DETERMINING CHARACTER SEQUENCE DIGEST

• US 20150242203A1
• Filed: 02/21/2014
• Published: 08/27/2015
• Est. Priority Date: 02/21/2014
• Status: Active Grant

• Current Assignee: Red Hat Israel Ltd. (International Business Machines Corporation)
• Original Assignee: Red Hat Israel Ltd. (International Business Machines Corporation)
• Inventors: Tsirkin, Michael
• Granted Patent: US 9,304,766 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 8/71 Version control security arrangements therefor G06F21/57; Configuration management

Abstract

Systems and methods for determining a character sequence digest. An example method may comprise: identifying, within a character sequence, one or more sections, wherein each section comprises a section header and one or more section bodies; performing the following operations for each identified section body: responsive to determining that the section body is not preceded by a section header, prepending a section header to the section body; calculating a section digest by applying a hash function to the section comprising the section header and the section body; and calculating a digest of the character sequence by applying a symmetric summing operation to one or more section digests.

Claims

1. A method, comprising:

identifying, within a character sequence, one or more sections, wherein each section comprises a section header and one or more section bodies;

for each identified section body;

responsive to determining that the section body is not preceded by a section header, prepending the section header to the section body;

calculating a section digest by applying a hash function to a respective section comprising the section header and the section body; and

calculating a digest of the character sequence by applying a symmetric summing operation to one or more section digests.

2. The method of claim 1, wherein the hash function is provided by a SHA-1 function.

3. The method of claim 1, wherein the symmetric summing operation is provided by an addition operation.

4. The method of claim 1, wherein identifying a section comprises identifying a first pre-defined text pattern.

5. The method of claim 1, further comprising:

discarding one or more carry bits that have been set by the symmetric summing operation.

6. The method of claim 1, wherein the character sequence represents a code patch.

7. The method of claim 6, wherein the section header comprises at least one of:

a name of an original file or a name of a new file.

8. The method of claim 6, wherein the section body comprises at least one of:

a line range definition for an original file or a line range definition for a new file.

9. A method, comprising:

identifying a section header within a character sequence;

calculating a section header digest by applying a hash function to the section header;

identifying, within the character sequence, a section body following the section header;

initializing a section digest with the section header digest;

calculating the section digest by applying the hash function to the section body; and

calculating a digest of the character sequence by applying a symmetric summing operation to one or more section digests.

10. The method of claim 9, further comprising:

repeating, until an end of the character sequence is reached, the operations of identifying a section header, calculating a header digest, identifying a section body, initializing a section digest, and calculating the section digest.

11. The method of claim 9, wherein the hash function is provided by a SHA-1 function.

12. The method of claim 9, wherein identifying a section header comprises identifying a first pre-defined text pattern.

13. The method of claim 9, wherein identifying a section body comprises identifying a second pre-defined text pattern.

14. The method of claim 9, wherein the symmetric summing operation is provided by an addition operation.

15. The method of claim 9, further comprising:

discarding one or more carry bits that have been set by the symmetric summing operation.

16. The method of claim 9, wherein the character sequence represents a code patch.

17. A system comprising:

a memory; and

one or more processors, coupled to the memory, to;

identify, within a character sequence, one or more sections, wherein each section comprises a section header and one or more section bodies;

perform the following operations for each identified section body;

responsive to determining that the section body is not preceded by a section header, prepend the section header to the section body;

calculate a section digest by applying a hash function to a respective section comprising the section header and the section body; and

calculate a digest of the character sequence by applying a symmetric summing operation to one or more section digests.

18. The system of claim 17, wherein the hash function is provided by a SHA-1 function.

19. A computer-readable non-transitory storage medium comprising executable instructions that, when executed by a computer system, cause the computer system to:

identify a section header within a character sequence;

calculate a section header digest by applying a hash function to the section header;

identify, within the character sequence, a section body following the section header;

initialize a section digest with the section header digest;

calculate the section digest by applying the hash function to the section body; and

calculating a digest of the character sequence by applying a symmetric summing operation to one or more section digests.

20. The computer-readable non-transitory storage medium of claim 19, further comprising executable instructions causing the computer system to:

repeat, until an end of the character sequence is reached, the operations of identifying a section header, calculating a header digest, identifying a section body, initializing a section digest, and calculating the section digest.