php - PHP的内置函数是如何在内部实现的？

这些函数的编写方式是否与用户函数相同？我是说用php代码和正则表达式之类的东西？例如：VShttp://www.totallyphp.co.uk/code/validate_an_email_address_using_regular_expressions.htm (adsbygoogle = window.adsbygoogle || []).push({}); 最佳答案 php是用c编写的，php函数是用高质量的c代码编写的，然后编译成php语言库。如果您想扩展php（编辑/编写）自己的函数，请查看：http://www.php.net/~wez/extending-php.pdf编辑：干得好：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); }}下面是您的验证电子邮件程序：--这回答了你的问题。是的，它是由regex内部完成的。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 }}/* }}} */ (adsbygoogle = window.adsbygoogle || []).push({});