System for compressed storage of 8-bit ASCII bytes using coded strings of 4 bit nibbles
US4597057A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 31, 1981 |
| Grant date | Jun 24, 1986 |
| Priority date | — |
| Expiry date | Dec 31, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/42
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Standard ASCII coded text is divided into alpha, numeric, and punctuation tokens. Each token is converted to a string of four-bit nibbles. One nibble is coded to identify the type of token. Additional nibbles are coded to identify the location, if any, of a corresponding alpha or punctuation token in a global dictionary. If no corresponding alpha token is in the dictionary, an alpha token is divided into prefixed, suffixes, and a stem. The location of any prefixes in a table of prefixes, suffixes in a table of suffixes, and the number, and location of corresponding individual characters in a table, of the remaining stem are then coded and stored as part of the string of four-bit nibbles for the alpha tokens. Numeric tokens are stored as a string of four-bit nibbles in which the first nibble identifies the type of token, the next nibble the length, followed by a nibble for each of the digits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.