ClickHouse/contrib/libpoco/Foundation/include/Poco/Token.h

175 lines
3.6 KiB
C++

//
// Token.h
//
// $Id: //poco/1.4/Foundation/include/Poco/Token.h#1 $
//
// Library: Foundation
// Package: Streams
// Module: StreamTokenizer
//
// Definition of the Token class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_Token_INCLUDED
#define Foundation_Token_INCLUDED
#include "Poco/Foundation.h"
#include <istream>
namespace Poco {
class Foundation_API Token
/// The base class for all token classes that can be
/// registered with the StreamTokenizer.
{
public:
enum Class
{
IDENTIFIER_TOKEN,
KEYWORD_TOKEN,
SEPARATOR_TOKEN,
OPERATOR_TOKEN,
STRING_LITERAL_TOKEN,
CHAR_LITERAL_TOKEN,
INTEGER_LITERAL_TOKEN,
LONG_INTEGER_LITERAL_TOKEN,
FLOAT_LITERAL_TOKEN,
DOUBLE_LITERAL_TOKEN,
COMMENT_TOKEN,
SPECIAL_COMMENT_TOKEN,
PREPROCESSOR_TOKEN,
WHITESPACE_TOKEN,
EOF_TOKEN,
INVALID_TOKEN,
USER_TOKEN
};
Token();
/// Creates the Token.
virtual ~Token();
/// Destroys the Token.
virtual bool start(char c, std::istream& istr);
/// Checks if the given character (and, optionally,
/// the next character in the input stream) start
/// a valid token. Returns true if so, false
/// otherwise.
///
/// The current read position in istr must not be
/// changed. In other words, only the peek() method
/// of istream may be used.
///
/// If the character starts the token, it should
/// be set as the token's value.
virtual void finish(std::istream& istr);
/// Builds the token by reading and appending
/// the remaining characters from istr.
virtual Class tokenClass() const;
/// Returns the kind of the token.
const std::string& tokenString() const;
/// Returns the token's raw string.
virtual std::string asString() const;
/// Returns a string representation of the token.
#if defined(POCO_HAVE_INT64)
virtual Int64 asInteger64() const;
/// Returns a 64-bit integer representation of the token.
virtual UInt64 asUnsignedInteger64() const;
/// Returns an unsigned 64-bit integer representation of the token.
#endif
virtual int asInteger() const;
/// Returns an integer representation of the token.
virtual unsigned asUnsignedInteger() const;
/// Returns an unsigned integer representation of the token.
virtual double asFloat() const;
/// Returns a floating-point representation of the token.
virtual char asChar() const;
/// Returns a char representation of the token.
bool is(Class tokenClass) const;
/// Returns true iff the token has the given class.
protected:
std::string _value;
private:
Token(const Token&);
Token& operator = (const Token&);
};
class Foundation_API InvalidToken: public Token
/// This token class is used for signalling that
/// an invalid character sequence has been encountered
/// in the input stream.
{
public:
InvalidToken();
~InvalidToken();
Class tokenClass() const;
};
class Foundation_API EOFToken: public Token
/// This token class is used to signal the
/// end of the input stream.
{
public:
EOFToken();
~EOFToken();
Class tokenClass() const;
};
class Foundation_API WhitespaceToken: public Token
/// This pseudo token class is used to eat
/// up whitespace in between real tokens.
{
public:
WhitespaceToken();
~WhitespaceToken();
Class tokenClass() const;
bool start(char c, std::istream& istr);
void finish(std::istream& istr);
};
//
// inlines
//
inline const std::string& Token::tokenString() const
{
return _value;
}
inline bool Token::is(Token::Class cls) const
{
return tokenClass() == cls;
}
} // namespace Poco
#endif // Foundation_Token_INCLUDED