kdu_metareq [struct]

JP2-family box 4 character code, or else 0 (wildcard).

Provides qualification of the conditions under which a box matching the box_type value should be considered to be of interest to the client. This member takes the logical OR of one or more of the following flags: KDU_MRQ_ALL, KDU_MRQ_GLOBAL, KDU_MRQ_STREAM or KDU_MRQ_WINDOW, corresponding to JPIP "metareq" request field qualifiers of "/a", "/g", "/s" and "/w", respectively. The word should not be equal to 0. Each of the flags represents a context, consisting of a collection of boxes which might be of interest. The boxes which are of interest to the client are restricted to those boxes which belong to one of the contexts for which a flag is present.

• KDU_MRQ_WINDOW identifies a context which consists of all boxes which are known to be directly associated with a spatial region, a limited range of resolutions and/or a limited set of image components, so long as the specific spatial region, resolutions and image components interect the requested view window.
• KDU_MRQ_STREAM identifies a context which consists of all boxes which are known to be associated with one or more code-streams which belong to the view window. The association must be with the code-stream or code-streams in their entirety, not just with a limited spatial region, a limited set of resolutions, or a limited set of image components within the code-stream or code-streams.
• KDU_MRQ_GLOBAL identifies a context which consists of all boxes associated with the logical target in general, not just with specific code-streams, spatial regions, resolutions or components.
• KDU_MRQ_ALL identifies a context consisting of all JP2 boxes in the entire target.

Note that the first three contexts mentioned above are mutually exclusive, yet their union is generally only a subset of the KDU_MRQ_ALL context. The union of the first 3 flags is conveniently given by the macro, KDU_MRQ_DEFAULT, since it is the default qualifier for JPIP metareq requests which do not explicitly identify a box context.

True if the boxes described by this record are to have higher priority than image data when delivered by the server. Otherwise, they have lower priority than the image data described by the request window.

Indicates the maximum number of bytes from the contents of any JP2 box conforming to the new kdu_metareq record, which are of interest to the client. May not be negative. Guaranteed to be 0 if recurse is true.

Indicates that the client is also interested in all descendants (via sub-boxes) of any box which matches the box_type and other attributes specified by the various members of this structure. If true, the byte_limit member will be 0, meaning that the client is assumed to be interested only in the header of boxes which match the box_type and the descendants of such boxes.

Indicates the meta data-bin identifier of the data-bin which is to be used as the root when processing this record. If non-zero, the scope of the record is reduced to the set of JP2 boxes which are found in the indicated data-bin or are linked from it via placeholders.

Provides a limit on the maximum depth to which the server is expected to descend within the meta-data tree to find JP2 boxes conforming to the other attributes of this record. A value of 0 means that the client is interested only in boxes which are found at the top level of the data-bin identified by root_bin_id. A value of 1 means that the client is additionally interested in sub-boxes of boxes which are found at the top level of the data-bin identified by root_bin_id; and so forth.

Link to the next element of the list, or else NULL.

The interpretation of this member is not formally defined here. It is provided to allow meta-data analyzers to save temporary state information. In particular, it is used by kdu_serve to save the maximum absolute depth of data-bins which are covered by the request, or else -1 if we are currently analyzing a point in the meta-data tree which is not descended from a meta data-bin with the root_bin_id identifier.