Functions for reading and writing gzip(.gz) compressed files transparently. The Zlib extension was added in PHP 3 and works with zlib version >= 1.0.9. Zlib was written by Jean-loup Gailly and Mark Adler. Zlib is a lossless data-compression library that can be used virtually anywhere. Its data format can span multiple platforms. Additional information can be found at www.gzip.org/zlib.