VIII. 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).

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