php实用功能小记

1.任意数目的参数

function fun(){
    $args = func_get_args();
    foreach ($args as $k => $v) {
        echo "arg".($k+1).":";
        var_dump($v);
        echo "<br>";
    }
}
fun();

echo "<hr>";
fun(11,'22',[22,33]);
echo "<hr>";

2.glob()

glob()函数返回匹配指定模式的文件名或目录。

可以使用glob函数来查找文件，也可以实现目录的遍历。

遍历当前目录下所有php文件

$files = glob('*.php');
var_dump($files);

Array ( [0] => algorithm.php [1] => createDatabaseDoc.php [2] => createDatabaseDoc1.php [3] => index.php [4] => jsonToMarkDown.php )

遍历当前目录下所有php和html文件

$files = glob('*.{php,html}', GLOB_BRACE);
print_r($files);

Array ( [0] => algorithm.php [1] => createDatabaseDoc.php [2] => createDatabaseDoc1.php [3] => index.php [4] => jsonToMarkDown.php [5] => dic.html )

带路径的

$files = glob('../*.{php,html}', GLOB_BRACE);
print_r($files);

Array ( [0] => ../test.php [1] => ../testwebservice.php [2] => ../aa.html [11] => ../bb.html [3] => ../element.html )

获取绝对路径

$files = glob('../*.{php,html}', GLOB_BRACE);
$files = array_map('realpath',$files);
print_r($files);

Array ( [0] => D:WWW est.php [1] => D:WWW estwebservice.php [2] => D:WWWaa.html [3] => D:WWWelement.html )

3.内存使用信息

memory_get_usage()能返回当前分配给PHP脚本的内存量，单位是字节（byte）

memory_get_peak_usage()函数返回内存使用峰值

echo "Initial: ".memory_get_usage()." bytes <br>";
// 使用内存
for ($i = 0; $i < 100000; $i++) {
    $array []= md5($i);
}
echo "center: ".memory_get_usage()." bytes <br>";
// 删除一半的内存
for ($i = 0; $i < 100000; $i++) {
    unset($array[$i]);
}
echo "Final: ".memory_get_usage()." bytes <br>";
echo "Peak: ".memory_get_peak_usage()." bytes <br>";

Initial: 375448 bytes 
center: 10169816 bytes 
Final: 4569816 bytes 
Peak: 10169888 bytes 

4.cpu使用信息

getrusage()返回CUP使用情况

print_r(getrusage());

Array ( [ru_majflt] => 14843 [ru_maxrss] => 19532 [ru_utime.tv_usec] => 717604 [ru_utime.tv_sec] => 0 [ru_stime.tv_usec] => 31200 [ru_stime.tv_sec] => 0 )

ru_majflt 页失效

ru_maxrss 最大驻留集大小

ru_utime.tv_usec 用户态时间 (microseconds)

ru_utime.tv_sec 用户态时间(seconds)

ru_stime.tv_usec 系统内核时间 (microseconds)

ru_stime.tv_sec 系统内核时间(seconds)

for($i=0;$i<10000000;$i++) {

}
$data = getrusage();
echo "User time: ".($data['ru_utime.tv_sec'] +$data['ru_utime.tv_usec'] / 1000000);
echo "<br>";
echo "System time: ".($data['ru_stime.tv_sec'] +$data['ru_stime.tv_usec'] / 1000000);

User time: 0.156001
System time: 0.0312

5.系统常量当前的行号 __LINE__

print_r( "Line ".__LINE__);

6.生成唯一的id

echo uniqid()."<br>";
echo uniqid('XYZ_')."<br>";
echo uniqid('',true)."<br>";
echo uniqid('XYZ_',true)."<br>";

5cda679f156c6
XYZ_5cda679f15aae
5cda679f15e967.34610847
XYZ_5cda679f1627e6.70270663

7.序列化、json转换

序列化

$old = [
    'abc',
    [1,'xx'],
    '111'
];
$string = serialize($old);
print_r($string);
echo "<br>";
$new = unserialize($string);
print_r($new);

a:3:{i:0;s:3:"abc";i:1;a:2:{i:0;i:1;i:1;s:2:"xx";}i:2;s:3:"111";}
Array ( [0] => abc [1] => Array ( [0] => 1 [1] => xx ) [2] => 111 )

$old = [
    'abc',
    [1,'xx'],
    '111'
];
$string = json_encode($old);
print_r($string);
echo "<br>";
$new = json_decode($string);
print_r($new);

["abc",[1,"xx"],"111"]
Array ( [0] => abc [1] => Array ( [0] => 1 [1] => xx ) [2] => 111 )

8.字符串压缩

压缩函数：gzcompress gzdeflate gzencode

解压函数：gzuncompress gzinflate gzdecode

gzcompress使用的是ZLIB格式；

gzdeflate使用的是纯粹的DEFLATE格式；

gzencode使用的是GZIP格式；

压缩数据时都使用了DEFLATE压缩算法

性能的维度看：DEFLATE好于 GZIP好于 ZLIB
从文本文件默认压缩率压缩后体积的维度看：DEFLATE好于 ZLIB好于 GZIP

（1）gzcompress和 gzuncompress

$string =
"Aspose.Slides for Java can be used with any kind of application either it's a Web or Desktop Application. Moreover, Aspose.Slides for Java also provides fully featured demos and working examples for developers to have a better understanding of the API.
Aspose.Slides for Java can not only open PowerPoint files from different sources, but it also allows you to save your presentations in a variety of ways. For example, you can save your presentation in not only PPT. Moreover, you can also save your slides as images. Aspose.Slides for Java gives you almost all those features that you may or may not find in Microsoft PowerPoint. The versatility of Aspose.Slides for Java is that you can not only add tables and different kinds of shapes to your slides, but also different kinds of frames (that is text, audio and video frames).";
// 压缩
$compressed = gzcompress($string);
echo "Original size: ". strlen($string)."<br>";
echo "Compressed size: ". strlen($compressed)."<br>";
// 解压缩
$original = gzuncompress($compressed);

Original size: 831
Compressed size: 407

（2）gzdeflate 和 gzinflate

$string =
"Aspose.Slides for Java can be used with any kind of application either it's a Web or Desktop Application. Moreover, Aspose.Slides for Java also provides fully featured demos and working examples for developers to have a better understanding of the API.
Aspose.Slides for Java can not only open PowerPoint files from different sources, but it also allows you to save your presentations in a variety of ways. For example, you can save your presentation in not only PPT. Moreover, you can also save your slides as images. Aspose.Slides for Java gives you almost all those features that you may or may not find in Microsoft PowerPoint. The versatility of Aspose.Slides for Java is that you can not only add tables and different kinds of shapes to your slides, but also different kinds of frames (that is text, audio and video frames).";
// 压缩
$compressed = gzdeflate($string);
echo "Original size: ". strlen($string)."<br>";
echo "Compressed size: ". strlen($compressed)."<br>";
// 解压缩
$original = gzinflate($compressed);

Original size: 831
Compressed size: 401

（3）gzencode 和 gzdecode

$string =
"Aspose.Slides for Java can be used with any kind of application either it's a Web or Desktop Application. Moreover, Aspose.Slides for Java also provides fully featured demos and working examples for developers to have a better understanding of the API.
Aspose.Slides for Java can not only open PowerPoint files from different sources, but it also allows you to save your presentations in a variety of ways. For example, you can save your presentation in not only PPT. Moreover, you can also save your slides as images. Aspose.Slides for Java gives you almost all those features that you may or may not find in Microsoft PowerPoint. The versatility of Aspose.Slides for Java is that you can not only add tables and different kinds of shapes to your slides, but also different kinds of frames (that is text, audio and video frames).";
// 压缩
$compressed = gzencode($string);
echo "Original size: ". strlen($string)."<br>";
echo "Compressed size: ". strlen($compressed)."<br>";
// 解压缩
$original = gzdecode($compressed);

Original size: 831
Compressed size: 419

$string =
"As an example, with traditional programming, the main function of an application might make function calls into a menu library to display a list of available commands and query the user to select one.[4] The library thus would return the chosen option as the value of the function call, and the main function uses this value to execute the associated command. This style was common in text based interfaces. For example, an email client may show a screen with commands to load new mail, answer the current mail, start a new mail, etc., and the program execution would block until the user presses a key to select a command.
With inversion of control, on the other hand, the program would be written using a software framework that knows common behavioral and graphical elements, such as windowing systems, menus, controlling the mouse, and so on. The custom code 'fills in the blanks' for the framework, such as supplying a table of menu items and registering a code subroutine for each item, but it is the framework that monitors the user's actions and invokes the subroutine when a menu item is selected. In the mail client example, the framework could follow both the keyboard and mouse inputs and call the command invoked by the user by either means, and at the same time monitor the network interface to find out if new messages arrive and refresh the screen when some network activity is detected. The same framework could be used as the skeleton for a spreadsheet program or a text editor. Conversely, the framework knows nothing about Web browsers, spreadsheets or text editors; implementing their functionality takes custom code.
Inversion of control carries the strong connotation that the reusable code and the problem-specific code are developed independently even though they operate together in an application. Software frameworks, callbacks, schedulers, event loops, dependency injection, and the template method are examples of design patterns that follow the inversion of control principle, although the term is most commonly used in the context of object-oriented programming.";
echo "Original size: ". strlen($string)."<br>";
$gzcompress = gzdeflate($string);
echo "gzcompress Compressed size: ". strlen($gzcompress)."<br>";$gzdeflate =  gzdeflate($string);
echo "gzdeflate Compressed size: ". strlen($gzdeflate)."<br>";$gzencode = gzencode($string);
echo "gzencode Compressed size: ". strlen($gzencode)."<br>";

Original size: 2096
gzcompress Compressed size: 967
gzdeflate Compressed size: 967
gzencode Compressed size: 985

9.注册停止函数

register_shutdown_function()这个函数，能够在脚本终止前回调注册的函数，也就是当 PHP 程序执行完成后执行的函数。

$clean = false;
function shutdown_func()
{
    global $clean;
    if (!$clean) {
        die("not a clean shutdown");
    }
    return false;
}
$a     = 1;
$a     = new FooClass(); // 将因为致命错误而失败
$clean = true;

Fatal error: Uncaught Error: Class 'FooClass' not found in D:WWWshowdocalgorithm.php:14 Stack trace: #0 {main} thrown in D:WWWshowdocalgorithm.php on line 14

<?php

$clean = false;
function shutdown_func()
{
    global $clean;
    if (!$clean) {
        die("not a clean shutdown");
    }
    return false;
}
register_shutdown_function("shutdown_func");
$a     = 1;
$a     = new FooClass(); // 将因为致命错误而失败
$clean = true;

Fatal error: Uncaught Error: Class 'FooClass' not found in D:WWWshowdocalgorithm.php:14 Stack trace: #0 {main} thrown in D:WWWshowdocalgorithm.php on line 14
not a clean shutdown

register_shutdown_function执行机制是：

　　PHP把要调用的函数调入内存。当页面所有PHP语句都执行完成时，再调用此 函数。

　　在这个时候从内存中调用，不是从PHP页面中调用，所以上面的例子不能使用相对路径，因为PHP已经当原来的页面不存在了

调用条件：
1、当页面被用户强制停止时
2、当程序代码运行超时时
3、当ＰＨＰ代码执行完成时，代码执行存在异常和错误、警告