/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "spdk/crc32.h"

#if defined(__x86_64__) && defined(__SSE4_2__)
#include <x86intrin.h>

uint32_t
spdk_crc32c_update(const void *buf, size_t len, uint32_t crc)
{
	uint64_t crc_tmp64;
	size_t count;

	/* _mm_crc32_u64() needs a 64-bit intermediate value */
	crc_tmp64 = crc;

	/* Process as much of the buffer as possible in 64-bit blocks. */
	count = len / 8;
	while (count--) {
		uint64_t block;

		/*
		 * Use memcpy() to avoid unaligned loads, which are undefined behavior in C.
		 * The compiler will optimize out the memcpy() in release builds.
		 */
		memcpy(&block, buf, sizeof(block));
		crc_tmp64 = _mm_crc32_u64(crc_tmp64, block);
		buf += sizeof(block);
	}
	crc = (uint32_t)crc_tmp64;

	/* Handle any trailing bytes. */
	count = len & 7;
	while (count--) {
		crc = _mm_crc32_u8(crc, *(const uint8_t *)buf);
		buf++;
	}

	return crc;
}

#else /* SSE 4.2 (CRC32 instruction) not available */

static struct spdk_crc32_table g_crc32c_table;

__attribute__((constructor)) static void
spdk_crc32c_init(void)
{
	spdk_crc32_table_init(&g_crc32c_table, SPDK_CRC32C_POLYNOMIAL_REFLECT);
}

uint32_t
spdk_crc32c_update(const void *buf, size_t len, uint32_t crc)
{
	return spdk_crc32_update(&g_crc32c_table, buf, len, crc);
}

#endif