Image Number 12 for United States Patent #5797008.
A data processing system includes at least one central processor for executing instructions of software programs. In addition the data processing system includes a memory containing a data structure common to the software programs. The common data structure includes a compressed index data structure. The index structure stores index entries referencing a database. The database includes multiple records, each having a unique address in the database. Each index entry includes a word entry if the index entry represents a compressed encoding of a unique portion of information sequentially parsed from the database. The word entry is followed by one or more location entries which reference occurrences of the portions of information. Each index entry includes a metaword entry if the index entry represents a unique attribute of one or more related words. The metaword entry is followed by one or more location entries referencing occurrences of the attributes. The index entries are sequentially organized according to a collating order of the words and metawords, and the location entries organized according to their collating order. The memory also stores a summary data structure including summary entries generated by periodically sampling the location entries. Each summary entry includes an encoding of the word entry associated with the sampled location entry, an encoding of the sampled location entry, and a pointer to a next location entry following the sampled entry.