mirror of
https://github.com/matrix-construct/construct
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57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
// The Construct
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//
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// Copyright (C) The Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_UTF8_H
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/// Unicode Transformation Format (8-bit)
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namespace ircd::utf8
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{
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// Get the utf8-encoded length from char32_t (decoded) codepoints
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template<class u32xN> u32xN length(const u32xN codepoints) noexcept;
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// Get the utf8 length at the first byte of each utf8-codepoint; 0x00 sep
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template<> u8x16 length(const u8x16 string) noexcept;
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// Encode char32_t codepoints into respective utf-8 encodings
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template<class u32xN> u32xN encode_sparse(const u32xN codepoints) noexcept;
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// Decode utf-8 string into char32_t unicode codepoints
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u32x16 decode_sparse(const u8x16 string) noexcept;
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// Decode utf-8 string into char32_t unicode codepoints packed left.
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u32x16 decode(const u8x16 string) noexcept;
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}
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template<>
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inline ircd::u8x16
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ircd::utf8::length(const u8x16 string)
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noexcept
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{
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const u8x16 is_single
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(
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string < 0x80
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);
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const u8x16 is_multi
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(
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(string - 0xc2) <= 0x32
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);
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const u8x16 num_trail
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(
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1
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+ ((string >= 0xc0) & 1)
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+ ((string >= 0xe0) & 1)
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+ ((string >= 0xf0) & 1)
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);
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return (is_single & 1) | (is_multi & num_trail);
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}
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