Editing Lossless compression (section)

=== Points of application in real compression theory ===
Real compression algorithm designers accept that streams of high information entropy cannot be compressed, and accordingly, include facilities for detecting and handling this condition.  An obvious way of detection is applying a raw compression algorithm and testing if its output is smaller than its input.  Sometimes, detection is made by [[heuristics]]; for example, a compression application may consider files whose names end in ".zip", ".arj" or ".lha" uncompressible without any more sophisticated detection. A common way of handling this situation is quoting input, or uncompressible parts of the input in the output, minimizing the compression overhead.  For example, the [[ZIP (file format)|zip]] data format specifies the 'compression method' of 'Stored' for input files that have been copied into the archive verbatim.<ref>{{cite web |url=http://www.pkware.com/documents/casestudies/APPNOTE.TXT |title=.ZIP File Format Specification |publisher=[[PKWARE, Inc.]] |at=chapter V, section J}}</ref>