zlib: PHP 4.0.4 - PHP 4.2.3 (systems with fopencookie only)
compress.zlib:// and compress.bzip2:// PHP 4.3 and up
zlib:
compress.zlib://
compress.bzip2://
zlib: works like gzopen(), except that the stream can be used with fread() and the other filesystem functions. This is deprecated as of PHP 4.3 due to ambiguities with filenames containing ':' characters; use compress.zlib:// instead.
compress.zlib:// and compress.bzip2:// are equivalent to gzopen() and bzopen() respectively, and operate even on systems that do not support fopencookie.