VTQL_Lexer.php

<?php
global $where_col,$orderby,$in_started,$count;
$where_col = false;
$orderby = false;
$in_started = false;
$count = false;
function incrementN($lexer, $count){
$i = 0;
for(;$i<$count;$i++){
incState($lexer);
}
}
function incState($lexer){
$lexer->current_state++;
if($lexer->current_state === sizeof($lexer->mandatory_states)){
$lexer->mandatory = false;
}
}
function handleselect($lexer, $val){
if($lexer->mandatory){
if(strcasecmp($val, $lexer->mandatory_states[$lexer->current_state])===0){
incState($lexer);
return VTQL_Parser::SELECT;
}
}
}
function handlecolumn_list($lexer, $val){
global $count;
if($lexer->mandatory){
if(!(strcasecmp($val, $lexer->mandatory_states[2])===0)){
if(strcmp($val, "*")===0){
if(!$count){
incrementN($lexer, 1);
}
return VTQL_Parser::ASTERISK;
}else if((strcmp($val, "(")===0)){
return VTQL_Parser::PARENOPEN;
}else if(strcmp($val, ")")===0){
return VTQL_Parser::PARENCLOSE;
}else if((strcasecmp($val, "count")===0)){
$count = true;
return VTQL_Parser::COUNT;
}else if(strcmp($val, ",")===0){
return VTQL_Parser::COMMA;
}else{
return VTQL_Parser::COLUMNNAME;
}
}else{
incrementN($lexer, 2);
return VTQL_Parser::FRM;
}
}
}
function handlefrom($lexer, $val){
if((strcasecmp($val, $lexer->mandatory_states[$lexer->current_state])===0)){
incState($lexer);
return VTQL_Parser::FRM;
}
}
function handletable($lexer, $val){
if($lexer->mandatory){
$lexer->current_state =0;
$lexer->mandatory = false;
if(!(strcasecmp($val, $lexer->optional_states[$lexer->current_state])===0)){
return VTQL_Parser::TABLENAME;
}
}
}
function handlewhere($lexer, $val){
global $where_col,$in_started;
$val = trim($val);
if((strcmp($val, "=")===0)){
return VTQL_Parser::EQ;
}else if((strcasecmp($val, $lexer->optional_states[$lexer->current_state])===0)){
return VTQL_Parser::WHERE;
}else if((strcmp($val, "<")===0)){
return VTQL_Parser::LT;
}else if((strcmp($val, "<=")===0)){
return VTQL_Parser::LTE;
}else if((strcmp($val, ">=")===0)){
return VTQL_Parser::GTE;
}else if((strcmp($val, "!=")===0)){
return VTQL_Parser::NE;
}else if((strcmp($val, ">")===0)){
return VTQL_Parser::GT;
}else if((strcmp($val, "(")===0)){
return VTQL_Parser::PARENOPEN;
}else if((strcmp($val, ")")===0)){
if($in_started){
$in_started = false;
$where_col = false;
}
return VTQL_Parser::PARENCLOSE;
}else if((strcasecmp($val, "and")===0)){
return VTQL_Parser::LOGICAL_AND;
}else if((strcasecmp($val, "or")===0)){
return VTQL_Parser::LOGICAL_OR;
}else if(!$where_col){
$where_col = true;
return VTQL_Parser::COLUMNNAME;
}else if((strcasecmp($val, "in")===0)){
$in_started = true;
return VTQL_Parser::IN;
}else if(strcmp($val, ",")===0){
return VTQL_Parser::COMMA;
}else if(strcasecmp($val, "like")===0){
return VTQL_Parser::LIKE;
}else if($where_col){
if(!$in_started){
$where_col = false;
}
return VTQL_Parser::VALUE;
}
}
function handleorderby($lexer, $val){
global $orderby;
if(!$orderby){
	$orderby = true;
	return VTQL_Parser::ORDERBY;
}
if(strcmp($val, ",")===0){
return VTQL_Parser::COMMA;
}else if(strcasecmp($val, "asc")===0){
return VTQL_Parser::ASC;
}else if(strcasecmp($val, "desc")===0){
return VTQL_Parser::DESC;
}else{
return VTQL_Parser::COLUMNNAME;
}
}
function handlelimit($lexer, $val){
if((strcasecmp($val, "limit")===0)){
return VTQL_Parser::LIMIT;
}else if((strcmp($val, "(")===0)){
return VTQL_Parser::PARENOPEN;
}else if((strcmp($val, ")")===0)){
return VTQL_Parser::PARENCLOSE;
}else if(strcmp($val, ",")===0){
return VTQL_Parser::COMMA;
}else{
return VTQL_Parser::VALUE;
}
}
function handleend($lexer, $val){
return VTQL_Parser::SEMICOLON;
}
class VTQL_Lexer{
private $index;
public $token;
public $value;
public $linenum;
public $state = 1;
private $data;
public $mandatory_states = array('select','column_list','from','table');
public $optional_states = array('where', 'orderby', 'limit');
public $mandatory ;
public $current_state ;
function __construct($data)
{
$this->index = 0;
$this->data = $data;
$this->linenum = 1;
$this->mandatory = true;
$this->current_state = 0;
}
function __toString(){
return $this->token."";
}

    private $_yy_state = 1;
    private $_yy_stack = array();

    function yylex()
    {
        return $this->{'yylex' . $this->_yy_state}();
    }

    function yypushstate($state)
    {
        array_push($this->_yy_stack, $this->_yy_state);
        $this->_yy_state = $state;
    }

    function yypopstate()
    {
        $this->_yy_state = array_pop($this->_yy_stack);
    }

    function yybegin($state)
    {
        $this->_yy_state = $state;
    }



    function yylex1()
    {
        $tokenMap = array (
              1 => 2,
              4 => 0,
            );
        if ($this->index >= strlen($this->data)) {
            return false; // end of input
        }
        $yy_global_pattern = "/^((\\w+|'(?:[^']|'')+'|\\(|\\)|(\\+|-)?\\d+|,|\\*|(?!<|>)=|<(?!=)|>(?!=)|<=|>=|!=|;))|^([ \t\r\n]+)/";

        do {
            if (preg_match($yy_global_pattern, substr($this->data, $this->index), $yymatches)) {
                $yysubmatches = $yymatches;
                $yymatches = array_filter($yymatches, 'strlen'); // remove empty sub-patterns
                if (!php7_count($yymatches)) {
                    throw new Exception('Error: lexing failed because a rule matched' .
                        'an empty string.  Input "' . substr($this->data,
                        $this->index, 5) . '... state INITR');
                }
                next($yymatches); // skip global match
                $this->token = key($yymatches); // token number
                if ($tokenMap[$this->token]) {
                    // extract sub-patterns for passing to lex function
                    $yysubmatches = array_slice($yysubmatches, $this->token + 1,
                        $tokenMap[$this->token]);
                } else {
                    $yysubmatches = array();
                }
                $this->value = current($yymatches); // token value
                $r = $this->{'yy_r1_' . $this->token}($yysubmatches);
                if ($r === null) {
                    $this->index += strlen($this->value);
                    $this->linenum += substr_count("\n", $this->value);
                    // accept this token
                    return true;
                } elseif ($r === true) {
                    // we have changed state
                    // process this token in the new state
                    return $this->yylex();
                } elseif ($r === false) {
                    $this->index += strlen($this->value);
                    $this->linenum += substr_count("\n", $this->value);
                    if ($this->index >= strlen($this->data)) {
                        return false; // end of input
                    }
                    // skip this token
                    continue;
                } else {                    $yy_yymore_patterns = array(
        1 => "^([ \t\r\n]+)",
        4 => "",
    );

                    // yymore is needed
                    do {
                        if (!strlen($yy_yymore_patterns[$this->token])) {
                            throw new Exception('cannot do yymore for the last token');
                        }
                        if (preg_match($yy_yymore_patterns[$this->token],
                              substr($this->data, $this->index), $yymatches)) {
                            $yymatches = array_filter($yymatches, 'strlen'); // remove empty sub-patterns
                            next($yymatches); // skip global match
                            $this->token = key($yymatches); // token number
                            $this->value = current($yymatches); // token value
                            $this->linenum = substr_count("\n", $this->value);
                        }
                    } while ($this->{'yy_r1_' . $this->token}() !== null);
                    // accept
                    $this->index += strlen($this->value);
                    $this->linenum += substr_count("\n", $this->value);
                    return true;
                }
            } else {
                throw new Exception('Unexpected input at line' . $this->linenum .
                    ': ' . $this->data[$this->index]);
            }
            break;
        } while (true);
    } // end function


    const INITR = 1;
    function yy_r1_1($yy_subpatterns)
    {

global $orderby;
//echo "<br> ql state: ",$this->current_state," ",$this->value,"<br>";
if($this->mandatory){
//echo "<br> ql state: ",$this->current_state," ",$this->value,"<br>";
$handler = 'handle'.$this->mandatory_states[$this->current_state];
$this->token = $handler($this, $this->value);
}else{
$str = $this->value;
if(strcmp($this->value, ";")===0){
$this->token = handleend($this, $this->value);
return;
}
if(strcasecmp($this->value, "order")===0){
$orderby = true;
return false;
}else if(strcasecmp($this->value, "by") ===0 && $orderby ===true){
$orderby = false;
$this->current_state = 1;
}
$index = array_search(strtolower($str), $this->optional_states, true);
if($index !== false){
$this->current_state = $index;
}
$handler = 'handle'.$this->optional_states[$this->current_state];
$this->token = $handler($this, $this->value);
}//$this->yypushstate($this->value);
    }
    function yy_r1_4($yy_subpatterns)
    {

return false;
    }

}

?>