Data compression apparatus and method
First Claim
1. A data compression system comprising:
- a history array means, said history array means having a plurality of entries, said entries of said history array means for storing an input data stream,a history array pointer, said history array pointer pointing to one of said entries in said history array means,a hash table means having a plurality of entries, each entry of said hash table means for storing a pointer indicating one of said entries of said history array means, andan offset array means, said offset array means having a plurality of entries, and each entry of said offset array means providing a link, if any, from one of said entries in said history array means to one or more other entries of said history array means.
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Accused Products
Abstract
An apparatus and method as disclosed for converting an input data character stream into a variable length encoded data stream in a data compression system. The data compression system includes a history array means. The history array means has a plurality of entries and each entry of the history array means is for storing a portion of the input data stream. The method for converting the input data character stream includes the following steps. Performing a search in a history array means for the longest data string which matches the input data string. If the matching data string is found within the history buffer means, the next step includes encoding the longest matching data string found by appending to the encoded data stream a tag indicating the longest matching data string was found and a string substitution code. If the matching data string is not found within the history array means, the next step includes encoding the first character of the input data string by appending to the encoded data stream a raw data tag indicating that no matching data string was found and the first character of the input data string.
274 Citations
10 Claims
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1. A data compression system comprising:
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a history array means, said history array means having a plurality of entries, said entries of said history array means for storing an input data stream, a history array pointer, said history array pointer pointing to one of said entries in said history array means, a hash table means having a plurality of entries, each entry of said hash table means for storing a pointer indicating one of said entries of said history array means, and an offset array means, said offset array means having a plurality of entries, and each entry of said offset array means providing a link, if any, from one of said entries in said history array means to one or more other entries of said history array means. - View Dependent Claims (2, 3, 4, 5)
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6. A method for compressing data in a data compression system which includes a history array means, said history array means having a plurality of entries, a history array pointer, a hash table means, said hash table means having a plurality of entries, and an offset array means, said offset array means having a plurality of entries, said method comprising the steps of:
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storing an input data stream in said entries of said history array means, pointing to one of said entries in said history array means by said history array pointer, storing a pointer indicating one of said entries of said history array means in each entry of said hash table means, and providing a link by each entry of said offset array means from one of said entries in said history array means to one or more other entries of said history array means. - View Dependent Claims (7, 8, 9, 10)
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Specification