<?php

// Copyright (C) 2010 Combodo SARL
//
//   This program is free software; you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation; version 3 of the License.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program; if not, write to the Free Software
//   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

/**
 * OQL syntax analyzer, to be used prior to run the lexical analyzer
 *
 * @author      Erwan Taloc <erwan.taloc@combodo.com>
 * @author      Romain Quetiez <romain.quetiez@combodo.com>
 * @author      Denis Flaven <denis.flaven@combodo.com>
 * @license     http://www.opensource.org/licenses/gpl-3.0.html LGPL
 */

// Notes (from the source file: oql-lexer.plex) - Romain
//
// The strval rule is a little bit cryptic.
// This is due to both a bug in the lexer generator and the complexity of our need
// The rule means: either a quoted string with ", or a quoted string with '
//                 literal " (resp. ') must be escaped by a \
//                 \ must be escaped by an additional \
// 
// Here are the issues and limitation found in the lexer generator:
// * Matching simple quotes is an issue, because regexp are not correctly escaped (and the ESC code is escaped itself)
//    Workaround: insert '.chr(39).' which will be a real ' in the end
// * Matching an alternate regexp is an issue because you must specify  "|^...."
//   and the regexp parser will not accept that syntax
//    Workaround: insert '.chr(94).' which will be a real ^
//
// Let's analyze an overview of the regexp, we have
// 1) The strval rule in the lexer definition
//     /"([^\\"]|\\"|\\\\)*"|'.chr(94).chr(39).'([^\\'.chr(39).']|\\'.chr(39).'|\\\\)*'.chr(39).'/
// 2) Becomes the php expression in the lexer
//    (note the escaped double quotes, hopefully having no effect, but showing where the issue is!)
//     $myRegexp = '/^\"([^\\\\\"]|\\\\\"|\\\\\\\\)*\"|'.chr(94).chr(39).'([^\\\\'.chr(39).']|\\\\'.chr(39).'|\\\\\\\\)*'.chr(39).'/';
//
// To be fixed in LexerGenerator/Parser.y, in doLongestMatch (doFirstMatch is ok)
//
//
// Now, let's explain how the regexp has been designed.
// Here is a simplified version, dealing with simple quotes, and based on the assumption that the lexer generator has been fixed!
// The strval rule in the lexer definition
//     /'([^\\']*(\\')*(\\\\)*)*'/
// This means anything containing \\ or \' or any other char but a standalone ' or \
// This means ' or \ could not be found without a preceding \
//
class OQLLexerRaw
{
    protected $data;  // input string
    public $token;  // token id
    public $value;  // token string representation
    protected $line;  // current line
    protected $count; // current column

    function __construct($data)
    {
        $this->data  = $data;
        $this->count = 0;
        $this->line  = 1;
    }

/*!lex2php
%input   $this->data
%counter $this->count
%token   $this->token
%value   $this->value
%line    $this->line
%matchlongest 1
whitespace = /[ \t\n\r]+/
select     = "SELECT"
from       = "FROM"
as_alias   = "AS"
where	     = "WHERE"
join	     = "JOIN"
on	        = "ON"
coma       = ","
par_open   = "("
par_close  = ")"
math_div   = "/"
math_mult  = "*"
math_plus  = "+"
math_minus = "-"
log_and    = "AND"
log_or     = "OR"
eq         = "="
not_eq     = "!="
gt         = ">"
lt         = "<"
ge         = ">="
le         = "<="
like       = "LIKE"
not_like   = "NOT LIKE"
in         = "IN"
not_in     = "NOT IN"
interval   = "INTERVAL"
f_if       = "IF"
f_elt      = "ELT"
f_coalesce = "COALESCE"
f_concat   = "CONCAT"
f_substr   = "SUBSTR"
f_trim     = "TRIM"
f_date     = "DATE"
f_date_format = "DATE_FORMAT"
f_current_date = "CURRENT_DATE"
f_now      = "NOW"
f_time     = "TIME"
f_to_days   = "TO_DAYS"
f_from_days = "FROM_DAYS"
f_year     = "YEAR"
f_month    = "MONTH"
f_day      = "DAY"
f_hour     = "HOUR"
f_minute   = "MINUTE"
f_second   = "SECOND"
f_date_add = "DATE_ADD"
f_date_sub = "DATE_SUB"
f_round    = "ROUND"
f_floor    = "FLOOR"
f_inet_aton = "INET_ATON"
f_inet_ntoa = "INET_NTOA"
numval     = /[0-9]+|0x[0-9a-fA-F]+/
strval     = /"([^\\"]|\\"|\\\\)*"|'.chr(94).chr(39).'([^\\'.chr(39).']|\\'.chr(39).'|\\\\)*'.chr(39).'/
name       = /([_a-zA-Z][_a-zA-Z0-9]*|`[^`]+`)/
varname    = /:([_a-zA-Z][_a-zA-Z0-9]*->[_a-zA-Z][_a-zA-Z0-9]*|[_a-zA-Z][_a-zA-Z0-9]*)/
dot       = "."
*/

/*!lex2php
whitespace {
	return false;
}
select {
	$this->token = OQLParser::SELECT;
}
from {
	$this->token = OQLParser::FROM;
}
as_alias {
	$this->token = OQLParser::AS_ALIAS;
}
where {
	$this->token = OQLParser::WHERE;
}
join {
	$this->token = OQLParser::JOIN;
}
on {
	$this->token = OQLParser::ON;
}
math_div {
	$this->token = OQLParser::MATH_DIV;
}
math_mult {
	$this->token = OQLParser::MATH_MULT;
}
math_plus {
	$this->token = OQLParser::MATH_PLUS;
}
math_minus {
	$this->token = OQLParser::MATH_MINUS;
}
log_and {
	$this->token = OQLParser::LOG_AND;
}
log_or {
	$this->token = OQLParser::LOG_OR;
}
coma {
	$this->token = OQLParser::COMA;
}
par_open {
	$this->token = OQLParser::PAR_OPEN;
}
par_close {
	$this->token = OQLParser::PAR_CLOSE;
}
eq {
	$this->token = OQLParser::EQ;
}
not_eq {
	$this->token = OQLParser::NOT_EQ;
}
gt {
	$this->token = OQLParser::GT;
}
lt {
	$this->token = OQLParser::LT;
}
ge {
	$this->token = OQLParser::GE;
}
le {
	$this->token = OQLParser::LE;
}
like {
	$this->token = OQLParser::LIKE;
}
not_like {
	$this->token = OQLParser::NOT_LIKE;
}
in {
	$this->token = OQLParser::IN;
}
not_in {
	$this->token = OQLParser::NOT_IN;
}
interval {
	$this->token = OQLParser::INTERVAL;
}
f_if {
	$this->token = OQLParser::F_IF;
}
f_elt {
	$this->token = OQLParser::F_ELT;
}
f_coalesce {
	$this->token = OQLParser::F_COALESCE;
}
f_concat {
	$this->token = OQLParser::F_CONCAT;
}
f_substr {
	$this->token = OQLParser::F_SUBSTR;
}
f_trim {
	$this->token = OQLParser::F_TRIM;
}
f_date {
	$this->token = OQLParser::F_DATE;
}
f_date_format {
	$this->token = OQLParser::F_DATE_FORMAT;
}
f_current_date {
	$this->token = OQLParser::F_CURRENT_DATE;
}
f_now {
	$this->token = OQLParser::F_NOW;
}
f_time {
	$this->token = OQLParser::F_TIME;
}
f_to_days {
	$this->token = OQLParser::F_TO_DAYS;
}
f_from_days {
	$this->token = OQLParser::F_FROM_DAYS;
}
f_year {
	$this->token = OQLParser::F_YEAR;
}
f_month {
	$this->token = OQLParser::F_MONTH;
}
f_day {
	$this->token = OQLParser::F_DAY;
}
f_hour {
	$this->token = OQLParser::F_HOUR;
}
f_minute {
	$this->token = OQLParser::F_MINUTE;
}
f_second {
	$this->token = OQLParser::F_SECOND;
}
f_date_add {
	$this->token = OQLParser::F_DATE_ADD;
}
f_date_sub {
	$this->token = OQLParser::F_DATE_SUB;
}
f_round {
	$this->token = OQLParser::F_ROUND;
}
f_floor {
	$this->token = OQLParser::F_FLOOR;
}
f_inet_aton {
	$this->token = OQLParser::F_INET_ATON;
}
f_inet_ntoa {
	$this->token = OQLParser::F_INET_NTOA;
}
numval {
	$this->token = OQLParser::NUMVAL;
}
strval {
	$this->token = OQLParser::STRVAL;
}
name {
	$this->token = OQLParser::NAME;
}
varname {
	$this->token = OQLParser::VARNAME;
}
dot {
	$this->token = OQLParser::DOT;
}
*/

}

define('UNEXPECTED_INPUT_AT_LINE', 'Unexpected input at line');

class OQLLexerException extends OQLException
{
	public function __construct($sInput, $iLine, $iCol, $sUnexpected)
	{
		parent::__construct("Syntax error", $sInput, $iLine, $iCol, $sUnexpected);
	}
}

class OQLLexer extends OQLLexerRaw 
{
	public function getTokenPos()
	{
		return max(0, $this->count - strlen($this->value));
	}

   function yylex()
   {
      try
      {
      	return parent::yylex();
		}
		catch (Exception $e)
		{
			$sMessage = $e->getMessage();
			if (substr($sMessage, 0, strlen(UNEXPECTED_INPUT_AT_LINE)) == UNEXPECTED_INPUT_AT_LINE)
			{
				$sLineAndChar = substr($sMessage, strlen(UNEXPECTED_INPUT_AT_LINE));
				if (preg_match('#^([0-9]+): (.+)$#', $sLineAndChar, $aMatches))
				{
					$iLine = $aMatches[1];
					$sUnexpected = $aMatches[2];
					throw new OQLLexerException($this->data, $iLine, $this->count, $sUnexpected);
				}
			}
			// Default: forward the exception
			throw $e;
		}
	}
}
?>