A data compression method includes receiving an input data stream including a previous data block and a current data block, and executing a first comparison of a part of the previous data block with part of a previous reference data block, and a second comparison of the current data block with a current reference data block, where the first and second comparisons are executed in parallel. The method further includes selectively, based on results of the first and second comparisons, outputting the current data block or compressing an extended data block, where the extended data block includes the part of the previous data block and the current data block.