unicode_bidi_class.hpp

// Copyright Take Vos 2020.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include <cstdint>
#include <string_view>
 
namespace tt {
 
enum class unicode_bidi_class : uint8_t {
    unknown = 0,
    L = 1, 
    R = 2, 
    AL = 3, 
    EN = 4, 
    ES = 5, 
    ET = 6, 
    AN = 7, 
    CS = 8, 
    NSM = 9, 
    BN = 10, 
    B = 11, 
    S = 12, 
    WS = 13, 
    ON = 14, 
    // Explicit values.
    LRE, 
    LRO, 
    RLE, 
    RLO, 
    PDF, 
    LRI, 
    RLI, 
    FSI, 
    PDI 
};
 
[[nodiscard]] constexpr bool is_isolate_starter(unicode_bidi_class const &rhs) noexcept
{
    using enum unicode_bidi_class;
    return rhs == LRI || rhs == RLI || rhs == FSI;
}
 
[[nodiscard]] constexpr bool is_isolate_formatter(unicode_bidi_class const &rhs) noexcept
{
    using enum unicode_bidi_class;
    return is_isolate_starter(rhs) || rhs == PDI;
}
 
[[nodiscard]] constexpr bool is_NI(unicode_bidi_class const &rhs) noexcept
{
    using enum unicode_bidi_class;
    return rhs == B || rhs == S || rhs == WS || rhs == ON || rhs == FSI || rhs == LRI || rhs == RLI || rhs == PDI;
}
 
[[nodiscard]] constexpr unicode_bidi_class unicode_bidi_class_from_string(std::string_view str) noexcept
{
    using enum unicode_bidi_class;
 
    if (str == "L") {
        return L;
    } else if (str == "R") {
        return R;
    } else if (str == "AL") {
        return AL;
    } else if (str == "EN") {
        return EN;
    } else if (str == "ES") {
        return ES;
    } else if (str == "ET") {
        return ET;
    } else if (str == "AN") {
        return AN;
    } else if (str == "CS") {
        return CS;
    } else if (str == "NSM") {
        return NSM;
    } else if (str == "BN") {
        return BN;
    } else if (str == "B") {
        return B;
    } else if (str == "S") {
        return S;
    } else if (str == "WS") {
        return WS;
    } else if (str == "ON") {
        return ON;
    } else if (str == "LRE") {
        return LRE;
    } else if (str == "LRO") {
        return LRO;
    } else if (str == "RLE") {
        return RLE;
    } else if (str == "RLO") {
        return RLO;
    } else if (str == "PDF") {
        return PDF;
    } else if (str == "LRI") {
        return LRI;
    } else if (str == "RLI") {
        return RLI;
    } else if (str == "FSI") {
        return FSI;
    } else if (str == "PDI") {
        return PDI;
    } else {
        tt_no_default();
    }
}
 
} // namespace tt