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Atmosphere/libraries/libvapours/source/util/util_utf8_string_util.cpp

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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/>.
*/
#include <vapours.hpp>
namespace ams::util {
namespace {
constexpr inline const u8 CodePointByteLengthTable[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,
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,
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,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
constexpr ALWAYS_INLINE size_t GetCodePointByteLength(u8 c) {
return CodePointByteLengthTable[c];
}
constexpr ALWAYS_INLINE bool IsValidTail(u8 c) {
return (c & 0xC0) == 0x80;
}
constexpr inline bool VerifyCode(const u8 *code, size_t size) {
switch (size) {
case 1:
break;
case 2:
if (!IsValidTail(code[1])) {
return false;
}
break;
case 3:
if (code[0] == 0xE0 && (code[1] & 0x20) == 0x00) {
return false;
}
if (code[0] == 0xED && (code[1] & 0x20) != 0x00) {
return false;
}
if (!IsValidTail(code[1]) || !IsValidTail(code[2])) {
return false;
}
break;
case 4:
if (code[0] == 0xF0 && (code[1] & 0x30) == 0x00) {
return false;
}
if (code[0] == 0xF4 && (code[1] & 0x30) != 0x00) {
return false;
}
if (!IsValidTail(code[1]) || !IsValidTail(code[2]) || !IsValidTail(code[3])) {
return false;
}
break;
default:
return false;
}
return true;
}
}
bool VerifyUtf8String(const char *str, size_t size) {
return GetCodePointCountOfUtf8String(str, size) != -1;
}
int GetCodePointCountOfUtf8String(const char *str, size_t size) {
/* Check pre-conditions. */
AMS_ASSERT(str != nullptr);
AMS_ASSERT(size > 0);
/* Parse codepoints. */
int count = 0;
while (size > 0) {
/* Get and check the current codepoint. */
const u8 *code = reinterpret_cast<const u8 *>(str);
const size_t code_size = GetCodePointByteLength(code[0]);
if (code_size > size || !VerifyCode(code, code_size)) {
return -1;
}
/* Advance. */
str += code_size;
size -= code_size;
/* Increment count. */
++count;
}
return count;
}
}