Data compression apparatus and method

A data compression method performed by a computer, the data compression method comprising:

• extracting a second character string as a matching string from a character string after a first character string in a character string of data before compression that is stored in a memory, the second character string being identical with the first character string, and identifying a length of the matching string, and a relative position indicating how many addresses the first character string precedes the second character string by;
• extracting a third character string having a length that is less than the relative position from the extracted second character string;
• encoding a length of the third character string;
• and
• encoding the relative position.

A computer-readable recording medium having stored therein a program for causing a computer to execute a process comprising:

• extracting a second character string as a matching string from a character string after a first character string in a character string of data before compression that is stored in a memory, the second character string being identical with the first character string, and identifying a length of the matching string, and a relative position indicating how many addresses the first character string precedes the second character string by;
• extracting a third character string having a length that is less than the relative position from the extracted second character string;
• detecting and encoding a length of the third character string;
• and
• encoding the relative position.