HyphenationAndroid.cpp   [plain text]

/*
 * Copyright 2010, The Android Open Source Project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * 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 THE COPYRIGHT HOLDERS ``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 "Hyphenation.h"

// For external hyphenation library.
#include "hyphen.h"
#include <utils/AssetManager.h>
#include <wtf/text/CString.h>
#include <wtf/text/WTFString.h>

extern android::AssetManager* globalAssetManager();

using namespace WTF;

namespace WebCore {

static HyphenDict* loadHyphenationDictionary()
{
    android::AssetManager* am = globalAssetManager();
    // Only support English for now.
    android::Asset* a = am->open("webkit/hyph_en_US.dic",
        android::Asset::ACCESS_BUFFER);
    if (!a) {
        // Asset webkit/hyph_en_US.dic not found!
        return 0;
    }
    const CString dictContents = String(static_cast<const char*>(a->getBuffer(false)),
        a->getLength()).utf8();
    HyphenDict* dict = hnj_hyphen_load_from_buffer(dictContents.data(),
        dictContents.length());
    delete a;

    return dict;
}

bool canHyphenate(const AtomicString& /* localeIdentifier */)
{
    // FIXME: Check that the locale identifier matches the available dictionary.
    return true;
}

size_t lastHyphenLocation(const UChar* characters, size_t length, size_t beforeIndex, const AtomicString& /* localeIdentifier */)
{
    static const size_t minWordLen = 5;
    static const size_t maxWordLen = 100;
    if (beforeIndex <= 0 || length < minWordLen || length > maxWordLen)
        return 0;

    static HyphenDict* dict = loadHyphenationDictionary();
    if (!dict)
        return 0;

    char word[maxWordLen];
    for (size_t i = 0; i < length; ++i) {
        const UChar ch = characters[i];
        // Only English for now.
        // To really make it language aware, we need something like language
        // detection or rely on the langAttr in the html element.  Though
        // seems right now the langAttr is not used or quite implemented in
        // webkit.
        if (!isASCIIAlpha(ch))
            return 0;
        word[i] = ch;
    }

    static const int extraBuffer = 5;
    char hyphens[maxWordLen + extraBuffer];
    if (!hnj_hyphen_hyphenate(dict, word, length, hyphens)) {
        for (size_t i = beforeIndex - 1; i > 0; --i) {
            if (hyphens[i] & 1)
                return i + 1;
        }
    }

    return 0;
}

} // namespace WebCore