Systems and methods for efficiently storing index data on an electronic device

摘要

A method for efficiently storing index data on an electronic device may include storing index data in data pages within an indexing data structure on the electronic device. The method may also include providing at least one directory for the indexing data structure. The method may also include dynamically modifying how many directory levels are provided for the indexing data structure in response to changes to the data pages within the indexing data structure.

主权项

1. A method for efficiently storing index data on an electronic book (e-book) reader, comprising:
storing the index data in data pages within an indexing data structure on the e-book reader, wherein the indexing data structure is stored in a disk file; providing at least one directory for the indexing data structure; and dynamically modifying how many directory levels are provided for the indexing data structure in response to changes to a number of data pages within the indexing data structure, wherein the dynamically modifying includes:
identifying an unused memory location within the indexing data structure; andremoving a directory level when changes to the data pages within the indexing data structure includes moving a data page from within the indexing data structure to the unused memory location within the indexing data structure causing the number of data pages within the indexing data structure to decrease such that a directory page corresponding to a lower-level directory is sufficiently large to store the entire lower level directory, wherein
each directory page stores a directory of one or more of the data pages, andthe moving the data page to the unused memory location frees disk space formerly storing the data page at the end of the disk file on the e-book reader.