<?php

/**

 * The plugin API is located in this file, which allows for creating actions

 * and filters and hooking functions, and methods. The functions or methods will

 * then be run when the action or filter is called.

 *

 * The API callback examples reference functions, but can be methods of classes.

 * To hook methods, you'll need to pass an array one of two ways.

 *

 * Any of the syntaxes explained in the PHP documentation for the

 * type are valid.

 *

 * Also see the {@link https://codex.wordpress.org/Plugin_API Plugin API} for

 * more information and examples on how to use a lot of these functions.

 *

 * @package WordPress

 * @subpackage Plugin

 * @since 1.5.0

 */

// Initialize the filter globals.

	$wp_filter = array();

if ( ! isset( $wp_actions ) )

	$wp_actions = array();

if ( ! isset( $wp_current_filter ) )

	$wp_current_filter = array();

/**

 * Hook a function or method to a specific filter action.

 *

 * WordPress offers filter hooks to allow plugins to modify

 * various types of internal data at runtime.

 *

 * A plugin can modify data by binding a callback to a filter hook. When the filter

 * is later applied, each bound callback is run in order of priority, and given

 * the opportunity to modify a value by returning a new value.

 *

 * The following example shows how a callback function is bound to a filter hook.

 *

 * Note that `$example` is passed to the callback, (maybe) modified, then returned:

 *

 *     function example_callback( $example ) {

 *         // Maybe modify $example in some way.

 *     }

 *     add_filter( 'example_filter', 'example_callback' );

 *

 *

 *

 * @since 0.71

 *

 * @global array $wp_filter      A multidimensional array of all hooks and the callbacks hooked to them.

 *

 * @param string   $tag             The name of the filter to hook the $function_to_add callback to.

 * @param int      $priority        Optional. Used to specify the order in which the functions

 *                                  associated with a particular action are executed. Default 10.

 *                                  Lower numbers correspond with earlier execution,

 *                                  and functions with the same priority are executed

 *                                  in the order in which they were added to the action.

 * @param int      $accepted_args   Optional. The number of arguments the function accepts. Default 1.

 */

function add_filter( $tag, $function_to_add, $priority = 10, $accepted_args = 1 ) {

	return true;

}

/**

 * Check if any filter has been registered for a hook.

 *

 * @since 2.5.0

 *

 * @global array $wp_filter Stores all of the filters.

 *

 * @param string        $tag               The name of the filter hook.

 */

function has_filter($tag, $function_to_check = false) {

	}

}

/**

 * Call the functions added to a filter hook.

 *

 * The callback functions attached to filter hook $tag are invoked by calling

 * this function. This function can be used to create a new filter hook by

 * simply calling this function with the name of the new hook specified using

 * the $tag parameter.

 *

 * The function allows for additional arguments to be added and passed to hooks.

 *

 *     // Our filter callback function

 *     function example_callback( $string, $arg1, $arg2 ) {

 *         // (maybe) modify $string

 *         return $string;

 *     }

 *     add_filter( 'example_filter', 'example_callback', 10, 3 );

 *

 *     /*

 *      * Apply the filters by calling the 'example_callback' function we

 *      * "hooked" to 'example_filter' using the add_filter() function above.

 *      * - 'example_filter' is the filter hook $tag

 *      * - 'filter me' is the value being filtered

 *      * - $arg1 and $arg2 are the additional arguments passed to the callback.

 *     $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );

 *

 * @since 0.71

 *

 * @global array $wp_filter         Stores all of the filters.

 * @global array $wp_current_filter Stores the list of current filters with the current one last.

 *

 * @return mixed The filtered value after all hooked functions are applied to it.

 */

function apply_filters( $tag, $value ) {

	$args = array();

	// Do 'all' actions first.

	if ( isset($wp_filter['all']) ) {

		$wp_current_filter[] = $tag;

		$args = func_get_args();

		_wp_call_all_hook($args);

	}

	if ( !isset($wp_filter[$tag]) ) {

		if ( isset($wp_filter['all']) )

			array_pop($wp_current_filter);

		return $value;

	}

	if ( !isset($wp_filter['all']) )

		$wp_current_filter[] = $tag;

	if ( empty($args) )

		$args = func_get_args();

	array_pop( $wp_current_filter );

}

/**

 * Execute functions hooked on a specific filter hook, specifying arguments in an array.

 *

 *

 * @see apply_filters() This function is identical, but the arguments passed to the

 * functions hooked to `$tag` are supplied using an array.

 *

 * @global array $wp_filter         Stores all of the filters

 * @global array $wp_current_filter Stores the list of current filters with the current one last

 *

 * @param string $tag  The name of the filter hook.

 * @param array  $args The arguments supplied to the functions hooked to $tag.

 * @return mixed The filtered value after all hooked functions are applied to it.

 */

function apply_filters_ref_array($tag, $args) {

	// Do 'all' actions first

	if ( isset($wp_filter['all']) ) {

		$wp_current_filter[] = $tag;

		$all_args = func_get_args();

		_wp_call_all_hook($all_args);

	}

	if ( !isset($wp_filter[$tag]) ) {

		if ( isset($wp_filter['all']) )

			array_pop($wp_current_filter);

		return $args[0];

	}

	if ( !isset($wp_filter['all']) )

		$wp_current_filter[] = $tag;

	array_pop( $wp_current_filter );

}

/**

 * Removes a function from a specified filter hook.

 *

 * This function removes a function attached to a specified filter hook. This

 * method can be used to remove default functions attached to a specific filter

 * hook and possibly replace them with a substitute.

 *

 * To remove a hook, the $function_to_remove and $priority arguments must match

 * when the hook was added. This goes for both filters and actions. No warning

 * will be given on removal failure.

 *

 * @since 1.2.0

 *

 * @param string   $tag                The filter hook to which the function to be removed is hooked.

 * @param int      $priority           Optional. The priority of the function. Default 10.

 */

function remove_filter( $tag, $function_to_remove, $priority = 10 ) {

		}

	}

	return $r;

}

/**

 * Remove all of the hooks from a filter.

 *

 * @since 2.7.0

 *

 * @param string   $tag      The filter to remove hooks from.

 * @param int|bool $priority Optional. The priority number to remove. Default false.

 */

function remove_all_filters( $tag, $priority = false ) {

	if ( isset( $wp_filter[ $tag ]) ) {

		}

	}

	return true;

}

/**

 * Retrieve the name of the current filter or action.

 *

 * @since 2.5.0

 *

 * @return string Hook name of the current filter or action.

 */

function current_filter() {

	global $wp_current_filter;

	return end( $wp_current_filter );

}

/**

 * Retrieve the name of the current action.

 *

 * @since 3.9.0

 *

 * @return string Hook name of the current action.

 */

function current_action() {

	return current_filter();

}

/**

 * Retrieve the name of a filter currently being processed.

 *

 * The function current_filter() only returns the most recent filter or action

 * being executed. did_action() returns true once the action is initially

 * processed.

 *

 * This function allows detection for any filter currently being

 * executed (despite not being the most recent filter to fire, in the case of

 * hooks called from hook callbacks) to be verified.

 *

 * @since 3.9.0

 *

 * @see current_filter()

 * @see did_action()

 * @global array $wp_current_filter Current filter.

 *

 * @param null|string $filter Optional. Filter to check. Defaults to null, which

 *                            checks if any filter is currently being run.

 * @return bool Whether the filter is currently in the stack.

 */

function doing_filter( $filter = null ) {

	global $wp_current_filter;

	if ( null === $filter ) {

		return ! empty( $wp_current_filter );

	}

	return in_array( $filter, $wp_current_filter );

}

/**

 * Retrieve the name of an action currently being processed.

 *

 * @since 3.9.0

 *

 * @param string|null $action Optional. Action to check. Defaults to null, which checks

 *                            if any action is currently being run.

 * @return bool Whether the action is currently in the stack.

 */

function doing_action( $action = null ) {

	return doing_filter( $action );

}

/**

 * Hooks a function on to a specific action.

 *

 * Actions are the hooks that the WordPress core launches at specific points

 * during execution, or when specific events occur. Plugins can specify that

 * one or more of its PHP functions are executed at these points, using the

 * Action API.

 *

 * @since 1.2.0

 *

 * @param string   $tag             The name of the action to which the $function_to_add is hooked.

 * @param int      $priority        Optional. Used to specify the order in which the functions

 *                                  associated with a particular action are executed. Default 10.

 *                                  Lower numbers correspond with earlier execution,

 *                                  and functions with the same priority are executed

 *                                  in the order in which they were added to the action.

 */

function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {

	return add_filter($tag, $function_to_add, $priority, $accepted_args);

}

/**

 * Execute functions hooked on a specific action hook.

 *

 * This function invokes all functions attached to action hook `$tag`. It is

 * possible to create new action hooks by simply calling this function,

 * specifying the name of the new hook using the `$tag` parameter.

 *

 *

 * @since 1.2.0

 *

 *

 */

function do_action($tag, $arg = '') {

	if ( ! isset($wp_actions[$tag]) )

		$wp_actions[$tag] = 1;

	else

		++$wp_actions[$tag];

	// Do 'all' actions first

	if ( isset($wp_filter['all']) ) {

		$wp_current_filter[] = $tag;

		$all_args = func_get_args();

		_wp_call_all_hook($all_args);

	}

	if ( !isset($wp_filter[$tag]) ) {

		if ( isset($wp_filter['all']) )

			array_pop($wp_current_filter);

		return;

	}