Method and apparatus for compressing data string
US6876774B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2002 |
| Grant date | Apr 5, 2005 |
| Priority date | — |
| Expiry date | Jan 31, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/3084
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention provides a data compression method in which a plurality of consecutive characters of a data string to be compressed are set as a character string to be searched for. Bits of a bit string representing the set character string are allocated to at least two codewords. Thus, first and second searching codewords are generated. These first and second codewords are used as array addresses. First and second array tables are prepared, in which information on the past occurrence positions of the set character string is previously entered as the contents thereof. When the first and second codewords are generated from the character string to be compressed, the first and second array tables are looked up by using these codewords as the addresses of the arrays. When results of looking up these tables match with each other, it is found that the set character string occurred in the past. Thus, information on the past occurrence position information of the set character string is obtained according to the obtained array content. Then, this information is encoded, so that data compression is performed. Thus, the amount of memory needed for the tables is significantly reduced, w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.