# Bzip2 Compression Functions

## Introduction

The bzip2 functions are used to transparently read and write bzip2 (.bz2) compressed files.

## Requirements

This module uses the functions of the » bzip2 library by Julian Seward. This module requires bzip2/libbzip2 version >= 1.0.x.

## Installation

Bzip2 support in PHP is not enabled by default. You will need to use the --with-bz2[=DIR] configuration option when compiling PHP to enable bzip2 support.

## Runtime Configuration

This extension has no configuration directives defined in php.ini.

## Resource Types

This extension defines one resource type: a file pointer identifying the bz2-file to work on.

## Predefined Constants

This extension has no constants defined.

## Examples

This example opens a temporary file and writes a test string to it, then prints out the contents of the file.

Example#1 Small bzip2 Example

`<?php
$filename = "/tmp/testfile.bz2";
$str = "This is a test string.\n";
// open file for writing
$bz = bzopen($filename, "w");
// write string to file
bzwrite($bz, $str);
// close file
bzclose($bz);
// open file for reading
$bz = bzopen($filename, "r");
// read 10 characters
echo bzread($bz, 10);
// output until end of the file (or the next 1024 char) and close it.
echo bzread($bz);
bzclose($bz);
?>`

## Table of Contents

- bzclose — Close a bzip2 file
- bzcompress — Compress a string into bzip2 encoded data
- bzdecompress — Decompresses bzip2 encoded data
- bzerrno — Returns a bzip2 error number
- bzerror — Returns the bzip2 error number and error string in an array
- bzerrstr — Returns a bzip2 error string
- bzflush — Force a write of all buffered data
- bzopen — Opens a bzip2 compressed file
- bzread — Binary safe bzip2 file read
- bzwrite — Binary safe bzip2 file write