Storage of a compressed file containing its own compression management table

摘要

A compressed file consists of: a header that carries information showing the position of a compression management table; compressed codes; and the compression management table that holds information showing the storage location of the compressed code of each original record. In a preferred mode, compression and decompression of data and access to compressed data are performed using input/output functions within an input/output function library so that the user need not be aware of the compression and decompression operations and the storage location of compressed data. In a further preferred mode, with these input/output functions it is judged whether a file being accessed is a compressed file or not, and if it is a compressed file, the operation is switched to input/output functions for a compressed file.