Patent Document ID: 4612532
Application ID: 06622547

Base Claim:
1. A system for the dynamic encoding of a stream of characters, the system comprising: an input for receiving the stream of characters; an output for providing encoded data; means, hereinafter referred to as "followset means," connected to the input, for storing, accessing, and updating, for each given character of a plurality of characters, a table listing the set of candidates for the character which may follow the given character in the stream, such table hereinafter referred to as a "followset table"; followset identification means, connected to the input, for identifying the followset table, hereinafter the "given followset table," for that character which immediately precedes a given character in the stream at the input; position encoding means for providing at the output, for the given character, a signal indicative of the position, occupied by the given character, in the followset table identified by the followset identification means; and updating means for updating a given followset table periodically when the position of a candidate therein has been signaled by the encoding means at the output, by interchanging the position of such candidate, unless such candidate is at the top of the followset table, with the position of a candidate thereabove in the given followset table.

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Claim 12:
12. A decoding system for decoding the output of an encoding system according to claim 1, the decoding system comprising: a decoding input for receiving the encoded data from the encoding system; a decoding output for providing a decoded data stream; decoding followset means, connected to the decoding output, for storing, accessing, and updating a followset table, for each of a plurality of characters, listing candidates for the character which may follow in the decoded data stream, the character with which the table is associated; decoding followset identification means, connected to the decoding output, for identifying the followset table for that character which has just been decoded; decoding means, connected to the decoding input, decoding output, and the followset identification means, for providing at the decoding output the character occupying, in that followset table identified by the decoding followset identification means, a position identified by a signal at the decoding input; and updating means for updating a given followset table periodically when the position of a candidate therein has been signaled by the decoding means at the input, by interchanging the position of such candidate, unless such candidate is at the top of the followset table, with the position of a candidate thereabove in the given followset table.