#!/usr/bin/env python

"""
$Id$

Copyright (c) 2006-2010 sqlmap developers (http://sqlmap.sourceforge.net/)
See the file 'doc/COPYING' for copying permission
"""

from lib.core.common import isDBMSVersionAtLeast
from lib.core.exception import sqlmapSyntaxException

from plugins.generic.syntax import Syntax as GenericSyntax

class Syntax(GenericSyntax):
    def __init__(self):
        GenericSyntax.__init__(self)

    # As ASCII_CHAR is only available from v2.1 we'll need to adapt this one to use the
    # commented-out part only if detected version>=2.1
    # Reference: wiki.firebirdsql.org/wiki/index.php?page=ASCII_CHAR

    @staticmethod
    def unescape(expression, quote=True):
        if isDBMSVersionAtLeast('2.1'):
            if quote:
                while True:
                    index = expression.find("'")
                    if index == -1:
                        break

                    firstIndex = index + 1
                    index = expression[firstIndex:].find("'")

                    if index == -1:
                        raise sqlmapSyntaxException, "Unenclosed ' in '%s'" % expression

                    lastIndex = firstIndex + index
                    old = "'%s'" % expression[firstIndex:lastIndex]
                    unescaped = ""

                    for i in range(firstIndex, lastIndex):
                        unescaped += "ASCII_CHAR(%d)" % (ord(expression[i]))
                        if i < lastIndex - 1:
                            unescaped += "||"

                    expression = expression.replace(old, unescaped)
            else:
                unescaped = "".join("ASCII_CHAR(%d)||" % ord(c) for c in expression)
                if unescaped[-1] == "||":
                    unescaped = unescaped[:-1]

                expression = unescaped

        return expression

    @staticmethod
    def escape(expression):
        while True:
            index = expression.find("ASCII_CHAR(")
            if index == -1:
                break

            firstIndex = index
            index = expression[firstIndex:].find(")")

            if index == -1:
                raise sqlmapSyntaxException, "Unenclosed ) in '%s'" % expression

            lastIndex = firstIndex + index + 1
            old = expression[firstIndex:lastIndex]
            oldUpper = old.upper()
            oldUpper = oldUpper.lstrip("ASCII_CHAR(").rstrip(")")
            oldUpper = oldUpper.split("||")

            escaped = "'%s'" % "".join([chr(int(char)) for char in oldUpper])
            expression = expression.replace(old, escaped).replace("'||'", "")

        return expression