Line data    Source code

       1             : /*
       2             :  * Copyright (C) 2019 Andrea Mazzoleni
       3             :  *
       4             :  * This program is free software: you can redistribute it and/or modify
       5             :  * it under the terms of the GNU General Public License as published by
       6             :  * the Free Software Foundation, either version 3 of the License, or
       7             :  * (at your option) any later version.
       8             :  *
       9             :  * This program is distributed in the hope that it will be useful,
      10             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             :  * GNU General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU General Public License
      15             :  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
      16             :  */
      17             : 
      18             : /*
      19             :  * Derivative work from metrohash128.cpp
      20             :  *
      21             :  * https://github.com/jandrewrogers/MetroHash/blob/master/src/metrohash128.cpp
      22             :  *
      23             :  * Copyright 2015-2018 J. Andrew Rogers
      24             :  *
      25             :  * Licensed under the Apache License, Version 2.0 (the "License");
      26             :  * you may not use this file except in compliance with the License.
      27             :  * You may obtain a copy of the License at
      28             :  *
      29             :  *     http://www.apache.org/licenses/LICENSE-2.0
      30             :  *
      31             :  * Unless required by applicable law or agreed to in writing, software
      32             :  * distributed under the License is distributed on an "AS IS" BASIS,
      33             :  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      34             :  * See the License for the specific language governing permissions and
      35             :  * limitations under the License.
      36             :  */
      37             : 
      38             : static const uint64_t k0 = 0xC83A91E1;
      39             : static const uint64_t k1 = 0x8648DBDB;
      40             : static const uint64_t k2 = 0x7BDEC03B;
      41             : static const uint64_t k3 = 0x2F5870A5;
      42             : 
      43         393 : void MetroHash128(const void* data, size_t size, const uint8_t* seed, uint8_t* digest)
      44             : {
      45         393 :         const uint8_t* ptr = data;
      46             :         uint64_t v[4];
      47             : 
      48         393 :         v[0] = (util_read64(seed) - k0) * k3;
      49         393 :         v[1] = (util_read64(seed + 8) + k1) * k2;
      50             : 
      51         393 :         if (size >= 32) {
      52         357 :                 v[2] = (util_read64(seed) + k0) * k2;
      53         357 :                 v[3] = (util_read64(seed + 8) - k1) * k3;
      54             : 
      55             :                 do {
      56     1049484 :                         v[0] += util_read64(ptr) * k0; ptr += 8; v[0] = util_rotr64(v[0], 29) + v[2];
      57     1049484 :                         v[1] += util_read64(ptr) * k1; ptr += 8; v[1] = util_rotr64(v[1], 29) + v[3];
      58     1049484 :                         v[2] += util_read64(ptr) * k2; ptr += 8; v[2] = util_rotr64(v[2], 29) + v[0];
      59     1049484 :                         v[3] += util_read64(ptr) * k3; ptr += 8; v[3] = util_rotr64(v[3], 29) + v[1];
      60     1049484 :                         size -= 32;
      61     1049484 :                 } while (size >= 32);
      62             : 
      63         357 :                 v[2] ^= util_rotr64(((v[0] + v[3]) * k0) + v[1], 21) * k1;
      64         357 :                 v[3] ^= util_rotr64(((v[1] + v[2]) * k1) + v[0], 21) * k0;
      65         357 :                 v[0] ^= util_rotr64(((v[0] + v[2]) * k0) + v[3], 21) * k1;
      66         357 :                 v[1] ^= util_rotr64(((v[1] + v[3]) * k1) + v[2], 21) * k0;
      67             :         }
      68             : 
      69         393 :         if (size >= 16) {
      70         132 :                 v[0] += util_read64(ptr) * k2; ptr += 8; v[0] = util_rotr64(v[0], 33) * k3;
      71         132 :                 v[1] += util_read64(ptr) * k2; ptr += 8; v[1] = util_rotr64(v[1], 33) * k3;
      72         132 :                 v[0] ^= util_rotr64((v[0] * k2) + v[1], 45) * k1;
      73         132 :                 v[1] ^= util_rotr64((v[1] * k3) + v[0], 45) * k0;
      74         132 :                 size -= 16;
      75             :         }
      76             : 
      77         393 :         if (size >= 8) {
      78         134 :                 v[0] += util_read64(ptr) * k2; ptr += 8; v[0] = util_rotr64(v[0], 33) * k3;
      79         134 :                 v[0] ^= util_rotr64((v[0] * k2) + v[1], 27) * k1;
      80         134 :                 size -= 8;
      81             :         }
      82             : 
      83         393 :         if (size >= 4) {
      84         132 :                 v[1] += util_read32(ptr) * k2; ptr += 4; v[1] = util_rotr64(v[1], 33) * k3;
      85         132 :                 v[1] ^= util_rotr64((v[1] * k3) + v[0], 46) * k0;
      86         132 :                 size -= 4;
      87             :         }
      88             : 
      89         393 :         if (size >= 2) {
      90         135 :                 v[0] += util_read16(ptr) * k2; ptr += 2; v[0] = util_rotr64(v[0], 33) * k3;
      91         135 :                 v[0] ^= util_rotr64((v[0] * k2) + v[1], 22) * k1;
      92         135 :                 size -= 2;
      93             :         }
      94             : 
      95         393 :         if (size >= 1) {
      96         133 :                 v[1] += util_read8(ptr) * k2; v[1] = util_rotr64(v[1], 33) * k3;
      97         133 :                 v[1] ^= util_rotr64((v[1] * k3) + v[0], 58) * k0;
      98             :         }
      99             : 
     100         393 :         v[0] += util_rotr64((v[0] * k0) + v[1], 13);
     101         393 :         v[1] += util_rotr64((v[1] * k1) + v[0], 37);
     102         393 :         v[0] += util_rotr64((v[0] * k2) + v[1], 13);
     103         393 :         v[1] += util_rotr64((v[1] * k3) + v[0], 37);
     104             : 
     105         393 :         util_write64(digest, v[0]);
     106         393 :         util_write64(digest + 8, v[1]);
     107         393 : }
     108             :