METHOD AND APPARATUS FOR STORING COMPRESSED DATA

A method and apparatus for storing data for a plurality of data blocks in a compressed format in memory is presented where the compression scheme used for compressing the data blocks may vary. For each data block included in the plurality of data blocks, the data block is compressed using a compression scheme that is included in a set of predetermined compression schemes. The resulting compressed data set is of a size included in a set of predetermined sizes that correspond to the particular compression scheme utilized. The compressed data set for each block is then stored in a compressed data set memory, where the compressed data sets are stored in groups. A descriptor data set corresponding to each group is then stored in a descriptor memory, where the descriptor data set includes an encoded compression descriptor for each data block included in the group. The data descriptor set also stores a base address that corresponds to a starting location for that group in the compressed data set memory. The encoded compression descriptor for each data block encodes the compression scheme used for that data block and the resulting compressed data set size. When the data for a particular data block is required in an uncompressed format, the storage location of the compressed data set corresponding to that block can be determined from the descriptor data set for the group that includes the particular block required. By combining the base address within the descriptor data set with the sizes of all of the compressed data blocks in the group that precede the particular block in the compressed data set memory, the address for the compressed data set required for decompression can be determined. The compressed data set can then be fetched from memory and decompressed based on the compression scheme as determined from the encoded compression descriptor corresponding to that data block.