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LXXIX. Zlib Compression Functions

This module uses the functions of zlib by Jean-loup Gailly and Mark Adler to transparently read and write gzip (.gz) compressed files. You have to use a zlib version >= 1.0.9 with this module.

This module contains versions of most of the filesystem functions which work with gzip-compressed files (and uncompressed files, too, but not with sockets).

Note: The current CVS version 4.0.4-dev introduces a fopen-wrapper for .gz-files, so that you can use a special 'zlib:' URL to access compressed files transparently using the normal f*() file access functions if you prepend the filename or path with a 'zlib:' prefix when calling fopen().

This feature requires a C runtime library that provides the fopencookie() function. To my current knowledge the GNU libc is the only library that provides this feature.

Small code example

Opens a temporary file and writes a test string to it, then it prints out the content of this file twice.

Example 1. Small Zlib Example

<?php  $filename = tempnam ('/tmp', 'zlibtest').'.gz'; print "<html>\n<head></head>\n<body>\n<pre>\n"; $s = "Only a test, test, test, test, test, test, test, test!\n";  // open file for writing with maximum compression $zp = gzopen($filename, "w9");  // write string to file gzwrite($zp, $s);  // close file gzclose($zp);  // open file for reading $zp = gzopen($filename, "r");  // read 3 char print gzread($zp, 3);  // output until end of the file and close it. gzpassthru($zp);  print "\n";  // open file and print content (the 2nd time). if (readgzfile($filename) != strlen($s)) {         echo "Error with zlib functions!"; } unlink($filename); print "</pre>\n</h1></body>\n</html>\n";  ?>      
Table of Contents
gzclose — Close an open gz-file pointer
gzeof — Test for end-of-file on a gz-file pointer
gzfile — Read entire gz-file into an array
gzgetc — Get character from gz-file pointer
gzgets — Get line from file pointer
gzgetss — Get line from gz-file pointer and strip HTML tags
gzopen — Open gz-file
gzpassthru — Output all remaining data on a gz-file pointer
gzputs — Write to a gz-file pointer
gzread — Binary-safe gz-file read
gzrewind — Rewind the position of a gz-file pointer
gzseek — Seek on a gz-file pointer
gztell — Tell gz-file pointer read/write position
gzwrite — Binary-safe gz-file write
readgzfile — Output a gz-file
gzcompress — Gz-compress a string
gzuncompress — Uncompress a gz-compressed string