2.6.1.1 ExtensionCompressionTablePage Structure

The ExtensionCompressionTablePage structure stores settings needed to decode the ExtensionDataPage structures. It MUST be aligned on a 4-kilobyte (4096-byte) page boundary.

0	1	2	3	4	5	6	7	8	9	1 0	1	2	3	4	5	6	7	8	9	2 0	1	2	3	4	5	6	7	8	9	3 0	1
Start page signature
Compression table signature																Number of symbol categories
...																Category descriptors (variable)
...
Coding table (variable)
...
Padding (variable)
...
End page signature

Start page signature (4 bytes): The start page signature of the BitStream page.

Compression table signature (2 bytes): A 16-bit integer that MUST be equal to 0x4b52.

Number of symbol categories (4 bytes): The number of records in the Category descriptors field. This MUST be equal to 0x00000005.

Category descriptors (variable): An array of SymbolCategory structures, as specified in section 2.6.1.1.1. The number of objects in this array is specified in the Number of symbol categories field.

Coding table (variable): An array of CodingTableEntry structures, as specified in section 2.6.1.1.2, that defines the bit sequence used for compression of document identifiers and OccCounts as specified in section 2.3.1. The number of objects in this array is the sum of values of the Number of symbols fields in the elements of the Category descriptors field. The coding table MUST NOT contain a bit sequence that is a prefix of another bit sequence.

Padding (variable): A field that exists to ensure that the total structure size is 4096 bytes. The value of this field is arbitrary and MUST be ignored.

End page signature (4 bytes): The End page signature of the BitStream page.