A method and apparatus for increasing the speed at which a block of data can be partitioning into variable-length subblocks is provided. The method combines a relatively high-speed partitioning algorithm (that can only partition a block into relatively small mean-length subblocks) with a relatively low-speed algorithm (that can partition a block into subblocks of any mean length) to yield a relatively high-speed partitioning algorithm that can partition blocks into subblocks of any mean-length.