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doctrine2/draft/Doctrine/Query/Scanner.php
2008-01-16 14:07:14 +00:00

152 lines
4.3 KiB
PHP

<?php
/*
* $Id$
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This software consists of voluntary contributions made by many individuals
* and is licensed under the LGPL. For more information, see
* <http://www.phpdoctrine.org>.
*/
/**
* ...
*
* @package Doctrine
* @subpackage Query
* @author Janne Vanhala <jpvanhal@cc.hut.fi>
* @license http://www.opensource.org/licenses/lgpl-license.php LGPL
* @link www.phpdoctrine.org
* @since 1.0
* @version $Revision$
*/
class Doctrine_Query_Scanner
{
/**
* Array of scanned tokens
*
* @var array
*/
protected $_tokens = array();
protected $_nextToken = 0;
protected $_peek = 0;
/**
* Creates a new query scanner object.
*
* @param string $input a query string
*/
public function __construct($input)
{
$this->_scan($input);
}
/**
* Checks if an identifier is a keyword and returns its correct type.
*
* @param string $identifier identifier name
* @return int token type
*/
public function _checkLiteral($identifier)
{
$name = 'Doctrine_Query_Token::T_' . strtoupper($identifier);
if (defined($name)) {
$type = constant($name);
if ($type > 100) {
return $type;
}
}
return Doctrine_Query_Token::T_IDENTIFIER;
}
/**
* Scans the input string for tokens.
*
* @param string $input a query string
*/
protected function _scan($input)
{
static $regex;
if ( ! isset($regex)) {
$patterns = array(
'[a-z_][a-z0-9_]*',
'(?:[0-9]+(?:[\.][0-9]+)?)(?:e[+-]?[0-9]+)?',
"'(?:[^']|'')*'",
'\?|:[a-z]+'
);
$regex = '/(' . implode(')|(', $patterns) . ')|\s+|(.)/i';
}
$flags = PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_OFFSET_CAPTURE;
$matches = preg_split($regex, $input, -1, $flags);
foreach ($matches as $match) {
$value = $match[0];
if (is_numeric($value)) {
$type = Doctrine_Query_Token::T_NUMERIC;
} elseif ($value[0] === "'" && $value[strlen($value) - 1] === "'") {
$type = Doctrine_Query_Token::T_STRING;
} elseif (ctype_alpha($value[0]) || $value[0] === '_') {
$type = $this->_checkLiteral($value);
} elseif ($value[0] === '?' || $value[0] === ':') {
$type = Doctrine_Query_Token::T_INPUT_PARAMETER;
} else {
$type = Doctrine_Query_Token::T_NONE;
}
$this->_tokens[] = array(
'value' => $value,
'type' => $type,
'position' => $match[1]
);
}
}
public function peek()
{
return $this->_tokens[$this->_nextToken + $this->_peek++];
}
public function resetPeek()
{
$this->_peek = 0;
}
/**
* Returns the next token in the input string.
*
* A token is an associative array containing three items:
* - 'value' : the string value of the token in the input string
* - 'type' : the type of the token (identifier, numeric, string, input
* parameter, none)
* - 'position' : the position of the token in the input string
*
* @return array|null the next token; null if there is no more tokens left
*/
public function next()
{
$this->_peek = 0;
return $this->_tokens[$this->_nextToken++];
}
}