lfg.h

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/*
 * This file is part of the Aaru Data Preservation Suite.
 * Copyright (c) 2019-2026 Natalia Portillo.
 *
 * This library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; version 2.1 of the License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see
 * <https://www.gnu.org/licenses/>.
 *
 * Lagged Fibonacci Generator for Nintendo GameCube/Wii junk fill.
 * Based on Dolphin emulator's LaggedFibonacciGenerator (CC0 licensed).
 */
 
#ifndef LIBAARUFORMAT_NGCW_LFG_H
#define LIBAARUFORMAT_NGCW_LFG_H
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C"
{
#endif
 
#define NGC_LFG_K         521 
#define NGC_LFG_J         32  
#define NGC_LFG_SEED_SIZE 17  

    struct ngc_lfg_ctx
    {
        uint32_t buffer[NGC_LFG_K];
        size_t   position_bytes;
    };

    void ngc_lfg_set_seed(struct ngc_lfg_ctx *ctx, const uint32_t seed[NGC_LFG_SEED_SIZE]);

    void ngc_lfg_get_bytes(struct ngc_lfg_ctx *ctx, uint8_t *out, size_t count);

    size_t ngc_lfg_get_seed(const uint8_t *data, size_t size, size_t data_offset, uint32_t seed_out[NGC_LFG_SEED_SIZE]);
 
#ifdef __cplusplus
}
#endif
 
#endif /* LIBAARUFORMAT_NGCW_LFG_H */