Method and apparatus for transporting interface definition language-defined data structures between heterogeneous systems

• US 5,860,072 A
• Filed: 07/11/1996
• Issued: 01/12/1999
• Est. Priority Date: 07/11/1996
• Status: Expired due to Term

• Current Assignee: Tantau Software, Inc. (Constellation Software Incorporated)
• Original Assignee: Tandem Computers Incorporated (HP Inc.)
• Inventors: Schofield, Andrew
• Primary Examiner(s): Lintz, Paul R.
• Assistant Examiner(s): RONES, CHARLES
• Application Number:
  US08/680,203
• Time in Patent Office: 915 Days
• Field of Search: 704/8, 345/335, 395/200.33, 395/553, 395/182.11, 395/701, 395/682, 395/683, 395/185.1, 379/100.07
• US Class Current: 707/756
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation

Abstract

A method and apparatus for transporting IDL-defined data structures to and from a format convenient for transport between two computers are disclosed. The data structures is originally described in a string. The string description is converted to a different format containing additional information about the alignment and size of the data structure. An application in the sending computer removes the alignment from the data structure and stores the data structure in a buffer. The data structure is stored in the output buffer in a predetermined format that is based upon the type of the data structure. The buffer is then transmitted to a data file or to the memory of the receiving computer. The receiving computer extracts the data structure from the buffer based upon the predetermined format. The data structure is realigned and stored in the memory of the second computer.

Claims

1. A method for transporting a data structure from a host computer to a client computer, the data structure having at least one field, the method comprising the steps of:

generating, by the host computer, a string description of the data structure;

generating, by the host computer, a host description of the string description, the host description describing the size, alignment, and type of each field in the data structure as used within the host computer;

generating, by the client computer, a client description of the string description, the client description describing the size, alignment, and type of each field in the data structure as used within the client computer;

packing, by the host computer, the data structure in an output buffer of the host computer based upon the description in the host description; and

transporting, by the host computer, the output buffer to an input buffer of the client computer.

2. A method for transporting a data structure, as recited in claim 1, further comprising the step, performed by the client computer, of:

generating a second data structure using the input buffer and the client description.

3. A method for transporting a data structure, as recited in claim 2, wherein the step of packing by the host computer further comprises the steps, performed by the host computer, of:

storing floating point and double type components of the data structure in a format for representing floating point numbers;

storing long, long long, unsigned long, unsigned long long, short, and unsigned short type components of the data structure in a format for representing integers; and

storing character type components of the data structure in a format for representing characters.

4. A method for transporting a data structure, as recited in claim 2, wherein the step of packing by the host computer comprises the steps, performed by the host computer, of:

converting "any" type components of the data structure to an unsigned long that specifies a length of the string description, the string description, and components of the "any" data structure;

storing the unsigned long in the format for representing integers;

storing the string as an unsigned long indicating the length of the string followed by a plurality of characters;

storing each of the plurality of characters in the format for representing characters; and

storing each component of the "any" data structure according to a predetermined format.

5. A method for transporting a data structure, as recited in claim 2, wherein the step of packing by the host computer further comprises the steps, performed by the host computer, of:

storing elements of an array component of the data structure in an unpadded format;

storing a sequence component of the data structure in the format for representing integers;

converting a string component of the data structure to an unsigned long type indicating a length of the string, followed by a plurality of characters;

storing the unsigned long representing the string component of the data structure in the format for representing integers; and

storing each of the plurality of characters in the format for representing characters.

6. A method for transporting a data structure, as recited in claim 2, wherein the format for storing floating point numbers is IEEE format.

7. A method for transporting a data structure, as recited in claim 2, wherein the format for storing floating point numbers is TANDEM T16 format.

8. A method for transporting a data structure, as recited in claim 2, wherein the format for storing integers specifies that byte significance of an integer decreases with increasing address.

9. A method for transporting a data structure, as recited in claim 2, wherein the format for storing integers specifies that byte significance of an integer increases with increasing address.

10. A method for transporting a data structure, as recited in claim 2, wherein the format for storing characters is ISO Latin-1.

11. A computer program product comprising:

a computer usable medium having computer readable code embodied therein for transporting a data structure from a host computer to a client computer, the computer program product comprising;

first computer readable program code devices configured to cause the host computer system to generate a string description of the data structure;

second computer readable program code devices configured to cause the host computer system to generate a host description, the host description describing the size, alignment, and type of each field in the data structure as used within the host computer;

third computer readable program code devices configured to cause the client computer system to generate a client description, the client description describing the size, alignment, and type of each field in the data structure as used within the client computer;

fourth computer readable program code devices configured to cause the host computer system to pack the data structure in an output buffer of the host computer based upon the description in the host description; and

fifth computer readable program code devices configured to cause the host computer system to transport the output buffer to an input buffer of the client computer.

12. A computer program product, as recited in claim 11, further comprising:

sixth computer readable program code devices configured to cause the client computer system to generate a second data structure using the input buffer and the client description.

13. A computer program product, as recited in claim 12, wherein the fourth computer readable program code devices are further configured to cause the host computer to:

store floating point and double type components of the data structure in a format for representing floating point numbers;

store long, long long, unsigned long, unsigned long long, short, and unsigned short type components of the data structure in a format for representing integers; and

store character type components of the data structure in a format for representing characters.

14. A computer program product, as recited in claim 12, wherein the fourth computer readable program code devices are further configured to cause the host computer to:

convert "any" type components of the data structure to an unsigned long that specifies a length of the string description, the string description, and components of the "any" data structure;

store the unsigned long in the format for representing integers;

store the string as an unsigned long indicating the length of the string followed by a plurality of characters;

store each of the plurality of characters in the format for representing characters; and

store each component of the "any" data structure according to a predetermined format.

15. A computer program product, as recited in claim 12, wherein the fourth computer readable program code devices are further configured to cause the host computer to:

store elements of an array component of the data structure in an unpadded format;

store a sequence component of the data structure in the format for representing integers;

convert a string component of the data structure to an unsigned long type indicating a length of the string, followed by a plurality of characters;

store the unsigned long representing the string component of the data structure in the format for representing integers; and

store each of the plurality of characters in the format for representing characters.

16. A computer program product, as recited in claim 12, wherein the format for storing floating point numbers is IEEE format.

17. A computer program product, as recited in claim 12, wherein the format for storing floating point numbers is TANDEM T16 format.

18. A computer program product, as recited in claim 12, wherein the format for storing integers specifies that byte significance of an integer decreases with increasing address.

19. A computer program product, as recited in claim 12, wherein the format for storing integers specifies that byte significance of an integer increases with increasing address.

20. A computer program product, as recited in claim 12, wherein the format for storing characters is ISO Latin-1.

21. A system for transporting a data structure from a host computer to a client computer, the system comprising:

means within the host computer system for generating a string description of the data structure;

means within the host computer system for generating a host description, the host description describing the size, alignment, and type of each field in the data structure as used within the host computer;

means within the client computer system for generating a client description, the client description describing the size, alignment, and type of each field in the data structure as used within the client computer;

means within the host computer system for packing the data structure in an output buffer of the host computer based upon the description in the host description; and

means within the host computer system for transporting the output buffer to an input buffer of the client computer.

22. A system for transporting a data structure, as recited in claim 21, further comprising:

means within the client computer system for generating a second data structure using the input buffer and the client description.

23. A system for transporting a data structure, as recited in claim 22, wherein the means within the host computer system for packing the data structure are further configured to:

store floating point and double type components of the data structure in a format for representing floating point numbers;

store long, long long, unsigned long, unsigned long long, short, and unsigned short type components of the data structure in a format for representing integers; and

store character type components of the data structure in a format for representing characters.

24. A system for transporting a data structure, as recited in claim 22, wherein the means within the host computer system for packing the data structure are further configured to:

convert "any" type components of the data structure to an unsigned long that specifies a length of the string description, the string description, and components of the "any" data structure;

store the unsigned long in the format for representing integers;

store the string as an unsigned long indicating the length of the string followed by a plurality of characters;

store each of the plurality of characters in the format for representing characters; and

store each component of the "any" data structure according to a predetermined format.

25. A system for transporting a data structure, as recited in claim 22, wherein the means within the host computer system for packing the data structure are further configured to:

store elements of an array component of the data structure in an unpadded format;

store a sequence component of the data structure in the format for representing integers;

convert a string component of the data structure to an unsigned long type indicating a length of the string, followed by a plurality of characters;

store the unsigned long representing the string component of the data structure in the format for representing integers; and

store each of the plurality of characters in the format for representing characters.

26. A system for transporting a data structure, as recited in claim 22, wherein the format for storing floating point numbers is IEEE format.

27. A system for transporting a data structure, as recited in claim 22, wherein the format for storing floating point numbers is TANDEM T16 format.

28. A system for transporting a data structure, as recited in claim 22, wherein the format for storing integers specifies that byte significance of an integer decreases with increasing address.

29. A system for transporting a data structure, as recited in claim 22, wherein the format for storing integers specifies that byte significance of an integer increases with increasing address.

30. A system for transporting a data structure, as recited in claim 22, wherein the format for storing characters is ISO Latin-1.