Zabbix

/*

** Zabbix

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

** GNU General Public License for more details.

**

** You should have received a copy of the GNU General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

#include "common.h"

​

#include "zbxalgo.h"

​

typedef unsigned char uchar;

​

/*

 * Bob Jenkins hash function (see http://burtleburtle.net/bob/hash/evahash.html)

 */

zbx_hash_t  zbx_hash_lookup2(const void *data, size_t len, zbx_hash_t seed)

{

    const uchar *p = (const uchar *)data;

​

    zbx_hash_t  a, b, c;

​

#define mix(a, b, c)                        \

{                               \

    a = a - b;  a = a - c;  a = a ^ (c >> 13);  \

    b = b - c;  b = b - a;  b = b ^ (a << 8);   \

    c = c - a;  c = c - b;  c = c ^ (b >> 13);  \

    a = a - b;  a = a - c;  a = a ^ (c >> 12);  \

    b = b - c;  b = b - a;  b = b ^ (a << 16);  \

    c = c - a;  c = c - b;  c = c ^ (b >> 5);   \

    a = a - b;  a = a - c;  a = a ^ (c >> 3);   \

    b = b - c;  b = b - a;  b = b ^ (a << 10);  \

    c = c - a;  c = c - b;  c = c ^ (b >> 15);  \

}

​

    a = b = 0x9e3779b9u;

    c = seed;

​

    while (len >= 12)

    {

        a = a + (p[0] + ((zbx_hash_t)p[1] << 8) + ((zbx_hash_t)p[2]  << 16) + ((zbx_hash_t)p[3]  << 24));

        b = b + (p[4] + ((zbx_hash_t)p[5] << 8) + ((zbx_hash_t)p[6]  << 16) + ((zbx_hash_t)p[7]  << 24));

        c = c + (p[8] + ((zbx_hash_t)p[9] << 8) + ((zbx_hash_t)p[10] << 16) + ((zbx_hash_t)p[11] << 24));

​

        mix(a, b, c);

​

        p += 12;

        len -= 12;

    }

​

    c = c + (zbx_hash_t)len;