Apparatus and method for comparing data groups
US4807182A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 12, 1986 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Mar 12, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99953
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for comparing original and modified versions of a document. The system of the present invention utilizes a hash number generator CPU to generate hash numbers for lines and sentences contained in the documents. Matching hash numbers are defined as anchorpoints and stored in an anchorpoint memory. A comparator CPU performs a character-by-character comparison of the respective documents radiating outward from each anchorpoint. This comparison generates identity blocks which are defined as blocks which are the same in both documents. Non-identity blocks are defined as difference blocks and are characterized as insertions or deletions depending on their status. A portion of the original and modified document is displayed in a split-screen format on a display, such as a CRT. Cursors on the top and bottom half of the screen identify corresponding portions of the documents. The second cursor is generated by taking advantage of the timer interrupt sequence of a CPU to direct the CPU to program instructions to generate the second cursor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.