/*
 * Copyright (C) 2006, 2007 Apple Inc.  All rights reserved.
 * Copyright (C) 2009 Dominik Röttsches <dominik.roettsches@access-company.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "platform/text/TextBoundaries.h"

#include "platform/text/TextBreakIterator.h"
#include "wtf/text/StringImpl.h"

using namespace WTF;
using namespace Unicode;

namespace blink {

int endOfFirstWordBoundaryContext(const UChar* characters, int length)
{
    for (int i = 0; i < length; ) {
        int first = i;
        UChar32 ch;
        U16_NEXT(characters, i, length, ch);
        if (!requiresContextForWordBoundary(ch))
            return first;
    }
    return length;
}

int startOfLastWordBoundaryContext(const UChar* characters, int length)
{
    for (int i = length; i > 0; ) {
        int last = i;
        UChar32 ch;
        U16_PREV(characters, 0, i, ch);
        if (!requiresContextForWordBoundary(ch))
            return last;
    }
    return 0;
}

int findNextWordFromIndex(const UChar* chars, int len, int position, bool forward)
{
    TextBreakIterator* it = wordBreakIterator(chars, len);

    if (forward) {
        position = it->following(position);
        while (position != TextBreakDone) {
            // We stop searching when the character preceeding the break
            // is alphanumeric.
            if (position < len && isAlphanumeric(chars[position - 1]))
                return position;

            position = it->following(position);
        }

        return len;
    } else {
        position = it->preceding(position);
        while (position != TextBreakDone) {
            // We stop searching when the character following the break
            // is alphanumeric.
            if (position > 0 && isAlphanumeric(chars[position]))
                return position;

            position = it->preceding(position);
        }

        return 0;
    }
}

static bool isWord(const UChar* chars, int start, int end)
{
    while (start < end) {
        if (isWhitespace(chars[start++]))
            return false;
    }
    return true;
}

static void findWordBoundaryInternal(const UChar* chars, int len, int position, int* start, int* end)
{
    TextBreakIterator* it = wordBreakIterator(chars, len);
    *end = it->following(position);
    if (*end < 0)
        *end = it->last();
    *start = it->previous();
}

void findWordBoundary(const UChar* chars, int len, int position, bool preferRight, int* start, int* end)
{
    findWordBoundaryInternal(chars, len, position, start, end);
    if (isWord(chars, *start, *end))
        return;

    unsigned newPosition = 0;
    if (preferRight) {
        newPosition = *end;
        unsigned ulen = len;
        U16_FWD_1(chars, newPosition, ulen);
    } else {
        if (*start <= 0)
            return;
        newPosition = *start;
        U16_BACK_1(chars, 0, newPosition);
    }
    findWordBoundaryInternal(chars, len, newPosition, start, end);
}

int findWordEndBoundary(const UChar* chars, int len, int position, bool preferRight)
{
    TextBreakIterator* it = wordBreakIterator(chars, len);
    int end = it->following(position);
    return end < 0 ? it->last() : end;
}

} // namespace blink
