You do not want to implement IFilter for the analysis of Office 2007 docx. You want to use Microsoft already written IFilter objects , so you can learn the contents of the file docx .
Then you use the standard IFilter mechanisms to analyze the contents of the file:
procedure TForm1.ProcessFile(filename: string); var Filter: IFilter; hr: HRESULT; chunk: PSTAT_CHUNK; // attr: FULLPROPSPEC; flags: ULONG; c: Cardinal; buffer: WideString; begin Log('Processing "'+filename+'"'); Log('Calling LoadIFilter'); filter := LoadIFilter(filename); if filter = nil then begin Log('filter is null; leaving'); Exit; end; try Log('Calling filter.Init(IFILTER_INIT_INDEXING_ONLY)'); hr := filter.Init(IFILTER_INIT_INDEXING_ONLY, 0, nil, flags); OleCheck(hr); Log('Init returned sucessfully, looking for chunks...'); while True do begin New(chunk); try hr := filter.GetChunk(chunk); if Failed(hr) then begin Log('No more chunks: '+IntToHex(hr, 8)+' ('+GetChunkHresultToStr(hr)+')'); Break; end; Log('== Got chunk. ChunkType='+IntToStr(chunk.flags)+' (1=text, 2=value) =='); if (chunk.Flags and CHUNK_TEXT) = CHUNK_TEXT then begin c := 2048; SetLength(buffer, c); hr := filter.GetText(c, PWideChar(buffer)); if Succeeded(hr) then begin Log('=== Got text ==='); SetLength(buffer, c); Log(buffer); while Succeeded(hr) do begin c := 2048; SetLength(buffer, c); hr := filter.GetText(c, PWideChar(buffer)); if Succeeded(hr) then begin SetLength(buffer, c); Log('==== Really long chunk, here' the next 2048 characters ===='); Log(buffer); end; end; end else begin Log('Could not get text from chunk: '+IntToHex(hr, 8)+' ('+GetChunkHResultToStr(hr)+')'); Log(' It might be a "Value" chunk, meaning i should call filter.GetValue rather than filter.GetText. But i''m too lazy'); end; end else if (chunk.flags and CHUNK_VALUE) = CHUNK_VALUE then begin Log('This is a "VALUE" chunk. i''m not going to read anything out of it cause it' too hard :('); end else Log('Unknown chunk type'); finally Dispose(chunk); end; end; //end while true getting chunks finally filter := nil; end; end;
If Windows already provides code that loads IFilter for the specified file name:
function TForm1.LoadIFilter(const filename: WideString): IFilter; var hr: HRESULT; unk: IUnknown; begin hr := ntQuery.LoadIFilter(PWideChar(filename), nil, unk); OleCheck(hr); Result := unk as IFilter; end;
IFilter ad unit:
unit Filter; interface uses Windows, SysUtils, Classes, ActiveX; type IFILTER_INIT = TOleEnum; const IFILTER_INIT_CANON_PARAGRAPHS = 1; IFILTER_INIT_HARD_LINE_BREAKS = 2; IFILTER_INIT_CANON_HYPHENS = 4; IFILTER_INIT_CANON_SPACES = 8; IFILTER_INIT_APPLY_INDEX_ATTRIBUTES = 16; IFILTER_INIT_APPLY_OTHER_ATTRIBUTES = 32; IFILTER_INIT_INDEXING_ONLY = 64; IFILTER_INIT_SEARCH_LINKS = 128; type IFILTER_FLAGS = TOleEnum; const IFILTER_FLAGS_OLE_PROPERTIES = 1; type CHUNKSTATE = TOleEnum; const CHUNK_TEXT = $01; CHUNK_VALUE = $02; type CHUNK_BREAKTYPE = TOleEnum; const CHUNK_NO_BREAK = 0; CHUNK_EOW = 1; CHUNK_EOS = 2; CHUNK_EOP = 3; CHUNK_EOC = 4; type FILTERREGION = packed record idChunk: ULONG; cwcStart: ULONG; cwcExtent: ULONG; end; tagFILTERREGION = FILTERREGION; const PRSPEC_LPWSTR = 0; PRSPEC_PROPID = 1; type PROPID = ULONG; type PROPSPEC = packed record ulKind: ULONG; case integer of 0: (prid: PROPID); 1: (lpws: PWideChar); end; tagPROPSPEC = PROPSPEC; type FULLPROPSPEC = packed record guidPropSet: TGUID; psProperty: PROPSPEC; end; tagFULLPROPSPEC = FULLPROPSPEC; PFULLPROPSPEC = ^FULLPROPSPEC; type STAT_CHUNK = packed record idChunk: ULONG; breakType: CHUNK_BREAKTYPE; flags: CHUNKSTATE; locale: LCID; attribute: FULLPROPSPEC; idChunkSource: ULONG; cwcStartSource: ULONG; cwcLenSource: ULONG; end; tagSTAT_CHUNK = STAT_CHUNK; PSTAT_CHUNK = ^STAT_CHUNK; // From filtererr.h const FILTER_E_END_OF_CHUNKS = HRESULT($80041700); // // MessageId: FILTER_E_NO_MORE_TEXT // // MessageText: // // No more text available in chunk. // const FILTER_E_NO_MORE_TEXT = HRESULT($80041701); // // MessageId: FILTER_E_NO_MORE_VALUES // // MessageText: // // No more property values available in chunk. // const FILTER_E_NO_MORE_VALUES = HRESULT($80041702); // // MessageId: FILTER_E_ACCESS // // MessageText: // // Unable to access object. // const FILTER_E_ACCESS = HRESULT($80041703); // // MessageId: FILTER_W_MONIKER_CLIPPED // // MessageText: // // Moniker doesn't cover entire region. // const FILTER_W_MONIKER_CLIPPED = HRESULT($80041704); // // MessageId: FILTER_E_NO_TEXT // // MessageText: // // No text in current chunk. // const FILTER_E_NO_TEXT = HRESULT($80041705); // // MessageId: FILTER_E_NO_VALUES // // MessageText: // // No values in current chunk. // const FILTER_E_NO_VALUES = HRESULT($80041706); // // MessageId: FILTER_E_EMBEDDING_UNAVAILABLE // // MessageText: // // Unable to bind IFilter for embedded object. // const FILTER_E_EMBEDDING_UNAVAILABLE = HRESULT($80041707); // // MessageId: FILTER_E_LINK_UNAVAILABLE // // MessageText: // // Unable to bind IFilter for linked object. // const FILTER_E_LINK_UNAVAILABLE = HRESULT($80041708); // // MessageId: FILTER_S_LAST_TEXT // // MessageText: // // This is the last text in the current chunk. // const FILTER_S_LAST_TEXT = HRESULT($00041709); // // MessageId: FILTER_S_LAST_VALUES // // MessageText: // // This is the last value in the current chunk. // const FILTER_S_LAST_VALUES = HRESULT($0004170A); // // MessageId: FILTER_E_PASSWORD // // MessageText: // // File was not filtered due to password protection. // const FILTER_E_PASSWORD = HRESULT($8004170B); // // MessageId: FILTER_E_UNKNOWNFORMAT // // MessageText: // // The document format is not recognized by the flter. // const FILTER_E_UNKNOWNFORMAT = HRESULT($8004170C); const IID_IFilter: TGUID = '{89BCB740-6119-101A-BCB7-00DD010655AF}'; type IFilter = interface(IUnknown) ['{89BCB740-6119-101A-BCB7-00DD010655AF}'] function Init(grfFlags: ULONG; cAttributes: ULONG; aAttributes: PFULLPROPSPEC; out pFlags: ULONG): HResult; stdcall; function GetChunk(pStat: PSTAT_CHUNK): HResult; stdcall; function GetText(var pcwcBuffer: ULONG; awcBuffer: PWideChar): HResult; stdcall; function GetValue(out ppPropValue: PROPVARIANT): HResult; stdcall; function BindRegion(origPos: FILTERREGION; riid: TGUID; out ppUnk): HResult; stdcall; end; implementation end.