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<?php
/**
* `WHERE` keyword parser.
*
* @package SqlParser
* @subpackage Components
*/
namespace SqlParserComponents;
use SqlParserComponent;
use SqlParserParser;
use SqlParserToken;
use SqlParserTokensList;
/**
* `WHERE` keyword parser.
*
* @category Keywords
* @package SqlParser
* @subpackage Components
* @author Dan Ungureanu <udan1107@gmail.com>
* @license http://opensource.org/licenses/GPL-2.0 GNU Public License
*/
class Condition extends Component
{
/**
* Logical operators that can be used to delimit expressions.
*
* @var array
*/
public static $DELIMITERS = array('&&', 'AND', 'OR', 'XOR', '||');
/**
* Hash map containing reserved keywords that are also operators.
*
* @var array
*/
public static $OPERATORS = array(
'AND' => 1,
'BETWEEN' => 1,
'IN' => 1,
'IS' => 1,
'LIKE' => 1,
'NOT NULL' => 1,
'NULL' => 1,
'OR' => 1,
'XOR' => 1,
);
/**
* Identifiers recognized.
*
* @var array
*/
public $identifiers = array();
/**
* Whether this component is an operator.
*
* @var bool
*/
public $isOperator = false;
/**
* The condition.
*
* @var string
*/
public $expr;
/**
* Constructor.
*
* @param string $expr The condition or the operator.
*/
public function __construct($expr = null)
{
$this->expr = trim($expr);
}
/**
* @param Parser $parser The parser that serves as context.
* @param TokensList $list The list of tokens that are being parsed.
* @param array $options Parameters for parsing.
*
* @return Condition[]
*/
public static function parse(Parser $parser, TokensList $list, array $options = array())
{
$ret = array();
$expr = new Condition();
/**
* Counts brackets.
*
* @var int $brackets
*/
$brackets = 0;
/**
* Whether there was a `BETWEEN` keyword before or not.
* It is required to keep track of them because their structure contains
* the keyword `AND`, which is also an operator that delimits
* expressions.
*
* @var bool $betweenBefore
*/
$betweenBefore = false;
for (; $list->idx < $list->count; ++$list->idx) {
/**
* Token parsed at this moment.
*
* @var Token $token
*/
$token = $list->tokens[$list->idx];
// End of statement.
if ($token->type === Token::TYPE_DELIMITER) {
break;
}
// Skipping whitespaces and comments.
if ($token->type === Token::TYPE_COMMENT) {
continue;
}
// Replacing all whitespaces (new lines, tabs, etc.) with a single
// space character.
if ($token->type === Token::TYPE_WHITESPACE) {
$expr->expr .= ' ';
continue;
}
// Conditions are delimited by logical operators.
if (in_array($token->value, static::$DELIMITERS, true)) {
if (($betweenBefore) && ($token->value === 'AND')) {
$betweenBefore = false;
} else {
$expr->expr = trim($expr->expr);
if (!empty($expr->expr)) {
// Adding the condition that is delimited by this operator.
$ret[] = $expr;
}
// Adding the operator.
$expr = new Condition($token->value);
$expr->isOperator = true;
$ret[] = $expr;
$expr = new Condition();
continue;
}
}
if ($token->type === Token::TYPE_OPERATOR) {
if ($token->value === '(') {
++$brackets;
} elseif ($token->value === ')') {
--$brackets;
}
}
// No keyword is expected.
if (($token->type === Token::TYPE_KEYWORD) && ($token->flags & Token::FLAG_KEYWORD_RESERVED)) {
if ($token->value === 'BETWEEN') {
$betweenBefore = true;
}
if (($brackets === 0) && (empty(static::$OPERATORS[$token->value]))) {
break;
}
}
$expr->expr .= $token->token;
if (($token->type === Token::TYPE_NONE)
|| (($token->type === Token::TYPE_KEYWORD) && (!($token->flags & Token::FLAG_KEYWORD_RESERVED)))
|| ($token->type === Token::TYPE_STRING)
|| ($token->type === Token::TYPE_SYMBOL)
) {
$expr->identifiers[] = $token->value;
}
}
// Last iteration was not processed.
$expr->expr = trim($expr->expr);
if (!empty($expr->expr)) {
$ret[] = $expr;
}
--$list->idx;
return $ret;
}
/**
* @param Condition[] $component The component to be built.
* @param array $options Parameters for building.
*
* @return string
*/
public static function build($component, array $options = array())
{
if (is_array($component)) {
return implode(' ', $component);
} else {
return $component->expr;
}
}
}
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