Dynamic dictionary-based data symbol encoding

A non-transitory machine-readable storage media having instructions for performing an encoding method which causes a computing device to:

• register, in a dynamic dictionary data structure, a plurality of evictable dictionary entries that are input symbols from an input data stream with said evictable dictionary entries including first and second evictable dictionary entries;
• encode said evictable dictionary entries with a dictionary index that is shorter than an original representation of the input symbols;
• associate, with each one of said evictable dictionary entries, a reference count that is initialized to a predetermined minimum threshold wherein said reference count is increasable from the predetermined minimum threshold to the predetermined maximum threshold;
• and
• provide a cyclic pointer that rotates among said evictable dictionary entries to determine whether to replace a currently pointed dictionary entry,
• wherein the reference count for the first evictable dictionary entry is reduced by one if:
• (1) an input symbol in the input data stream is different from all dictionary entries, (2) the cyclic pointer is at the first evictable dictionary entry, and (3) the reference count for the first evictable dictionary entry is greater than the predetermined minimum threshold.