JUCE/modules/juce_graphics/unicode/juce_UnicodeLine.cpp

/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
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   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

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   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

class TR14
{
public:
    TR14() = delete;

    template <typename Callback>
    static size_t analyseLineBreaks (Span<const UnicodeAnalysisPoint> span, Callback&& callback)
    {
        uint32_t resultIndex     = 0;
        uint32_t regionalCounter = 0;
        std::optional<LineBreakType> lb9;
        bool lb21a{};

        const auto data = span.data();
        const auto len  = span.size();

        const auto emit = [&] (auto op) { callback ((int) resultIndex++, op); };

        for (size_t i = 0; i < len;)
        {
            const auto isSOT = i == 0;
            const auto isEOT = i == len - 1;

            const auto resolved = resolve (data[i]);
            const auto prev = isSOT ? resolveSOT (resolved)
                                    : lb9.value_or (resolved);
            const auto finalBreak = lb9.has_value() ? LineBreakType::al
                                                    : LineBreakType::cm;
            const auto next = isEOT ? finalBreak
                                    : resolve (data[i + 1]);
            lb9.reset();

            // LB3
            if (isEOT)
            {
                if (contains ({ LineBreakType::cr, LineBreakType::lf, LineBreakType::nl }, prev))
                    emit (TextBreakType::hard);
                else
                    emit (TextBreakType::soft);

                break;
            }

            //==============================================================================
            // LB4-6
            if (prev == LineBreakType::bk)
            {
                emit (TextBreakType::hard);
                i++;
                continue;
            }

            if (prev == LineBreakType::cr && next == LineBreakType::lf)
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            if (contains ({ LineBreakType::cr, LineBreakType::lf, LineBreakType::nl }, prev))
            {
                emit (TextBreakType::hard);
                i++;
                continue;
            }

            if (contains ({ LineBreakType::cr, LineBreakType::lf, LineBreakType::nl, LineBreakType::bk }, next))
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            //==============================================================================
            // LB7
            if (contains ({ LineBreakType::sp, LineBreakType::zw }, next))
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            // LB8a
            if (prev == LineBreakType::zwj)
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            // LB13
            if (contains ({ LineBreakType::cl, LineBreakType::cp, LineBreakType::ex, LineBreakType::is, LineBreakType::sy }, next))
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            // lb21a
            if (lb21a && contains ({ LineBreakType::hy, LineBreakType::ba }, prev))
            {
                emit (TextBreakType::none);
                i++;
                continue;
            }

            lb21a = prev == LineBreakType::hl;

            // LB30a
            if (prev == LineBreakType::ri)
            {
                regionalCounter++;

                if (next == LineBreakType::ri && regionalCounter % 2 == 0)
                {
                    regionalCounter = 0;
                    emit (TextBreakType::soft);
                    i++;
                    continue;
                }
            }
            else
            {
                regionalCounter = 0;
            }

            const auto bt = BreakPairTable::getLineBreakOpportunity (prev, next);

            switch (bt)
            {
                case BreakOpportunity::direct:
                {
                    emit (TextBreakType::soft);
                    i++;
                    continue;
                }

                case BreakOpportunity::prohibited:
                {
                    emit (TextBreakType::none);
                    i++;
                    continue;
                }

                case BreakOpportunity::indirect:
                {
                    emit (next == LineBreakType::sp || next == LineBreakType::cm ? TextBreakType::soft
                                                                                 : TextBreakType::none);
                    i++;
                    continue;
                }

                case BreakOpportunity::combinedIndirect:
                case BreakOpportunity::combinedProhibited:
                {
                    if (! contains ({ LineBreakType::bk, LineBreakType::cr,
                                      LineBreakType::lf, LineBreakType::nl,
                                      LineBreakType::sp, LineBreakType::zw }, prev))
                    {
                        lb9 = std::make_optional (prev);
                    }

                    while (i < len)
                    {
                        if (i == len - 1)
                        {
                            emit (TextBreakType::soft);
                            i++;
                            break;
                        }

                        emit (TextBreakType::none);

                        if (! contains ({ LineBreakType::cm, LineBreakType::zwj }, resolve (data[i])))
                            break;

                        i++;
                    }

                    i++;
                    continue;
                }
            }

            i++;
            continue;
        }

        return resultIndex;
    }

private:
    static LineBreakType resolve (const UnicodeAnalysisPoint& point)
    {
        const auto bc = point.getBreakType();

        JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wswitch-enum")
        switch (bc)
        {
            case LineBreakType::ai:
            case LineBreakType::sg:
            case LineBreakType::xx:
                return LineBreakType::al;

            case LineBreakType::cj:
                return LineBreakType::ns;

            case LineBreakType::sa:
                return contains ({ (SBGeneralCategory) SBGeneralCategoryMN,
                                   (SBGeneralCategory) SBGeneralCategoryMC },
                                 point.getGeneralCategory())
                    ? LineBreakType::cm
                    : LineBreakType::al;

            default: break;
        }
        JUCE_END_IGNORE_WARNINGS_GCC_LIKE

        return bc;
    }

    static LineBreakType resolveSOT (LineBreakType bc)
    {
        JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wswitch-enum")
        switch (bc)
        {
            case LineBreakType::lf:
            case LineBreakType::nl:
                return LineBreakType::bk;

            case LineBreakType::sp:
                return LineBreakType::wj;

            default: break;
        }
        JUCE_END_IGNORE_WARNINGS_GCC_LIKE

        return bc;
    }
};

}