Code point translation for computer text, using state tables

• US 6,055,365 A
• Filed: 11/04/1997
• Issued: 04/25/2000
• Est. Priority Date: 11/08/1996
• Status: Expired due to Term

• Current Assignee: Computer Associates Think Inc. (Broadcom, Inc.)
• Original Assignee: Sterling Software, Inc. (Northrop Grumman Corporation)
• Inventors: Tye, Timothy T.
• Primary Examiner(s): Hafiz, Tariq R.
• Assistant Examiner(s): Vo, Ted T.
• Application Number:
  US08/963,891
• Time in Patent Office: 903 Days
• Field of Search: 717/1, 717/2, 717/3, 717/4, 717/5, 717/6, 717/7
• US Class Current: 716/123
• CPC Class Codes: G06F 8/51 Source to source

Abstract

A method of using a computer (11) to translate a source text file (10) to a destination text file (15). The source text file (11) is written with code points from one code page; whereas the destination text file (15) is written with code points from another code page. The computer (11) accesses a state table library (13a) and executes a translate process (13b). A state table (25) from the library (13a) has rows of cells, each row being associated with a different state. Each cell contains or implies a next state and may also contain an output code point sequence. During translation, the table (25) uses a current state to select a row and uses an input code point sequence from the source text file to select a table entry. The input code point sequence is processed until an output code point is produced. For multi-byte translations, the table (25) has a cells containing a state that results in reprocessing of input code point sequences.

Claims

1. A method of using a computer to translate a source text whose glyphs and control codes are represented by a string of code points from a set of source code points to a destination text whose glyphs and control codes are represented by a string of code points from a set of destination code points, comprising the steps of:

accessing a translation state table, said translation state table having at least one row of cells, each said row having an associated state value, and said cells being indexed by said source code points;

using a current state to select a row of said translation state table;

using an input code point sequence from said source text to select a cell within said row;

if said cell contains a next state value, repeating said steps of using said current state and of using an input code point sequence until a desired destination code point sequence is provided;

updating said current state with a next state value;

repeating said steps of using a current state, using an input code point sequence, and repeating, for each next input code point sequence.

2. The method of claim 1, wherein said step of repeating said steps of using said current state and of using an input code point sequence is repeated until said cell contains a destination code point sequence and does not contain a next state.

3. The method of claim 1, wherein said updating step is performed with a next state implied by said cell.

4. The method of claim 1, wherein said table represents translation of single-byte code points to single-byte code points, and wherein said cells contain said destination code points, and where in said next state is the current state.

5. The method of claim 1, wherein said table represents translation of multi-byte code points to multi-byte code points, wherein said table has at least one row whose cells contain either a destination code point sequence or a next state.

6. The method of claim 1, wherein said table represents translation of multi-byte code points to multi-byte code points, and wherein said table has at least one row whose cells result in re-processing of said input code point sequence.

7. The method of claim 1, wherein said table represents translation of multi-byte code points to multi-byte code points, and wherein said table has at least one row whose cells contain both a destination code point sequence and a next state.

8. The method of claim 1, wherein said table represents translation of multi-byte code points to multi-byte code points, and wherein said table has at least one row that maps each input code point sequence to a true or false value thereby providing for a conditional destination code point sequence.

9. The method of claim 1, wherein said input code point sequence is a single byte of a multi-byte code point.

10. The method of claim 1, wherein said input code point sequence is an entire multi-byte code point.

11. A method of generating a state table for use in translating a source text whose glyphs and control codes are represented by a string of code points from a set of source code points to a destination text whose glyphs and control codes are represented by a string of code points from a set of destination code points, comprising the steps of:

assigning a common identifier to gylphs and control codes used in both said source text and said destination text;

creating a source code page definition file containing each source code point and its associated common identifier;

creating a destination code page definition file containing each destination code point and its associated common identifier;

reading a source code point in said source code page definition file and using said common identifier to locate a destination code point in said destination code page definition file, thereby locating a table entry for said source code point, wherein said table entry may represent either a state value or an output destination code point sequence;

determining a row of said table in which to place said table entry, said row having an associated state;

placing said table entry in said row; and

repeating said steps of reading, determining, and placing for each of said source code points.

12. The method of claim 11, wherein said step of determining a row is performed by placing said table entry in a row whose cells contain said destination code points, and wherein said next state is the current state.

13. The method of claim 11, wherein said step of determining a row is performed by placing said table entry in a row whose cells contain either a destination code point sequence or a next state.

14. The method of claim 11, wherein said step of determining a row is performed by placing said table entry in a row whose cells result in re-processing of said input code point sequence.

15. The method of claim 11, wherein said step of determining a row is performed by placing said table entry in a row whose cells contain both a destination code point sequence and a next state.

16. The method of claim 11, wherein said step of determining a row is performed by placing said table entry in a row that maps each input code point sequence to a true or false value thereby providing for a conditional destination code point sequence.