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{ Copyright (C) <2010> <Andrew Haines> itfstransform.pas
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
for more details.
You should have received a copy of the GNU Library General Public License
along with this library; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301, USA.
}
{
See the file COPYING.modifiedLGPL, included in this distribution,
for details about the copyright.
}
unit ITSFTransform;
{ $DEFINE DEBUG_HELP2}
{$mode objfpc}{$H+}
interface
uses
Classes, paslzx, ITOLITLSTypes;
type
TGetObject = function(AName: String): TMemoryStream of object;
TITSFTransformList = class;
TITSFTransform = class;
{ TITSFTransform }
TITSFTransform = class
private
FDataStream: TStream;
FPrefix: String;
FParentTransform: TITSFTransform;
public
GetObject: TGetObject; // GetObject(Name: String): TMemoryStream;
OutStream: TMemoryStream;
constructor Create(AGetObject: TGetObject; AParentTransform: TITSFTransform); virtual;
function WantData(APrefix: String; ADataStream: TStream; const DataStart, DataLength: Integer; AOutStream: TMemoryStream): Boolean; virtual;
property ParentTransform : TITSFTransform read FParentTransform;
property Prefix: String read FPrefix write FPrefix;
property DataStream: TStream read FDataStream write FDataStream;
class function GUID: TGuid; virtual;
class function GUIDString: String; virtual;
end;
TITSFTransformClass = class of TITSFTransform;
{ TPlainTransform }
TPlainTransform = class(TITSFTransform)
function WantData(APrefix: String; ADataStream: TStream; const DataStart, DataLength: Integer; AOutStream: TMemoryStream): Boolean; override;
end;
{ TLZXv3Transform }
TLZXv3Transform = class(TITSFTransform)
private
Entries: array of QWord;
Data: TLZXv3ControlData;
Table: TLZXv3ResetTable;
function GetControlData: Boolean;
function GetResetTable: Boolean;
function FindChunkCompressedSize(AEntryIndex: Integer): DWord;
function FindFirstChunkFromOffset(AOffset, ASize: QWord; out ChunkCount: DWord): Integer;
function ExtractChunks(AFirstChunkIndex, AChunkCount: DWord; out ExtractedOffsetStart: QWord): TMemoryStream;
public
function WantData(APrefix: String; ADataStream: TStream; const DataStart, DataLength: Integer; AOutStream: TMemoryStream): Boolean; override;
class function GUID: TGuid; override;
end;
{ TITSFTransformList }
TITSFTransformList = class(TFPList)
private
function GetTransform(AGuid: TGuid): TITSFTransformClass;
function GetTransformIndex(AIndex: DWord): TITSFTransformClass;
function GetTransformInstance(AIndex: DWord): TITSFTransform;
procedure SetTransformInstance(AIndex: DWord; const AValue: TITSFTransform);
public
function AddTransform(ATransform: TITSFTransformClass): Integer;
procedure Delete(AIndex: Integer);
property Transform[AGuid: TGuid]: TITSFTransformClass read GetTransform;
property TransformIndex[AIndex: DWord]: TITSFTransformClass read GetTransformIndex;
property TransformInstance[AIndex: DWord]: TITSFTransform read GetTransformInstance write SetTransformInstance;
end;
function RegisteredTransforms: TITSFTransformList;
implementation
uses
SysUtils;
var
LocTransforms: TITSFTransformList = nil;
type
PITSFTranformItem = ^TITSFTranformItem;
TITSFTranformItem = record
//Guid: TGuid;
Transform: TITSFTransformClass;
Instance: TITSFTransform;
end;
function RegisteredTransforms: TITSFTransformList;
begin
if LocTransforms = nil then
LocTransforms := TITSFTransformList.Create;
Result := LocTransforms;
end;
{ TITSFTransform }
constructor TITSFTransform.Create(AGetObject: TGetObject; AParentTransform: TITSFTransform);
begin
GetObject:=AGetObject;
FParentTransform := AParentTransform;
end;
function TITSFTransform.WantData(APrefix: String; ADataStream: TStream;
const DataStart, DataLength: Integer; AOutStream: TMemoryStream): Boolean;
begin
Prefix := APrefix;
DataStream := ADataStream;
OutStream := AOutStream;
{$IFDEF DEBUG_HELP2}
WriteLn('WantData Class = ', ClassName);
{$ENDIF}
end;
class function TITSFTransform.GUID: TGuid;
const
AGuid: TGuid = '{00000000-0000-0000-0000-000000000000}';
begin
Result := AGuid;
end;
class function TITSFTransform.GUIDString: String;
begin
Result := GUIDToString(GUID);
end;
{ TITSFTransformList }
function TITSFTransformList.GetTransform(AGuid: TGuid): TITSFTransformClass;
var
Item: PITSFTranformItem;
i: Integer;
GUID: TGuid;
begin
Result := nil;
for i := 0 to Count-1 do
begin
Item := PITSFTranformItem(Items[i]);
GUID := Item^.Transform.GUID;
if CompareByte(GUID,AGuid, 16) = 0 then
Exit(Item^.Transform);
end;
end;
function TITSFTransformList.GetTransformIndex(AIndex: DWord): TITSFTransformClass;
begin
Result := PITSFTranformItem(Items[AIndex])^.Transform;
end;
function TITSFTransformList.GetTransformInstance(AIndex: DWord): TITSFTransform;
begin
Result := PITSFTranformItem(Items[AIndex])^.Instance;
end;
procedure TITSFTransformList.SetTransformInstance(AIndex: DWord;
const AValue: TITSFTransform);
begin
PITSFTranformItem(Items[AIndex])^.Instance := AValue;
end;
function TITSFTransformList.AddTransform(ATransform: TITSFTransformClass): Integer;
var
Item: PITSFTranformItem;
begin
if not Assigned(ATransform) then
Exit;
New(Item);
Item^.Transform:= ATransform;
Item^.Instance := nil;
Add(Item);
end;
procedure TITSFTransformList.Delete(AIndex: Integer);
var
Item: PITSFTranformItem;
begin
Item := PITSFTranformItem(Items[AIndex]);
Dispose(Item);
Inherited Delete(AIndex);
end;
{ TLZXv3Transform }
function TLZXv3Transform.FindFirstChunkFromOffset(AOffset, ASize: QWord; out ChunkCount: DWord): Integer;
var
EndChunk: DWord;
begin
Result := AOffset div Table.BlockSize;
EndChunk := (AOffset + ASize) div Table.BlockSize;
ChunkCount:=EndChunk-Result;
//if ChunkCount = 0 then
Inc(ChunkCount);
end;
function TLZXv3Transform.GetControlData: Boolean;
var
ControlDataStream: TStream;
ESize: LongWord;
begin
Result := False;
try
ControlDataStream := GetObject(Prefix+'ControlData');
if ControlDataStream = nil then
Exit;
ESize := NtoLE(ControlDataStream.ReadDWord);
while ESize <> 7 do
begin
ControlDataStream.Seek(ESize*4, soFromCurrent);
ESize := LEtoN(ControlDataStream.ReadDWord);
end;
if ESize = 7 then
ControlDataStream.Read(Data, SizeOf(TLZXv3ControlData));
finally
if Assigned(ControlDataStream) then
ControlDataStream.Free;
end;
Result := ESize = 7;
//WriteLn('GetControlData = ', REsult);
end;
function TLZXv3Transform.GetResetTable: Boolean;
var
WholePrefix: String;
ResetStream: TStream;
{$IFDEF ENDIAN_BIG}
i: Integer;
{$ENDIF}
begin
Result := False;
WholePrefix:=Prefix+'Transform/'+GUIDString+'/';
ResetStream := GetObject(WholePrefix+'InstanceData/ResetTable');
if ResetStream = nil then
Exit;
ResetStream.Read(Table, SizeOf(TLZXv3ResetTable));
SetLength(Entries, Table.EntryCount);
ResetStream.Read(Entries[0], Table.EntryCount*8);
{$IFDEF ENDIAN_BIG}
for i := Low(Entries) to High(Entries) do
Entries[i] := LEtoN(Entries[i]);
{$ENDIF}
{$IFDEF DEBUG_HELP2}
//for i := Low(Entries) to High(Entries) do
// WriteLn('Entry[',i,'] = ',Entries[i] ,' UnCompressStart = ', i*$8000);
{$ENDIF}
ResetStream.Free;
Result := True;
end;
function TLZXv3Transform.FindChunkCompressedSize(AEntryIndex: Integer): DWord;
begin
if AEntryIndex < High(Entries) then
Result := Entries[AEntryIndex+1] - Entries[AEntryIndex]
else
Result := DataStream.Size-Entries[AEntryIndex];
end;
function TLZXv3Transform.ExtractChunks(AFirstChunkIndex, AChunkCount: DWord;
out ExtractedOffsetStart: QWord): TMemoryStream;
var
LZX: PLZXState;
CStart,
CSize: DWord;
//CBuf: Pointer;
Buf: TMemoryStream;
CBuf: Pointer;
UBuf: Pointer;
USize: Dword;
URes: DWord;
WinCode: DWord;
WinSize: QWord;
BlockMask: Byte;
begin
BlockMask := (Data.ResetInterval shl 1) - 1;
// must start on a even numbered block
while (AFirstChunkIndex mod Data.ResetInterval <> 0) and (AFirstChunkIndex > 0) do
begin
Dec(AFirstChunkIndex);
Inc(AChunkCount);
end;
ExtractedOffsetStart := Table.BlockSize*AFirstChunkIndex;
{$IFDEF DEBUG_HELP2}
WriteLn('Getting Data, StartChunk=', AFirstChunkIndex,' Count = ', AChunkCount);
WriteLn('Version = ', Data.Version);
WriteLn('Window Size = ',Data.WindowSize);
WriteLn('Block Size = ',Hexstr(Table.BlockSize,16));
WriteLn('Block Size = ',Table.BlockSize);
{$ENDIF}
WinSize := (Data.WindowSize * Table.BlockSize);
WinCode := 0;
while WinSize > 1 do
begin
Inc(WinCode);
//WriteLn(HexStr(WinSize, 16));
WinSize := WinSize shr 1;
end;
LZX := LZXinit(WinCode);//ata.WindowSize);
CBuf := GetMem(Table.BlockSize);
UBuf := GetMem(Table.BlockSize);
Result := TMemoryStream.Create;
Buf := TMemoryStream.Create;
CStart := Entries[AFirstChunkIndex];
CSize := Entries[AFirstChunkIndex+AChunkCount]+FindChunkCompressedSize(AFirstChunkIndex+AChunkCount);
ParentTransform.WantData(Prefix, DataStream, CStart, CSize, Buf);
Buf.Position:=0;
while AChunkCount > 0 do
begin
Dec(AChunkCount);
CSize := FindChunkCompressedSize(AFirstChunkIndex);
CSize := Buf.Read(CBuf^, CSize);
if AFirstChunkIndex mod Data.ResetInterval = 0 then
begin
LZXreset(LZX);
{$IFDEF DEBUG_HELP2}
WriteLn('Reset LZX Window');
{$ENDIF}
end;
URes := LZXdecompress(LZX, CBuf, UBuf, CSize, Table.BlockSize);
//CBuf.Size := 0;
{$IFDEF DEBUG_HELP2}
WriteLn('Decompress = ', URes);
{$ENDIF}
Result.Write(UBuf^, Table.BlockSize);
Inc(AFirstChunkIndex);
end;
Buf.Free;
Freemem(UBuf);
Freemem(CBuf);
Result.Position:=0;
LZXteardown(LZX);
end;
function TLZXv3Transform.WantData(APrefix: String; ADataStream: TStream; const DataStart,
DataLength: Integer; AOutStream: TMemoryStream): Boolean;
var
LZXData: TLZXv3ControlData;
ResetTable: TLZXv3ResetTable;
ChunkStart,
ChunkCount: DWord;
RawChunks: TStream;
ChunkDataStart: QWord;
begin
inherited WantData(APrefix, ADataStream, DataStart, DataLength, AOutStream);
{$IFDEF DEBUG_HELP2}
WriteLn('WantData Pre=',APrefix,' DS=', DataStart,' DL=',DataLength);
{$ENDIF}
Result := False;
if not (GetControlData and GetResetTable) then
Exit;
{$IFDEF DEBUG_HELP2}
WriteLn('Got Needed Info');
{$ENDIF}
ChunkStart := FindFirstChunkFromOffset(DataStart,DataLength, ChunkCount);
RawChunks := ExtractChunks(ChunkStart, ChunkCount, ChunkDataStart);
RawChunks.Position := DataStart-ChunkDataStart;
AOutStream.CopyFrom(RawChunks, DataLength);
RawChunks.Free;
Result := True;
end;
class function TLZXv3Transform.GUID: TGuid;
const
AGuid: TGuid = '{0A9007C6-4076-11D3-8789-0000F8105754}';
begin
Result := AGuid;
end;
{ TPlainTransform }
function TPlainTransform.WantData(APrefix: String; ADataStream: TStream; const DataStart, DataLength: Integer;
AOutStream: TMemoryStream): Boolean;
begin
inherited WantData(APrefix, ADataStream, DataStart, DataLength, AOutStream);
ADataStream.Position:=DataStart;
AOutStream.CopyFrom(ADataStream, DataLength);
Result := True;
end;
initialization
RegisteredTransforms.AddTransform(TPlainTransform);
RegisteredTransforms.AddTransform(TLZXv3Transform);
finalization
if Assigned(LocTransforms) then
LocTransforms.Free;
end.
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