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/*
* Copyright (C) 2015-2020 "IoT.bzh"
* Author: José Bollo <jose.bollo@iot.bzh>
*
* 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 <stdint.h>
/*
* Returns a tiny hash value for the 'text'.
*
* Tiny hash function inspired from pearson
*/
uint8_t pearson4(const char *text)
{
static uint8_t T[16] = {
4, 1, 6, 0, 9, 14, 11, 5,
2, 3, 12, 15, 10, 7, 8, 13
};
uint8_t r, c;
for (r = 0; (c = (uint8_t)*text) ; text++) {
r = T[r ^ (15 & c)];
r = T[r ^ (c >> 4)];
}
return r; // % HEADCOUNT;
}
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