dtc/src/agent/hashkit/da_one_at_a_time.c

/*
* Copyright [2021] JD.com, Inc.
*
* 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 "da_hashkit.h"

uint32_t
hash_one_at_a_time(const char *key, size_t key_length)
{
    const char *ptr = key;
    uint32_t value = 0;

    while (key_length--) {
        uint32_t val = (uint32_t) *ptr++;
        value += val;
        value += (value << 10);
        value ^= (value >> 6);
    }
    value += (value << 3);
    value ^= (value >> 11);
    value += (value << 15);

    return value;
}