/*
 * Copyright (C) 2006 Lars Knoll <lars@trolltech.com>
 * Copyright (C) 2007, 2011, 2012 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef TextBreakIterator_h
#define TextBreakIterator_h

#include <wtf/text/AtomicString.h>
#include <wtf/unicode/Unicode.h>

namespace WebCore {

    class TextBreakIterator;

    // Note: The returned iterator is good only until you get another iterator, with the exception of acquireLineBreakIterator.

    // This is similar to character break iterator in most cases, but is subject to
    // platform UI conventions. One notable example where this can be different
    // from character break iterator is Thai prepend characters, see bug 24342.
    // Use this for insertion point and selection manipulations.
    TextBreakIterator* cursorMovementIterator(const UChar*, int length);

    TextBreakIterator* wordBreakIterator(const UChar*, int length);
    TextBreakIterator* acquireLineBreakIterator(const LChar*, int length, const AtomicString& locale);
    TextBreakIterator* acquireLineBreakIterator(const UChar*, int length, const AtomicString& locale);
    void releaseLineBreakIterator(TextBreakIterator*);
    TextBreakIterator* sentenceBreakIterator(const UChar*, int length);

    int textBreakFirst(TextBreakIterator*);
    int textBreakLast(TextBreakIterator*);
    int textBreakNext(TextBreakIterator*);
    int textBreakPrevious(TextBreakIterator*);
    int textBreakCurrent(TextBreakIterator*);
    int textBreakPreceding(TextBreakIterator*, int);
    int textBreakFollowing(TextBreakIterator*, int);
    bool isTextBreak(TextBreakIterator*, int);
    bool isWordTextBreak(TextBreakIterator*);

    const int TextBreakDone = -1;

class LazyLineBreakIterator {
public:
    LazyLineBreakIterator()
        : m_iterator(0)
        , m_lastCharacter(0)
        , m_secondToLastCharacter(0)
    {
    }

    LazyLineBreakIterator(String string, const AtomicString& locale = AtomicString())
        : m_string(string)
        , m_locale(locale)
        , m_iterator(0)
        , m_lastCharacter(0)
        , m_secondToLastCharacter(0)
    {
    }

    ~LazyLineBreakIterator()
    {
        if (m_iterator)
            releaseLineBreakIterator(m_iterator);
    }

    String string() const { return m_string; }

    UChar lastCharacter() const { return m_lastCharacter; }
    UChar secondToLastCharacter() const { return m_secondToLastCharacter; }
    void setLastTwoCharacters(UChar last, UChar secondToLast)
    {
        m_lastCharacter = last;
        m_secondToLastCharacter = secondToLast;
    }
    void updateLastTwoCharacters(UChar last)
    {
        m_secondToLastCharacter = m_lastCharacter;
        m_lastCharacter = last;
    }
    void resetLastTwoCharacters()
    {
        m_lastCharacter = 0;
        m_secondToLastCharacter = 0;
    }

    TextBreakIterator* get()
    {
        if (!m_iterator) {
            if (m_string.is8Bit())
                m_iterator = acquireLineBreakIterator(m_string.characters8(), m_string.length(), m_locale);
            else
                m_iterator = acquireLineBreakIterator(m_string.characters16(), m_string.length(), m_locale);
        }
        return m_iterator;
    }

    void reset(String string, const AtomicString& locale)
    {
        if (m_iterator)
            releaseLineBreakIterator(m_iterator);

        m_string = string;
        m_locale = locale;
        m_iterator = 0;
    }

private:
    String m_string;
    AtomicString m_locale;
    TextBreakIterator* m_iterator;
    UChar m_lastCharacter;
    UChar m_secondToLastCharacter;
};

// Iterates over "extended grapheme clusters", as defined in UAX #29.
// Note that platform implementations may be less sophisticated - e.g. ICU prior to
// version 4.0 only supports "legacy grapheme clusters".
// Use this for general text processing, e.g. string truncation.

class NonSharedCharacterBreakIterator {
    WTF_MAKE_NONCOPYABLE(NonSharedCharacterBreakIterator);
public:
    NonSharedCharacterBreakIterator(const UChar*, int length);
    ~NonSharedCharacterBreakIterator();

    operator TextBreakIterator*() const { return m_iterator; }

private:
    TextBreakIterator* m_iterator;
};

// Counts the number of grapheme clusters. A surrogate pair or a sequence
// of a non-combining character and following combining characters is
// counted as 1 grapheme cluster.
unsigned numGraphemeClusters(const String&);
// Returns the number of characters which will be less than or equal to
// the specified grapheme cluster length.
unsigned numCharactersInGraphemeClusters(const String&, unsigned);

}

#endif