US5142282A
Expired / Lapsed
US
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Data compression dictionary access minimization
Assignee: HP Inc
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Filing: 1990-11-07
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Granted: 1992-08-25
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Expires: 2010-11-07
Abstract
Abstract A logic circuit in an integrated circuit implementation of an adaptive data compression algorithm which uses a RAM to store dictionary entries. The logic circuit generates predetermined codewords for single-character strings without accessing the dictionary. The logic circuit also generates single-character strings for corresponding codewords without accessing the dictionary.
Inventors
- 👤 Jeffrey P. Tobin
- 👤 Carl B. Lantz
- 👤 Jeff J. Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:16
CPC Classifications
H; H03; H03M; H03M7/00; H03M7/30; H03M7/3084
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
157 words
A system for compressing a character stream, comprising: (a) dictionary means for storing codewords; (b) compressor means for processing the character stream according to a predetermined adaptive compression strategy which substitutes codewords for both single-character strings and multiple-character strings, where the codewords for the multiple-character strings are selected during processing of the character stream, the compression strategy having a predetermined set of codewords for single-character strings, each of said codewords for single-character string being equal to a sum of a predetermined positive offset and a corresponding one of said single-character strings, said compressor means storing the selected codewords for multiple-character strings in said dictionary means; and (c) logic means, connected between said compressor means and said dictionary means, for generating one of said predetermined set of codewords for single-character strings in response to receiving a first single-character string and a control single from said compressor means by adding said predetermined positive offset to said first single-character strings.
Claim 2
Independent Claim
157 words
A system for compressing a character stream, comprising: (a) dictionary means for storing codewords; (b) compressor means for processing the character stream according to a predetermined adaptive compression strategy which substitutes codewords for both single-character strings and multiple-character strings, where the codewords for the multiple-character strings are selected during processing of the character stream, the compression strategy having a predetermined set of codewords for single-character strings, each of said codewords for single-character string being equal to a sum of a predetermined positive offset and a corresponding one of said single-character strings, said compressor means storing the selected codewords for multiple-character strings in said dictionary means; and (c) logic means, connected between said compressor means and said dictionary means, for generating one of said predetermined set of codewords for single-character strings in response to receiving a first single-character string and a control single from said compressor means by adding said predetermined positive offset to said first single-character strings.
Claim 3
Independent Claim
153 words
A system for decompressing a codeword stream, comprising: (a) dictionary means for storing codewords; (b) decompressor means for processing the codeword stream according to a predetermined adaptive decompression strategy which substitutes both single-character nd multiple-character strings for codewords, where the codewords for the multiple-character strings are determined during processing of the codewords stream, the decompression strategy having a predetermined set of codewords for single-character strings, each of said codewords for said single-character strings being equal to a sum of a predetermined positive offset and a corresponding one of said single-character strings, said decompressor means storing the determined codewords for multiple-character strings in said dictionary means; and (c) logic means, connected between said decompressor means and said dictionary means for generating a single-character string corresponding to one of said predetermined set of codewords in response to receiving a first codeword from said decompressor means by subtracting said predetermined positive offset from said first codeword.
Claim 4
Independent Claim
153 words
A system for decompressing a codeword stream, comprising: (a) dictionary means for storing codewords; (b) decompressor means for processing the codeword stream according to a predetermined adaptive decompression strategy which substitutes both single-character nd multiple-character strings for codewords, where the codewords for the multiple-character strings are determined during processing of the codewords stream, the decompression strategy having a predetermined set of codewords for single-character strings, each of said codewords for said single-character strings being equal to a sum of a predetermined positive offset and a corresponding one of said single-character strings, said decompressor means storing the determined codewords for multiple-character strings in said dictionary means; and (c) logic means, connected between said decompressor means and said dictionary means for generating a single-character string corresponding to one of said predetermined set of codewords in response to receiving a first codeword from said decompressor means by subtracting said predetermined positive offset from said first codeword.
References Cited (Backward Citations)
US4814746A
Cited
US4558302A
Cited
US4558302B1
Cited
US4881075A
Cited
US4847619A
Cited
US4929946A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |