Data compression method and system

A computer-implemented data compression method of compressing an input stream of data, comprising:

• parsing the input stream by dividing the input stream into tokens and assigning a token type to each token;
• searching for a matching sequence of already processed tokens that matches a current sequence of tokens;
• determining that a selected token of the current sequence and a corresponding token of the matching sequence are each of a first token type;
• determining a match length indicating the number of tokens in the matching sequence;
• determining a token offset indicating the number of already processed tokens of the first token type between the current sequence and the matching sequence;
• and
• appending to an encoded data stream a match flag code indicating the token offset and the match length.

A method in a computer system for compressing data, the data comprising a multiplicity of tokens, each token having a token value and one of a plurality of token types, the method comprising the steps of:

• determining the token type of each token;
• finding a matching sequence of tokens having the same token values as a current sequence and having a token with the same token type as a corresponding token in the current sequence;
• and
• representing the current sequence based on a count of tokens having the same token type, the count of tokens indicating a position of the matching sequence.

A data compression system for compressing an input stream of data, comprising:

• a parser that parses the input stream by dividing the input stream into tokens and assigns a token type to each token;
• a match finder that finds a matching sequence of tokens that matches a current sequence of tokens, the matching sequence having a token with the same token type as a corresponding token in the current sequence;
• and
• an encoder that encodes the current sequence as a match code indicating a count of tokens of the same token type, the count of tokens indicating a position of the matching sequence.

A computer storage medium for controlling a computer to compress data, the data including a plurality of tokens, each token having a token value and one of a plurality of token types, comprising:

• computer instructions for determining the token type of each token;
• computer instructions for finding a matching sequence of tokens having the same token values as a current sequence and having a token with the same token type as a corresponding token in the current sequence;
• and
• computer instructions for representing the current sequence based on a count of tokens having the same token type, the count of tokens indicating a position of the matching sequence.

A method in a computer system for decompressing encoded data into decoded data having a multiplicity of tokens, each token having a token value and one of a plurality of token types, the encoded data comprising an encoded match code associated with a matched sequence of tokens, the method comprising the steps of:

• determining the token type of a selected token of the matched sequence;
• determining from the encoded match code a count of tokens having the same token type as the selected token of the matched sequence, the count of tokens indicating a position of a matching sequence of tokens that match the matched sequence of tokens:
• accessing the matching sequence using the count of tokens;
• and
• decoding the matched sequence based on the token values of the matching sequence.

A method in a computer system for compressing a data string having a sequence of data values, each data value having one of a plurality of data value types, the method comprising:

• identifying the data value type of a current data value in the data string;
• determining whether a matching data value and its data value type in the data string matches the current data value and its data value type;
• and
• encoding the current data value based on a count of data values having the same data value type as the current data value, the count of data values indicating a position of the matching data value in the data string.