/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   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 .

 */

#pragma once

#include <sal/types.h>

#include <rtl/ustring.hxx>

#include <o3tl/hash_combine.hxx>

#include <vcl/dllapi.h>

#include <unicode/uscript.h>

#include <vector>

namespace vcl::text

{

struct Run

{

    int32_t nStart;

    int32_t nEnd;

    UScriptCode nCode;

    Run(int32_t nStart_, int32_t nEnd_, UScriptCode nCode_)

        : nStart(nStart_)

        , nEnd(nEnd_)

        , nCode(nCode_)

    {

    }

};

class VCL_DLLPUBLIC TextLayoutCache

{

public:

    std::vector<vcl::text::Run> runs;

    TextLayoutCache(sal_Unicode const* pStr, sal_Int32 const nEnd);

    // Creates a cached instance.

    static std::shared_ptr<const vcl::text::TextLayoutCache> Create(OUString const&);

};

struct FirstCharsStringHash

{

    size_t operator()(const OUString& str) const

    {

        // Strings passed to GenericSalLayout::CreateTextLayoutCache() may be very long,

        // and computing an entire hash could almost negate the gain of hashing. Hash just first

        // characters, that should be good enough.

        size_t hash

            = rtl_ustr_hashCode_WithLength(str.getStr(), std::min<size_t>(100, str.getLength()));

        o3tl::hash_combine(hash, str.getLength());

        return hash;

    }

};

struct FastStringCompareEqual

{

    bool operator()(const OUString& str1, const OUString& str2) const

    {

        // Strings passed to GenericSalLayout::CreateTextLayoutCache() may be very long,

        // and OUString operator == compares backwards and using hard-written code, while

        // memcmp() compares much faster.

        if (str1.getLength() != str2.getLength())

            return false;

        if (str1.getStr() == str2.getStr())

            return true;

        return memcmp(str1.getStr(), str2.getStr(), str1.getLength() * sizeof(str1.getStr()[0]))

               == 0;

    }

};

}

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