Method and system for compressing unicode data within a data processing system

• US 6,070,179 A
• Filed: 02/20/1998
• Issued: 05/30/2000
• Est. Priority Date: 02/20/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Craft, David John
• Primary Examiner(s): Mai, Tan V.
• Application Number:
  US09/026,677
• Time in Patent Office: 830 Days
• Field of Search: 708/203, 341/55, 341/67, 341/90, 341/50
• US Class Current: 708/203
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction

Abstract

A method for compressing data within a data processing system is disclosed. Each unit of data is at least two bytes. As each byte from a data stream is received, a determination is made as to whether or not an identical data byte occurs at a pre-selected interval within a group of bytes already received. In response to a determination that an identical data byte occurs at a pre-selected interval within a group of bytes already received, only a portion of a subsequent unit of data from the data stream is passed to an output.

Claims

1. A method for compressing data within a data processing system, wherein each unit of said data is at least two bytes, said method comprising the steps of:

receiving a data stream;

as each byte from said data stream is received, determining whether or not an identical data byte occurs at a pre-selected interval within a plurality of bytes already received; and

in response to a determination that an identical data byte occurs at a pre-selected interval within a plurality of bytes already received, passing only a portion of a subsequent unit of data from said data stream to an output.

2. The method for compressing data according to claim 1, wherein said each unit of said data is a UNICODE byte-pair.

3. The method for compressing data according to claim 1, wherein said determining step further includes a step of determining whether or not an identical data byte occurs at an even-ordered predecessor location within a plurality of bytes already received.

4. The method for compressing data according to claim 3, wherein said determining step further includes a step of determining whether or not an identical data byte occurs at three or more even-ordered predecessor locations.

5. The method for compressing data according to claim 1, wherein said method further includes a step of exiting said passing step when a preselected exit character is encountered within said data stream.

6. The method for compressing data according to claim 1, wherein said method further includes a step of passing each byte of a subsequent data unit to an output, in response to a determination that an identical data byte does not occur at a pre-selected interval within a plurality of bytes already received.

7. A data compressing system capable of compressing data, wherein each unit of said data is at least two bytes, said data compressing system comprising:

means for receiving a data stream;

means for determining whether or not an identical data byte occurs at a pre-selected interval within a plurality of bytes already received, as each byte from said data stream is received; and

means for passing only a portion of a subsequent unit of data from said data stream to an output, in response to a determination that an identical data byte occurs at a pre-selected interval within a plurality of bytes already received.

8. The data compressing system according to claim 7, wherein said each unit of said data is a UNICODE byte-pair.

9. The data compressing system according to claim 7, wherein said determining means further includes a means for determining whether or not an identical data byte occurs at an even-ordered predecessor location within a plurality of bytes already received.

10. The data compressing system according to claim 9, wherein said determining means further includes a means for determining whether or not an identical data byte occurs at three or more even-ordered predecessor locations.

11. The data compressing system according to claim 7, wherein said data compressing system further includes a means for exiting said passing means when a preselected exit character is encountered within said data stream.

12. The data compressing system according to claim 7, wherein said data compressing system further includes a means for passing each byte of a subsequent data unit to an output, in response to a determination that an identical data byte does not occur at a pre-selected interval within a plurality of bytes already received.

13. A computer program product residing on a computer usable medium for compressing data, wherein each unit of said data is at least two bytes, said computer program product comprising:

computer code means for receiving a data stream;

computer code means for determining whether or not an identical data byte occurs at a pre-selected interval within a plurality of bytes already received, as each byte from said data stream is received; and

computer code means for passing only a portion of a subsequent unit of data from said data stream to an output, in response to a determination that an identical data byte occurs at a pre-selected interval within a plurality of bytes already received.

14. The computer program product according to claim 13, wherein said each unit of said data is a UNICODE byte-pair.

15. The computer program product according to claim 13, wherein said computer code means for determining further includes a computer code means for determining whether or not an identical data byte occurs at an even-ordered predecessor location within a plurality of bytes already received.

16. The computer program product according to claim 15, wherein said computer code means for determining further includes a computer code means for determining whether or not an identical data byte occurs at three or more even-ordered predecessor locations.

17. The computer program product according to claim 13, wherein said computer program product further includes a program code means for exiting said program code means for passing when a preselected exit character is encountered within said data stream.

18. The computer program product according to claim 13, wherein said computer program product further includes a computer code means for passing each byte of a subsequent data unit to an output, in response to a determination that an identical data byte does not occur at a pre-selected interval within a plurality of bytes already received.