ladybird/AK/UnicodeUtils.h

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/*
* Copyright (c) 2021, Max Wipfli <mail@maxwipfli.ch>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Concepts.h>
#include <AK/Error.h>
#include <AK/Forward.h>
namespace AK::UnicodeUtils {
constexpr int bytes_to_store_code_point_in_utf8(u32 code_point)
{
if (code_point <= 0x7f)
return 1;
if (code_point <= 0x7ff)
return 2;
if (code_point <= 0xffff)
return 3;
if (code_point <= 0x10ffff)
return 4;
return 0;
}
template<typename Callback>
[[nodiscard]] constexpr int code_point_to_utf8(u32 code_point, Callback callback)
{
if (code_point <= 0x7f) {
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callback(static_cast<char>(code_point));
return 1;
} else if (code_point <= 0x07ff) {
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callback(static_cast<char>(((code_point >> 6) & 0x1f) | 0xc0));
callback(static_cast<char>(((code_point >> 0) & 0x3f) | 0x80));
return 2;
} else if (code_point <= 0xffff) {
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callback(static_cast<char>(((code_point >> 12) & 0x0f) | 0xe0));
callback(static_cast<char>(((code_point >> 6) & 0x3f) | 0x80));
callback(static_cast<char>(((code_point >> 0) & 0x3f) | 0x80));
return 3;
} else if (code_point <= 0x10ffff) {
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callback(static_cast<char>(((code_point >> 18) & 0x07) | 0xf0));
callback(static_cast<char>(((code_point >> 12) & 0x3f) | 0x80));
callback(static_cast<char>(((code_point >> 6) & 0x3f) | 0x80));
callback(static_cast<char>(((code_point >> 0) & 0x3f) | 0x80));
return 4;
}
return -1;
}
template<FallibleFunction<char> Callback>
[[nodiscard]] ErrorOr<int> try_code_point_to_utf8(u32 code_point, Callback&& callback)
{
if (code_point <= 0x7f) {
TRY(callback(static_cast<char>(code_point)));
return 1;
}
if (code_point <= 0x07ff) {
TRY(callback(static_cast<char>((((code_point >> 6) & 0x1f) | 0xc0))));
TRY(callback(static_cast<char>((((code_point >> 0) & 0x3f) | 0x80))));
return 2;
}
if (code_point <= 0xffff) {
TRY(callback(static_cast<char>((((code_point >> 12) & 0x0f) | 0xe0))));
TRY(callback(static_cast<char>((((code_point >> 6) & 0x3f) | 0x80))));
TRY(callback(static_cast<char>((((code_point >> 0) & 0x3f) | 0x80))));
return 3;
}
if (code_point <= 0x10ffff) {
TRY(callback(static_cast<char>((((code_point >> 18) & 0x07) | 0xf0))));
TRY(callback(static_cast<char>((((code_point >> 12) & 0x3f) | 0x80))));
TRY(callback(static_cast<char>((((code_point >> 6) & 0x3f) | 0x80))));
TRY(callback(static_cast<char>((((code_point >> 0) & 0x3f) | 0x80))));
return 4;
}
return -1;
}
}