lazarus/components/chmhelp/packages/chm/chmreader.pas
andrew cdae7c2e28 Added some stuff for chmwriting
git-svn-id: trunk@11390 -
2007-06-27 10:51:53 +00:00

1034 lines
32 KiB
ObjectPascal

{ Copyright (C) <2005> <Andrew Haines> chmreader.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
}
{
See the file COPYING.modifiedLGPL, included in this distribution,
for details about the copyright.
}
unit chmreader;
{$mode objfpc}{$H+}
{$DEFINE CHM_DEBUG}
interface
uses
Classes, SysUtils, chmbase, paslzx;
type
TLZXResetTableArr = array of QWord;
PContextItem = ^TContextItem;
TContextItem = record
Context: THelpContext;
Url: String;
end;
TContextList = class(TList)
public
procedure AddContext(Context: THelpContext; Url: String);
function GetURL(Context: THelpContext): String;
procedure Clear; override;
end;
{ TChmReader }
TChmReader = class(TObject)
fStream: TStream;
fFreeStreamOnDestroy: Boolean;
fChmHeader: TITSFHeader;
fHeaderSuffix: TITSFHeaderSuffix;
fDirectoryHeader: TITSPHeader;
fDirectoryHeaderPos: Int64;
fDirectoryHeaderLength: QWord;
fDirectoryEntriesStartPos: Int64;
fDirectoryEntries: array of TPMGListChunkEntry;
fCachedEntry: TPMGListChunkEntry; //contains the last entry found by ObjectExists
fDirectoryEntriesCount: LongWord;
fDefaultPage: String;
fIndexFile: String;
fTOCFile: String;
fTitle: String;
fPreferedFont: String;
fContextList: TContextList;
fLocaleID: DWord;
private
procedure ReadHeader;
procedure ReadCommonData;
function GetChunkType(Stream: TMemoryStream; ChunkIndex: LongInt): TPMGchunktype;
procedure LookupPMGLchunk(Stream: TMemoryStream; ChunkIndex: LongInt; out PMGLChunk: TPMGListChunk);
function ReadPMGLchunkEntryFromStream(Stream: TMemoryStream; var PMGLEntry: TPMGListChunkEntry): Boolean;
procedure LookupPMGIchunk(Stream: TMemoryStream; ChunkIndex: LongInt; out PMGIChunk: TPMGIIndexChunk);
function ReadPMGIchunkEntryFromStream(Stream: TMemoryStream; var PMGIEntry: TPMGIIndexChunkEntry): Boolean;
procedure FillDirectoryEntries(StartCount: Integer);
procedure GetSections(out Sections: TStringList);
function GetBlockFromSection(SectionPrefix: String; StartPos: QWord; BlockLength: QWord): TMemoryStream;
function FindBlocksFromUnCompressedAddr(var ResetTableEntry: TPMGListChunkEntry;
out CompressedSize: Int64; out UnCompressedSize: Int64; out LZXResetTable: TLZXResetTableArr): QWord; // Returns the blocksize
public
constructor Create(AStream: TStream; FreeStreamOnDestroy: Boolean);
destructor Destroy; override;
public
ChmLastError: LongInt;
function IsValidFile: Boolean;
procedure GetCompleteFileList(var Strings: TStrings);
function ObjectExists(Name: String): QWord; // zero if no. otherwise it is the size of the object
// NOTE directories will return zero size even if they exist
function GetObject(Name: String): TMemoryStream; // YOU must Free the stream
function GetContextUrl(Context: THelpContext): String;
function HasContextList: Boolean;
property DefaultPage: String read fDefaultPage;
property IndexFile: String read fIndexFile;
property TOCFile: String read fTOCFile;
property Title: String read fTitle write fTitle;
property PreferedFont: String read fPreferedFont;
property LocaleID: dword read fLocaleID;
end;
{ TChmFileList }
TChmFileList = class;
TChmFileOpenEvent = procedure(ChmFileList: TChmFileList; Index: Integer) of object;
TChmFileList = class(TStringList)
protected
fLastChm: TChmReader;
fUnNotifiedFiles: TList;
fOnOpenNewFile: TChmFileOpenEvent;
procedure Delete(Index: Integer); override;
function GetChm(AIndex: Integer): TChmReader;
function GetFileName(AIndex: Integer): String;
procedure OpenNewFile(AFileName: String);
function CheckOpenFile(AFileName: String): Boolean;
function MetaObjectExists(var Name: String): QWord;
function MetaGetObject(Name: String): TMemoryStream;
procedure SetOnOpenNewFile(AValue: TChmFileOpenEvent);
public
constructor Create(PrimaryFileName: String);
destructor Destroy;
function GetObject(Name: String): TMemoryStream;
function IsAnOpenFile(AFileName: String): Boolean;
function ObjectExists(Name: String; fChm: TChmReader = nil): QWord;
//properties
property Chm[Index: Integer]: TChmReader read GetChm;
property FileName[Index: Integer]: String read GetFileName;
property OnOpenNewFile: TChmFileOpenEvent read fOnOpenNewFile write SetOnOpenNewFile;
end;
//ErrorCodes
const
ERR_NO_ERR = 0;
ERR_STREAM_NOT_ASSIGNED = 1;
ERR_NOT_SUPPORTED_VERSION = 2;
ERR_NOT_VALID_FILE = 3;
ERR_UNKNOWN_ERROR = 10;
function ChmErrorToStr(Error: Integer): String;
implementation
function ChmErrorToStr(Error: Integer): String;
begin
Result := '';
case Error of
ERR_STREAM_NOT_ASSIGNED : Result := 'ERR_STREAM_NOT_ASSIGNED';
ERR_NOT_SUPPORTED_VERSION : Result := 'ERR_NOT_SUPPORTED_VERSION';
ERR_NOT_VALID_FILE : Result := 'ERR_NOT_VALID_FILE';
ERR_UNKNOWN_ERROR : Result := 'ERR_UNKNOWN_ERROR';
end;
end;
{ TChmReader }
procedure TChmReader.ReadHeader;
var
fHeaderEntries: array [0..1] of TITSFHeaderEntry;
begin
fStream.Position := 0;
fStream.Read(fChmHeader,SizeOf(fChmHeader));
// Fix endian issues
{$IFDEF ENDIAN_BIG}
fChmHeader.Version := LEtoN(fChmHeader.Version);
fChmHeader.HeaderLength := LEtoN(fChmHeader.HeaderLength);
//Unknown_1
fChmHeader.TimeStamp := BEtoN(fChmHeader.TimeStamp);//bigendian
fChmHeader.LanguageID := LEtoN(fChmHeader.LanguageID);
//Guid1
//Guid2
{$ENDIF}
if not IsValidFile then Exit;
// Copy EntryData into memory
fStream.Read(fHeaderEntries[0], SizeOf(fHeaderEntries));
if fChmHeader.Version > 2 then
fStream.Read(fHeaderSuffix.Offset, SizeOf(QWord));
fHeaderSuffix.Offset := LEtoN(fHeaderSuffix.Offset);
// otherwise this is set in fill directory entries
fStream.Position := LEtoN(fHeaderEntries[1].PosFromZero);
fDirectoryHeaderPos := LEtoN(fHeaderEntries[1].PosFromZero);
fStream.Read(fDirectoryHeader, SizeOf(fDirectoryHeader));
{$IFDEF ENDIAN_BIG}
with fDirectoryHeader do begin
Version := LEtoN(Version);
DirHeaderLength := LEtoN(DirHeaderLength);
//Unknown1
ChunkSize := LEtoN(ChunkSize);
Density := LEtoN(Density);
IndexTreeDepth := LEtoN(IndexTreeDepth);
IndexOfRootChunk := LEtoN(IndexOfRootChunk);
FirstPMGLChunkIndex := LEtoN(FirstPMGLChunkIndex);
LastPMGLChunkIndex := LEtoN(LastPMGLChunkIndex);
//Unknown2
DirectoryChunkCount := LEtoN(DirectoryChunkCount);
LanguageID := LEtoN(LanguageID);
//GUID: TGuid;
LengthAgain := LEtoN(LengthAgain);
end;
{$ENDIF}
fDirectoryEntriesStartPos := fStream.Position;
fDirectoryHeaderLength := LEtoN(fHeaderEntries[1].Length);
end;
procedure TChmReader.ReadCommonData;
// A little helper proc to make reading a null terminated string easier
function ReadString(const Stream: TStream): String;
var
buf: array[0..49] of char;
begin
Result := '';
repeat
Stream.Read(buf, 50);
Result := Result + buf;
until Pos(#0, buf) > -1;
end;
procedure ReadFromSystem;
var
//Version: DWord;
EntryType: Word;
EntryLength: Word;
Data: array[0..511] of char;
fSystem: TMemoryStream;
Tmp: String;
begin
fSystem := TMemoryStream(GetObject('/#SYSTEM'));
if fSystem = nil then begin
exit;
end;
fSystem.Position := 0;
if fSystem.Size < SizeOf(DWord) then begin
fSystem.Free;
Exit;
end;
{Version := }LEtoN(fSystem.ReadDWord);
while fSystem.Position < fSystem.Size do begin
EntryType := LEtoN(fSystem.ReadWord);
EntryLength := LEtoN(fSystem.ReadWord);
case EntryType of
0: // Table of contents
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
fTOCFile := '/'+Data;
end;
1: // Index File
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
fIndexFile := '/'+Data;
end;
2: // DefaultPage
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
fDefaultPage := '/'+Data;
end;
3: // Title of chm
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
fTitle := Data;
end;
4: // Locale ID
begin
fLocaleID := LEtoN(fSystem.ReadDWord);
fSystem.Position := (fSystem.Position + EntryLength) - SizeOf(DWord);
end;
6: // chm file name. use this to get the index and toc name
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
if (fIndexFile = '') then begin
Tmp := '/'+Data+'.hhk';
if (ObjectExists(Tmp) > 0) then begin
fIndexFile := Tmp;
end
end;
if (fTOCFile = '') then begin
Tmp := '/'+Data+'.hhc';
if (ObjectExists(Tmp) > 0) then begin
fTOCFile := Tmp;
end;
end;
end;
16: // Prefered font
begin
if EntryLength > 511 then EntryLength := 511;
fSystem.Read(Data[0], EntryLength);
Data[EntryLength] := #0;
fPreferedFont := Data;
end;
else
// Skip entries we are not interested in
fSystem.Position := fSystem.Position + EntryLength;
end;
end;
fSystem.Free;
end;
procedure ReadFromWindows;
var
fWindows,
fStrings: TMemoryStream;
EntryCount,
EntrySize: DWord;
EntryStart: Int64;
StrPosition: DWord;
X: Integer;
OffSet: Int64;
begin
fWindows := TMemoryStream(GetObject('/#WINDOWS'));
if fWindows = nil then begin
exit;
end;
fStrings := TMemoryStream(GetObject('/#STRINGS'));
if fStrings = nil then begin
if fWindows <> nil then fWindows.Free;
Exit;
end;
fWindows.Position := 0;
if (fWindows.Size = 0) or (fStrings.Size = 0) then begin
fWindows.Free;
fStrings.Free;
Exit;
end;
EntryCount := LEtoN(fWindows.ReadDWord);
EntrySize := LEtoN(fWindows.ReadDWord);
OffSet := fWindows.Position;
for X := 0 to EntryCount -1 do begin
EntryStart := OffSet + (X*EntrySize);
if fTitle = '' then begin
fWindows.Position := EntryStart + $14;
StrPosition := LEtoN(fWindows.ReadDWord);
fStrings.Position := StrPosition;
fTitle := '/'+ReadString(fStrings);
end;
if fTOCFile = '' then begin
fWindows.Position := EntryStart + $60;
StrPosition := LEtoN(fWindows.ReadDWord);
fStrings.Position := StrPosition;
fTOCFile := '/'+ReadString(fStrings);
end;
if fIndexFile = '' then begin
fWindows.Position := EntryStart + $64;
StrPosition := LEtoN(fWindows.ReadDWord);
fStrings.Position := StrPosition;
fIndexFile := '/'+ReadString(fStrings);
end;
if fDefaultPage = '' then begin
fWindows.Position := EntryStart + $68;
StrPosition := LEtoN(fWindows.ReadDWord);
fStrings.Position := StrPosition;
fDefaultPage := '/'+ReadString(fStrings);
end;
end;
end;
procedure ReadContextIds;
var
fIVB,
fStrings: TStream;
Str: String;
Value: DWord;
OffSet: DWord;
//TotalSize: DWord;
begin
fIVB := GetObject('/#IBV');
if fIVB = nil then Exit;
fStrings := GetObject('/#STRINGS');
if fStrings = nil then begin
fIVB.Free;
Exit;
end;
fIVB.Position := 0;
{TotalSize := }LEtoN(fIVB.ReadDWord);
while fIVB.Position < fIVB.Size do begin
Value := LEtoN(fIVB.ReadDWord);
OffSet := LEtoN(fIVB.ReadDWord);
fStrings.Position := Offset;
Str := '/'+ReadString(fStrings);
fContextList.AddContext(Value, Str);
end;
end;
begin
ReadFromSystem;
ReadFromWindows;
ReadContextIds;
{$IFDEF CHM_DEBUG}
WriteLn('TOC=',fTocfile);
WriteLn('DefaultPage=',fDefaultPage);
{$ENDIF}
end;
function TChmReader.GetChunkType(Stream: TMemoryStream; ChunkIndex: LongInt): TPMGchunktype;
var
Sig: array[0..3] of char;
begin
Result := ctUnknown;
Stream.Position := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * ChunkIndex);
Stream.Read(Sig, 4);
if Sig = 'PMGL' then Result := ctPMGL
else if Sig = 'PMGI' then Result := ctPMGI;
end;
procedure TChmReader.LookupPMGLchunk(Stream: TMemoryStream; ChunkIndex: LongInt; out PMGLChunk: TPMGListChunk);
begin
Stream.Position := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * ChunkIndex);
Stream.Read(PMGLChunk, SizeOf(PMGLChunk));
{$IFDEF ENDIAN_BIG}
with PMGLChunk do begin
UnusedSpace := LEtoN(UnusedSpace);
//Unknown1
PreviousChunkIndex := LEtoN(PreviousChunkIndex);
NextChunkIndex := LEtoN(NextChunkIndex);
end;
{$ENDIF}
end;
function TChmReader.ReadPMGLchunkEntryFromStream(Stream: TMemoryStream; var PMGLEntry: TPMGListChunkEntry): Boolean;
var
Buf: array [0..1023] of char;
NameLength: LongInt;
begin
Result := False;
//Stream.Position := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * ChunkIndex);
NameLength := LongInt(GetCompressedInteger(Stream));
if NameLength > 1023 then NameLength := 1023;
Stream.Read(buf, NameLength);
buf[NameLength] := #0;
PMGLEntry.Name := buf;
PMGLEntry.ContentSection := LongWord(GetCompressedInteger(Stream));
PMGLEntry.ContentOffset := GetCompressedInteger(Stream);
PMGLEntry.DecompressedLength := GetCompressedInteger(Stream);
if NameLength = 0 then Exit; // failed GetCompressedInteger sanity check
Result := True;
end;
procedure TChmReader.LookupPMGIchunk(Stream: TMemoryStream; ChunkIndex: LongInt; out
PMGIChunk: TPMGIIndexChunk);
begin
Stream.Position := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * ChunkIndex);
Stream.Read(PMGIChunk, SizeOf(PMGIChunk));
{$IFDEF ENDIAN_BIG}
with PMGIChunk do begin
UnusedSpace := LEtoN(UnusedSpace);
end;
{$ENDIF}
end;
function TChmReader.ReadPMGIchunkEntryFromStream(Stream: TMemoryStream;
var PMGIEntry: TPMGIIndexChunkEntry): Boolean;
var
Buf: array [0..1023] of char;
NameLength: LongInt;
begin
Result := False;
//Stream.Position := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * ChunkIndex);
NameLength := LongInt(GetCompressedInteger(Stream));
if NameLength > 1023 then NameLength := 1023;
Stream.Read(buf, NameLength);
buf[NameLength] := #0;
PMGIEntry.Name := buf;
PMGIEntry.ListingChunk := GetCompressedInteger(Stream);
if NameLength = 0 then Exit; // failed GetCompressedInteger sanity check
Result := True;
end;
constructor TChmReader.Create(AStream: TStream; FreeStreamOnDestroy: Boolean);
begin
fStream := AStream;
fFreeStreamOnDestroy := FreeStreamOnDestroy;
ReadHeader;
if not IsValidFile then Exit;
FillDirectoryEntries(4096); // the default size of the array
fContextList := TContextList.Create;
ReadCommonData;
end;
destructor TChmReader.Destroy;
begin
SetLength(fDirectoryEntries, 0);
if fFreeStreamOnDestroy then FreeAndNil(fStream);
fContextList.Free;
inherited Destroy;
end;
function TChmReader.IsValidFile: Boolean;
begin
if (fStream = nil) then ChmLastError := ERR_STREAM_NOT_ASSIGNED
else if (fChmHeader.ITSFsig <> 'ITSF') then ChmLastError := ERR_NOT_VALID_FILE
else if (fChmHeader.Version <> 2) and (fChmHeader.Version <> 3) then
ChmLastError := ERR_NOT_SUPPORTED_VERSION;
Result := ChmLastError = ERR_NO_ERR;
end;
procedure TChmReader.GetCompleteFileList(var Strings: TStrings);
var
X : LongInt;
begin
Strings.Clear;
for X := 0 to fDirectoryEntriesCount-1 do begin
Strings.AddObject(fDirectoryEntries[X].Name, TObject(@fDirectoryEntries[X]));
end;
end;
function TChmReader.ObjectExists(Name: String): QWord;
var
X: Integer;
begin
Result := 0;
X := Pos('#', Name);
if X > 2 then Name := Copy(Name, 1, X-1);
NAme := Lowercase(Name);
if Name = LowerCase(fCachedEntry.Name) then begin
Result := fCachedEntry.DecompressedLength;
Exit;
end;
if (Length(Name) > 0) and (Name[1] = ':') then begin
for X := fDirectoryEntriesCount-1 downto 0 do begin //Start at the end
//WriteLn('Comparing ', Name ,' to ', LowerCase(fDirectoryEntries[X].Name));
if LowerCase(fDirectoryEntries[X].Name) = Name then begin
fCachedEntry := fDirectoryEntries[X];
Result := fCachedEntry.DecompressedLength;
Exit;
end;
end;
//WriteLn('Didn''t find it');
exit;
end;
//else
for X := 0 to fDirectoryEntriesCount-1 do begin //start at the beginning
if LowerCase(fDirectoryEntries[X].Name) = Name then begin
fCachedEntry := fDirectoryEntries[X];
Result := fCachedEntry.DecompressedLength;
Exit;
end;
end;
end;
function TChmReader.GetObject(Name: String): TMemoryStream;
var
SectionNames: TStringList;
Entry: TPMGListChunkEntry;
SectionName: String;
begin
Result := nil;
if ObjectExists(Name) = 0 then begin
//WriteLn('Object ', name,' Doesn''t exist or is zero sized.');
Exit;
end;
Entry := fCachedEntry;
if Entry.ContentSection = 0 then begin
Result := TMemoryStream.Create;
fStream.Position := fHeaderSuffix.Offset+ Entry.ContentOffset;
Result.CopyFrom(fStream, fCachedEntry.DecompressedLength);
end
else begin // we have to get it from ::DataSpace/Storage/[MSCompressed,Uncompressed]/ControlData
GetSections(SectionNames);
//WriteLn('Section names: >>>',SectionNames.Text, '<<<');
FmtStr(SectionName, '::DataSpace/Storage/%s/',[SectionNames[Entry.ContentSection-1]]);
Result := GetBlockFromSection(SectionName, Entry.ContentOffset, Entry.DecompressedLength);
SectionNames.Free;
end;
if Result <> nil then Result.Position := 0;
end;
function TChmReader.GetContextUrl(Context: THelpContext): String;
begin
// will get '' if context not found
Result := fContextList.GetURL(Context);
end;
function TChmReader.HasContextList: Boolean;
begin
Result := fContextList.Count > 0;
end;
procedure TChmReader.FillDirectoryEntries(StartCount: Integer);
var
ChunkStart: QWord;
PMGLChunk: TPMGListChunk;
PMGIChunk: TPMGIIndexChunk;
PMGIChunkEntry: TPMGIIndexChunkEntry;
X: Integer;
DirEntrySize: LongWord;
// for speed we load this section into a tmemorystream
EntriesBuffer: TMemoryStream;
CopySize: Int64;
begin
EntriesBuffer := TMemoryStream.Create;
CopySize := fDirectoryEntriesStartPos + (fDirectoryHeader.ChunkSize * fDirectoryHeader.DirectoryChunkCount);
fStream.Position := 0;
EntriesBuffer.CopyFrom(fStream, CopySize);
SetLength(fDirectoryEntries, StartCount);
DirEntrySize := StartCount;
{$IFDEF CHM_DEBUG}
WriteLn('Chunk count=', fDirectoryHeader.DirectoryChunkCount);
{$ENDIF}
for X := 0 to fDirectoryHeader.DirectoryChunkCount-1 do begin
if GetChunkType(EntriesBuffer, X) = ctPMGL then begin
//WriteLn('PGML');
ChunkStart := EntriesBuffer.Position-4;
LookupPMGLchunk(EntriesBuffer, X, PMGLChunk);
while EntriesBuffer.Position < ChunkStart + fDirectoryHeader.ChunkSize - PMGLChunk.UnusedSpace do begin
if fDirectoryEntriesCount >= DirEntrySize-1 then begin
Inc(DirEntrySize, 1024);
SetLength(fDirectoryEntries, DirEntrySize);
end;
if ReadPMGLchunkEntryFromStream(EntriesBuffer, fDirectoryEntries[fDirectoryEntriesCount])
then Inc(fDirectoryEntriesCount);
end;
end
else begin
//WriteLn('PGMI-------------------');
{$IFDEF CHM_DEBUG}
// we don't use the indexes
ChunkStart := EntriesBuffer.Position-4;
LookupPMGIchunk(EntriesBuffer, X, PMGIChunk);
while EntriesBuffer.Position < ChunkStart + fDirectoryHeader.ChunkSize - PMGIChunk.UnusedSpace do begin
if ReadPMGIchunkEntryFromStream(EntriesBuffer, PMGIChunkEntry)
then begin
WriteLn(PMGIChunkEntry.Name, ' ', PMGIChunkEntry.ListingChunk);
end;
end;
{$ENDIF}
end;
end;
EntriesBuffer.Free;
if fChmHeader.Version = 2 then
fHeaderSuffix.Offset := ChunkStart + fDirectoryHeader.ChunkSize;
SetLength(fDirectoryEntries,fDirectoryEntriesCount);
end;
procedure TChmReader.GetSections(out Sections: TStringList);
var
Stream: TStream;
EntryCount: Word;
X, I: Integer;
WString: array [0..31] of WideChar;
StrLength: Word;
begin
Sections := TStringList.Create;
//WriteLn('::DataSpace/NameList Size = ', ObjectExists('::DataSpace/NameList'));
Stream := GetObject('::DataSpace/NameList');
if Stream = nil then begin
//WriteLn('Failed to get ::DataSpace/NameList!');
exit;
end;
Stream.Position := 2;
EntryCount := LEtoN(Stream.ReadWord);
for X := 0 to EntryCount -1 do begin
StrLength := LEtoN(Stream.ReadWord);
if StrLength > 31 then StrLength := 31;
Stream.Read(WString, SizeOf(WideChar)*(StrLength+1)); // the strings are stored null terminated
{$IFDEF ENDIAN_BIG}
for I := 0 to StrLength-1 do
WString[I] := WideChar(LEtoN(Ord(WString[I])));
{$ENDIF}
Sections.Add(WString);
end;
// the sections are sorted alphabetically, this way section indexes will jive
Sections.Sort;
Stream.Free;
end;
function TChmReader.GetBlockFromSection(SectionPrefix: String; StartPos: QWord;
BlockLength: QWord): TMemoryStream;
var
Compressed: Boolean;
Sig: Array [0..3] of char;
CompressionVersion: LongWord;
CompressedSize: Int64;
UnCompressedSize: Int64;
//LZXResetInterval: LongWord;
//LZXWindowSize: LongWord;
//LZXCacheSize: LongWord;
ResetTableEntry: TPMGListChunkEntry;
ResetTable: TLZXResetTableArr;
WriteCount: QWord;
BlockWriteLength: QWord;
WriteStart: LongWord;
ReadCount:LongInt;
LZXState: PLZXState;
InBuf: array of Byte;
OutBuf: PByte;
BlockSize: QWord;
X: Integer;
FirstBlock, LastBlock: LongInt;
ResultCode: LongInt;
procedure ReadBlock;
begin
if ReadCount > Length(InBuf) then
SetLength(InBuf, ReadCount);
fStream.Read(InBuf[0], ReadCount);
end;
begin
// okay now the fun stuff ;)
Result := nil;
Compressed := ObjectExists(SectionPrefix+'Transform/{7FC28940-9D31-11D0-9B27-00A0C91E9C7C}/InstanceData/ResetTable')>0;
// the easy method
if Not(Compressed) then begin
if ObjectExists(SectionPrefix+'Content') > 0 then begin
Result := TMemoryStream.Create;
fStream.Position := fHeaderSuffix.Offset + fCachedEntry.ContentOffset + StartPos;
Result.CopyFrom(fStream, BlockLength);
end;
Exit;
end
else
ResetTableEntry := fCachedEntry;
// First make sure that it is a compression we can read
if ObjectExists(SectionPrefix+'ControlData') > 0 then begin
fStream.Position := fHeaderSuffix.Offset + fCachedEntry.ContentOffset + 4;
fStream.Read(Sig, 4);
if Sig <> 'LZXC' then Exit;
CompressionVersion := LEtoN(fStream.ReadDWord);
if CompressionVersion > 2 then exit;
{LZXResetInterval := }LEtoN(fStream.ReadDWord);
{LZXWindowSize := }LEtoN(fStream.ReadDWord);
{LZXCacheSize := }LEtoN(fStream.ReadDWord);
BlockSize := FindBlocksFromUnCompressedAddr(ResetTableEntry, CompressedSize, UnCompressedSize, ResetTable);
if StartPos > 0 then
FirstBlock := StartPos div BlockSize
else
FirstBlock := 0;
LastBlock := (StartPos+BlockLength) div BlockSize;
if ObjectExists(SectionPrefix+'Content') = 0 then exit;
//WriteLn('Compressed Data start''s at: ', fHeaderSuffix.Offset + fCachedEntry.ContentOffset,' Size is: ', fCachedEntry.DecompressedLength);
Result := TMemoryStream.Create;
Result.Size := BlockLength;
SetLength(InBuf,BlockSize);
OutBuf := GetMem(BlockSize);
// First Init a PLZXState
LZXState := LZXinit(16);
if LZXState = nil then begin
Exit;
end;
// if FirstBlock is odd (1,3,5,7 etc) we have to read the even block before it first.
if (FirstBlock <> 0) and (FirstBlock mod 2 > 0) then begin
fStream.Position := fHeaderSuffix.Offset + fCachedEntry.ContentOffset + (ResetTable[FirstBLock-1]);
ReadCount := ResetTable[FirstBlock] - ResetTable[FirstBlock-1];
BlockWriteLength:=BlockSize;
ReadBlock;
ResultCode := LZXdecompress(LZXState, @InBuf[0], OutBuf, ReadCount, LongInt(BlockWriteLength));
end;
// now start the actual decompression loop
for X := FirstBlock to LastBlock do begin
fStream.Position := fHeaderSuffix.Offset + fCachedEntry.ContentOffset + (ResetTable[X]);
if X = FirstBLock then
WriteStart := StartPos - (X*BlockSize)
else
WriteStart := 0;
if X = High(ResetTable) then
ReadCount := CompressedSize - ResetTable[X]
else
ReadCount := ResetTable[X+1] - ResetTable[X];
BlockWriteLength := BlockSize;
if FirstBlock = LastBlock then begin
WriteCount := BlockLength;
end
else if X = LastBlock then
WriteCount := (StartPos+BlockLength) - (X*BlockSize)
else WriteCount := BlockSize - WriteStart;
ReadBlock;
ResultCode := LZXdecompress(LZXState, @InBuf[0], OutBuf, ReadCount, LongInt(BlockWriteLength));
//now write the decompressed data to the stream
if ResultCode = DECR_OK then begin
Result.Write(OutBuf[WriteStart], Int64(WriteCount));
end
else begin
{$IFDEF CHM_DEBUG} // windows gui program will cause an exception with writeln's
WriteLn('Decompress FAILED with error code: ', ResultCode);
{$ENDIF}
Result.Free;
Result := Nil;
FreeMem(OutBuf);
SetLength(ResetTable,0);
LZXteardown(LZXState);
Exit;
end;
// if the next block is an even numbered block we have to reset the decompressor state
if (X < LastBlock) and (X mod 2 > 0) then LZXreset(LZXState);
end;
FreeMem(OutBuf);
SetLength(ResetTable,0);
LZXteardown(LZXState);
end;
end;
function TChmReader.FindBlocksFromUnCompressedAddr(var ResetTableEntry: TPMGListChunkEntry;
out CompressedSize: Int64; out UnCompressedSize: Int64; out LZXResetTable: TLZXResetTableArr): QWord;
var
BlockCount: LongWord;
I: Integer;
begin
Result := 0;
fStream.Position := fHeaderSuffix.Offset + ResetTableEntry.ContentOffset;
fStream.ReadDWord;
BlockCount := LEtoN(fStream.ReadDWord);
fStream.ReadDWord;
fStream.ReadDWord; // TableHeaderSize;
fStream.Read(UnCompressedSize, SizeOf(QWord));
UnCompressedSize := LEtoN(UnCompressedSize);
fStream.Read(CompressedSize, SizeOf(QWord));
CompressedSize := LEtoN(CompressedSize);
fStream.Read(Result, SizeOf(QWord)); // block size
Result := LEtoN(Result);
// now we are located at the first block index
SetLength(LZXResetTable, BlockCount);
fStream.Read(LZXResetTable[0], SizeOf(QWord)*BlockCount);
{$IFDEF ENDIAN_BIG}
for I := 0 to High(LZXResetTable) do
LZXResetTable[I] := LEtoN(LZXResetTable[I]);
{$ENDIF}
end;
{ TContextList }
procedure TContextList.AddContext(Context: THelpContext; Url: String);
var
ContextItem: PContextItem;
begin
New(ContextItem);
Add(ContextItem);
ContextItem^.Context := Context;
ContextItem^.Url := Url;
end;
function TContextList.GetURL(Context: THelpContext): String;
var
X: Integer;
begin
Result := '';
for X := 0 to Count-1 do begin
if PContextItem(Get(X))^.Context = Context then begin
Result := PContextItem(Get(X))^.Url;
Exit;
end;
end;
end;
procedure TContextList.Clear;
var
X: Integer;
begin
for X := Count-1 downto 0 do begin
Dispose(PContextItem(Get(X)));
Delete(X);
end;
end;
{ TChmFileList }
procedure TChmFileList.Delete(Index: Integer);
begin
Chm[Index].Free;
inherited Delete(Index);
end;
function TChmFileList.GetChm(AIndex: Integer): TChmReader;
begin
Result := TChmReader(Objects[AIndex]);
end;
function TChmFileList.GetFileName(AIndex: Integer): String;
begin
Result := Strings[AIndex];
end;
procedure TChmFileList.OpenNewFile(AFileName: String);
var
AStream: TFileStream;
AChm: TChmReader;
AIndex: Integer;
begin
if not FileExists(AFileName) then exit;
AStream := TFileStream.Create(AFileName, fmOpenRead);
AChm := TChmReader.Create(AStream, True);
AIndex := AddObject(AFileName, AChm);
fLastChm := AChm;
if Assigned(fOnOpenNewFile) then fOnOpenNewFile(Self, AIndex)
else fUnNotifiedFiles.Add(AChm);
end;
function TChmFileList.CheckOpenFile(AFileName: String): Boolean;
var
X: Integer;
begin
Result := False;
for X := 0 to Count-1 do begin
if ExtractFileName(FileName[X]) = AFileName then begin
fLastChm := Chm[X];
Result := True;
Exit;
end;
end;
if not Result then begin
AFileName := ExtractFilePath(FileName[0])+AFileName;
if FileExists(AFileName) and (ExtractFileExt(AFileName) = '.chm') then OpenNewFile(AFileName);
Result := True;
end;
end;
function TChmFileList.MetaObjectExists(var Name: String): QWord;
var
AFileName: String;
URL: String;
fStart, fEnd: Integer;
Found: Boolean;
begin
Found := False;
Result := 0;
//Known META file link types
// ms-its:name.chm::/topic.htm
//mk:@MSITStore:name.chm::/topic.htm
if Pos('ms-its:', Name) > 0 then begin
fStart := Pos('ms-its:', Name)+Length('ms-its:');
fEnd := Pos('::', Name)-fStart;
AFileName := Copy(Name, fStart, fEnd);
fStart := fEnd+fStart+2;
fEnd := Length(Name) - (fStart-1);
URL := Copy(Name, fStart, fEnd);
Found := True;
end
else if Pos('mk:@MSITStore:', Name) > 0 then begin
fStart := Pos('mk:@MSITStore:', Name)+Length('mk:@MSITStore:');
fEnd := Pos('::', Name)-fStart;
AFileName := Copy(Name, fStart, fEnd);
fStart := fEnd+fStart+2;
fEnd := Length(Name) - (fStart-1);
URL := Copy(Name, fStart, fEnd);
Found := True;
end;
if not Found then exit;
if CheckOpenFile(AFileName) then
Result := fLastChm.ObjectExists(URL);
if Result > 0 then NAme := Url;
end;
function TChmFileList.MetaGetObject(Name: String): TMemoryStream;
begin
Result := nil;
if MetaObjectExists(Name) > 0 then Result := fLastChm.GetObject(Name);
end;
constructor TChmFileList.Create(PrimaryFileName: String);
begin
inherited Create;
fUnNotifiedFiles := TList.Create;
OpenNewFile(PrimaryFileName);
end;
destructor TChmFileList.Destroy;
begin
fUnNotifiedFiles.Free;
end;
procedure TChmFileList.SetOnOpenNewFile(AValue: TChmFileOpenEvent);
var
X: Integer;
begin
fOnOpenNewFile := AValue;
if AValue = nil then exit;
for X := 0 to fUnNotifiedFiles.Count-1 do
AValue(Self, X);
fUnNotifiedFiles.Clear;
end;
function TChmFileList.ObjectExists(Name: String; fChm: TChmReader = nil): QWord;
begin
Result := 0;
if Count = 0 then exit;
if fChm <> nil then fLastChm := fChm;
Result := fLastChm.ObjectExists(Name);
if Result = 0 then begin
Result := Chm[0].ObjectExists(Name);
if Result > 0 then fLastChm := Chm[0];
end;
if Result = 0 then begin
Result := MetaObjectExists(Name);
end;
end;
function TChmFileList.GetObject(Name: String): TMemoryStream;
begin
Result := nil;
if Count = 0 then exit;
Result := fLastChm.GetObject(Name);
if Result = nil then Result := MetaGetObject(Name);
end;
function TChmFileList.IsAnOpenFile(AFileName: String): Boolean;
var
X: Integer;
begin
Result := False;
for X := 0 to Count-1 do begin
if AFileName = FileName[X] then Exit(True);
end;
end;
end.