mirror of
https://github.com/dolphin-emu/dolphin.git
synced 2024-09-21 03:41:42 +02:00
f4e34703c0
Public domain does not have an internationally agreed upon definition, As such it's generally preferred to use an extremely liberal license, which can explicitly list the rights granted by the copyright holder. The CC0 license is the usual choice here. This "relicensing" is done without hunting down copyright holders, since it is presumed that their release of this work into the public domain authorizes us to redistribute this code under any other license of our choosing.
51 lines
1.5 KiB
C++
51 lines
1.5 KiB
C++
// SPDX-License-Identifier: CC0-1.0
|
|
|
|
#pragma once
|
|
|
|
#include <array>
|
|
#include <cstddef>
|
|
|
|
#include "Common/CommonTypes.h"
|
|
|
|
namespace DiscIO
|
|
{
|
|
class LaggedFibonacciGenerator
|
|
{
|
|
public:
|
|
static constexpr size_t SEED_SIZE = 17;
|
|
|
|
// Reconstructs a seed and writes it to seed_out, then returns the number of bytes which can
|
|
// be reconstructed using that seed. Can return any number between 0 and size, inclusive.
|
|
// data - data_offset must be 4-byte aligned.
|
|
static size_t GetSeed(const u8* data, size_t size, size_t data_offset, u32 seed_out[SEED_SIZE]);
|
|
|
|
// SetSeed must be called before using the functions below
|
|
void SetSeed(const u32 seed[SEED_SIZE]);
|
|
void SetSeed(const u8 seed[SEED_SIZE * sizeof(u32)]);
|
|
|
|
// Outputs a number of bytes and advances the internal state by the same amount.
|
|
void GetBytes(size_t count, u8* out);
|
|
u8 GetByte();
|
|
|
|
// Advances the internal state like GetBytes, but without outputting data. O(N), like GetBytes.
|
|
void Forward(size_t count);
|
|
|
|
private:
|
|
static bool GetSeed(const u32* data, size_t size, size_t data_offset,
|
|
LaggedFibonacciGenerator* lfg, u32 seed_out[SEED_SIZE]);
|
|
|
|
void Forward();
|
|
void Backward(size_t start_word = 0, size_t end_word = LFG_K);
|
|
|
|
bool Reinitialize(u32 seed_out[SEED_SIZE]);
|
|
bool Initialize(bool check_existing_data);
|
|
|
|
static constexpr size_t LFG_K = 521;
|
|
static constexpr size_t LFG_J = 32;
|
|
|
|
std::array<u32, LFG_K> m_buffer;
|
|
|
|
size_t m_position_bytes = 0;
|
|
};
|
|
|
|
} // namespace DiscIO
|