56 lines
1.6 KiB
C++
56 lines
1.6 KiB
C++
// MassBuilderSaveTool
|
|
// Copyright (C) 2021-2024 Guillaume Jacquemin
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that 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 <https://www.gnu.org/licenses/>.
|
|
|
|
#include "Crc32.h"
|
|
|
|
namespace mbst::Utilities {
|
|
|
|
std::uint32_t
|
|
crc32(std::uint32_t initial, Containers::ArrayView<const void> data) {
|
|
static const auto table = []{
|
|
std::uint32_t polynomial = 0xEDB88320u;
|
|
Containers::StaticArray<256, std::uint32_t> temp{ValueInit};
|
|
|
|
for(std::uint32_t i = 0; i < 256; i++) {
|
|
std::uint32_t c = i;
|
|
|
|
for(std::size_t j = 0; j < 8; j++) {
|
|
if(c & 1) {
|
|
c = polynomial ^ (c >> 1);
|
|
}
|
|
else {
|
|
c >>= 1;
|
|
}
|
|
}
|
|
|
|
temp[i] = c;
|
|
}
|
|
|
|
return temp;
|
|
}();
|
|
|
|
std::uint32_t c = initial ^ 0xFFFFFFFF;
|
|
|
|
auto u = Containers::arrayCast<const std::uint8_t>(data);
|
|
|
|
for(std::size_t i = 0; i < data.size(); ++i) {
|
|
c = table[(c ^ u[i]) & 0xFF] ^ (c >> 8);
|
|
}
|
|
|
|
return c ^ 0xFFFFFFFF;
|
|
}
|
|
|
|
}
|