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PHP bz2 compression extension tool installation process, I believe many inexperienced people are helpless, for this reason this article summarizes the causes of the problem and solutions, through this article I hope you can solve this problem.

PHP bz2 compression extension tool

In daily development and computer use, we often come into contact with some tools for compression and decompression, PHP also prepared a lot of related operation expansion packages for us, there are directly available functions to facilitate the operation of some compression and decompression functions. Today, we'll start with a simpler but less commonly used compression format: Bzip2.

installation extension

Installation of this extension requires that the system has bzip2-devel. So we need to install support for this package first, and then this extension is distributed with PHP installation packages, so just compile PHP and install it in./ Add the corresponding compile command to configure.

# yum install bzip2-devel

# ./ configure xxxx --with-bz2

# make && make install

basic operation

Bzip2 provides few functions and is very simple, we first look at saving strings to a file.

$bz = bzopen('/tmp/test.bz', 'w');

// -rw-r--r-- 1 root root 14 Jun 28 09:51 test.bz

$text = "This is Bz Compress";

bzwrite($bz, $text);

// -rw-r--r-- 1 root root 59 Jun 28 09:53 test.bz

bzclose($bz);

$bz = bzopen('/tmp/test.bz', 'r');

$v = bzread($bz);

echo $v, PHP_EOL;

// This is Bz Compress

bzclose($bz);

Just like file manipulation functions, we need to first open the file to get the handle via bzopen(). Then use bzwrite() to write to the file and bzread() to read the file. Finally use bzclose() to close the file.

Note here that the second argument to bzopen(), which is the form of the file open, can only be written as "w" or "r". There are no other types, and they cannot be read and written simultaneously, that is, they cannot be written in the form "wr." So we have to write the file and then use "r" to open the file to read.

Read length setting $bz = bzopen ('/tmp/test.bz'r');

$v = bzread($bz, 10);

echo $v, PHP_EOL;

// This is Bz

$v = bzread($bz);

echo $v, PHP_EOL;

// Compress

bzclose($bz);

The second argument to bzread() is an optional byte length, which defaults to 1024 bytes and can read up to 8192 uncompressed bytes at a time.

string encoding

The Bzip2 extension also gives us functions that encode strings directly. This way our compressed content can be saved to the file every time, if it is the same string, the function encoded with the string and the content output to the file is the same garbled binary content.

$str = "Test compress String";

$bzstr = bzcompress($str, 9);

echo $bzstr, PHP_EOL;

// BZh91AY&SY��J���@

//

// �� 1

// df����2�h>.�p�!��//

$newStr = bzdecompress($bzstr);

echo $newStr, PHP_EOL;

$chineseStr = "Test";

$bzstr = bzcompress($chineseStr, 9);

echo bzdecompress($bzstr), PHP_EOL;

bzcompress() is used to encode and compress the string. The second parameter is the compression ratio. 9 is the highest level. The encoded content is non-human binary garbled content. bzdecompress() is used to decode encoded content. I believe many friends have discovered that this can be used to encrypt some confidential content transmission. Also, in the test code, we can see that it is also normally supported for Chinese.

error message

Finally, let's look at Bzip2's error-handling functions.

$bz = bzopen('/tmp/test.bz', 'r');

bzwrite($bz, 'aaa');

print_r(bzerror($bz));

// Array

// (

// [errno] => -1

// [errstr] => SEQUENCE_ERROR

// )

echo bzerrno($bz), PHP_EOL; // -1

echo bzerrstr($bz), PHP_EOL; // SEQUENCE_ERROR

bzclose($bz);

We first created an error environment. Use "r" to open the file and get the handle, then write to the file. bzerror() returns an array of error messages containing the error number and error message content. bzerrno() and bzerrstr() return the error number and error content separately. Three very simple and understandable functions.

This extension is still very simple, the most important is Bzip2 this compressed file type is not a very common type, so there may not be many people who know. But we did find a bit of a surprise, which is that it provides string codec functions, so that these two functions can be used as a means of encrypting information in some scenarios.

After reading the above, do you know how to install the PHP bz2 compression extension tool? If you still want to learn more skills or want to know more related content, welcome to pay attention to the industry information channel, thank you for reading!

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