IFilter::GetChunk method (filter.h)

Article
10/13/2021

Note

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Positions the filter at the beginning of the next chunk, or at the first chunk if this is the first call to the GetChunk method, and returns a description of the current chunk.

Syntax

SCODE GetChunk(
  [out] STAT_CHUNK *pStat
);

Parameters

[out] pStat

A pointer to a STAT_CHUNK structure containing a description of the current chunk.

Return value

This method can return one of these values.

Return code	Description
S_OK	The operation was completed successfully.
FILTER_E_END_OF_CHUNKS	The previous chunk is the last chunk.
FILTER_E_EMBEDDING_UNAVAILABLE	The next chunk is an embedding and no content filter is available.
FILTER_E_LINK_UNAVAILABLE	The next chunk is a link and no content filter is available.
FILTER_E_PASSWORD	Password or other security-related access failure.
FILTER_E_ACCESS	General access failure.

Remarks

If upon return pStat points to a STAT_CHUNK structure with the breakType member equal to CHUNK_NO_BREAK, only the idChunk member will be updated with the new chunk identifier (ID) value. The other members of the STAT_CHUNK structure remain unchanged.

Internal value-type properties (chunks with a CHUNKSTATE enumeration value of CHUNK_VALUE) cannot be concatenated using CHUNK_NO_BREAK. A single word cannot span more than two glued chunks.

Chunk ID zero is invalid.

Before the GetChunk method is called for the first time, there is no current chunk. After an error return code of anything other than FILTER_E_END_OF_CHUNKS the next call to the GetChunk method nevertheless retrieves the next chunk after the unavailable one.

Notes to Callers

When the GetChunk method finishes, the chunk described in *pStat is the current chunk. The chunk descriptor is owned by the routine calling the GetChunk method, but the property name pointer, which can be set in the property specification, is owned by the GetChunk method and should not be freed.

Notes to Implementers

If a call to the GetChunk method of the content filter of a linked or embedded object returns FILTER_E_END_OF_CHUNKS, the implementation should return the next chunk of the linking or embedding object. For example, if a document has two embedded objects and the first has returned FILTER_E_END_OF_CHUNKS, then the outer content filter must call the GetChunk method of the content filter for the embedded object.

Before returning the results of a call to the GetChunk method on an embedded or linked object, check to make sure that the chunk ID is unique. If not, the implementer must renumber the chunk and keep a mapping of the new chunk ID.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	filter.h

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