aeshash.c

#include <x86intrin.h>

static uint64_t aesnihash(uint8_t *in, unsigned long src_sz)
{
	uint8_t tmp_buf[16] = {0};
	__m128i rk0 = {0x736f6d6570736575ULL, 0x646f72616e646f6dULL};
	__m128i rk1 = {0x1231236570743245ULL, 0x126f12321321456dULL};
	__m128i hash = rk0;

	while (src_sz >= 16) {
	onemoretry:;
		__m128i piece = _mm_loadu_si128((__m128i *)in);
		in += 16;
		src_sz -= 16;
		hash = _mm_aesenc_si128(_mm_xor_si128(hash, piece), rk0);
		hash = _mm_aesenc_si128(hash, rk1);
	}

	if (src_sz > 0) {
		unsigned long i;
		for (i = 0; i < src_sz && i < 16; i++) {
			tmp_buf[i] = in[i];
		}
		src_sz = 16;
		in = &tmp_buf[0];
		goto onemoretry;
	}

	hash = _mm_aesenc_si128(hash, _mm_set_epi64x(src_sz, src_sz));

	return hash[0] ^ hash[1];
}