize then
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+ Move(P^,T^,OldSize)
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+ else
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+ Move(P^,T^,NewSize);
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+ DFreeMem(P);
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+end;
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+
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+function zlibAllocMem(AppData: Pointer; Items, Size: Integer): Pointer;cdecl;
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+begin
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+ Result:=DGetMem(Items*Size);
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+end;
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+
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+procedure zlibFreeMem(AppData, Block: Pointer);cdecl;
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+begin
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+ DFreeMem(Block);
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+end;
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+
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+
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+procedure TCompressionStream.CompressBuf(const InBuf: Pointer; InBytes: Integer;
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+ var OutBuf: Pointer; var OutBytes: Integer);
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+var
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+ strm: TZStream;
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+ P: Pointer;
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+ oldout : longint;
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+begin
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+ FillChar(strm, sizeof(strm), 0);
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+ strm.zalloc := @zlibAllocMem;
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+ strm.zfree := @zlibFreeMem;
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+ OutBytes := ((InBytes + (InBytes div 10) + 12) + 255) and not 255;
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+ OutBuf:=DGetMem(OutBytes);
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+ try
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+ strm.next_in := InBuf;
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+ strm.avail_in := InBytes;
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+ strm.next_out := OutBuf;
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+ strm.avail_out := OutBytes;
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+ CompressionCheck(deflateInit_(strm, Z_BEST_COMPRESSION, zlibversion, sizeof(strm)));
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+ try
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+ while CompressionCheck(deflate(strm, Z_FINISH)) <> Z_STREAM_END do
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+ begin
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+ P := OutBuf;
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+ Inc(OutBytes, 256);
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+ DReallocMem(OutBuf,OutBytes);
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+ strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
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+ strm.avail_out := 256;
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+ end;
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+ finally
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+ CompressionCheck(deflateEnd(strm));
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+ end;
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+ DReallocMem(OutBuf,strm.total_out);
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+ OutBytes := strm.total_out;
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+ except
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+ DFreeMem(OutBuf);
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+ raise;
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+ end;
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+end;
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+
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+
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+procedure TDecompressionStream.DecompressBuf(const InBuf: Pointer; InBytes: Integer;
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+ OutEstimate: Integer; var OutBuf: Pointer; var OutBytes: Integer);
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+var
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+ strm: TZStream;
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+ P: Pointer;
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+ BufInc: Integer;
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+begin
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+ FillChar(strm, sizeof(strm), 0);
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+ strm.zalloc := @zlibAllocMem;
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+ strm.zfree := @zlibFreeMem;
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+ BufInc := (InBytes + 255) and not 255;
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+ if OutEstimate = 0 then
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+ OutBytes := BufInc
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+ else
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+ OutBytes := OutEstimate;
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+ OutBuf:=DGetMem(OutBytes);
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+ try
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+ strm.next_in := InBuf;
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+ strm.avail_in := InBytes;
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+ strm.next_out := OutBuf;
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+ strm.avail_out := OutBytes;
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+ DecompressionCheck(inflateInit_(strm, zlibversion, sizeof(strm)));
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+ try
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+ while DecompressionCheck(inflate(strm, Z_FINISH)) <> Z_STREAM_END do
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+ begin
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+ P := OutBuf;
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+ Inc(OutBytes, BufInc);
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+ DReallocMem(OutBuf, OutBytes);
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+ strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
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+ strm.avail_out := BufInc;
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+ end;
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+ finally
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+ DecompressionCheck(inflateEnd(strm));
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+ end;
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+ DReallocMem(OutBuf, strm.total_out);
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+ OutBytes := strm.total_out;
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+ except
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+ DFreeMem(OutBuf);
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+ raise;
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+ end;
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+end;
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+
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+
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+// TCustomZlibStream
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+
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+constructor TCustomZLibStream.Create(Strm: TStream);
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+begin
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+ inherited Create;
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+ FStrm := Strm;
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+ FStrmPos := Strm.Position;
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+ FZRec.zalloc := @zlibAllocMem;
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+ FZRec.zfree := @zlibFreeMem;
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+end;
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+
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+procedure TCustomZLibStream.Progress(Sender: TObject);
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+begin
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+ if Assigned(FOnProgress) then FOnProgress(Sender);
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+end;
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+
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+
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+// TCompressionStream
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+
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+constructor TCompressionStream.Create(CompressionLevel: TCompressionLevel;
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+ Dest: TStream);
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+const
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+ Levels: array [TCompressionLevel] of ShortInt =
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+ (Z_NO_COMPRESSION, Z_BEST_SPEED, Z_DEFAULT_COMPRESSION, Z_BEST_COMPRESSION);
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+begin
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+ inherited Create(Dest);
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+ FZRec.next_out := FBuffer;
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+ FZRec.avail_out := sizeof(FBuffer);
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+ CompressionCheck(deflateInit_(FZRec, Levels[CompressionLevel], zlibversion, sizeof(FZRec)));
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+end;
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+
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+destructor TCompressionStream.Destroy;
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+begin
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+ FZRec.next_in := nil;
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+ FZRec.avail_in := 0;
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+ try
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+ if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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+ while (CompressionCheck(deflate(FZRec, Z_FINISH)) <> Z_STREAM_END)
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+ and (FZRec.avail_out = 0) do
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+ begin
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+ FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
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+ FZRec.next_out := FBuffer;
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+ FZRec.avail_out := sizeof(FBuffer);
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+ end;
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+ if FZRec.avail_out < sizeof(FBuffer) then
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+ FStrm.WriteBuffer(FBuffer, sizeof(FBuffer) - FZRec.avail_out);
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+ finally
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+ deflateEnd(FZRec);
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+ end;
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+ inherited Destroy;
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+end;
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+
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+function TCompressionStream.CompressionCheck(code: Integer): Integer;
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+begin
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+ Result := code;
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+ if (code < 0) then
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+ if code < -6 then
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+ raise ECompressionError.CreateFmt(Errorstrings[0],[Code])
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+ else
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+ raise ECompressionError.Create(ErrorStrings[Abs(Code)]);
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+end;
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+
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+
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+function TCompressionStream.Read(var Buffer; Count: Longint): Longint;
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+begin
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+ raise ECompressionError.Create('Invalid stream operation');
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+end;
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+
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+function TCompressionStream.Write(const Buffer; Count: Longint): Longint;
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+begin
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+ FZRec.next_in := @Buffer;
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+ FZRec.avail_in := Count;
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+ if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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+ while (FZRec.avail_in > 0) do
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+ begin
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+ CompressionCheck(deflate(FZRec, 0));
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+ if FZRec.avail_out = 0 then
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+ begin
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+ FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
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+ FZRec.next_out := FBuffer;
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+ FZRec.avail_out := sizeof(FBuffer);
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+ FStrmPos := FStrm.Position;
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+ Progress(Self);
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+ end;
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+ end;
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+ Result := Count;
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+end;
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+
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+function TCompressionStream.Seek(Offset: Longint; Origin: Word): Longint;
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+begin
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+ if (Offset = 0) and (Origin = soFromCurrent) then
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+ Result := FZRec.total_in
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+ else
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+ raise ECompressionError.Create('Invalid stream operation');
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+end;
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+
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+function TCompressionStream.GetCompressionRate: extended;
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+begin
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+ Result:=0.0;
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+{ With FZrec do
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+ if total_in = 0 then
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+ GetCompressionRate:=0.0
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+ else
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+ GetCompressionRate:=1.0E2*(1.0E0-(total_out/total_in));
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+}
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+end;
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+
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+
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+// TDecompressionStream
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+
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+constructor TDecompressionStream.Create(Source: TStream);
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+begin
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+ inherited Create(Source);
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+ FZRec.next_in := FBuffer;
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+ FZRec.avail_in := 0;
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+ DecompressionCheck(inflateInit_(FZRec, zlibversion, sizeof(FZRec)));
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+end;
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+
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+destructor TDecompressionStream.Destroy;
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+begin
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+ inflateEnd(FZRec);
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+ inherited Destroy;
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+end;
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+
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+function TDecompressionStream.DecompressionCheck(code: Integer): Integer;
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+begin
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+ Result := code;
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+ If Code<0 then
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+ if code < -6 then
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+ raise EDecompressionError.CreateFmt(Errorstrings[0],[Code])
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+ else
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+ raise EDecompressionError.Create(ErrorStrings[Abs(Code)]);
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+end;
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+
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+function TDecompressionStream.Read(var Buffer; Count: Longint): Longint;
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+begin
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+ FZRec.next_out := @Buffer;
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+ FZRec.avail_out := Count;
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+ if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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+ while (FZRec.avail_out > 0) do
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+ begin
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+ if FZRec.avail_in = 0 then
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+ begin
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+ FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer));
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+ if FZRec.avail_in = 0 then
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+ begin
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+ Result := Count - FZRec.avail_out;
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+ Exit;
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+ end;
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+ FZRec.next_in := FBuffer;
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+ FStrmPos := FStrm.Position;
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+ Progress(Self);
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+ end;
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+ DeCompressionCheck(inflate(FZRec, 0));
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+ end;
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+ Result := Count;
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+end;
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+
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+function TDecompressionStream.Write(const Buffer; Count: Longint): Longint;
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+begin
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+ raise EDecompressionError.Create('Invalid stream operation');
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+end;
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+
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+function TDecompressionStream.Seek(Offset: Longint; Origin: Word): Longint;
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+var
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+ I: Integer;
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+ Buf: array [0..4095] of Char;
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+begin
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+ if (Offset = 0) and (Origin = soFromBeginning) then
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+ begin
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+ DecompressionCheck(inflateReset(FZRec));
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+ FZRec.next_in := FBuffer;
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+ FZRec.avail_in := 0;
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+ FStrm.Position := 0;
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+ FStrmPos := 0;
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+ end
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+ else if ( (Offset >= 0) and (Origin = soFromCurrent)) or
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+ ( ((Offset - FZRec.total_out) > 0) and (Origin = soFromBeginning)) then
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+ begin
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+ if Origin = soFromBeginning then Dec(Offset, FZRec.total_out);
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+ if Offset > 0 then
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+ begin
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+ for I := 1 to Offset div sizeof(Buf) do
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+ ReadBuffer(Buf, sizeof(Buf));
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+ ReadBuffer(Buf, Offset mod sizeof(Buf));
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+ end;
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+ end
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+ else
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+ raise EDecompressionError.Create('Invalid stream operation');
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+ Result := FZRec.total_out;
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+end;
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+
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+
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+
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+end.
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michael