Advanced guide to the underlying development principles of PHP7: Learn the advanced features and techniques of the PHP kernel

Advanced guide to the underlying development principles of PHP7: Learn the advanced features and techniques of the PHP kernel

Introduction

With the rapid development of the Internet, PHP has become One of the most popular scripting languages. In the development process of PHP, the release of PHP7 can be said to be an important milestone. PHP7 not only brings new features and performance improvements, but also provides more low-level development opportunities. In this article, we will explore the underlying development principles of PHP7, as well as some advanced features and techniques.

1. The underlying development principles of PHP7

1. Kernel architecture

Before understanding the underlying development principles of PHP7, first understand the kernel architecture of PHP7. The core of PHP7 is composed of multiple modules, the core module of which is Zend Engine. Zend Engine is the core of the PHP language interpreter and is responsible for parsing and executing PHP code. In addition, PHP7 also includes some extension modules to provide various functions and features.

2. Compilation process

In PHP7, the compilation process of PHP code can be divided into two stages: lexical analysis and syntax analysis. The task of lexical analysis is to convert the source code into tokens, while the task of syntactic analysis is to build a syntax tree based on these tokens. Through these two stages, the PHP code will eventually be compiled into a series of instructions and then executed by Zend Engine.

2. Advanced features and techniques of PHP kernel

1. Zval

In PHP7, Zval (Zend Value) is a very important data structure . Zval is used to save the value and type information of PHP variables. Through Zval, PHP implements dynamic typing of variables and automatic memory management. In the underlying development, we can implement some advanced features and techniques by operating Zval.

The following is a simple example:

zval myVar;
ZVAL_STRING(&myVar, "Hello PHP");
php_printf("%s", Z_STRVAL(myVar));

In the above code, we create a Zval variable myVar and set its value to the string "Hello PHP". Then, through the Z_STRVAL macro, we can get the value of myVar and output it.

2. Memory Management

In PHP7, memory management is a very important topic. PHP7 introduces new APIs for memory management (such as zend_mm and zend_string), which can manage memory resources more efficiently.

The following is a sample code:

zend_string *str;
str = zend_string_init("Hello PHP", strlen("Hello PHP"), 0);
php_printf("%s", ZSTR_VAL(str));
zend_string_release(str);

In the above code, we use the zend_string_init function to create a string object and set its value to "Hello PHP". Then, through the ZSTR_VAL macro, we can get the value of the string and output it. Finally, the memory of the string object is released through the zend_string_release function.

3. Extension development

The underlying development of PHP7 also includes extension development. By developing extensions, we can extend PHP with new functionality and features.

The following is an example of extension development:

#include "php.h"

zend_function_entry my_functions[] = {
    PHP_FE(my_function, NULL)
    {NULL, NULL, NULL}
};

PHP_FUNCTION(my_function)
{
    php_printf("This is my function
");
}

zend_module_entry my_module_entry = {
    STANDARD_MODULE_HEADER,
    "my_module",
    my_functions,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    "1.0",
    ZEND_MODULE_GLOBALS(my_module),
    PHP_MODULE_SHUTDOWN_N(my_module),
    NULL,
    STANDARD_MODULE_PROPERTIES_EX
};

#ifdef COMPILE_DL_MY_MODULE
ZEND_GET_MODULE(my_module)
#endif

The above code is a simple example of extension development. We define a function called my_function and register it in the my_functions array. Then, register the function as a PHP module by defining a zend_module_entry structure. Finally, the module is exported as a dynamic extension via the ZEND_GET_MODULE macro.

Conclusion

In this article we have learned about the underlying development principles of PHP7, as well as some advanced features and techniques. By learning the underlying development of the PHP kernel, we can better understand the working principle of PHP7 and further improve our programming skills and performance optimization capabilities. I hope this article will be helpful to readers who are interested in low-level development.

Reference:

1. PHP Internals Book - https://www.phpinternalsbook.com/
2. Zend Engine - https://www.php.net /manual/en/internals2.thin-layer.php

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