fletcher16.h

/*
 * This file is part of the Aaru Data Preservation Suite.
 * Copyright (c) 2019-2025 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; either version 2.1 of the
 * License, or (at your option) any later version.
 *
 * 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 <http://www.gnu.org/licenses/>.
 */

#ifndef AARU_CHECKSUMS_NATIVE_FLETCHER16_H
#define AARU_CHECKSUMS_NATIVE_FLETCHER16_H

#define FLETCHER16_MODULE 0xFF
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(FLETCHER16_MODULE-1) <= 2^32-1 */
#define NMAX              5802

typedef struct
{
    uint8_t sum1;
    uint8_t sum2;
} fletcher16_ctx;

AARU_EXPORT fletcher16_ctx *AARU_CALL fletcher16_init();
AARU_EXPORT int AARU_CALL             fletcher16_update(fletcher16_ctx *ctx, const uint8_t *data, uint32_t len);
AARU_EXPORT int AARU_CALL             fletcher16_final(fletcher16_ctx *ctx, uint16_t *checksum);
AARU_EXPORT void AARU_CALL            fletcher16_free(fletcher16_ctx *ctx);

#if defined(__x86_64__) || defined(__amd64) || defined(_M_AMD64) || defined(_M_X64) || defined(__I386__) || \
    defined(__i386__) || defined(__THW_INTEL) || defined(_M_IX86)

AARU_EXPORT TARGET_WITH_AVX2 void AARU_CALL  fletcher16_avx2(uint8_t *sum1, uint8_t *sum2, const uint8_t *data,
                                                             long len);
AARU_EXPORT TARGET_WITH_SSSE3 void AARU_CALL fletcher16_ssse3(uint8_t *sum1, uint8_t *sum2, const uint8_t *data,
                                                              long len);

#endif

#if defined(__aarch64__) || defined(_M_ARM64) || defined(__arm__) || defined(_M_ARM)

AARU_EXPORT TARGET_WITH_NEON void AARU_CALL fletcher16_neon(uint8_t *sum1, uint8_t *sum2, const uint8_t *data,
                                                            uint32_t len);

#endif

#endif  // AARU_CHECKSUMS_NATIVE_FLETCHER16_H