Method and system for processing mixed binary length encodings containing definite and indefinite length formats

• US 5,436,627 A
• Filed: 05/21/1993
• Issued: 07/25/1995
• Est. Priority Date: 04/30/1992
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited, Ricoh Corporation (Ricoh Company Limited)
• Inventors: Motoyama, Tetsuro, Mangat, Satwinder S.
• Primary Examiner(s): Young, Brian K.
• Application Number:
  US08/066,383
• Time in Patent Office: 795 Days
• Field of Search: 341/67, 341/81, 341/82, 341/59, 375/19, 360/45, 369/59
• US Class Current: 341/67
• CPC Class Codes: G06F 3/1297 Printer code translation, conversion, emulation, compression; Configuration of printer parameters
• CPC Class Codes: G06F 40/103 Formatting, i.e. changing of presentation of documents automatic justification G06F40/189; automatic line break hyphenation G06F40/191
• CPC Class Codes: G06F 40/151 Transformation
• CPC Class Codes: G06F 40/154 Tree transformation for tree-structured or markup documents, e.g. XSLT, XSL-FO or stylesheets
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 15/1828 characterized by the kind of storage accessed
• CPC Class Codes: G06K 15/1849 using an intermediate representation, e.g. a list of graphical primitives
• CPC Class Codes: G06K 2215/0011 characterised by a particular command or data flow, e.g. Page Description Language, configuration commands

Abstract

A method and apparatus for processing binary mixed indefinite and definite length encodings. The length of a definite length encoding is stated at the beginning of the encoding whereas for an indefinite length encoding, the length is unknown. The present invention processes encodings which contain indefinite length encodings with definite length encodings nested therein by keeping track of the levels of nesting. When a definite length encoding is being processed which is nested within an indefinite length encoding, the end of the indefinite length encoding cannot be searched for as data within the definite length encoding might be identical to the flag or marker which signifies the end of the indefinite length encoding. A stack can be used to keep track of the number of bytes within a definite length encoding which have been processed. As an indefinite length encoding within a definite length encoding is being processed, the stack keeps track of the number of bytes within the indefinite length encoding which have been processed as those bytes within the indefinite length encoding are part of the definite length encoding.

Claims

1. An apparatus for processing mixed definite length and indefinite length encodings, comprising:

a communication means for receiving a document data stream having mixed definite length and indefinite length encodings, both of which have preamble and content information;

a processing means, connected to the communication means, for processing the document data stream having mixed definite length and indefinite length encodings; and

a temporary storage means, connected to the processing means, for storing the preamble information of the definite length and indefinite length encodings as the processing means is processing the document data stream,

wherein the temporary storage means comprises;

a stack for storing length information contained in the preamble information of the definite length encoding.

2. An apparatus according to claim 1, wherein a top entry of the stack is for storing the length information of the definite length encoding, and as the definite length encoding is being processed, the processing means decrements the top entry in the stack by the number of bytes of the definite length encoding which have been processed.

3. A method of processing an indefinite length encoding having at least one definite length encoding nested therein, wherein both the indefinite length encoding and the at least one definite length encoding contain preamble information and content information, comprising the sequential steps of:

(A) processing a portion of bytes of the indefinite length encoding;

(B) processing bytes of said at least one definite length format encoding nested therein;

(C) processing bytes of said indefinite length encoding which have not been processed in step (A).

4. A method according to claim 3, wherein step (B) further comprises the substeps of:

pushing a length of the definite length encoding onto a stack; and

as the definite length encoding is being processed, decrementing the length of the definite length encoding on the stack by a number of bytes of the definite length encoding which have been processed.

5. A method according to claim 3, wherein step (B) further comprises the substeps of:

storing a length of the definite length encoding in a temporary storage device; and

as the definite length encoding is being processed, decrementing the length of the definite length encoding in the temporary storage buffer by a number of bytes of the definite length encoding which have been processed.

6. A method of processing an indefinite length encoding having a definite length encoding nested therein, both the indefinite length encoding and the definite length encoding containing preamble information and content information, comprising the steps:

processing the preamble information of the indefinite length encoding;

processing the content information of the indefinite length encoding which contains the definite length encoding, by performing the steps;

processing the preamble information of the definite length encoding to determine a number of bytes of content information of the definite encoding, and;

processing the content information of the definite length encoding by processing bytes until the number of the bytes of the content information of the encoding have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding;

examining bytes of the indefinite length encoding after the content information of the definite length encoding for a marker indicating an end of the indefinite length encoding, after processing the content information of the definite length encoding; and

terminating the processing of the indefinite length encoding if bytes after the content information of the definite length encoding indicate an end of the indefinite length encoding.

7. A method according to claim 6, further comprising the step:

processing the bytes subsequent to the definite length encoding as a subsequent nested procedure within the indefinite length encoding if the bytes subsequent to the content information of the definite length encoding do not indicate an end of the indefinite length encoding.

8. A method of processing an indefinite length encoding having a definite length encoding nested therein, both the indefinite length encoding and the definite length encoding containing preamble information and content information, comprising the steps:

processing the preamble information of the indefinite length encoding;

processing the content information of the indefinite length encoding which contains the definite length encoding, by performing the steps;

processing preamble information of the definite length encoding to determine a number of bytes of content information of the definite encoding, and storing the number of bytes of the content information of the definite encoding in a temporary storage means, and;

processing the content information of the definite length encoding by processing bytes until the number of bytes of content information stored in the temporary storage means have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the definite length encoding is being processed, counting in said temporary storage means, the number of bytes of the definite length encoding which have been processed;

examining bytes of the encoding after the content information of the definite length encoding for bytes indicating an end of the indefinite length encoding, after processing the content information of the definite length encoding; and

terminating the processing of the indefinite length encoding if bytes subsequent to the contents of the definite length encoding indicate an end of the indefinite length encoding.

9. A method according to claim 8, wherein the step of storing the number of bytes of the content information of the definite length encoding pushes the length information onto a stack;

and

the step of processing the content information of the definite length encoding processes bytes until the number of bytes of content on the stack have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the definite length encoding is being processed, counting in said stack, the number of bytes of the definite length encoding which have been processed.

10. A method of processing a first definite length encoding having an indefinite length encoding nested therein, the indefinite length encoding having nested therein a second definite length encoding, the indefinite length encoding and the first and second definite length encodings each containing preamble information and content information, comprising the steps:

processing the preamble information of the first definite length encoding;

processing the content information of the first definite length encoding by performing the steps;

processing the preamble information of the indefinite length encoding and as the preamble information of the indefinite length encoding is being processed, counting in a first entry in a storage means, the number of bytes of the preamble information of the indefinite length encoding which have been processed;

processing the content information of the indefinite length encoding, by performing the steps;

processing the preamble information of the second definite length encoding to determine a number of bytes of the content information of the second definite length encoding and storing in a second entry of the temporary storage means, the number of bytes of the content information of the second definite length encoding, and as the preamble information of the second definite length encoding is being processed, counting in the first entry of the temporary storage means, the number of bytes of the second definite length encoding which have been processed, and;

processing the content information of the second definite length encoding by processing the second definite length encoding until the number of bytes of content information of the second definite length encoding have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the second definite length encoding is being processed, counting in said second entry of the temporary storage means, the number of bytes of the definite length encoding which have been processed;

examining bytes of the encoding after the content information of the second definite length encoding for bytes indicating an end of the indefinite length encoding, after processing the content information of the second definite length encoding;

terminating the processing of the indefinite length encoding, if bytes subsequent to the content information of the second definite length encoding indicate an end of the indefinite length encoding; and

processing subsequent bytes of content of the first definite length encoding until all bytes of the first definite length encoding have been processed.

11. An apparatus for processing mixed definite length and indefinite length encodings, comprising:

a communication means for receiving a document data stream having mixed definite length and indefinite length encodings, both of which have preamble and content information;

a processing means, connected to the communication means, for processing the document data stream having mixed definite length and indefinite length encodings and for processing an SPDL document data stream; and

a temporary storage means, connected to the processing means, for storing the preamble information of the definite length and indefinite length encodings as the processing means is processing the document data stream.

12. A system for processing an indefinite length encoding having a definite length encoding nested therein, both the indefinite length encoding and the definite length encoding containing preamble information and content information, comprising:

means for processing the preamble information of the indefinite length encoding;

means for processing the content information of the indefinite length encoding which contains the definite length encoding, including;

means for processing the preamble information of the definite length encoding to determine a number of bytes of content information of the definite encoding; and

means for processing the content information of the definite length encoding by processing bytes until the number of the bytes of the content information of the encoding have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding;

means for examining bytes of the indefinite length encoding after the content information of the definite length encoding for a marker indicating an end of the indefinite length encoding, after processing the content information of the definite length encoding; and

means for terminating the processing of the indefinite length encoding if bytes after the content information of the definite length encoding indicate an end of the indefinite length encoding.

13. A system according to claim 12, further comprising:

means for processing the bytes subsequent to the definite length encoding as a subsequent nested procedure within the indefinite length encoding if the bytes subsequent to the content information of the definite length encoding do not indicate an end of the indefinite length encoding.

14. A system for processing an indefinite length encoding having a definite length encoding nested therein, both the indefinite length encoding and the definite length encoding containing preamble information and content information, comprising:

means for processing the preamble information of the indefinite length encoding;

means for processing the content information of the indefinite length encoding which contains the definite length encoding, including;

means for processing preamble information of the definite length encoding to determine a number of bytes of content information of the definite encoding, and storing the number of bytes of the content information of the definite encoding in a temporary storage means; and

means for processing the content information of the definite length encoding by processing bytes until the number of bytes of content information stored in the temporary storage means have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the definite length encoding is being processed, counting in said temporary storage means, the number of bytes of the definite length encoding which have been processed;

means for examining bytes of the encoding after the content information of the definite length encoding for bytes indicating an end of the indefinite length encoding, after processing the content information of the definite length encoding; and

means for terminating the processing of the indefinite length encoding if bytes subsequent to the contents of the definite length encoding indicate an end of the indefinite length encoding.

15. A method according to claim 14, wherein the means for storing the number of bytes of the content information of the definite length encoding pushes the length information onto a stack;

and

the means for processing the content information of the definite length encoding processes bytes until the number of bytes of content on the stack have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the definite length encoding is being processed, counting in said stack, the number of bytes of the definite length encoding which have been processed.

16. A system for processing a first definite length encoding having an indefinite length encoding nested therein, the indefinite length encoding having nested therein a second definite length encoding, the indefinite length encoding and the first and second definite length encodings each containing preamble information and content information:

means for processing the preamble information of the first definite length encoding;

means for processing the content information of the first definite length encoding including;

means for processing the preamble information of the indefinite length encoding and as the preamble information of the indefinite length encoding is being processed, counting in a first entry in a storage means, the number of bytes of the preamble information of the indefinite length encoding which have been processed;

means for processing the content information of the indefinite length encoding, including;

means for processing the preamble information of the second definite length encoding to determine a number of bytes of the content information of the second definite length encoding and storing in a second entry of the temporary storage means, the number of bytes of the content information of the second definite length encoding, and as the preamble information of the second definite length encoding is being processed, counting in the first entry of the temporary storage means, the number of bytes of the second definite length encoding which have been processed; and

means for processing the content information of the second definite length encoding by processing the second definite length encoding until the number of bytes of content information of the second definite length encoding have been processed without determining whether a marker indicating an end of the indefinite length encoding exists in the encoding, and as the content information of the second definite length encoding is being processed, counting in said second entry of the temporary storage means, the number of bytes of the definite length encoding which have been processed;

means for examining bytes of the encoding after the content information of the second definite length encoding for bytes indicating an end of the indefinite length encoding, after processing the content information of the second definite length encoding;

means for terminating the processing of the indefinite length encoding, if bytes subsequent to the content information of the second definite length encoding indicate an end of the indefinite length encoding; and

means for processing subsequent bytes of content of the first definite length encoding until all bytes of the first definite length encoding have been processed.