LZ77 is known as the basic loseless data compression algorithm. It is used very wide. For example, common *.png, *.zip, *.gzip, *.jar, *.war file formats use LZ77 compressing algrightm.
For more details about LZ77 algorithm, you may check here.
You can test this compressor on latest Prototype.js, it will compress 70k to 33k (48%) without "RegEx trimming before LZ77" option (loseless, comments left). If with "RegEx trimming before LZ77" option on, there will be compressed to 28k (40%). If Prototype.js is compressed by native compressor, like 7-Zip, it will be 16k (24%).
June 4, 2007 (Last updated: November 22, 2009)