A hardware data compressor includes a first hardware engine that scans an input block of characters to produce a stream of tokens, the stream of tokens comprising replacement back pointers to matched strings of characters of the input block and non-replaced characters of the input block. The hardware data compressor also includes a second hardware engine that receives the stream of tokens and maintains a sorted list of symbols associated with the tokens. The hardware data compressor also includes the second hardware engine concurrently maintains the sorted list of symbols by frequency of occurrence as the first hardware engine produces the tokens of the stream.