/blog/wp-includes/functions.php

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<?php
/**
 * Main WordPress API
 *
 * @package WordPress
 */

/**
 * Converts MySQL DATETIME field to user specified date format.
 *
 * If $dateformatstring has 'G' value, then gmmktime() function will be used to
 * make the time. If $dateformatstring is set to 'U', then mktime() function
 * will be used to make the time.
 *
 * The $translate will only be used, if it is set to true and it is by default
 * and if the $wp_locale object has the month and weekday set.
 *
 * @since 0.71
 *
 * @param string $dateformatstring Either 'G', 'U', or php date format.
 * @param string $mysqlstring Time from mysql DATETIME field.
 * @param bool $translate Optional. Default is true. Will switch format to locale.
 * @return string Date formated by $dateformatstring or locale (if available).
 */
function mysql2date( $dateformatstring, $mysqlstring, $translate = true ) {
	global $wp_locale;
	$m = $mysqlstring;
	if ( empty( $m ) )
		return false;

	if( 'G' == $dateformatstring ) {
		return strtotime( $m . ' +0000' );
	}

	$i = strtotime( $m );

	if( 'U' == $dateformatstring )
		return $i;

	if ( $translate)
	    return date_i18n( $dateformatstring, $i );
	else
	    return date( $dateformatstring, $i );
}

/**
 * Retrieve the current time based on specified type.
 *
 * The 'mysql' type will return the time in the format for MySQL DATETIME field.
 * The 'timestamp' type will return the current timestamp.
 *
 * If $gmt is set to either '1' or 'true', then both types will use GMT time.
 * if $gmt is false, the output is adjusted with the GMT offset in the WordPress option.
 *
 * @since 1.0.0
 *
 * @param string $type Either 'mysql' or 'timestamp'.
 * @param int|bool $gmt Optional. Whether to use GMT timezone. Default is false.
 * @return int|string String if $type is 'gmt', int if $type is 'timestamp'.
 */
function current_time( $type, $gmt = 0 ) {
	switch ( $type ) {
		case 'mysql':
			return ( $gmt ) ? gmdate( 'Y-m-d H:i:s' ) : gmdate( 'Y-m-d H:i:s', ( time() + ( get_option( 'gmt_offset' ) * 3600 ) ) );
			break;
		case 'timestamp':
			return ( $gmt ) ? time() : time() + ( get_option( 'gmt_offset' ) * 3600 );
			break;
	}
}

/**
 * Retrieve the date in localized format, based on timestamp.
 *
 * If the locale specifies the locale month and weekday, then the locale will
 * take over the format for the date. If it isn't, then the date format string
 * will be used instead.
 *
 * @since 0.71
 *
 * @param string $dateformatstring Format to display the date.
 * @param int $unixtimestamp Optional. Unix timestamp.
 * @param bool $gmt Optional, default is false. Whether to convert to GMT for time.
 * @return string The date, translated if locale specifies it.
 */
function date_i18n( $dateformatstring, $unixtimestamp = false, $gmt = false ) {
	global $wp_locale;
	$i = $unixtimestamp;
	// Sanity check for PHP 5.1.0-
	if ( false === $i || intval($i) < 0 ) {
		if ( ! $gmt )
			$i = current_time( 'timestamp' );
		else
			$i = time();
		// we should not let date() interfere with our
		// specially computed timestamp
		$gmt = true;
	}

	// store original value for language with untypical grammars
	// see http://core.trac.wordpress.org/ticket/9396
	$req_format = $dateformatstring;

	$datefunc = $gmt? 'gmdate' : 'date';

	if ( ( !empty( $wp_locale->month ) ) && ( !empty( $wp_locale->weekday ) ) ) {
		$datemonth = $wp_locale->get_month( $datefunc( 'm', $i ) );
		$datemonth_abbrev = $wp_locale->get_month_abbrev( $datemonth );
		$dateweekday = $wp_locale->get_weekday( $datefunc( 'w', $i ) );
		$dateweekday_abbrev = $wp_locale->get_weekday_abbrev( $dateweekday );
		$datemeridiem = $wp_locale->get_meridiem( $datefunc( 'a', $i ) );
		$datemeridiem_capital = $wp_locale->get_meridiem( $datefunc( 'A', $i ) );
		$dateformatstring = ' '.$dateformatstring;
		$dateformatstring = preg_replace( "/([^\\\])D/", "\\1" . backslashit( $dateweekday_abbrev ), $dateformatstring );
		$dateformatstring = preg_replace( "/([^\\\])F/", "\\1" . backslashit( $datemonth ), $dateformatstring );
		$dateformatstring = preg_replace( "/([^\\\])l/", "\\1" . backslashit( $dateweekday ), $dateformatstring );
		$dateformatstring = preg_replace( "/([^\\\])M/", "\\1" . backslashit( $datemonth_abbrev ), $dateformatstring );
		$dateformatstring = preg_replace( "/([^\\\])a/", "\\1" . backslashit( $datemeridiem ), $dateformatstring );
		$dateformatstring = preg_replace( "/([^\\\])A/", "\\1" . backslashit( $datemeridiem_capital ), $dateformatstring );

		$dateformatstring = substr( $dateformatstring, 1, strlen( $dateformatstring ) -1 );
	}
	$j = @$datefunc( $dateformatstring, $i );
	// allow plugins to redo this entirely for languages with untypical grammars
	$j = apply_filters('date_i18n', $j, $req_format, $i, $gmt);
	return $j;
}

/**
 * Convert number to format based on the locale.
 *
 * @since 2.3.0
 *
 * @param mixed $number The number to convert based on locale.
 * @param int $decimals Precision of the number of decimal places.
 * @return string Converted number in string format.
 */
function number_format_i18n( $number, $decimals = null ) {
	global $wp_locale;
	// let the user override the precision only
	$decimals = ( is_null( $decimals ) ) ? $wp_locale->number_format['decimals'] : intval( $decimals );

	$num = number_format( $number, $decimals, $wp_locale->number_format['decimal_point'], $wp_locale->number_format['thousands_sep'] );

	// let the user translate digits from latin to localized language
	return apply_filters( 'number_format_i18n', $num );
}

/**
 * Convert number of bytes largest unit bytes will fit into.
 *
 * It is easier to read 1kB than 1024 bytes and 1MB than 1048576 bytes. Converts
 * number of bytes to human readable number by taking the number of that unit
 * that the bytes will go into it. Supports TB value.
 *
 * Please note that integers in PHP are limited to 32 bits, unless they are on
 * 64 bit architecture, then they have 64 bit size. If you need to place the
 * larger size then what PHP integer type will hold, then use a string. It will
 * be converted to a double, which should always have 64 bit length.
 *
 * Technically the correct unit names for powers of 1024 are KiB, MiB etc.
 * @link http://en.wikipedia.org/wiki/Byte
 *
 * @since 2.3.0
 *
 * @param int|string $bytes Number of bytes. Note max integer size for integers.
 * @param int $decimals Precision of number of decimal places.
 * @return bool|string False on failure. Number string on success.
 */
function size_format( $bytes, $decimals = null ) {
	$quant = array(
		// ========================= Origin ====
		'TB' => 1099511627776,  // pow( 1024, 4)
		'GB' => 1073741824,     // pow( 1024, 3)
		'MB' => 1048576,        // pow( 1024, 2)
		'kB' => 1024,           // pow( 1024, 1)
		'B ' => 1,              // pow( 1024, 0)
	);

	foreach ( $quant as $unit => $mag )
		if ( doubleval($bytes) >= $mag )
			return number_format_i18n( $bytes / $mag, $decimals ) . ' ' . $unit;

	return false;
}

/**
 * Get the week start and end from the datetime or date string from mysql.
 *
 * @since 0.71
 *
 * @param string $mysqlstring Date or datetime field type from mysql.
 * @param int $start_of_week Optional. Start of the week as an integer.
 * @return array Keys are 'start' and 'end'.
 */
function get_weekstartend( $mysqlstring, $start_of_week = '' ) {
	$my = substr( $mysqlstring, 0, 4 ); // Mysql string Year
	$mm = substr( $mysqlstring, 8, 2 ); // Mysql string Month
	$md = substr( $mysqlstring, 5, 2 ); // Mysql string day
	$day = mktime( 0, 0, 0, $md, $mm, $my ); // The timestamp for mysqlstring day.
	$weekday = date( 'w', $day ); // The day of the week from the timestamp
	$i = 86400; // One day
	if( !is_numeric($start_of_week) )
		$start_of_week = get_option( 'start_of_week' );

	if ( $weekday < $start_of_week )
		$weekday = 7 - $start_of_week - $weekday;

	while ( $weekday > $start_of_week ) {
		$weekday = date( 'w', $day );
		if ( $weekday < $start_of_week )
			$weekday = 7 - $start_of_week - $weekday;

		$day -= 86400;
		$i = 0;
	}
	$week['start'] = $day + 86400 - $i;
	$week['end'] = $week['start'] + 604799;
	return $week;
}

/**
 * Unserialize value only if it was serialized.
 *
 * @since 2.0.0
 *
 * @param string $original Maybe unserialized original, if is needed.
 * @return mixed Unserialized data can be any type.
 */
function maybe_unserialize( $original ) {
	if ( is_serialized( $original ) ) // don't attempt to unserialize data that wasn't serialized going in
		return @unserialize( $original );
	return $original;
}

/**
 * Check value to find if it was serialized.
 *
 * If $data is not an string, then returned value will always be false.
 * Serialized data is always a string.
 *
 * @since 2.0.5
 *
 * @param mixed $data Value to check to see if was serialized.
 * @return bool False if not serialized and true if it was.
 */
function is_serialized( $data ) {
	// if it isn't a string, it isn't serialized
	if ( !is_string( $data ) )
		return false;
	$data = trim( $data );
	if ( 'N;' == $data )
		return true;
	if ( !preg_match( '/^([adObis]):/', $data, $badions ) )
		return false;
	switch ( $badions[1] ) {
		case 'a' :
		case 'O' :
		case 's' :
			if ( preg_match( "/^{$badions[1]}:[0-9]+:.*[;}]\$/s", $data ) )
				return true;
			break;
		case 'b' :
		case 'i' :
		case 'd' :
			if ( preg_match( "/^{$badions[1]}:[0-9.E-]+;\$/", $data ) )
				return true;
			break;
	}
	return false;
}

/**
 * Check whether serialized data is of string type.
 *
 * @since 2.0.5
 *
 * @param mixed $data Serialized data
 * @return bool False if not a serialized string, true if it is.
 */
function is_serialized_string( $data ) {
	// if it isn't a string, it isn't a serialized string
	if ( !is_string( $data ) )
		return false;
	$data = trim( $data );
	if ( preg_match( '/^s:[0-9]+:.*;$/s', $data ) ) // this should fetch all serialized strings
		return true;
	return false;
}

/**
 * Retrieve option value based on setting name.
 *
 * If the option does not exist or does not have a value, then the return value
 * will be false. This is useful to check whether you need to install an option
 * and is commonly used during installation of plugin options and to test
 * whether upgrading is required.
 *
 * You can "short-circuit" the retrieval of the option from the database for
 * your plugin or core options that aren't protected. You can do so by hooking
 * into the 'pre_option_$option' with the $option being replaced by the option
 * name. You should not try to override special options, but you will not be
 * prevented from doing so.
 *
 * There is a second filter called 'option_$option' with the $option being
 * replaced with the option name. This gives the value as the only parameter.
 *
 * If the option was serialized, when the option was added and, or updated, then
 * it will be unserialized, when it is returned.
 *
 * @since 1.5.0
 * @package WordPress
 * @subpackage Option
 * @uses apply_filters() Calls 'pre_option_$optionname' false to allow
 *		overwriting the option value in a plugin.
 * @uses apply_filters() Calls 'option_$optionname' with the option name value.
 *
 * @param string $setting Name of option to retrieve. Should already be SQL-escaped
 * @return mixed Value set for the option.
 */
function get_option( $setting, $default = false ) {
	global $wpdb;

	// Allow plugins to short-circuit options.
	$pre = apply_filters( 'pre_option_' . $setting, false );
	if ( false !== $pre )
		return $pre;

	// prevent non-existent options from triggering multiple queries
	$notoptions = wp_cache_get( 'notoptions', 'options' );
	if ( isset( $notoptions[$setting] ) )
		return $default;

	$alloptions = wp_load_alloptions();

	if ( isset( $alloptions[$setting] ) ) {
		$value = $alloptions[$setting];
	} else {
		$value = wp_cache_get( $setting, 'options' );

		if ( false === $value ) {
			if ( defined( 'WP_INSTALLING' ) )
				$suppress = $wpdb->suppress_errors();
			// expected_slashed ($setting)
			$row = $wpdb->get_row( "SELECT option_value FROM $wpdb->options WHERE option_name = '$setting' LIMIT 1" );
			if ( defined( 'WP_INSTALLING' ) )
				$wpdb->suppress_errors($suppress);

			if ( is_object( $row) ) { // Has to be get_row instead of get_var because of funkiness with 0, false, null values
				$value = $row->option_value;
				wp_cache_add( $setting, $value, 'options' );
			} else { // option does not exist, so we must cache its non-existence
				$notoptions[$setting] = true;
				wp_cache_set( 'notoptions', $notoptions, 'options' );
				return $default;
			}
		}
	}

	// If home is not set use siteurl.
	if ( 'home' == $setting && '' == $value )
		return get_option( 'siteurl' );

	if ( in_array( $setting, array('siteurl', 'home', 'category_base', 'tag_base') ) )
		$value = untrailingslashit( $value );

	return apply_filters( 'option_' . $setting, maybe_unserialize( $value ) );
}

/**
 * Protect WordPress special option from being modified.
 *
 * Will die if $option is in protected list. Protected options are 'alloptions'
 * and 'notoptions' options.
 *
 * @since 2.2.0
 * @package WordPress
 * @subpackage Option
 *
 * @param string $option Option name.
 */
function wp_protect_special_option( $option ) {
	$protected = array( 'alloptions', 'notoptions' );
	if ( in_array( $option, $protected ) )
		die( sprintf( __( '%s is a protected WP option and may not be modified' ), esc_html( $option ) ) );
}

/**
 * Print option value after sanitizing for forms.
 *
 * @uses attr Sanitizes value.
 * @since 1.5.0
 * @package WordPress
 * @subpackage Option
 *
 * @param string $option Option name.
 */
function form_option( $option ) {
	echo esc_attr(get_option( $option ) );
}

/**
 * Retrieve all autoload options or all options, if no autoloaded ones exist.
 *
 * This is different from wp_load_alloptions() in that this function does not
 * cache its results and will retrieve all options from the database every time
 *
 * it is called.
 *
 * @since 1.0.0
 * @package WordPress
 * @subpackage Option
 * @uses apply_filters() Calls 'pre_option_$optionname' hook with option value as parameter.
 * @uses apply_filters() Calls 'all_options' on options list.
 *
 * @return array List of all options.
 */
function get_alloptions() {
	global $wpdb;
	$show = $wpdb->hide_errors();
	if ( !$options = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) )
		$options = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
	$wpdb->show_errors($show);

	foreach ( (array) $options as $option ) {
		// "When trying to design a foolproof system,
		//  never underestimate the ingenuity of the fools :)" -- Dougal
		if ( in_array( $option->option_name, array( 'siteurl', 'home', 'category_base', 'tag_base' ) ) )
			$option->option_value = untrailingslashit( $option->option_value );
		$value = maybe_unserialize( $option->option_value );
		$all_options->{$option->option_name} = apply_filters( 'pre_option_' . $option->option_name, $value );
	}
	return apply_filters( 'all_options', $all_options );
}

/**
 * Loads and caches all autoloaded options, if available or all options.
 *
 * This is different from get_alloptions(), in that this function will cache the
 * options and will return the cached options when called again.
 *
 * @since 2.2.0
 * @package WordPress
 * @subpackage Option
 *
 * @return array List all options.
 */
function wp_load_alloptions() {
	global $wpdb;

	$alloptions = wp_cache_get( 'alloptions', 'options' );

	if ( !$alloptions ) {
		$suppress = $wpdb->suppress_errors();
		if ( !$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) )
			$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
		$wpdb->suppress_errors($suppress);
		$alloptions = array();
		foreach ( (array) $alloptions_db as $o )
			$alloptions[$o->option_name] = $o->option_value;
		wp_cache_add( 'alloptions', $alloptions, 'options' );
	}
	return $alloptions;
}

/**
 * Update the value of an option that was already added.
 *
 * You do not need to serialize values, if the value needs to be serialize, then
 * it will be serialized before it is inserted into the database. Remember,
 * resources can not be serialized or added as an option.
 *
 * If the option does not exist, then the option will be added with the option
 * value, but you will not be able to set whether it is autoloaded. If you want
 * to set whether an option autoloaded, then you need to use the add_option().
 *
 * Before the option is updated, then the filter named
 * 'pre_update_option_$option_name', with the $option_name as the $option_name
 * parameter value, will be called. The hook should accept two parameters, the
 * first is the new value and the second is the old value.  Whatever is
 * returned will be used as the new value.
 *
 * After the value has been updated the action named 'update_option_$option_name'
 * will be called.  This action receives two parameters the first being the old
 * value and the second the new value.
 *
 * @since 1.0.0
 * @package WordPress
 * @subpackage Option
 *
 * @param string $option_name Option name. Expected to not be SQL-escaped
 * @param mixed $newvalue Option value.
 * @return bool False if value was not updated and true if value was updated.
 */
function update_option( $option_name, $newvalue ) {
	global $wpdb;

	wp_protect_special_option( $option_name );

	$safe_option_name = $wpdb->escape( $option_name );
	$newvalue = sanitize_option( $option_name, $newvalue );

	$oldvalue = get_option( $safe_option_name );

	$newvalue = apply_filters( 'pre_update_option_' . $option_name, $newvalue, $oldvalue );

	// If the new and old values are the same, no need to update.
	if ( $newvalue === $oldvalue )
		return false;

	if ( false === $oldvalue ) {
		add_option( $option_name, $newvalue );
		return true;
	}

	$notoptions = wp_cache_get( 'notoptions', 'options' );
	if ( is_array( $notoptions ) && isset( $notoptions[$option_name] ) ) {
		unset( $notoptions[$option_name] );
		wp_cache_set( 'notoptions', $notoptions, 'options' );
	}

	$_newvalue = $newvalue;
	$newvalue = maybe_serialize( $newvalue );

	$alloptions = wp_load_alloptions();
	if ( isset( $alloptions[$option_name] ) ) {
		$alloptions[$option_name] = $newvalue;
		wp_cache_set( 'alloptions', $alloptions, 'options' );
	} else {
		wp_cache_set( $option_name, $newvalue, 'options' );
	}

	$wpdb->update($wpdb->options, array('option_value' => $newvalue), array('option_name' => $option_name) );

	if ( $wpdb->rows_affected == 1 ) {
		do_action( "update_option_{$option_name}", $oldvalue, $_newvalue );
		return true;
	}
	return false;
}

/**
 * Add a new option.
 *
 * You do not need to serialize values, if the value needs to be serialize, then
 * it will be serialized before it is inserted into the database. Remember,
 * resources can not be serialized or added as an option.
 *
 * You can create options without values and then add values later. Does not
 * check whether the option has already been added, but does check that you
 * aren't adding a protected WordPress option. Care should be taken to not name
 * options, the same as the ones which are protected and to not add options
 * that were already added.
 *
 * The filter named 'add_option_$optionname', with the $optionname being
 * replaced with the option's name, will be called. The hook should accept two
 * parameters, the first is the option name, and the second is the value.
 *
 * @package WordPress
 * @subpackage Option
 * @since 1.0.0
 * @link http://alex.vort-x.net/blog/ Thanks Alex Stapleton
 *
 * @param string $name Option name to add. Expects to NOT be SQL escaped.
 * @param mixed $value Optional. Option value, can be anything.
 * @param mixed $deprecated Optional. Description. Not used anymore.
 * @param bool $autoload Optional. Default is enabled. Whether to load the option when WordPress starts up.
 * @return null returns when finished.
 */
function add_option( $name, $value = '', $deprecated = '', $autoload = 'yes' ) {
	global $wpdb;

	wp_protect_special_option( $name );
	$safe_name = $wpdb->escape( $name );
	$value = sanitize_option( $name, $value );

	// Make sure the option doesn't already exist. We can check the 'notoptions' cache before we ask for a db query
	$notoptions = wp_cache_get( 'notoptions', 'options' );
	if ( !is_array( $notoptions ) || !isset( $notoptions[$name] ) )
		if ( false !== get_option( $safe_name ) )
			return;

	$value = maybe_serialize( $value );
	$autoload = ( 'no' === $autoload ) ? 'no' : 'yes';

	if ( 'yes' == $autoload ) {
		$alloptions = wp_load_alloptions();
		$alloptions[$name] = $value;
		wp_cache_set( 'alloptions', $alloptions, 'options' );
	} else {
		wp_cache_set( $name, $value, 'options' );
	}

	// This option exists now
	$notoptions = wp_cache_get( 'notoptions', 'options' ); // yes, again... we need it to be fresh
	if ( is_array( $notoptions ) && isset( $notoptions[$name] ) ) {
		unset( $notoptions[$name] );
		wp_cache_set( 'notoptions', $notoptions, 'options' );
	}

	$wpdb->insert($wpdb->options, array('option_name' => $name, 'option_value' => $value, 'autoload' => $autoload) );

	do_action( "add_option_{$name}", $name, $value );
	return;
}

/**
 * Removes option by name and prevents removal of protected WordPress options.
 *
 * @package WordPress
 * @subpackage Option
 * @since 1.2.0
 *
 * @param string $name Option name to remove.
 * @return bool True, if succeed. False, if failure.
 */
function delete_option( $name ) {
	global $wpdb;

	wp_protect_special_option( $name );

	// Get the ID, if no ID then return
	// expected_slashed ($name)
	$option = $wpdb->get_row( "SELECT option_id, autoload FROM $wpdb->options WHERE option_name = '$name'" );
	if ( is_null($option) || !$option->option_id )
		return false;
	// expected_slashed ($name)
	$wpdb->query( "DELETE FROM $wpdb->options WHERE option_name = '$name'" );
	if ( 'yes' == $option->autoload ) {
		$alloptions = wp_load_alloptions();
		if ( isset( $alloptions[$name] ) ) {
			unset( $alloptions[$name] );
			wp_cache_set( 'alloptions', $alloptions, 'options' );
		}
	} else {
		wp_cache_delete( $name, 'options' );
	}
	return true;
}

/**
 * Delete a transient
 *
 * @since 2.8.0
 * @package WordPress
 * @subpackage Transient
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped
 * @return bool true if successful, false otherwise
 */
function delete_transient($transient) {
	global $_wp_using_ext_object_cache, $wpdb;

	if ( $_wp_using_ext_object_cache ) {
		return wp_cache_delete($transient, 'transient');
	} else {
		$transient = '_transient_' . $wpdb->escape($transient);
		return delete_option($transient);
	}
}

/**
 * Get the value of a transient
 *
 * If the transient does not exist or does not have a value, then the return value
 * will be false.
 *
 * @since 2.8.0
 * @package WordPress
 * @subpackage Transient
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped
 * @return mixed Value of transient
 */
function get_transient($transient) {
	global $_wp_using_ext_object_cache, $wpdb;

	$pre = apply_filters( 'pre_transient_' . $transient, false );
	if ( false !== $pre )
		return $pre;

	if ( $_wp_using_ext_object_cache ) {
		$value = wp_cache_get($transient, 'transient');
	} else {
		$transient_option = '_transient_' . $wpdb->escape($transient);
		// If option is not in alloptions, it is not autoloaded and thus has a timeout
		$alloptions = wp_load_alloptions();
		if ( !isset( $alloptions[$transient_option] ) ) {
			$transient_timeout = '_transient_timeout_' . $wpdb->escape($transient);
			if ( get_option($transient_timeout) < time() ) {
				delete_option($transient_option);
				delete_option($transient_timeout);
				return false;
			}
		}

		$value = get_option($transient_option);
	}

	return apply_filters('transient_' . $transient, $value);
}

/**
 * Set/update the value of a transient
 *
 * You do not need to serialize values, if the value needs to be serialize, then
 * it will be serialized before it is set.
 *
 * @since 2.8.0
 * @package WordPress
 * @subpackage Transient
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped
 * @param mixed $value Transient value.
 * @param int $expiration Time until expiration in seconds, default 0
 * @return bool False if value was not set and true if value was set.
 */
function set_transient($transient, $value, $expiration = 0) {
	global $_wp_using_ext_object_cache, $wpdb;

	if ( $_wp_using_ext_object_cache ) {
		return wp_cache_set($transient, $value, 'transient', $expiration);
	} else {
		$transient_timeout = '_transient_timeout_' . $transient;
		$transient = '_transient_' . $transient;
		$safe_transient = $wpdb->escape($transient);
		if ( false === get_option( $safe_transient ) ) {
			$autoload = 'yes';
			if ( 0 != $expiration ) {
				$autoload = 'no';
				add_option($transient_timeout, time() + $expiration, '', 'no');
			}
			return add_option($transient, $value, '', $autoload);
		} else {
			if ( 0 != $expiration )
				update_option($transient_timeout, time() + $expiration);
			return update_option($transient, $value);
		}
	}
}

/**
 * Saves and restores user interface settings stored in a cookie.
 *
 * Checks if the current user-settings cookie is updated and stores it. When no
 * cookie exists (different browser used), adds the last saved cookie restoring
 * the settings.
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.7.0
 */
function wp_user_settings() {

	if ( ! is_admin() )
		return;

	if ( defined('DOING_AJAX') )
		return;

	if ( ! $user = wp_get_current_user() )
		return;

	$settings = get_user_option( 'user-settings', $user->ID, false );

	if ( isset( $_COOKIE['wp-settings-' . $user->ID] ) ) {
		$cookie = preg_replace( '/[^A-Za-z0-9=&_]/', '', $_COOKIE['wp-settings-' . $user->ID] );

		if ( ! empty( $cookie ) && strpos( $cookie, '=' ) ) {
			if ( $cookie == $settings )
				return;

			$last_time = (int) get_user_option( 'user-settings-time', $user->ID, false );
			$saved = isset( $_COOKIE['wp-settings-time-' . $user->ID]) ? preg_replace( '/[^0-9]/', '', $_COOKIE['wp-settings-time-' . $user->ID] ) : 0;

			if ( $saved > $last_time ) {
				update_user_option( $user->ID, 'user-settings', $cookie, false );
				update_user_option( $user->ID, 'user-settings-time', time() - 5, false );
				return;
			}
		}
	}

	setcookie( 'wp-settings-' . $user->ID, $settings, time() + 31536000, SITECOOKIEPATH );
	setcookie( 'wp-settings-time-' . $user->ID, time(), time() + 31536000, SITECOOKIEPATH );
	$_COOKIE['wp-settings-' . $user->ID] = $settings;
}

/**
 * Retrieve user interface setting value based on setting name.
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.7.0
 *
 * @param string $name The name of the setting.
 * @param string $default Optional default value to return when $name is not set.
 * @return mixed the last saved user setting or the default value/false if it doesn't exist.
 */
function get_user_setting( $name, $default = false ) {

	$all = get_all_user_settings();

	return isset($all[$name]) ? $all[$name] : $default;
}

/**
 * Add or update user interface setting.
 *
 * Both $name and $value can contain only ASCII letters, numbers and underscores.
 * This function has to be used before any output has started as it calls setcookie().
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.8.0
 *
 * @param string $name The name of the setting.
 * @param string $value The value for the setting.
 * @return bool true if set successfully/false if not.
 */
function set_user_setting( $name, $value ) {

	if ( headers_sent() )
		return false;

	$all = get_all_user_settings();
	$name = preg_replace( '/[^A-Za-z0-9_]+/', '', $name );

	if ( empty($name) )
		return false;

	$all[$name] = $value;

	return wp_set_all_user_settings($all);
}

/**
 * Delete user interface settings.
 *
 * Deleting settings would reset them to the defaults.
 * This function has to be used before any output has started as it calls setcookie().
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.7.0
 *
 * @param mixed $names The name or array of names of the setting to be deleted.
 * @return bool true if deleted successfully/false if not.
 */
function delete_user_setting( $names ) {

	if ( headers_sent() )
		return false;

	$all = get_all_user_settings();
	$names = (array) $names;

	foreach ( $names as $name ) {
		if ( isset($all[$name]) ) {
			unset($all[$name]);
			$deleted = true;
		}
	}

	if ( isset($deleted) )
		return wp_set_all_user_settings($all);

	return false;
}

/**
 * Retrieve all user interface settings.
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.7.0
 *
 * @return array the last saved user settings or empty array.
 */
function get_all_user_settings() {
	global $_updated_user_settings;

	if ( ! $user = wp_get_current_user() )
		return array();

	if ( isset($_updated_user_settings) && is_array($_updated_user_settings) )
		return $_updated_user_settings;

	$all = array();
	if ( isset($_COOKIE['wp-settings-' . $user->ID]) ) {
		$cookie = preg_replace( '/[^A-Za-z0-9=&_]/', '', $_COOKIE['wp-settings-' . $user->ID] );

		if ( $cookie && strpos($cookie, '=') ) // the '=' cannot be 1st char
			parse_str($cookie, $all);

	} else {
		$option = get_user_option('user-settings', $user->ID);
		if ( $option && is_string($option) )
			parse_str( $option, $all );
	}

	return $all;
}

/**
 * Private. Set all user interface settings.
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.8.0
 *
 */
function wp_set_all_user_settings($all) {
	global $_updated_user_settings;

	if ( ! $user = wp_get_current_user() )
		return false;

	$_updated_user_settings = $all;
	$settings = '';
	foreach ( $all as $k => $v ) {
		$v = preg_replace( '/[^A-Za-z0-9_]+/', '', $v );
		$settings .= $k . '=' . $v . '&';
	}

	$settings = rtrim($settings, '&');

	update_user_option( $user->ID, 'user-settings', $settings, false );
	update_user_option( $user->ID, 'user-settings-time', time(), false );

	return true;
}

/**
 * Delete the user settings of the current user.
 *
 * @package WordPress
 * @subpackage Option
 * @since 2.7.0
 */
function delete_all_user_settings() {
	if ( ! $user = wp_get_current_user() )
		return;

	update_user_option( $user->ID, 'user-settings', '', false );
	setcookie('wp-settings-' . $user->ID, ' ', time() - 31536000, SITECOOKIEPATH);
}

/**
 * Serialize data, if needed.
 *
 * @since 2.0.5
 *
 * @param mixed $data Data that might be serialized.
 * @return mixed A scalar data
 */
function maybe_serialize( $data ) {
	if ( is_array( $data ) || is_object( $data ) )
		return serialize( $data );

	if ( is_serialized( $data ) )
		return serialize( $data );

	return $data;
}

/**
 * Strip HTML and put links at the bottom of stripped content.
 *
 * Searches for all of the links, strips them out of the content, and places
 * them at the bottom of the content with numbers.
 *
 * @since 0.71
 *
 * @param string $content Content to get links
 * @return string HTML stripped out of content with links at the bottom.
 */
function make_url_footnote( $content ) {
	preg_match_all( '/<a(.+?)href=\"(.+?)\"(.*?)>(.+?)<\/a>/', $content, $matches );
	$links_summary = "\n";
	for ( $i=0; $i<count($matches[0]); $i++ ) {
		$link_match = $matches[0][$i];
		$link_number = '['.($i+1).']';
		$link_url = $matches[2][$i];
		$link_text = $matches[4][$i];
		$content = str_replace( $link_match, $link_text . ' ' . $link_number, $content );
		$link_url = ( ( strtolower( substr( $link_url, 0, 7 ) ) != 'http://' ) && ( strtolower( substr( $link_url, 0, 8 ) ) != 'https://' ) ) ? get_option( 'home' ) . $link_url : $link_url;
		$links_summary .= "\n" . $link_number . ' ' . $link_url;
	}
	$content  = strip_tags( $content );
	$content .= $links_summary;
	return $content;
}

/**
 * Retrieve post title from XMLRPC XML.
 *
 * If the title element is not part of the XML, then the default post title from
 * the $post_default_title will be used instead.
 *
 * @package WordPress
 * @subpackage XMLRPC
 * @since 0.71
 *
 * @global string $post_default_title Default XMLRPC post title.
 *
 * @param string $content XMLRPC XML Request content
 * @return string Post title
 */
function xmlrpc_getposttitle( $content ) {
	global $post_default_title;
	if ( preg_match( '/<title>(.+?)<\/title>/is', $content, $matchtitle ) ) {
		$post_title = $matchtitle[1];
	} else {
		$post_title = $post_default_title;
	}
	return $post_title;
}

/**
 * Retrieve the post category or categories from XMLRPC XML.
 *
 * If the category element is not found, then the default post category will be
 * used. The return type then would be what $post_default_category. If the
 * category is found, then it will always be an array.
 *
 * @package WordPress
 * @subpackage XMLRPC
 * @since 0.71
 *
 * @global string $post_default_category Default XMLRPC post category.
 *
 * @param string $content XMLRPC XML Request content
 * @return string|array List of categories or category name.
 */
function xmlrpc_getpostcategory( $content ) {
	global $post_default_category;
	if ( preg_match( '/<category>(.+?)<\/category>/is', $content, $matchcat ) ) {
		$post_category = trim( $matchcat[1], ',' );
		$post_category = explode( ',', $post_category );
	} else {
		$post_category = $post_default_category;
	}
	return $post_category;
}

/**
 * XMLRPC XML content without title and category elements.
 *
 * @package WordPress
 * @subpackage XMLRPC
 * @since 0.71
 *
 * @param string $content XMLRPC XML Request content
 * @return string XMLRPC XML Request content without title and category elements.
 */
function xmlrpc_removepostdata( $content ) {
	$content = preg_replace( '/<title>(.+?)<\/title>/si', '', $content );
	$content = preg_replace( '/<category>(.+?)<\/category>/si', '', $content );
	$content = trim( $content );
	return $content;
}

/**
 * Open the file handle for debugging.
 *
 * This function is used for XMLRPC feature, but it is general purpose enough
 * to be used in anywhere.
 *
 * @see fopen() for mode options.
 * @package WordPress
 * @subpackage Debug
 * @since 0.71
 * @uses $debug Used for whether debugging is enabled.
 *
 * @param string $filename File path to debug file.
 * @param string $mode Same as fopen() mode parameter.
 * @return bool|resource File handle. False on failure.
 */
function debug_fopen( $filename, $mode ) {
	global $debug;
	if ( 1 == $debug ) {
		$fp = fopen( $filename, $mode );
		return $fp;
	} else {
		return false;
	}
}

/**
 * Write contents to the file used for debugging.
 *
 * Technically, this can be used to write to any file handle when the global
 * $debug is set to 1 or true.
 *
 * @package WordPress
 * @subpackage Debug
 * @since 0.71
 * @uses $debug Used for whether debugging is enabled.
 *
 * @param resource $fp File handle for debugging file.
 * @param string $string Content to write to debug file.
 */
function debug_fwrite( $fp, $string ) {
	global $debug;
	if ( 1 == $debug )
		fwrite( $fp, $string );
}

/**
 * Close the debugging file handle.
 *
 * Technically, this can be used to close any file handle when the global $debug
 * is set to 1 or true.
 *
 * @package WordPress
 * @subpackage Debug
 * @since 0.71
 * @uses $debug Used for whether debugging is enabled.
 *
 * @param resource $fp Debug File handle.
 */
function debug_fclose( $fp ) {
	global $debug;
	if ( 1 == $debug )
		fclose( $fp );
}

/**
 * Check content for video and audio links to add as enclosures.
 *
 * Will not add enclosures that have already been added and will
 * remove enclosures that are no longer in the post. This is called as
 * pingbacks and trackbacks.
 *
 * @package WordPress
 * @since 1.5.0
 *
 * @uses $wpdb
 *
 * @param string $content Post Content
 * @param int $post_ID Post ID
 */
function do_enclose( $content, $post_ID ) {
	global $wpdb;
	include_once( ABSPATH . WPINC . '/class-IXR.php' );

	$log = debug_fopen( ABSPATH . 'enclosures.log', 'a' );
	$post_links = array();
	debug_fwrite( $log, 'BEGIN ' . date( 'YmdHis', time() ) . "\n" );

	$pung = get_enclosed( $post_ID );

	$ltrs = '\w';
	$gunk = '/#~:.?+=&%@!\-';
	$punc = '.:?\-';
	$any = $ltrs . $gunk . $punc;

	preg_match_all( "{\b http : [$any] +? (?= [$punc] * [^$any] | $)}x", $content, $post_links_temp );

	debug_fwrite( $log, 'Post contents:' );
	debug_fwrite( $log, $content . "\n" );

	foreach ( $pung as $link_test ) {
		if ( !in_array( $link_test, $post_links_temp[0] ) ) { // link no longer in post
			$wpdb->query( $wpdb->prepare("DELETE FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = 'enclosure' AND meta_value LIKE (%s)", $post_ID, $link_test . '%') );
		}
	}

	foreach ( (array) $post_links_temp[0] as $link_test ) {
		if ( !in_array( $link_test, $pung ) ) { // If we haven't pung it already
			$test = parse_url( $link_test );
			if ( isset( $test['query'] ) )
				$post_links[] = $link_test;
			elseif ( $test['path'] != '/' && $test['path'] != '' )
				$post_links[] = $link_test;
		}
	}

	foreach ( (array) $post_links as $url ) {
		if ( $url != '' && !$wpdb->get_var( $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = 'enclosure' AND meta_value LIKE (%s)", $post_ID, $url . '%' ) ) ) {
			if ( $headers = wp_get_http_headers( $url) ) {
				$len = (int) $headers['content-length'];
				$type = $headers['content-type'];
				$allowed_types = array( 'video', 'audio' );
				if ( in_array( substr( $type, 0, strpos( $type, "/" ) ), $allowed_types ) ) {
					$meta_value = "$url\n$len\n$type\n";
					$wpdb->insert($wpdb->postmeta, array('post_id' => $post_ID, 'meta_key' => 'enclosure', 'meta_value' => $meta_value) );
				}
			}
		}
	}
}

/**
 * Perform a HTTP HEAD or GET request.
 *
 * If $file_path is a writable filename, this will do a GET request and write
 * the file to that path.
 *
 * @since 2.5.0
 *
 * @param string $url URL to fetch.
 * @param string|bool $file_path Optional. File path to write request to.
 * @param bool $deprecated Deprecated. Not used.
 * @return bool|string False on failure and string of headers if HEAD request.
 */
function wp_get_http( $url, $file_path = false, $deprecated = false ) {
	@set_time_limit( 60 );

	$options = array();
	$options['redirection'] = 5;

	if ( false == $file_path )
		$options['method'] = 'HEAD';
	else
		$options['method'] = 'GET';

	$response = wp_remote_request($url, $options);

	if ( is_wp_error( $response ) )
		return false;

	$headers = wp_remote_retrieve_headers( $response );
	$headers['response'] = $response['response']['code'];

	if ( false == $file_path )
		return $headers;

	// GET request - write it to the supplied filename
	$out_fp = fopen($file_path, 'w');
	if ( !$out_fp )
		return $headers;

	fwrite( $out_fp,  $response['body']);
	fclose($out_fp);

	return $headers;
}

/**
 * Retrieve HTTP Headers from URL.
 *
 * @since 1.5.1
 *
 * @param string $url
 * @param bool $deprecated Not Used.
 * @return bool|string False on failure, headers on success.
 */
function wp_get_http_headers( $url, $deprecated = false ) {
	$response = wp_remote_head( $url );

	if ( is_wp_error( $response ) )
		return false;

	return wp_remote_retrieve_headers( $response );
}

/**
 * Whether today is a new day.
 *
 * @since 0.71
 * @uses $day Today
 * @uses $previousday Previous day
 *
 * @return int 1 when new day, 0 if not a new day.
 */
function is_new_day() {
	global $day, $previousday;
	if ( $day != $previousday )
		return 1;
	else
		return 0;
}

/**
 * Build URL query based on an associative and, or indexed array.
 *
 * This is a convenient function for easily building url queries. It sets the
 * separator to '&' and uses _http_build_query() function.
 *
 * @see _http_build_query() Used to build the query
 * @link http://us2.php.net/manual/en/function.http-build-query.php more on what
 *		http_build_query() does.
 *
 * @since 2.3.0
 *
 * @param array $data URL-encode key/value pairs.
 * @return string URL encoded string
 */
function build_query( $data ) {
	return _http_build_query( $data, null, '&', '', false );
}

/**
 * Retrieve a modified URL query string.
 *
 * You can rebuild the URL and append a new query variable to the URL query by
 * using this function. You can also retrieve the full URL with query data.
 *
 * Adding a single key & value or an associative array. Setting a key value to
 * emptystring removes the key. Omitting oldquery_or_uri uses the $_SERVER
 * value.
 *
 * @since 1.5.0
 *
 * @param mixed $param1 Either newkey or an associative_array
 * @param mixed $param2 Either newvalue or oldquery or uri
 * @param mixed $param3 Optional. Old query or uri
 * @return string New URL query string.
 */
function add_query_arg() {
	$ret = '';
	if ( is_array( func_get_arg(0) ) ) {
		if ( @func_num_args() < 2 || false === @func_get_arg( 1 ) )
			$uri = $_SERVER['REQUEST_URI'];
		else
			$uri = @func_get_arg( 1 );
	} else {
		if ( @func_num_args() < 3 || false === @func_get_arg( 2 ) )
			$uri = $_SERVER['REQUEST_URI'];
		else
			$uri = @func_get_arg( 2 );
	}

	if ( $frag = strstr( $uri, '#' ) )
		$uri = substr( $uri, 0, -strlen( $frag ) );
	else
		$frag = '';

	if ( preg_match( '|^https?://|i', $uri, $matches ) ) {
		$protocol = $matches[0];
		$uri = substr( $uri, strlen( $protocol ) );
	} else {
		$protocol = '';
	}

	if ( strpos( $uri, '?' ) !== false ) {
		$parts = explode( '?', $uri, 2 );
		if ( 1 == count( $parts ) ) {
			$base = '?';
			$query = $parts[0];
		} else {
			$base = $parts[0] . '?';
			$query = $parts[1];
		}
	} elseif ( !empty( $protocol ) || strpos( $uri, '=' ) === false ) {
		$base = $uri . '?';
		$query = '';
	} else {
		$base = '';
		$query = $uri;
	}

	wp_parse_str( $query, $qs );
	$qs = urlencode_deep( $qs ); // this re-URL-encodes things that were already in the query string
	if ( is_array( func_get_arg( 0 ) ) ) {
		$kayvees = func_get_arg( 0 );
		$qs = array_merge( $qs, $kayvees );
	} else {
		$qs[func_get_arg( 0 )] = func_get_arg( 1 );
	}

	foreach ( (array) $qs as $k => $v ) {
		if ( $v === false )
			unset( $qs[$k] );
	}

	$ret = build_query( $qs );
	$ret = trim( $ret, '?' );
	$ret = preg_replace( '#=(&|$)#', '$1', $ret );
	$ret = $protocol . $base . $ret . $frag;
	$ret = rtrim( $ret, '?' );
	return $ret;
}

/**
 * Removes an item or list from the query string.
 *
 * @since 1.5.0
 *
 * @param string|array $key Query key or keys to remove.
 * @param bool $query When false uses the $_SERVER value.
 * @return string New URL query string.
 */
function remove_query_arg( $key, $query=false ) {
	if ( is_array( $key ) ) { // removing multiple keys
		foreach ( $key as $k )
			$query = add_query_arg( $k, false, $query );
		return $query;
	}
	return add_query_arg( $key, false, $query );
}

/**
 * Walks the array while sanitizing the contents.
 *
 * @uses $wpdb Used to sanitize values
 * @since 0.71
 *
 * @param array $array Array to used to walk while sanitizing contents.
 * @return array Sanitized $array.
 */
function add_magic_quotes( $array ) {
	global $wpdb;

	foreach ( (array) $array as $k => $v ) {
		if ( is_array( $v ) ) {
			$array[$k] = add_magic_quotes( $v );
		} else {
			$array[$k] = $wpdb->escape( $v );
		}
	}
	return $array;
}

/**
 * HTTP request for URI to retrieve content.
 *
 * @since 1.5.1
 * @uses wp_remote_get()
 *
 * @param string $uri URI/URL of web page to retrieve.
 * @return bool|string HTTP content. False on failure.
 */
function wp_remote_fopen( $uri ) {
	$parsed_url = @parse_url( $uri );

	if ( !$parsed_url || !is_array( $parsed_url ) )
		return false;

	$options = array();
	$options['timeout'] = 10;

	$response = wp_remote_get( $uri, $options );

	if ( is_wp_error( $response ) )
		return false;

	return $response['body'];
}

/**
 * Setup the WordPress query.
 *
 * @since 2.0.0
 *
 * @param string $query_vars Default WP_Query arguments.
 */
function wp( $query_vars = '' ) {
	global $wp, $wp_query, $wp_the_query;
	$wp->main( $query_vars );

	if( !isset($wp_the_query) )
		$wp_the_query = $wp_query;
}

/**
 * Retrieve the description for the HTTP status.
 *
 * @since 2.3.0
 *
 * @param int $code HTTP status code.
 * @return string Empty string if not found, or description if found.
 */
function get_status_header_desc( $code ) {
	global $wp_header_to_desc;

	$code = absint( $code );

	if ( !isset( $wp_header_to_desc ) ) {
		$wp_header_to_desc = array(
			100 => 'Continue',
			101 => 'Switching Protocols',
			102 => 'Processing',

			200 => 'OK',
			201 => 'Created',
			202 => 'Accepted',
			203 => 'Non-Authoritative Information',
			204 => 'No Content',
			205 => 'Reset Content',
			206 => 'Partial Content',
			207 => 'Multi-Status',
			226 => 'IM Used',

			300 => 'Multiple Choices',
			301 => 'Moved Permanently',
			302 => 'Found',
			303 => 'See Other',
			304 => 'Not Modified',
			305 => 'Use Proxy',
			306 => 'Reserved',
			307 => 'Temporary Redirect',

			400 => 'Bad Request',
			401 => 'Unauthorized',
			402 => 'Payment Required',
			403 => 'Forbidden',
			404 => 'Not Found',
			405 => 'Method Not Allowed',
			406 => 'Not Acceptable',
			407 => 'Proxy Authentication Required',
			408 => 'Request Timeout',
			409 => 'Conflict',
			410 => 'Gone',
			411 => 'Length Required',
			412 => 'Precondition Failed',
			413 => 'Request Entity Too Large',
			414 => 'Request-URI Too Long',
			415 => 'Unsupported Media Type',
			416 => 'Requested Range Not Satisfiable',
			417 => 'Expectation Failed',
			422 => 'Unprocessable Entity',
			423 => 'Locked',
			424 => 'Failed Dependency',
			426 => 'Upgrade Required',

			500 => 'Internal Server Error',
			501 => 'Not Implemented',
			502 => 'Bad Gateway',
			503 => 'Service Unavailable',
			504 => 'Gateway Timeout',
			505 => 'HTTP Version Not Supported',
			506 => 'Variant Also Negotiates',
			507 => 'Insufficient Storage',
			510 => 'Not Extended'
		);
	}

	if ( isset( $wp_header_to_desc[$code] ) )
		return $wp_header_to_desc[$code];
	else
		return '';
}

/**
 * Set HTTP status header.
 *
 * @since 2.0.0
 * @uses apply_filters() Calls 'status_header' on status header string, HTTP
 *		HTTP code, HTTP code description, and protocol string as separate
 *		parameters.
 *
 * @param int $header HTTP status code
 * @return null Does not return anything.
 */
function status_header( $header ) {
	$text = get_status_header_desc( $header );

	if ( empty( $text ) )
		return false;

	$protocol = $_SERVER["SERVER_PROTOCOL"];
	if ( 'HTTP/1.1' != $protocol && 'HTTP/1.0' != $protocol )
		$protocol = 'HTTP/1.0';
	$status_header = "$protocol $header $text";
	if ( function_exists( 'apply_filters' ) )
		$status_header = apply_filters( 'status_header', $status_header, $header, $text, $protocol );

	return @header( $status_header, true, $header );
}

/**
 * Gets the header information to prevent caching.
 *
 * The several different headers cover the different ways cache prevention is handled
 * by different browsers
 *
 * @since 2.8
 *
 * @uses apply_filters()
 * @return array The associative array of header names and field values.
 */
function wp_get_nocache_headers() {
	$headers = array(
		'Expires' => 'Wed, 11 Jan 1984 05:00:00 GMT',
		'Last-Modified' => gmdate( 'D, d M Y H:i:s' ) . ' GMT',
		'Cache-Control' => 'no-cache, must-revalidate, max-age=0',
		'Pragma' => 'no-cache',
	);

	if ( function_exists('apply_filters') ) {
		$headers = apply_filters('nocache_headers', $headers);
	}
	return $headers;
}

/**
 * Sets the headers to prevent caching for the different browsers.
 *
 * Different browsers support different nocache headers, so several headers must
 * be sent so that all of them get the point that no caching should occur.
 *
 * @since 2.0.0
 * @uses wp_get_nocache_headers()
 */
function nocache_headers() {
	$headers = wp_get_nocache_headers();
	foreach( (array) $headers as $name => $field_value )
		@header("{$name}: {$field_value}");
}

/**
 * Set the headers for caching for 10 days with JavaScript content type.
 *
 * @since 2.1.0
 */
function cache_javascript_headers() {
	$expiresOffset = 864000; // 10 days
	header( "Content-Type: text/javascript; charset=" . get_bloginfo( 'charset' ) );
	header( "Vary: Accept-Encoding" ); // Handle proxies
	header( "Expires: " . gmdate( "D, d M Y H:i:s", time() + $expiresOffset ) . " GMT" );
}

/**
 * Retrieve the number of database queries during the WordPress execution.
 *
 * @since 2.0.0
 *
 * @return int Number of database queries
 */
function get_num_queries() {
	global $wpdb;
	return $wpdb->num_queries;
}

/**
 * Whether input is yes or no. Must be 'y' to be true.
 *
 * @since 1.0.0
 *
 * @param string $yn Character string containing either 'y' or 'n'
 * @return bool True if yes, false on anything else
 */
function bool_from_yn( $yn ) {
	return ( strtolower( $yn ) == 'y' );
}

/**
 * Loads the feed template from the use of an action hook.
 *
 * If the feed action does not have a hook, then the function will die with a
 * message telling the visitor that the feed is not valid.
 *
 * It is better to only have one hook for each feed.
 *
 * @since 2.1.0
 * @uses $wp_query Used to tell if the use a comment feed.
 * @uses do_action() Calls 'do_feed_$feed' hook, if a hook exists for the feed.
 */
function do_feed() {
	global $wp_query;

	$feed = get_query_var( 'feed' );

	// Remove the pad, if present.
	$feed = preg_replace( '/^_+/', '', $feed );

	if ( $feed == '' || $feed == 'feed' )
		$feed = get_default_feed();

	$hook = 'do_feed_' . $feed;
	if ( !has_action($hook) ) {
		$message = sprintf( __( 'ERROR: %s is not a valid feed template' ), esc_html($feed));
		wp_die($message);
	}

	do_action( $hook, $wp_query->is_comment_feed );
}

/**
 * Load the RDF RSS 0.91 Feed template.
 *
 * @since 2.1.0
 */
function do_feed_rdf() {
	load_template( ABSPATH . WPINC . '/feed-rdf.php' );
}

/**
 * Load the RSS 1.0 Feed Template
 *
 * @since 2.1.0
 */
function do_feed_rss() {
	load_template( ABSPATH . WPINC . '/feed-rss.php' );
}

/**
 * Load either the RSS2 comment feed or the RSS2 posts feed.
 *
 * @since 2.1.0
 *
 * @param bool $for_comments True for the comment feed, false for normal feed.
 */
function do_feed_rss2( $for_comments ) {
	if ( $for_comments )
		load_template( ABSPATH . WPINC . '/feed-r…