JUCE/modules/juce_graphics/unicode/juce_Unicode.h

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

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

namespace juce
{
enum class TextBreakType { none, soft, hard };
enum class TextDirection { ltr, rtl };

struct Unicode
{
    struct Codepoint
    {
        auto getLogicalIndex() const { return logicalIndex; }
        auto getVisualIndex()  const { return visualIndex; }

        uint32_t codepoint;

        // Index of the character in the source string
        size_t logicalIndex;
        size_t visualIndex;

        // Breaking characteristics of this codepoint
        TextBreakType breaking;

        // Direction of this codepoint
        TextDirection direction;

        // Script class for this codepoint
        TextScript script;
    };

    template <typename Value>
    static auto prefix (Span<Value> v, size_t num)
    {
        return Span { v.data(), std::min (v.size(), num) };
    }

    template <typename Value>
    static auto removePrefix (Span<Value> v, size_t num)
    {
        const auto increment = std::min (v.size(), num);
        return Span { v.data() + increment, v.size() - increment };
    }

    static Array<Codepoint> performAnalysis (const String&);
    static Array<Codepoint> convertLogicalToVisual (Span<const Codepoint>);

    template <typename Traits>
    struct Iterator
    {
        using ValueType = typename Traits::ValueType;

        Iterator() = default;
        explicit Iterator (Span<ValueType> s) : data (s) {}

        std::optional<Span<ValueType>> next()
        {
            if (data.empty())
                return {};

            const auto breakpoint = std::find_if (data.begin(), data.end(), [&] (const auto& i)
            {
                return ! Traits::compare (i, data.front());
            });
            const auto lengthToBreak = (size_t) std::distance (data.begin(), breakpoint) + (Traits::includeBreakingIndex() ? 1 : 0);
            const ScopeGuard scope { [&] { data = removePrefix (data, lengthToBreak); } };
            return prefix (data, lengthToBreak);
        }

    private:
        Span<ValueType> data;
    };

    struct BidiTraits
    {
        using ValueType = const Codepoint;

        static bool compare (const Codepoint& t1, const Codepoint& t2)
        {
            return t1.direction == t2.direction;
        }

        static bool includeBreakingIndex() { return false; }
    };

    using BidiRunIterator = Iterator<BidiTraits>;

    struct LineTraits
    {
        using ValueType = const Codepoint;

        static bool compare (const Codepoint& t1, const Codepoint&)
        {
            return t1.breaking != TextBreakType::hard;
        }

        static bool includeBreakingIndex() { return true; }
    };

    using LineBreakIterator = Iterator<LineTraits>;

    struct WordTraits
    {
        using ValueType = const Codepoint;

        static bool compare (const Codepoint& t1, const Codepoint&)
        {
            return t1.breaking != TextBreakType::soft;
        }

        static bool includeBreakingIndex() { return false; }
    };

    using WordBreakIterator = Iterator<WordTraits>;

    struct ScriptTraits
    {
        using ValueType = const Codepoint;

        static bool compare (const Codepoint& t1, const Codepoint& t2)
        {
            return t1.script == t2.script;
        }

        static bool includeBreakingIndex() { return false; }
    };

    using ScriptRunIterator = Iterator<ScriptTraits>;
};

struct UnicodeFunctions
{
    static bool isRenderableCharacter (juce_wchar character);
    static bool isBreakableWhitespace (juce_wchar character);
    static bool isEmoji (juce_wchar character);
    static bool shouldVerticalGlyphRotate (juce_wchar character);
};
} // namespace juce