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// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012-2022 OpenVPN Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License Version 3
// as published by the Free Software Foundation.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program in the COPYING file.
// If not, see <http://www.gnu.org/licenses/>.
// A set of lexical analyzer classes. These classes can be combined
// with the methods in split.hpp to create parsers.
#pragma once
#include <openvpn/common/string.hpp>
namespace openvpn {
// This class (or others that define an is_space method) is used as a
// template parameter to methods in split.hpp.
struct SpaceMatch
{
static bool is_space(char c)
{
return string::is_space(c);
}
};
/**
* @brief Helper class to handle quote processing
*
* This class provides functionality to handle single and double quotes within a text.
* It allows treating single quotes as regular characters when inside double quotes,
* and vice versa.
*/
class LexQuoteMixin
{
public:
/**
* @brief Check if currently inside a quote
* @return true if inside single or double quote, false otherwise
*/
bool in_quote() const
{
return in_squote | in_dquote;
}
protected:
/**
* @brief Handle a character as a potential quote
*
* Toggles quote state if `c` is a single or double quote,
* considering the current context.
*
* @param c Character to process
* @return true if `c` is treated as a quote, false otherwise
*/
bool handle_quote(char c)
{
if ((c == '\"') && (!in_squote))
{
in_dquote = !in_dquote;
return true;
}
if ((c == '\'') && (!in_dquote))
{
in_squote = !in_squote;
return true;
}
return false;
}
private:
bool in_squote = false; /**< State for single quotes */
bool in_dquote = false; /**< State for double quotes */
};
// A basic lexical analyzer that understands quoting
class StandardLex : public LexQuoteMixin
{
public:
void put(char c)
{
in_backslash_ = false;
if (backslash_)
{
ch = c;
backslash_ = false;
in_backslash_ = true;
}
else if (c == '\\')
{
backslash_ = true;
ch = -1;
}
else if (handle_quote(c))
{
ch = -1;
}
else
ch = c;
}
bool available() const
{
return ch != -1;
}
int get() const
{
return ch;
}
void reset()
{
ch = -1;
}
bool in_backslash() const
{
return in_backslash_;
}
private:
bool backslash_ = false;
bool in_backslash_ = false;
int ch = -1;
};
// A null lexical analyzer has no special understanding
// of any particular string character.
class NullLex
{
public:
void put(char c)
{
ch = c;
}
bool available() const
{
return ch != -1;
}
int get() const
{
return ch;
}
void reset()
{
ch = -1;
}
bool in_quote() const
{
return false;
}
bool in_backslash() const
{
return false;
}
private:
int ch = -1;
};
} // namespace openvpn
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