ClickHouse/base/poco/Foundation/include/Poco/UTF8Encoding.h

//
// UTF8Encoding.h
//
// Library: Foundation
// Package: Text
// Module:  UTF8Encoding
//
// Definition of the UTF8Encoding class.
//
// Copyright (c) 2004-2007, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_UTF8Encoding_INCLUDED
#define Foundation_UTF8Encoding_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/TextEncoding.h"


namespace Poco
{


class Foundation_API UTF8Encoding : public TextEncoding
/// UTF-8 text encoding, as defined in RFC 2279.
{
public:
    UTF8Encoding();
    ~UTF8Encoding();
    const char * canonicalName() const;
    bool isA(const std::string & encodingName) const;
    const CharacterMap & characterMap() const;
    int convert(const unsigned char * bytes) const;
    int convert(int ch, unsigned char * bytes, int length) const;
    int queryConvert(const unsigned char * bytes, int length) const;
    int sequenceLength(const unsigned char * bytes, int length) const;

    static bool isLegal(const unsigned char * bytes, int length);
    /// Utility routine to tell whether a sequence of bytes is legal UTF-8.
    /// This must be called with the length pre-determined by the first byte.
    /// The sequence is illegal right away if there aren't enough bytes
    /// available. If presented with a length > 4, this function returns false.
    /// The Unicode definition of UTF-8 goes up to 4-byte sequences.
    ///
    /// Adapted from ftp://ftp.unicode.org/Public/PROGRAMS/CVTUTF/ConvertUTF.c
    /// Copyright 2001-2004 Unicode, Inc.

private:
    static const char * _names[];
    static const CharacterMap _charMap;
};


} // namespace Poco


#endif // Foundation_UTF8Encoding_INCLUDED