Step-by-step preparation of PHP extensions

Step-by-step preparation of PHP extensions

1. Preface With the rapid development of the Internet and the prevalence of lamp architecture, php supports more and more extensions, which directly promotes the development of php. However, php also has an inevitable problem with the scripting language. There are many differences in the performance ratio, such as C, among other compiled languages. Therefore, it is best to use php extension to solve the problem of performance. So, how to make a php extension. The following is an example (C basics are required in this article ). 2. solve a problem In a system, if the sum of squares of an array is often required, we can write it like this. Function array_square_sum ($ data ){ $ Sum = 0; Foreach ($ data as $ value ){ $ Sum + = $ value * $ value; } Return $ sum; } During actual execution, the php zend Engine translates this passage into a C language, and memory allocation is required each time. Therefore, the performance is poor. Furthermore, based on performance considerations, we can write an extension to do this. 3. write extensions Building an extension requires at least two files. One is the Configulator file, which will tell the compiler which dependent libraries are required to compile this extension at least, and the second is the actually executed file. 3.1 generate framework It sounds complicated. In fact, there is a tool that can help us deal with an extended framework. There is an ext_skel tool in the php source code, which can help us generate an extension framework. Liujun @ ubuntu :~ /Test/php-5.5.8/ext $ ls ext_skel Ext_skel Now we use it to generate the extended array_square_sum. ($ Indicates the prompt command) $./Ext_skel -- extname = array_square_sum Creating directory array_square_sum Creating basic files: config. m4 config. w32. svnignore array_square_sum.c php_array_square_sum.h credits experimental tests/001. phpt array_square_sum.php [done]. To use your new extension, you will have to execute the following steps: 1. $ cd .. 2. $ vi ext/array_square_sum/config. m4 3. $./buildconf 4. $./configure -- [with | enable]-array_square_sum 5. $ make 6. $./php-f ext/array_square_sum/array_square_sum.php 7. $ vi ext/array_square_sum/array_square_sum.c 8. $ make Repeat steps 3-6 until you are satisfied with ext/array_square_sum/config. m4 and Step 6 confirms that your module is compiled into PHP. Then, start writing Code and repeat the last two steps as often as necessary. After executing the command, the terminal tells us how to produce new extensions. Check the file content and find several more important files: config. m4, php_array_square_sum.h, and array_square_sum.c. Liujun @ ubuntu :~ /Test/php-5.5.8/ext $ ll array_square_sum/ Total 44 Drwxr-xr-x 3 liujun 4096 Jan 29 :40 ./ Drwxr-xr-x 80 liujun 4096 Jan 29 ../ -Rw-r -- 1 liujun 5548 Jan 29 array_square_sum.c -Rw-r -- 1 liujun 532 Jan 29 array_square_sum.php -Rw-r -- 1 liujun 2354 Jan 29 config. m4 -Rw-r -- 1 liujun 366 Jan 29 config. w32 -Rw-r -- 1 liujun 16 Jan 29 :40 CREDITS -Rw-r -- 1 liujun 0 Jan 29 15:40 EXPERIMENTAL -Rw-r -- 1 liujun 3112 Jan 29 php_array_square_sum.h -Rw-r -- 1 liujun 16 Jan 29 :40. svnignore Drwxr-xr-x 2 liujun 4096 Jan 29 tests/ 3.2 configuration file config. m4 Dnl PHP_ARG_WITH (array_square_sum, for array_square_sum support, Dnl Make sure that the comment is aligned: Dnl [-- with-array_square_sum Include array_square_sum support]) Remove dnl PHP_ARG_WITH (array_square_sum, for array_square_sum support, Make sure that the comment is aligned: [-- With-array_square_sum Include array_square_sum support]) This is. /The minimum requirement for the enable-sample option to be called during configure. the second parameter of PHP_ARG_ENABLE will be in. /displayed when the extended configuration file is reached during configure processing. the third parameter will be executed by the end user. /configure -- help is displayed as help information 3.3 header files Modify php_array_square_sum.h, and change role to confirm_array_square_sum. this is the name of the function actually called in the future. of course, you can add the function confirm_array_square_sum without deleting the role. PHP_FUNCTION (confirm_array_square_sum_compiled ); The PHP_FUNCTION (array_square_sum ); Source code 3.3 Modify array_square_sum.c, and change sums to confirm_array_square_sum. this is the function for registering this extension. if The struct is directly added to 3.2, you can add confirm_array_square_sum in this step. Const zend_function_entry array_square_sum_functions [] = { PHP_FE (confirm_array_square_sum_compiled, NULL)/* For testing, remove later .*/ PHP_FE_END/* Must be the last line in array_square_sum_functions [] */ }; Change Const zend_function_entry array_square_sum_functions [] = { PHP_FE (array_square_sum, NULL)/* For testing, remove later .*/ PHP_FE_END/* Must be the last line in array_square_sum_functions [] */ }; Then, rewrite confirm_array_square_sum in the most critical step. in this case, you only need to rewrite the statement to confirm_array_square_sum (the statement is not deleted in 3.1, so you need to add confirm_array_square_sum ). PHP_FUNCTION (confirm_array_square_sum_compiled) Rewrite PHP_FUNCTION (array_square_sum) { Zval * array_data; HashTable * ht_data; Int ret; Char * key; Uint index; Zval ** pdata; Double sum = 0; If (zend_parse_parameters (ZEND_NUM_ARGS () TSRMLS_CC, "a", & array_data) = FAILURE ){ Return; } Ht_data = Z_ARRVAL_P (array_data ); Zend_hash_internal_pointer_reset (ht_data ); While (HASH_KEY_NON_EXISTANT! = (Ret = zend_hash_get_current_key (ht_data, & key, & index, 0 ))){ Ret = zend_hash_get_current_data (ht_data, & pdata ); If (Z_TYPE_P (* pdata) = IS_LONG ){ Sum + = Z_LVAL_P (* pdata) * Z_LVAL_P (* pdata ); } Else { RETURN_FALSE; } Zend_hash_move_forward (ht_data ); } Zend_hash_internal_pointer_end (Z_ARRVAL_P (array_data )); RETVAL_DOUBLE (sum ); } Php is a weak language, and its data is stored in the zval structure (for details, see more professional materials, such as "phpextended development pipeline "). Typedef union _ zval { Long lval; Double dval; Struct { Char * val; Int len; } Str; HashTable * ht; Zend_object_value obj; } Zval; To obtain the parameters passed by the function, you can use the zend_parse_parameters () API function. The following is a prototype of the function: Zend_parse_parameters (int num_args TSRMLS_DC, char * type_spec ,...); The first few parameters of the zend_parse_parameters () function can be directly generated using the macro in the kernel. the format is ZEND_NUM_ARGS () TSRMLS_CC. Note that there is a space between the two, but there is no comma. It can be seen from the name that ZEND_NUM_ARGS () represents the number of this parameter. Followed by a common parameter type (similar to the C language printf), followed by a list of common parameters. The following table lists common parameter types. Parameter type Object C type Description L Long Integer B Bool Boolean S Char * String D Double Floating point number A Array (zval *) Array Z Zval * Uncertainty zval In addition, the array is implemented by a large hashtable, so zend_hash_get_current_key can traverse the array and use the macro Z_LVAL_P (zval *) to obtain the actual value. Finally, you can put the result into sum. RETVAL_DOUBLE (value) is also a macro. the returned result is double and the value is value. for details, see "phpextended development detail ". Finally, the development of the main function is completed. 3.4 generate the configure file Then execute ~ /Php/bin/phpize /Home/liujun/php/bin/phpize Processing ING: PHP Api Version: 20121113 Zend Module Api No: 20121212 Zend Extension Api No: 220121212 It can be found that the executable script configure appears in array_square_sum. 3.5 Compile It is best to include the php-config PATH when compiling, because the default php-config-path in the system may not be your current php PATH. Liujun @ ubuntu :~ /Test/php-5.5.8/ext/array_square_sum $./configure -- with-php-config =/home/liujun/php/bin/php-config If the compilation is successful, the terminal will prompt as follows: Creating libtool Appending configuration tag "CXX" to libtool Configure: creating./config. status Config. status: creating config. h Config. status: config. h is unchanged View the module directory of the array_square_sum directory and you will find that array_square_sum.so is generated in it. this is the extension we need. Liujun @ ubuntu :~ /Test/php-5.5.8/ext/array_square_sum $ ls modules/ Array_square_sum.la array_square_sum.so 4. use extension 4.1 and configuration extension Modify the php configuration php. ini and add the configuration content. [Array_square_sum] Extension = array_square_sum.so 4.2 Add module Php extensions are generally found in $ PHP_PATH/lib/php/extensions/no-debug-non-zts-yyyymmdd. if you cannot find them, baidu or Google. there are many. so file. Copy array_sum_square.so produced in 3.5. If fastcgi mode is used, restart php. in this case, we should have extended array_square_sum in php. for details, see phpinfo (not Baidu orGoogle ). 4.2 Write code Since writing extensions can improve the running efficiency, here we use extensions and directly use php code to compare and test the performance. Multiple experiments can reduce the error. Therefore, 2000 times are performed to calculate the sum of squares of the 100000 numbers. The code is as follows: $ Data = array (); $ Max_index = 100000; $ Test_time = 2000; For ($ I = 0; $ I <$ max_index; $ I ++ ){ $ Data [] = $ I; } $ Php_test_time_start = time (); Php_test ($ test_time, $ data ); $ Php_test_time_stop = time (); Echo "php test ext time is". ($ php_test_time_stop-$ php_test_time_start). "\ n "; $ C_test_time_start = time (); C_test ($ test_time, $ data ); $ C_test_time_stop = time (); Echo "php test time is". ($ c_test_time_stop-$ c_test_time_start). "\ n "; Function php_test ($ test_time, $ test_data ){ For ($ I = 0; $ I <$ test_time; $ I ++ ){ $ Sum = 0; Foreach ($ test_data as $ data ){ $ Sum + = $ data * $ data; } } } Function c_test ($ test_time, $ test_data ){ For ($ I = 0; $ I <$ test_time; $ I ++ ){ $ Sum = array_square_sum ($ test_data ); } } The test results are as follows: Liujun @ ubuntu :~ /Php $ ~ /Php/bin/php test. php Php test ext time is 30 Php test time is 2 It can be seen that the extension is 15 times faster than using php directly. As the business logic becomes more complex, the difference will increase. Then we can directly use the C language to do this. The following code is also provided for testing (the test conditions are exactly the same ): # Include # Include # Include # Define TEST_TIME 2000 # Define MAX_INDEX 100000 Int main () { Int data [MAX_INDEX]; Double sum = 0; For (int I = 0; I Data [I] = I; } Struct timeval start; Struct timeval end; Gettimeofday (& start, NULL ); For (int I = 0; I For (int j = 0; j Sum + = data [j] * data [j]; } } Gettimeofday (& end, NULL ); Double time = (end. TV _sec-start. TV _sec) + (end. TV _usec-start. TV _usec) * 1.0/1000000; Printf ("total time is % lf \ n", time ); Printf ("sum time is % lf \ n", sum ); Return 0; } Run the command to check the effect. it can be seen that the time to directly use C is only 0.261746, which is 13.09% of the C extension and 0.87% of php. Of course, if complicated operations such as I/O are involved, C/C ++ will be ten thousand times faster than php (tested ). Liujun @ ubuntu :~ /Php $ g ++ test. cpp-O2-o test Liujun @ ubuntu :~ /Php $./test Total time is 0.261746 Sum time is 36207007178615872.000000 Therefore, in actual services that have high performance requirements, such as indexing and word segmentation, you can use C for a set of underlying services and php for encapsulation and calling.