TS 102 323 - V1.4.1 - Digital Video Broadcasting (DVB ... - ETSI

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ETSI
ETSI TS 102 323 V1.4.1 (2010-01)
overlapping_subindices: When set to '1' indicates that one or more of the cri_prepend_index structures which form this
index have ranges of values which overlap. Where cri_prepend_indices overlap entries in the cri_index structure are in
descending order of search priority. When set to '0' indicates that the sub indices do not overlap, in which case the
declared cri_prepend_index structures shall be ordered in ascending lexicographical order (see clause 6.2).
reserved_other_use: This field shall be set to '0'.
reserved: All bits marked as being reserved shall be set to '1'.
result_locator_format: Identifies the format of the result locator structure within cri_leaf_index CRI structures
referenced from this structure. This field shall be encoded according to table 40.
Table 40: result_locator_format
Value Meaning
0x00 local_result_locator
0x01 remote_result_locator
0x02 to 0xFF DVB reserved
See clause 7.3.3.5 for definitions of the local_result_locator and remote_result_locator.
low_key_value_CRID: This 16 bit field is the offset, in bytes, from the first byte of the data repository to the first byte
of an abbreviated CRID string omitting the characters "crid://". This CRID string must have a lexicographical value
equal to or less than any CRID string referred to by the referenced cri_prepend_index structure (see clause 6.2).
If the overlapping_subindices field is set to '0' then this field shall not be used. In this case, every CRID string referred
to by the referenced cri_sub_index structure must have a lexicographical value greater than the high_key_value_CRID
of the previous entry in this structure.
high_key_value_CRID: This 16 bit field is the offset, in bytes, from the first byte of the data repository to the first byte
of an abbreviated CRID string omitting the characters "crid://". This CRID string must have a lexicographical value
equal to or higher than any CRID string referred to by the referenced cri_prepend_index structure (see clause 6.2).
NOTE: When defining the range of values which a particular sub index is to cover, sufficient space can be left in
containers to permit adding further CRID results without necessitating reallocation of the ranges of the
sub index structures.
prepend_index_container: This field is the container ID of the container carrying the cri_prepend_index structure.
prepend_index_identifier: This 8 bit field shall be equal to the value of the cri_structure_id field of the target
cri_prepend_index structure.
7.3.3.3 Cri_prepend_index
The cri_prepend_index CRI structure comprises the second level of indexing. Each cri_prepend_index structure
provides references (via a cri_leaf_index structure) to CRID results that are within the lexicographical range of values
specified by the cri_index structure.
For every cri_prepend_index structure there shall be a cri_leaf_index structure in the same container. These structures
have the same cri_structure_type but are differentiated by their cri_structure_id values. All references to a
cri_prepend_index or cri_leaf_index contain the cri_structure_id of the target structure, preventing confusion.
Cri_prepend_index and cri_leaf_index CRI structures are also differentiable by the value of the leaf_flag field, which is
present in both structures.
All entries within the sub index shall be ordered in ascending lexicographical order (see clause 6.2). When trying to
select the appropriate prepend string used for a CRID being resolved, the receiver shall select the longest matching
prepend string. A matching prepend string is defined as one where all characters in the prepend string match the
corresponding characters in the CRID.
All entries that share the same prepend string shall be grouped together in the subordinate cri_leaf_index structure.
These groups shall be in the same order as defined in the cri_prepend_index structure. For a given prepend string the
correct range of cri_leaf_index entries is defined as being from one after the range_end_offset for the previous prepend
string to the range_end_offset for the current prepend string. The start of the range for the first prepend string listed in a
cri_prepend_index is the first entry in the subordinate cri_leaf_index.