/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * $Id$
 */

#if !defined(XERCESC_INCLUDE_GUARD_REGXUTIL_HPP)
#define XERCESC_INCLUDE_GUARD_REGXUTIL_HPP

// ---------------------------------------------------------------------------
//  Includes
// ---------------------------------------------------------------------------
#include <xercesc/util/XMLUniDefs.hpp>


XERCES_CPP_NAMESPACE_BEGIN

class MemoryManager;

class XMLUTIL_EXPORT RegxUtil {
public:

    // -----------------------------------------------------------------------
    //  Constructors and destructors
    // -----------------------------------------------------------------------
    ~RegxUtil() {}

    static XMLInt32 composeFromSurrogate(const XMLCh high, const XMLCh low);
    static bool isEOLChar(const XMLCh);
    static bool isWordChar(const XMLCh);
    static bool isLowSurrogate(const XMLCh ch);
    static bool isHighSurrogate(const XMLCh ch);
    static void decomposeToSurrogates(XMLInt32 ch, XMLCh& high, XMLCh& low);

    static XMLCh* decomposeToSurrogates(XMLInt32 ch,
                                        MemoryManager* const manager);
    static XMLCh* stripExtendedComment(const XMLCh* const expression,
                                       MemoryManager* const manager = 0);

private:
    // -----------------------------------------------------------------------
    //  Unimplemented constructors and operators
    // -----------------------------------------------------------------------
    RegxUtil();
};


inline bool RegxUtil::isEOLChar(const XMLCh ch) {

    return (ch == chLF || ch == chCR || ch == chLineSeparator
           || ch == chParagraphSeparator);
}

inline XMLInt32 RegxUtil::composeFromSurrogate(const XMLCh high, const XMLCh low) {
    // see http://unicode.org/unicode/faq/utf_bom.html#35
    const XMLInt32 SURROGATE_OFFSET = 0x10000 - (0xD800 << 10) - 0xDC00;
    return (high << 10) + low + SURROGATE_OFFSET;
}

inline bool RegxUtil::isLowSurrogate(const XMLCh ch) {

    return (ch & 0xFC00) == 0xDC00;
}

inline bool RegxUtil::isHighSurrogate(const XMLCh ch) {

    return (ch & 0xFC00) == 0xD800;
}

inline void RegxUtil::decomposeToSurrogates(XMLInt32 ch, XMLCh& high, XMLCh& low) {
    // see http://unicode.org/unicode/faq/utf_bom.html#35
    const XMLInt32 LEAD_OFFSET = 0xD800 - (0x10000 >> 10);
    high = XMLCh(LEAD_OFFSET + (ch >> 10));
    low = XMLCh(0xDC00 + (ch & 0x3FF));
}

inline bool RegxUtil::isWordChar(const XMLCh ch) {

    if ((ch == chUnderscore)
        || (ch >= chDigit_0 && ch <= chDigit_9)
        || (ch >= chLatin_A && ch <= chLatin_Z)
        || (ch >= chLatin_a && ch <= chLatin_z))
        return true;

    return false;
}

XERCES_CPP_NAMESPACE_END

#endif

/**
  * End of file RegxUtil.hpp
  */
