Atmosphere/libraries/libstratosphere/source/diag/impl/diag_utf8_util.cpp

92 lines
2.7 KiB
C++

/*
* 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 <stratosphere.hpp>
namespace ams::diag::impl {
namespace {
bool IsHeadOfCharacter(u8 c) {
return (c & 0xC0) != 0x80;
}
size_t GetCharacterSize(u8 c) {
if ((c & 0x80) == 0) {
return 1;
} else if ((c & 0xE0) == 0xC0) {
return 2;
} else if ((c & 0xF0) == 0xE0) {
return 3;
} else if ((c & 0xF8) == 0xF0) {
return 4;
}
return 0;
}
const char *FindLastCharacterPointer(const char *str, size_t len) {
/* Find the head of the last character. */
const char *cur;
for (cur = str + len - 1; cur >= str && !IsHeadOfCharacter(*reinterpret_cast<const u8 *>(cur)); --cur) {
/* ... */
}
/* Return the last character. */
if (AMS_LIKELY(cur >= str)) {
return cur;
} else {
return nullptr;
}
}
}
int GetValidSizeAsUtf8String(const char *str, size_t len) {
/* Check pre-condition. */
AMS_ASSERT(str != nullptr);
/* Check if we have no data. */
if (len == 0) {
return 0;
}
/* Get the last character pointer. */
const auto *last_char_ptr = FindLastCharacterPointer(str, len);
if (last_char_ptr == nullptr) {
return -1;
}
/* Get sizes. */
const size_t actual_size = (str + len) - last_char_ptr;
const size_t last_char_size = GetCharacterSize(*reinterpret_cast<const u8 *>(last_char_ptr));
if (last_char_size == 0) {
return -1;
} else if (actual_size >= last_char_size) {
if (actual_size == last_char_size) {
return len;
} else {
return -1;
}
} else if (actual_size >= len) {
AMS_ASSERT(actual_size == len);
return -1;
} else {
return static_cast<int>(len - actual_size);
}
}
}