The last evolution of our dynamic codes is known as lightweight D-ETDC and D-SCDC. These new techniques take advantage of the simple ETDC and SCDC encoding schemas in order to create "more stable" codewords, such that the codeword associated to a given word does not vary during the dynamic update() process (see Section DETDC) unless not changing it would lead to a loss of compression.

As the number of changes of codewords during the compression process is very small, it is feasible that the compressor/sender can notify all of them to the decompressor/receiver, so the receiver can be much more "lightweight" and fast. Moreover, as the codewords are much more stable, it is possible to perform searches inside the compressed text without decompression using Boyer-Moore type searching.

DLETDC was first presented in [brisaboa et al. SIGIR 2005].

A more recent paper has been published at ACM-Transactions on Information Systems (TOIS) in 2010 including improvements on DLETDC, and including also a DLSCDC, a new dynamic lightweight compressor based on D-SCDC. [brisaboa et al. TOIS 2010].

Psedocode for both DLETDC compressor and decompressor follows:

Psedocode for DLSCDC compressor and decompressor is shown in the next figure. Apart from the operations done by DLETDC, it also include the checking needed to detect when the coding parameter "s" has to change.

Supported in part by Ministerio de Ciencia e Innovación (PGE and FEDER) [TIN2006-15071-C03-03, TIN2009-14560-C03-02, TIN2010-21246-C02-01, and CDTI CEN-20091048]; Xunta de Galicia (Feder) [2010/17] and (Agrupación Estratéxica) [CN 2012/211]; and Fondecyt [1-110066]