Data compression program, data compression method, and data compression device

The data compression method for compressing data, comprising the steps of:

• (a) performing compression processing of a portion of a data item which is to be compressed;
• (b) comparing volumes of said portion of said data item before and after said compression processing in step (a), and determining whether or not the compression processing is effective;
• and
• (c) performing compression processing of a remaining portion of said data item only when it is determined in step (b) that the compression processing is effective.

A data compression device for compressing data, comprising:

• compression means which performs processing for successively compressing a plurality of unit data elements constituting a data item which is to be compressed, while a compressibility indication flag provided for indicating whether or not compression is necessary indicates that compression is necessary;
• determination means which compares volumes of at least one of said plurality of unit data elements before and after said processing is performed on the at least one of the plurality of unit data elements by said compression means, and determines whether or not compression is effective;
• and
• flag setting means which changes said compressibility indication flag so as to indicate that compression is unnecessary, when said determination means determines that compression is not effective.

A computer-readable recording medium which stores a data compression program for compressing data, said data compression program makes a computer perform a sequence of processing which comprises the steps of:

• (a) performing compression processing of a portion of a data item which is to be compressed;
• (b) comparing volumes of said portion of said data item before and after said compression processing in step (a), and determining whether or not the compression processing is effective;
• and
• (c) performing compression processing of a remaining portion of said data item only when it is determined in step (b) that the compression processing is effective.