/*
// Copyright (c) 2010-2017 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/

#include <stdio.h>
#include <stdint.h>
#include "toeplitz.h"

/* From XL710 Datasheet, 7.1.10 */

uint8_t toeplitz_init_key[TOEPLITZ_KEY_LEN] =
	{0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x8f, 0xb0,
	 0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
	 0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
	 0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
	 0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa,
	 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	 0x00, 0x00, 0x00, 0x00
};

uint32_t toeplitz_hash(uint8_t *buf_p, int buflen)
{
	uint32_t result = 0;
	uint8_t *key_p = toeplitz_init_key;
	uint8_t byte, *byte4_p = key_p+4;
	int i, pos = 0;
	int bit = 0;
	uint32_t key_word = __builtin_bswap32(*(uint32_t *)key_p);

	for (i = 0; i < buflen; ++i) {
		byte = buf_p[i];
		for (bit = 0; bit <= 7; ++bit) {
			if (byte & (1 << (7 - bit))) {
				result ^= key_word;
			}
			key_word = (key_word << 1) | ((*byte4_p >> (7 - bit)) & 1);
		}
		if (pos >= TOEPLITZ_KEY_LEN - 4) {
			pos = 0;
			byte4_p = key_p;
		}
		else {
			pos++;
			byte4_p++;
		}
	}
	return result;
}