Patent ID: 6906644

Claim:
A data compressing apparatus having an input buffer for holding a string of data to be compressed, said input buffer comprising a Lempel buffer for storing an already compressed portion and a Ziv buffer for storing a portion to be compressed, comprising: hash code generation means for generating a hash code from a character string having the length n; occurrence position holding means for holding an occurrence position of the n-character string in the Lempel buffer in association with the hash code generated from the n-character string in the Lempel buffer; occurrence position obtaining means for obtaining an occurrence position associated with the hash code from said occurrence position holding means by retrieving the hash code generated from the character string having the length n immediately before the Ziv buffer from said occurrence position holding means; matching length obtaining means for comparing a character string after the occurrence position with a character string after a start of the Ziv buffer, and obtaining a matching length; and matching length coding means for coding the character string after the start of the Ziv buffer based on the matching length.