ascii.hpp

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// Copyright Take Vos 2022.
// 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 "char_converter.hpp"
#include "../cast.hpp"
#include "../utility.hpp"
#include "../architecture.hpp"
#include <cstdint>
#include <utility>
#include <tuple>
 
namespace hi { inline namespace v1 {
 
template<>
struct char_map<"ascii"> {
    using char_type = char;
 
    [[nodiscard]] constexpr std::endian guess_endian(void const *ptr, size_t size, std::endian endian) const noexcept
    {
        return std::endian::native;
    }
 
    template<typename It, typename EndIt>
    [[nodiscard]] constexpr std::pair<char32_t, bool> read(It& it, EndIt last) const noexcept
    {
        hi_axiom(it != last);
 
        hilet c = char_cast<char32_t>(*it++);
        if (c < 0x80) {
            return {c, true};
        } else {
            return {0xfffd, false};
        }
    }
 
    [[nodiscard]] constexpr std::pair<uint8_t, bool> size(char32_t code_point) const noexcept
    {
        hi_axiom(code_point < 0x11'0000);
        hi_axiom(not(code_point >= 0xd800 and code_point < 0xe000));
 
        if (code_point < 0x80) {
            return {uint8_t{1}, true};
 
        } else {
            return {uint8_t{1}, false};
        }
    }
 
    template<typename It>
    constexpr void write(char32_t code_point, It& dst) const noexcept
    {
        hi_axiom(code_point < 0x11'0000);
        hi_axiom(not(code_point >= 0xd800 and code_point < 0xe000));
 
        if (code_point < 0x80) {
            *dst++ = char_cast<char>(code_point);
 
        } else {
            *dst++ = '?';
        }
    }
 
#if defined(HI_HAS_SSE2)
    template<typename It>
    hi_force_inline __m128i read_ascii_chunk16(It it) const noexcept
    {
        return _mm_loadu_si128(reinterpret_cast<__m128i const *>(std::addressof(*it)));
    }
 
    template<typename It>
    hi_force_inline void write_ascii_chunk16(__m128i chunk, It dst) const noexcept
    {
        _mm_storeu_si128(reinterpret_cast<__m128i *>(std::addressof(*dst)), chunk);
    }
#endif
};
 
}} // namespace hi::v1