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/*
* This file is part of PowerDNS or dnsdist.
* Copyright -- PowerDNS.COM B.V. and its contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* In addition, for the avoidance of any doubt, permission is granted to
* link this program with OpenSSL and to (re)distribute the binaries
* produced as the result of such linking.
*
* 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.
*/
#pragma once
#include <cinttypes>
inline void burtlemix(uint32_t& a, uint32_t& b, uint32_t& c)
{
a -= b;
a -= c;
a ^= (c >> 13);
b -= c;
b -= a;
b ^= (a << 8);
c -= a;
c -= b;
c ^= (b >> 13);
a -= b;
a -= c;
a ^= (c >> 12);
b -= c;
b -= a;
b ^= (a << 16);
c -= a;
c -= b;
c ^= (b >> 5);
a -= b;
a -= c;
a ^= (c >> 3);
b -= c;
b -= a;
b ^= (a << 10);
c -= a;
c -= b;
c ^= (b >> 15);
}
inline uint32_t burtle(const unsigned char* k, uint32_t length, uint32_t initval)
{
uint32_t a, b, c, len;
/* Set up the internal state */
len = length;
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
c = initval; /* the previous hash value */
/*---------------------------------------- handle most of the key */
while (len >= 12) {
a += (k[0] + ((uint32_t)k[1] << 8) + ((uint32_t)k[2] << 16) + ((uint32_t)k[3] << 24));
b += (k[4] + ((uint32_t)k[5] << 8) + ((uint32_t)k[6] << 16) + ((uint32_t)k[7] << 24));
c += (k[8] + ((uint32_t)k[9] << 8) + ((uint32_t)k[10] << 16) + ((uint32_t)k[11] << 24));
burtlemix(a, b, c);
k += 12;
len -= 12;
}
/*------------------------------------- handle the last 11 bytes */
c += length;
switch (len) { /* all the case statements fall through */
case 11:
c += ((uint32_t)k[10] << 24);
/* fall-through */
case 10:
c += ((uint32_t)k[9] << 16);
/* fall-through */
case 9:
c += ((uint32_t)k[8] << 8);
/* the first byte of c is reserved for the length */
/* fall-through */
case 8:
b += ((uint32_t)k[7] << 24);
/* fall-through */
case 7:
b += ((uint32_t)k[6] << 16);
/* fall-through */
case 6:
b += ((uint32_t)k[5] << 8);
/* fall-through */
case 5:
b += k[4];
/* fall-through */
case 4:
a += ((uint32_t)k[3] << 24);
/* fall-through */
case 3:
a += ((uint32_t)k[2] << 16);
/* fall-through */
case 2:
a += ((uint32_t)k[1] << 8);
/* fall-through */
case 1:
a += k[0];
/* case 0: nothing left to add */
}
burtlemix(a, b, c);
/*-------------------------------------------- report the result */
return c;
}
inline uint32_t burtleCI(const unsigned char* k, uint32_t length, uint32_t initval)
{
uint32_t a, b, c, len;
/* Set up the internal state */
len = length;
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
c = initval; /* the previous hash value */
/*---------------------------------------- handle most of the key */
while (len >= 12) {
a += (dns_tolower(k[0]) + ((uint32_t)dns_tolower(k[1]) << 8) + ((uint32_t)dns_tolower(k[2]) << 16) + ((uint32_t)dns_tolower(k[3]) << 24));
b += (dns_tolower(k[4]) + ((uint32_t)dns_tolower(k[5]) << 8) + ((uint32_t)dns_tolower(k[6]) << 16) + ((uint32_t)dns_tolower(k[7]) << 24));
c += (dns_tolower(k[8]) + ((uint32_t)dns_tolower(k[9]) << 8) + ((uint32_t)dns_tolower(k[10]) << 16) + ((uint32_t)dns_tolower(k[11]) << 24));
burtlemix(a, b, c);
k += 12;
len -= 12;
}
/*------------------------------------- handle the last 11 bytes */
c += length;
switch (len) { /* all the case statements fall through */
case 11:
c += ((uint32_t)dns_tolower(k[10]) << 24);
/* fall-through */
case 10:
c += ((uint32_t)dns_tolower(k[9]) << 16);
/* fall-through */
case 9:
c += ((uint32_t)dns_tolower(k[8]) << 8);
/* the first byte of c is reserved for the length */
/* fall-through */
case 8:
b += ((uint32_t)dns_tolower(k[7]) << 24);
/* fall-through */
case 7:
b += ((uint32_t)dns_tolower(k[6]) << 16);
/* fall-through */
case 6:
b += ((uint32_t)dns_tolower(k[5]) << 8);
/* fall-through */
case 5:
b += dns_tolower(k[4]);
/* fall-through */
case 4:
a += ((uint32_t)dns_tolower(k[3]) << 24);
/* fall-through */
case 3:
a += ((uint32_t)dns_tolower(k[2]) << 16);
/* fall-through */
case 2:
a += ((uint32_t)dns_tolower(k[1]) << 8);
/* fall-through */
case 1:
a += dns_tolower(k[0]);
/* case 0: nothing left to add */
}
burtlemix(a, b, c);
/*-------------------------------------------- report the result */
return c;
}
template <typename T>
inline uint32_t burtleCI(const T& k, uint32_t initval)
{
return burtleCI(reinterpret_cast<const unsigned char*>(k.data()), k.length(), initval); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast): can't static_cast because of sign difference
}
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