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https://github.com/aaru-dps/Aaru.Checksums.Native.git
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68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
/*
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* This file is part of the Aaru Data Preservation Suite.
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* Copyright (c) 2019-2023 Natalia Portillo.
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of the
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* License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef AARU_CHECKSUMS_NATIVE_SPAMSUM_H
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#define AARU_CHECKSUMS_NATIVE_SPAMSUM_H
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#define SPAMSUM_LENGTH 64
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#define NUM_BLOCKHASHES 31
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#define ROLLING_WINDOW 7
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#define HASH_INIT 0x28021967
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#define HASH_PRIME 0x01000193
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#define MIN_BLOCKSIZE 3
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#define FUZZY_MAX_RESULT ((2 * SPAMSUM_LENGTH) + 20)
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typedef struct
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{
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uint32_t h;
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uint32_t half_h;
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uint8_t digest[SPAMSUM_LENGTH];
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uint8_t half_digest;
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uint32_t d_len;
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} blockhash_ctx;
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typedef struct
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{
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uint8_t window[ROLLING_WINDOW];
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uint32_t h1;
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uint32_t h2;
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uint32_t h3;
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uint32_t n;
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} roll_state;
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typedef struct
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{
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uint32_t bh_start;
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uint32_t bh_end;
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blockhash_ctx bh[NUM_BLOCKHASHES];
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uint64_t total_size;
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roll_state roll;
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} spamsum_ctx;
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AARU_EXPORT spamsum_ctx* AARU_CALL spamsum_init(void);
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AARU_EXPORT int AARU_CALL spamsum_update(spamsum_ctx* ctx, const uint8_t* data, uint32_t len);
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AARU_EXPORT int AARU_CALL spamsum_final(spamsum_ctx* ctx, uint8_t* result);
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AARU_EXPORT void AARU_CALL spamsum_free(spamsum_ctx* ctx);
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AARU_LOCAL void fuzzy_engine_step(spamsum_ctx* ctx, uint8_t c);
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AARU_LOCAL void roll_hash(spamsum_ctx* ctx, uint8_t c);
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AARU_LOCAL void fuzzy_try_reduce_blockhash(spamsum_ctx* ctx);
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AARU_LOCAL void fuzzy_try_fork_blockhash(spamsum_ctx* ctx);
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#endif // AARU_CHECKSUMS_NATIVE_SPAMSUM_H
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