How Computers Compress Data Using Dictionary Building

This patent details a system that shrinks data, like text or files, making them take up less space. It works by reading through the data and building a 'dictionary' of frequently occurring sequences of characters, called strings. When it finds a string in the data that's already in its dictionary, it replaces that string with a short code. If it finds a string that's not quite in the dictionary but is close, it adds a new, longer string to the dictionary. This new string is made up of the longest matching string it found and the very next character in the data. The system uses a clever 'hashing' technique to quickly search its dictionary for matches. To get the original data back, a separate 'decompressor' uses the same dictionary-building logic to reconstruct the data from the codes.

The clever bit

The innovation lies in dynamically building the dictionary on the fly. Instead of needing a pre-defined dictionary, the compressor learns the data's patterns as it goes, creating new dictionary entries from the longest match found plus the next character. This adaptive approach makes it highly effective for a wide variety of data.

What it does not cover

• ×Data compression that doesn't involve building a dictionary of previously seen strings.
• ×Compression methods that don't use a 'longest match' strategy to find patterns.
• ×Systems that don't use a hashing function to speed up dictionary lookups.
• ×Decompression methods that don't reconstruct the dictionary in a similar way to the compressor.
• ×Compression that doesn't extend a matched string with the next input character to create a new dictionary entry.

Heuristic Value Estimate

What this patent might be worth

$96K – $307K

Midpoint $192K · expired or expiring · industry ×1.6