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Atmosphere/libraries/libvapours/include/vapours/util/util_character_encoding.hpp

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/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <vapours/common.hpp>
#include <vapours/assert.hpp>
namespace ams::util {
enum CharacterEncodingResult {
CharacterEncodingResult_Success = 0,
CharacterEncodingResult_InsufficientLength = 1,
CharacterEncodingResult_InvalidFormat = 2,
};
namespace impl {
class CharacterEncodingHelper {
public:
static constexpr int8_t Utf8NBytesInnerTable[0x100 + 1] = {
-1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8,
};
static constexpr ALWAYS_INLINE char GetUtf8NBytes(size_t i) {
return static_cast<char>(Utf8NBytesInnerTable[1 + i]);
}
};
}
constexpr inline CharacterEncodingResult ConvertCharacterUtf8ToUtf32(u32 *dst, const char *src) {
/* Check pre-conditions. */
AMS_ASSERT(dst != nullptr);
AMS_ASSERT(src != nullptr);
/* Perform the conversion. */
const auto *p = src;
switch (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[0]))) {
case 1:
*dst = static_cast<u32>(p[0]);
return CharacterEncodingResult_Success;
case 2:
if ((static_cast<u32>(p[0]) & 0x1E) != 0) {
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0) {
*dst = (static_cast<u32>(p[0] & 0x1F) << 6) | (static_cast<u32>(p[1] & 0x3F) << 0);
return CharacterEncodingResult_Success;
}
}
break;
case 3:
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0) {
const u32 c = (static_cast<u32>(p[0] & 0xF) << 12) | (static_cast<u32>(p[1] & 0x3F) << 6) | (static_cast<u32>(p[2] & 0x3F) << 0);
if ((c & 0xF800) != 0 && (c & 0xF800) != 0xD800) {
*dst = c;
return CharacterEncodingResult_Success;
}
}
return CharacterEncodingResult_InvalidFormat;
case 4:
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[3])) == 0) {
const u32 c = (static_cast<u32>(p[0] & 0x7) << 18) | (static_cast<u32>(p[1] & 0x3F) << 12) | (static_cast<u32>(p[2] & 0x3F) << 6) | (static_cast<u32>(p[3] & 0x3F) << 0);
if (c >= 0x10000 && c < 0x110000) {
*dst = c;
return CharacterEncodingResult_Success;
}
}
return CharacterEncodingResult_InvalidFormat;
default:
break;
}
/* We failed to convert. */
return CharacterEncodingResult_InvalidFormat;
}
constexpr inline CharacterEncodingResult PickOutCharacterFromUtf8String(char *dst, const char **str) {
/* Check pre-conditions. */
AMS_ASSERT(dst != nullptr);
AMS_ASSERT(str != nullptr);
AMS_ASSERT(*str != nullptr);
/* Clear the output. */
dst[0] = 0;
dst[1] = 0;
dst[2] = 0;
dst[3] = 0;
/* Perform the conversion. */
const auto *p = *str;
u32 c = static_cast<u32>(*p);
switch (impl::CharacterEncodingHelper::GetUtf8NBytes(c)) {
case 1:
dst[0] = (*str)[0];
++(*str);
break;
case 2:
if ((p[0] & 0x1E) != 0) {
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0) {
c = (static_cast<u32>(p[0] & 0x1F) << 6) | (static_cast<u32>(p[1] & 0x3F) << 0);
dst[0] = (*str)[0];
dst[1] = (*str)[1];
(*str) += 2;
break;
}
}
return CharacterEncodingResult_InvalidFormat;
case 3:
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0) {
c = (static_cast<u32>(p[0] & 0xF) << 12) | (static_cast<u32>(p[1] & 0x3F) << 6) | (static_cast<u32>(p[2] & 0x3F) << 0);
if ((c & 0xF800) != 0 && (c & 0xF800) != 0xD800) {
dst[0] = (*str)[0];
dst[1] = (*str)[1];
dst[2] = (*str)[2];
(*str) += 3;
break;
}
}
return CharacterEncodingResult_InvalidFormat;
case 4:
if (impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[1])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[2])) == 0 && impl::CharacterEncodingHelper::GetUtf8NBytes(static_cast<unsigned char>(p[3])) == 0) {
c = (static_cast<u32>(p[0] & 0x7) << 18) | (static_cast<u32>(p[1] & 0x3F) << 12) | (static_cast<u32>(p[2] & 0x3F) << 6) | (static_cast<u32>(p[3] & 0x3F) << 0);
if (c >= 0x10000 && c < 0x110000) {
dst[0] = (*str)[0];
dst[1] = (*str)[1];
dst[2] = (*str)[2];
dst[3] = (*str)[3];
(*str) += 4;
break;
}
}
return CharacterEncodingResult_InvalidFormat;
default:
return CharacterEncodingResult_InvalidFormat;
}
return CharacterEncodingResult_Success;
}
}
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