Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
1 parent
fa57b6a
commit 81051f2
Showing
4 changed files
with
113 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,101 @@ | ||
/***************************************************************************** | ||
* Copyright (c) 2014-2021 OpenRCT2 developers | ||
* | ||
* For a complete list of all authors, please refer to contributors.md | ||
* Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2 | ||
* | ||
* OpenRCT2 is licensed under the GNU General Public License version 3. | ||
*****************************************************************************/ | ||
|
||
#include "Crypt.h" | ||
|
||
#include <algorithm> | ||
#include <cassert> | ||
#include <cstdint> | ||
#include <cstdlib> | ||
#include <cstring> | ||
|
||
using namespace Crypt; | ||
|
||
class OpenRCT2FNV1aAlgorithm : public FNV1aAlgorithm | ||
{ | ||
private: | ||
static constexpr uint64_t Offset = 0xCBF29CE484222325ULL; | ||
static constexpr uint64_t Prime = 0x00000100000001B3ULL; | ||
|
||
uint64_t _data = Offset; | ||
uint8_t _rem[8]{}; | ||
size_t _remLen{}; | ||
|
||
void ProcessRemainder() | ||
{ | ||
if (_remLen > 0) | ||
{ | ||
uint64_t temp{}; | ||
std::memcpy(&temp, _rem, _remLen); | ||
_data ^= temp; | ||
_data *= Prime; | ||
_remLen = 0; | ||
} | ||
} | ||
|
||
public: | ||
HashAlgorithm* Clear() override | ||
{ | ||
_data = Offset; | ||
return this; | ||
} | ||
|
||
HashAlgorithm* Update(const void* data, size_t dataLen) override | ||
{ | ||
if (dataLen == 0) | ||
return this; | ||
|
||
auto src = reinterpret_cast<const uint64_t*>(data); | ||
if (_remLen > 0) | ||
{ | ||
// We have remainder, so fill rest of it with bytes from src | ||
auto fillLen = sizeof(uint64_t) - _remLen; | ||
assert(_remLen + fillLen <= sizeof(uint64_t)); | ||
std::memcpy(_rem + _remLen, src, fillLen); | ||
src = reinterpret_cast<const uint64_t*>(reinterpret_cast<const uint8_t*>(src) + fillLen); | ||
_remLen += fillLen; | ||
dataLen -= fillLen; | ||
ProcessRemainder(); | ||
} | ||
|
||
// Process every block of 8 bytes | ||
while (dataLen >= sizeof(uint64_t)) | ||
{ | ||
auto temp = *src++; | ||
_data ^= temp; | ||
_data *= Prime; | ||
dataLen -= sizeof(uint64_t); | ||
} | ||
|
||
// Store the remaining data (< 8 bytes) | ||
if (dataLen > 0) | ||
{ | ||
_remLen = dataLen; | ||
std::memcpy(&_rem, src, dataLen); | ||
} | ||
return this; | ||
} | ||
|
||
Result Finish() override | ||
{ | ||
ProcessRemainder(); | ||
|
||
Result res; | ||
std::memcpy(res.data(), &_data, sizeof(_data)); | ||
return res; | ||
} | ||
}; | ||
|
||
namespace Crypt | ||
{ | ||
std::unique_ptr<FNV1aAlgorithm> CreateFNV1a() | ||
{ | ||
return std::make_unique<OpenRCT2FNV1aAlgorithm>(); | ||
} | ||
} // namespace Crypt |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters