sqlite-integration/functions.php

<?php
/**
 * This file contains the class that defines user defined functions for PDO library.
 *
 * This file is for PHP 5.3.x or later. For PHP 5.2.x or lesser, functions-5-2.php is
 * loaded. PHP version is checked in the db.php and that will load the apropriate
 * one.
 *
 * @package SQLite Integration
 * @author Kojima Toshiyasu
 *
 */

/**
 * This class defines user defined functions(UDFs) for PDO library.
 *
 * These functions replace those used in the SQL statement with the PHP functions.
 *
 * Usage:
 *
 * <code>
 * new PDOSQLiteUDFS(ref_to_pdo_obj);
 * </code>
 *
 * This automatically enables ref_to_pdo_obj to replace the function in the SQL statement
 * to the ones defined here.
 */
class PDOSQLiteUDFS {
	/**
	 * The class constructor
	 *
	 * Initializes the use defined functions to PDO object with PDO::sqliteCreateFunction().
	 *
	 * @param reference to PDO object $pdo
	 */
	public function __construct(&$pdo){
		if (!$pdo) {
			wp_die('Database is not initialized.', 'Database Error');
		}
		foreach ($this->functions as $f=>$t) {
			$pdo->sqliteCreateFunction($f, array($this, $t));
		}
	}
	/**
	 * array to define MySQL function => function defined with PHP.
	 *
	 * Replaced functions must be public.
	 *
	 * @var associative array
	 */
	private $functions = array(
		'month'          => 'month',
		'year'           => 'year',
		'day'            => 'day',
		'unix_timestamp' => 'unix_timestamp',
		'now'            => 'now',
		'char_length'    => 'char_length',
		'md5'            => 'md5',
		'curdate'        => 'curdate',
		'rand'           => 'rand',
		'substring'      => 'substring',
		'dayofmonth'     => 'day',
		'second'         => 'second',
		'minute'         => 'minute',
		'hour'           => 'hour',
		'date_format'    => 'dateformat',
		'from_unixtime'  => 'from_unixtime',
		'date_add'       => 'date_add',
		'date_sub'       => 'date_sub',
		'adddate'        => 'date_add',
		'subdate'        => 'date_sub',
		'localtime'      => 'now',
		'localtimestamp' => 'now',
		'isnull'         => 'isnull',
		'if'             => '_if',
		'regexpp'        => 'regexp',
		'concat'         => 'concat',
		'field'          => 'field',
		'log'            => 'log',
		'least'          => 'least',
		'greatest'       => 'greatest',
		'get_lock'       => 'get_lock',
		'release_lock'   => 'release_lock',
		'ucase'          => 'ucase',
		'lcase'          => 'lcase',
		'inet_ntoa'      => 'inet_ntoa',
		'inet_aton'      => 'inet_aton',
		'datediff'       => 'datediff',
		'locate'         => 'locate',
		'utc_date'       => 'utc_date',
		'utc_time'       => 'utc_time',
		'utc_timestamp'  => 'utc_timestamp',
		'version'        => 'version'
	);
	/**
	 * Method to extract the month value from the date.
	 *
	 * @param string representing the date formated as 0000-00-00.
	 * @return string representing the number of the month between 1 and 12.
	 */
	public function month($field){
		$t = strtotime($field);
		return date('n', $t);
	}
	/**
	 * Method to extract the year value from the date.
	 *
	 * @param string representing the date formated as 0000-00-00.
	 * @return string representing the number of the year.
	 */
	public function year($field){
		$t = strtotime($field);
		return date('Y', $t);
	}
	/**
	 * Method to extract the day value from the date.
	 *
	 * @param string representing the date formated as 0000-00-00.
	 * @return string representing the number of the day of the month from 1 and 31.
	 */
	public function day($field){
		$t = strtotime($field);
		return date('j', $t);
	}
	/**
	 * Method to return the unix timestamp.
	 *
	 * Used without an argument, it returns PHP time() function (total seconds passed
	 * from '1970-01-01 00:00:00' GMT). Used with the argument, it changes the value
	 * to the timestamp.
	 *
	 * @param string representing the date formated as '0000-00-00 00:00:00'.
	 * @return number of unsigned integer
	 */
	public function unix_timestamp($field = null){
		return is_null($field) ? time() : strtotime($field);
	}
	/**
	 * Method to emulate MySQL SECOND() function.
	 *
	 * @param string representing the time formated as '00:00:00'.
	 * @return number of unsigned integer
	 */
	public function second($field){
		$t = strtotime($field);
		return intval( date("s", $t) );
	}
	/**
	 * Method to emulate MySQL MINUTE() function.
	 *
	 * @param string representing the time formated as '00:00:00'.
	 * @return number of unsigned integer
	 */
	public function minute($field){
		$t = strtotime($field);
		return  intval(date("i", $t));
	}
	/**
	 * Method to emulate MySQL HOUR() function.
	 *
	 * @param string representing the time formated as '00:00:00'.
	 * @return number
	 */
	public function hour($time){
		list($hours, $minutes, $seconds) = explode(":", $time);
		return intval($hours);
	}
	/**
	 * Method to emulate MySQL FROM_UNIXTIME() function.
	 *
	 * @param integer of unix timestamp
	 * @param string to indicate the way of formatting(optional)
	 * @return string formatted as '0000-00-00 00:00:00'.
	 */
	public function from_unixtime($field, $format=null){
		// $field is a timestamp
		//convert to ISO time
		$date = date("Y-m-d H:i:s", $field);
		//now submit to dateformat
		return is_null($format) ? $date : $self->dateformat($date, $format);
	}
	/**
	 * Method to emulate MySQL NOW() function.
	 *
	 * @return string representing current time formatted as '0000-00-00 00:00:00'.
	 */
	public function now(){
		return date("Y-m-d H:i:s");
	}
	/**
	 * Method to emulate MySQL CURDATE() function.
	 *
	 * @return string representing current time formatted as '0000-00-00'.
	 */
	public function curdate() {
		return date("Y-m-d");
	}
	/**
	 * Method to emulate MySQL CHAR_LENGTH() function.
	 *
	 * @param string
	 * @return unsigned integer for the length of the argument.
	 */
	public function char_length($field){
		return strlen($field);
	}
	/**
	 * Method to emulate MySQL MD5() function.
	 *
	 * @param string
	 * @return string of the md5 hash value of the argument.
	 */
	public function md5($field){
		return md5($field);
	}
	/**
	 * Method to emulate MySQL RAND() function.
	 *
	 * SQLite does have a random generator, but it is called RANDOM() and returns random
	 * number between -9223372036854775808 and +9223372036854775807. So we substitute it
	 * with PHP random generator.
	 *
	 * This function uses mt_rand() which is four times faster than rand() and returns
	 * the random number between 0 and 1.
	 *
	 * @return unsigned integer
	 */
	public function rand(){
		return mt_rand(0, 1);
	}
	/**
	 * Method to emulate MySQL SUBSTRING() function.
	 *
	 * This function rewrites the function name to SQLite compatible substr(),
	 * which can manipulate UTF-8 characters.
	 *
	 * @param string $text
	 * @param integer $pos representing the start point.
	 * @param integer $len representing the length of the substring(optional).
	 * @return string
	 */
	public function substring($text, $pos, $len=null){
		return "substr($text, $pos, $len)";
	}
	/**
	 * Method to emulate MySQL DATEFORMAT() function.
	 *
	 * @param string date formatted as '0000-00-00' or datetime as '0000-00-00 00:00:00'.
	 * @param string $format
	 * @return string formatted according to $format
	 */
	public function dateformat($date, $format){
		$mysql_php_dateformats = array ( '%a' => 'D', '%b' => 'M', '%c' => 'n', '%D' => 'jS', '%d' => 'd', '%e' => 'j', '%H' => 'H', '%h' => 'h', '%I' => 'h', '%i' => 'i', '%j' => 'z', '%k' => 'G', '%l' => 'g', '%M' => 'F', '%m' => 'm', '%p' => 'A', '%r' => 'h:i:s A', '%S' => 's', '%s' => 's', '%T' => 'H:i:s', '%U' => 'W', '%u' => 'W', '%V' => 'W', '%v' => 'W', '%W' => 'l', '%w' => 'w', '%X' => 'Y', '%x' => 'o', '%Y' => 'Y', '%y' => 'y', );
		$t      = strtotime($date);
		$format = strtr($format, $mysql_php_dateformats);
		$output =  date($format, $t);
		return $output;
	}
	/**
	 * Method to emulate MySQL DATE_ADD() function.
	 *
	 * This function adds the time value of $interval expression to $date.
	 * $interval is a single quoted strings rewritten by SQLiteQueryDriver::rewrite_query().
	 * It is calculated in the private function deriveInterval().
	 *
	 * @param string $date representing the start date.
	 * @param string $interval representing the expression of the time to add.
	 * @return string date formated as '0000-00-00 00:00:00'.
	 */
	public function date_add($date, $interval) {
		$interval = $this->deriveInterval($interval);
		switch (strtolower($date)) {
			case "curdate()":
				$objDate   = new Datetime($this->curdate());
				$objDate->add(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d");
				break;
			case "now()":
				$objDate   = new Datetime($this->now());
				$objDate->add(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d H:i:s");
				break;
			default:
				$objDate   = new Datetime($date);
				$objDate->add(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d H:i:s");
		}
		return $returnval;
	}
	/**
	 * Method to emulate MySQL DATE_SUB() function.
	 *
	 * This function substracts the time value of $interval expression from $date.
	 * $interval is a single quoted strings rewritten by SQLiteQueryDriver::rewrite_query().
	 * It is calculated in the private function deriveInterval().
	 *
	 * @param string $date representing the start date.
	 * @param string $interval representing the expression of the time to substract.
	 * @return string date formated as '0000-00-00 00:00:00'.
	 */
	public function date_sub($date, $interval) {
		$interval = $this->deriveInterval($interval);
		switch (strtolower($date)) {
			case "curdate()":
				$objDate   = new Datetime($this->curdate());
				$objDate->sub(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d");
				break;
			case "now()":
				$objDate   = new Datetime($this->now());
				$objDate->sub(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d H:i:s");
				break;
			default:
				$objDate   = new Datetime($date);
				$objDate->sub(new DateInterval($interval));
				$returnval = $objDate->format("Y-m-d H:i:s");
		}
		return $returnval;
	}
	/**
	 * Method to calculate the interval time between two dates value.
	 *
	 * @access private
	 * @param string $interval white space separated expression.
	 * @return string representing the time to add or substract.
	 */
	private function deriveInterval($interval) {
		$interval = trim(substr(trim($interval), 8));
		$parts = explode(' ', $interval);
		foreach ($parts as $part) {
			if (!empty($part)) {
				$_parts[] = $part;
			}
		}
		$type = strtolower(end($_parts));
		switch ($type) {
			case "second": $unit = 'S'; return 'PT' . $_parts[0] . $unit; break;
			case "minute": $unit = 'M'; return 'PT' . $_parts[0] . $unit; break;
			case "hour":   $unit = 'H'; return 'PT' . $_parts[0] . $unit; break;
			case "day":    $unit = 'D'; return 'P'  . $_parts[0] . $unit; break;
			case "week":   $unit = 'W'; return 'P'  . $_parts[0] . $unit; break;
			case "month":  $unit = 'M'; return 'P'  . $_parts[0] . $unit; break;
			case "year":   $unit = 'Y'; return 'P'  . $_parts[0] . $unit; break;
			case "minute_second":
				list($minutes, $seconds) = explode(':', $_parts[0]);
				return 'PT' . $minutes . 'M' . $seconds . 'S';
			case "hour_second":
				list($hours, $minutes, $seconds) = explode (':', $_parts[0]);
				return 'PT' . $hours . 'H' . $minutes . 'M' . $seconds . 'S';
			case "hour_minute":
				list($hours, $minutes) = explode (':', $_parts[0]);
				return 'PT' . $hours . 'H' . $minutes . 'M';
			case "day_second":
				$days = intval($_parts[0]);
				list($hours, $minutes, $seconds) = explode (':', $_parts[1]);
				return 'P' . $days . 'D' . 'T' . $hours . 'H' . $minutes . 'M' . $seconds . 'S';
			case "day_minute":
				$days = intval($_parts[0]);
				list($hours, $minutes) = explode(':', $parts[1]);
				return 'P' . $days . 'D' . 'T' . $hours . 'H' . $minutes . 'M';
			case "day_hour":
				$days  = intval($_parts[0]);
				$hours = intval($_parts[1]);
				return 'P' . $days . 'D' . 'T' . $hours . 'H';
			case "year_month":
				list($years, $months) = explode ('-', $_parts[0]);
				return 'P' . $years . 'Y' . $months . 'M';
		}
	}
	/**
	 * Method to emulate MySQL DATE() function.
	 *
	 * @param string $date formatted as unix time.
	 * @return string formatted as '0000-00-00'.
	 */
	public function date($date){
		return date("Y-m-d", strtotime($date));
	}
	/**
	 * Method to emulate MySQL ISNULL() function.
	 *
	 * This function returns true if the argument is null, and true if not.
	 *
	 * @param various types $field
	 * @return boolean
	 */
	public function isnull($field){
		return is_null($field);
	}
	/**
	 * Method to emulate MySQL IF() function.
	 *
	 * As 'IF' is a reserved word for PHP, function name must be changed.
	 *
	 * @param unknonw $expression the statement to be evaluated as true or false.
	 * @param unknown $true statement or value returned if $expression is true.
	 * @param unknown $false statement or value returned if $expression is false.
	 * @return unknown
	 */
	public function _if($expression, $true, $false){
		return ($expression == true) ? $true : $false;
	}
	/**
	 * Method to emulate MySQL REGEXP() function.
	 *
	 * @param string $field haystack
	 * @param string $pattern: regular expression to match.
	 * @return integer 1 if matched, 0 if not matched.
	 */
	public function regexp($field, $pattern){
		$pattern = str_replace('/', '\/', $pattern);
		$pattern = "/" . $pattern ."/i";
		return preg_match ($pattern, $field);
	}
	/**
	 * Method to emulate MySQL CONCAT() function.
	 *
	 * SQLite does have CONCAT() function, but it has a different syntax from MySQL.
	 * So this function must be manipulated here.
	 *
	 * @param string
	 * @return NULL if the argument is null | string conatenated if the argument is given.
	 */
	public function concat() {
		$returnValue = "";
		$argsNum  = func_num_args();
		$argsList = func_get_args();
		for ($i = 0; $i < $argsNum; $i++) {
			if (is_null($argsList[$i])) {
				return null;
			}
			$returnValue .= $argsList[$i];
		}
		return $returnValue;
	}
	/**
	 * Method to emulate MySQL FIELD() function.
	 *
	 * This function gets the list argument and compares the first item to all the others.
	 * If the same value is found, it returns the position of that value. If not, it
	 * returns 0.
	 *
	 * @param variable number of string, integer or double
	 * @return unsigned integer
	 */
	public function field() {
		global $wpdb;
		$numArgs = func_num_args();
		if ($numArgs < 2 or is_null(func_get_arg(0))) {
			return 0;
		} else {
			$arg_list = func_get_args();
		}
		$searchString = array_shift($arg_list);
		$str_to_check = substr($searchString, 0, strpos($searchString, '.'));
		$str_to_check = str_replace($wpdb->prefix, '', $str_to_check);
		if ($str_to_check && in_array(trim($str_to_check), $wpdb->tables)) return;
		for ($i = 0; $i < $numArgs-1; $i++) {
			if ($searchString === strtolower($arg_list[$i])) {
				return $i + 1;
			}
		}
		return 0;
	}
	/**
	 * Method to emulate MySQL LOG() function.
	 *
	 * Used with one argument, it returns the natural logarithm of X.
	 * <code>
	 * LOG(X)
	 * </code>
	 * Used with two arguments, it returns the natural logarithm of X base B.
	 * <code>
	 * LOG(B, X)
	 * </code>
	 * In this case, it returns the value of log(X) / log(B).
	 *
	 * Used without an argument, it returns false. This returned value will be
	 * rewritten to 0, because SQLite doesn't understand true/false value.
	 *
	 * @param integer representing the base of the logarithm, which is optional.
	 * @param double value to turn into logarithm.
	 * @return double | NULL
	 */
	public function log() {
		$numArgs = func_num_args();
		if ($numArgs == 1) {
			$arg1 = func_get_arg(0);
			return log($arg1);
		} else if ($numArgs == 2) {
			$arg1 = func_get_arg(0);
			$arg2 = func_get_arg(1);
			return log($arg1)/log($arg2);
		} else {
			return null;
		}
	}
	/**
	 * Method to emulate MySQL LEAST() function.
	 *
	 * This function rewrites the function name to SQLite compatible function name.
	 *
	 * @return mixed
	 */
	public function least() {
		$arg_list = func_get_args();
		return "min($arg_list)";
	}
	/**
	 * Method to emulate MySQL GREATEST() function.
	 *
	 * This function rewrites the function name to SQLite compatible function name.
	 *
	 * @return mixed
	 */
	public function greatest() {
		$arg_list = func_get_args();
		return "max($arg_list)";
	}
	/**
	 * Method to dummy out MySQL GET_LOCK() function.
	 *
	 * This function is meaningless in SQLite, so we do nothing.
	 *
	 * @param string $name
	 * @param integer $timeout
	 * @return string
	 */
	public function get_lock($name, $timeout) {
		return '1=1';
	}
	/**
	 * Method to dummy out MySQL RELEASE_LOCK() function.
	 *
	 * This function is meaningless in SQLite, so we do nothing.
	 *
	 * @param string $name
	 * @return string
	 */
	public function release_lock($name) {
		return '1=1';
	}
	/**
	 * Method to emulate MySQL UCASE() function.
	 *
	 * This is MySQL alias for upper() function. This function rewrites it
	 * to SQLite compatible name upper().
	 *
	 * @param string
	 * @return string SQLite compatible function name.
	 */
	public function ucase($string) {
		return "upper($string)";
	}
	/**
	 * Method to emulate MySQL LCASE() function.
	 *
	 *
	 * This is MySQL alias for lower() function. This function rewrites it
	 * to SQLite compatible name lower().
	 *
	 * @param string
	 * @return string SQLite compatible function name.
	 */
	public function lcase($string) {
		return "lower($string)";
	}
	/**
	 * Method to emulate MySQL INET_NTOA() function.
	 *
	 * This function gets 4 or 8 bytes integer and turn it into the network address.
	 *
	 * @param unsigned long integer
	 * @return string
	 */
	public function inet_ntoa($num) {
		return long2ip($num);
	}
	/**
	 * Method to emulate MySQL INET_ATON() function.
	 *
	 * This function gets the network address and turns it into integer.
	 *
	 * @param string
	 * @return unsigned long integer
	 */
	public function inet_aton($addr) {
		$int_data = ip2long($addr);
		$unsigned_int_data = sprintf('%u', $address);
		return $unsigned_int_data;
	}
	/**
	 * Method to emulate MySQL DATEDIFF() function.
	 *
	 * This function compares two dates value and returns the difference.
	 *
	 * PHP 5.3.2 has a serious bug in DateTime::diff(). So if users' PHP is that version,
	 * we don't use that function. See https://bugs.php.net/bug.php?id=51184.
	 *
	 * @param string start
	 * @param string end
	 * @return string
	 */
	public function datediff($start, $end) {
		if (version_compare(PHP_VERSION, '5.3.2', '==')) {
			$start_date = strtotime($start);
			$end_date   = strtotime($end);
			$interval   = floor(($start_date - $end_date)/(3600*24));
			return $interval;
		} else {
			$start_date = new DateTime($start);
			$end_date   = new DateTime($end);
			$interval   = $end_date->diff($start_date, false);
			return $interval->format('%r%a');
		}
	}
	/**
	 * Method to emulate MySQL LOCATE() function.
	 *
	 * This function returns the position if $substr is found in $str. If not,
	 * it returns 0. If mbstring extension is loaded, mb_strpos() function is
	 * used.
	 *
	 * @param string needle
	 * @param string haystack
	 * @param integer position
	 * @return integer
	 */
	public function locate($substr, $str, $pos = 0) {
		if (!extension_loaded('mbstring')) {
			if (($val = stros($str, $substr, $pos)) !== false) {
				return $val + 1;
			} else {
				return 0;
			}
		} else {
			if (($val = mb_strpos($str, $substr, $pos)) !== false) {
				return $val + 1;
			} else {
				return 0;
			}
		}
	}
	/**
	 * Method to return GMT date in the string format.
	 *
	 * @param none
	 * @return string formatted GMT date 'dddd-mm-dd'
	 */
	public function utc_date() {
		return gmdate('Y-m-d', time());
	}
	/**
	 * Method to return GMT time in the string format.
	 *
	 * @param none
	 * @return string formatted GMT time '00:00:00'
	 */
	public function utc_time() {
		return gmdate('H:i:s', time());
	}
	/**
	 * Method to return GMT time stamp in the string format.
	 *
	 * @param none
	 * @return string formatted GMT timestamp 'yyyy-mm-dd 00:00:00'
	 */
	public function utc_timestamp() {
		return gmdate('Y-m-d H:i:s', time());
	}
	/**
	 * Method to return MySQL version.
	 *
	 * This function only returns the current newest version number of MySQL,
	 * because it is meaningless for SQLite database.
	 *
	 * @param none
	 * @return string representing the version number: major_version.minor_version
	 */
	public function version() {
		//global $required_mysql_version;
		//return $required_mysql_version;
		return '5.5';
	}
}
?>