PHP 的内置函数是如何在内部实现的？
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【中文标题】PHP 的内置函数是如何在内部实现的？【英文标题】：How are PHP's built-in functions implemented internally? 【发布时间】：2011-08-06 15:05:48 【问题描述】：这些函数的编写方式是否与用户函数相同？我的意思是 php 代码和正则表达式之类的东西？
例如：
filter_var($email, FILTER_VALIDATE_EMAIL);
对比
http://www.totallyphp.co.uk/code/validate_an_email_address_using_regular_expressions.htm
【问题讨论】：
【参考方案1】：PHP 是用 C 语言编写的。PHP 函数是用高质量的 C 代码编写的，然后编译形成 PHP 语言库
如果您想扩展 PHP（编辑/编写）自己的功能，请查看：http://www.php.net/~wez/extending-php.pdf
编辑：
给你：
这是函数的原始 C 代码：
/* proto mixed filter_var(mixed variable [, long filter [, mixed options]])
* Returns the filtered version of the vriable.
*/
PHP_FUNCTION(filter_var)
long filter = FILTER_DEFAULT;
zval **filter_args = NULL, *data;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z/|lZ", &data, &filter, &filter_args) == FAILURE)
return;
if (!PHP_FILTER_ID_EXISTS(filter))
RETURN_FALSE;
MAKE_COPY_ZVAL(&data, return_value);
php_filter_call(&return_value, filter, filter_args, 1, FILTER_REQUIRE_SCALAR TSRMLS_CC);
/* */
static void php_filter_call(zval **filtered, long filter, zval **filter_args, const int copy, long filter_flags TSRMLS_DC) /* */
zval *options = NULL;
zval **option;
char *charset = NULL;
if (filter_args && Z_TYPE_PP(filter_args) != IS_ARRAY)
long lval;
PHP_FILTER_GET_LONG_OPT(filter_args, lval);
if (filter != -1) /* handler for array apply */
/* filter_args is the filter_flags */
filter_flags = lval;
if (!(filter_flags & FILTER_REQUIRE_ARRAY || filter_flags & FILTER_FORCE_ARRAY))
filter_flags |= FILTER_REQUIRE_SCALAR;
else
filter = lval;
else if (filter_args)
if (zend_hash_find(HASH_OF(*filter_args), "filter", sizeof("filter"), (void **)&option) == SUCCESS)
PHP_FILTER_GET_LONG_OPT(option, filter);
if (zend_hash_find(HASH_OF(*filter_args), "flags", sizeof("flags"), (void **)&option) == SUCCESS)
PHP_FILTER_GET_LONG_OPT(option, filter_flags);
if (!(filter_flags & FILTER_REQUIRE_ARRAY || filter_flags & FILTER_FORCE_ARRAY))
filter_flags |= FILTER_REQUIRE_SCALAR;
if (zend_hash_find(HASH_OF(*filter_args), "options", sizeof("options"), (void **)&option) == SUCCESS)
if (filter != FILTER_CALLBACK)
if (Z_TYPE_PP(option) == IS_ARRAY)
options = *option;
else
options = *option;
filter_flags = 0;
if (Z_TYPE_PP(filtered) == IS_ARRAY)
if (filter_flags & FILTER_REQUIRE_SCALAR)
if (copy)
SEPARATE_ZVAL(filtered);
zval_dtor(*filtered);
if (filter_flags & FILTER_NULL_ON_FAILURE)
ZVAL_NULL(*filtered);
else
ZVAL_FALSE(*filtered);
return;
php_zval_filter_recursive(filtered, filter, filter_flags, options, charset, copy TSRMLS_CC);
return;
if (filter_flags & FILTER_REQUIRE_ARRAY)
if (copy)
SEPARATE_ZVAL(filtered);
zval_dtor(*filtered);
if (filter_flags & FILTER_NULL_ON_FAILURE)
ZVAL_NULL(*filtered);
else
ZVAL_FALSE(*filtered);
return;
php_zval_filter(filtered, filter, filter_flags, options, charset, copy TSRMLS_CC);
if (filter_flags & FILTER_FORCE_ARRAY)
zval *tmp;
ALLOC_ZVAL(tmp);
MAKE_COPY_ZVAL(filtered, tmp);
zval_dtor(*filtered);
array_init(*filtered);
add_next_index_zval(*filtered, tmp);
这是您的验证电子邮件程序： ——这回答了你的问题。 是的，它是由内部的正则表达式完成的。
void php_filter_validate_email(PHP_INPUT_FILTER_PARAM_DECL) /* */
/*
* The regex below is based on a regex by Michael Rushton.
* However, it is not identical. I changed it to only consider routeable
* addresses as valid. Michael's regex considers a@b a valid address
* which conflicts with section 2.3.5 of RFC 5321 which states that:
*
* Only resolvable, fully-qualified domain names (FQDNs) are permitted
* when domain names are used in SMTP. In other words, names that can
* be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
* in Section 5) are permitted, as are CNAME RRs whose targets can be
* resolved, in turn, to MX or address RRs. Local nicknames or
* unqualified names MUST NOT be used.
*
* This regex does not handle comments and folding whitespace. While
* this is technically valid in an email address, these parts aren't
* actually part of the address itself.
*
* Michael's regex carries this copyright:
*
* Copyright © Michael Rushton 2009-10
* http://squiloople.com/
* Feel free to use and redistribute this code. But please keep this copyright notice.
*
*/
const char regexp[] = "/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))255,)(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?))65,@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]64,)(?:(?:(?:xn--)?[a-z0-9]+(?:-[a-z0-9]+)*\\.)1,126)1,(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]1,4(?::[a-f0-9]1,4)7)|(?:(?!(?:.*[a-f0-9][:\\]])7,)(?:[a-f0-9]1,4(?::[a-f0-9]1,4)0,5)?::(?:[a-f0-9]1,4(?::[a-f0-9]1,4)0,5)?)))|(?:(?:IPv6:(?:(?:[a-f0-9]1,4(?::[a-f0-9]1,4)5:)|(?:(?!(?:.*[a-f0-9]:)5,)(?:[a-f0-9]1,4(?::[a-f0-9]1,4)0,3)?::(?:[a-f0-9]1,4(?::[a-f0-9]1,4)0,3:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]2)|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]2)|(?:[1-9]?[0-9])))3))\\]))$/iD";
pcre *re = NULL;
pcre_extra *pcre_extra = NULL;
int preg_options = 0;
int ovector[150]; /* Needs to be a multiple of 3 */
int matches;
/* The maximum length of an e-mail address is 320 octets, per RFC 2821. */
if (Z_STRLEN_P(value) > 320)
RETURN_VALIDATION_FAILED
re = pcre_get_compiled_regex((char *)regexp, &pcre_extra, &preg_options TSRMLS_CC);
if (!re)
RETURN_VALIDATION_FAILED
matches = pcre_exec(re, NULL, Z_STRVAL_P(value), Z_STRLEN_P(value), 0, 0, ovector, 3);
/* 0 means that the vector is too small to hold all the captured substring offsets */
if (matches < 0)
RETURN_VALIDATION_FAILED
/* */
【讨论】：
那个正则表达式字符串很大。 php版本不是更快吗？【参考方案2】：PHP 函数是：
用 C 语言而不是 PHP 编写 或者只是其他库提供的函数的包装器（例如，PHP 的 curl 扩展只是 curl 库的包装器）。如果你好奇，可以看看 PHP 的源代码——这里是它的 SVN：http://svn.php.net/viewvc/
例如，filter_var() 函数应该在 filter extension 的源代码中的某处定义。
【讨论】：
【参考方案3】：不。 PHP 内部函数是用 C 编写的，而不是 PHP 代码。由于许多 Zend 运行时宏以及参数如何从 PHP 传输到 C 结构，这看起来相当笨拙。
那个特定的函数确实使用了正则表达式。它也是一个很好的例子：http://svn.php.net/repository/php/php-src/branches/PHP_5_3/ext/filter/logical_filters.c
在中间某处寻找regexp[]。
【讨论】：
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