(no version information, might be only in CVS)
PharFileInfo->setCompressedGZ -- Compresses the current Phar entry within the phar using gz compressionThis method compresses the file inside the Phar archive using gzip compression. The zlib extension must be enabled to take advantage of this feature. In addition, if the file is already compressed using bzip2 compression, the bzip2 extension must be enabled in order to decompress the file. As with all functionality that modifies the contents of a phar, the phar.readonly INI variable must be off in order to succeed.
Throws BadMethodCallException if the phar.readonly INI variable is on, or if the zlib extension is not available.