code / tomo

   1 // This file has an implementation of the SipHash hashing function.
   2 
   3 #include <stddef.h>
   4 #include <stdint.h>
   5 #include <string.h>
   6 
   7 #include "siphash.h"
   8 #include "util.h"
   9 
  10 public
  11 uint64_t TOMO_HASH_KEY[2] = {23, 42}; // Randomized in tomo_init()
  12 
  13 /* <MIT License>
  14  Copyright (c) 2013  Marek Majkowski <marek@popcount.org>
  15  Copyright (c) 2018  Samantha McVey <samantham@posteo.net>
  16  Copyright (c) 2024  Bruce Hill <bruce@bruce-hill.com>
  17 
  18  Permission is hereby granted, free of charge, to any person obtaining a copy
  19  of this software and associated documentation files (the "Software"), to deal
  20  in the Software without restriction, including without limitation the rights
  21  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  22  copies of the Software, and to permit persons to whom the Software is
  23  furnished to do so, subject to the following conditions:
  24 
  25  The above copyright notice and this permission notice shall be included in
  26  all copies or substantial portions of the Software.
  27 
  28  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  29  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  31  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  32  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  33  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  34  THE SOFTWARE.
  35  </MIT License>
  36 
  37  Original location:
  38         https://github.com/majek/csiphash/
  39 
  40  Original solution inspired by code from:
  41         Samuel Neves (supercop/crypto_auth/siphash24/little)
  42         djb (supercop/crypto_auth/siphash24/little2)
  43         Jean-Philippe Aumasson (https://131002.net/siphash/siphash24.c)
  44 
  45  Extensive modifications for MoarVM by Samantha McVey
  46 
  47  Further modifications for Tomo by Bruce Hill
  48 */
  49 
  50 #include "siphash-internals.h"
  51 
  52 PUREFUNC public uint64_t siphash24(const uint8_t *src, size_t src_sz) {
  53     siphash sh;
  54     if ((uint64_t)src % __alignof__(uint64_t) == 0) {
  55 #ifdef __GNUC__
  56 #pragma GCC diagnostic push
  57 #pragma GCC diagnostic ignored "-Wcast-align"
  58 #endif
  59         const uint64_t *in = (uint64_t *)src;
  60         /* Find largest src_sz evenly divisible by 8 bytes. */
  61         const ptrdiff_t src_sz_nearest_8bits = ((ptrdiff_t)src_sz >> 3) << 3;
  62         const uint64_t *goal = (uint64_t *)(src + src_sz_nearest_8bits);
  63 #ifdef __GNUC__
  64 #pragma GCC diagnostic pop
  65 #endif
  66         siphashinit(&sh, src_sz);
  67         src_sz -= (size_t)src_sz_nearest_8bits;
  68         while (in < goal) {
  69             siphashadd64bits(&sh, *in);
  70             in++;
  71         }
  72         return siphashfinish(&sh, (uint8_t *)in, src_sz);
  73     } else {
  74         const uint8_t *in = src;
  75         siphashinit(&sh, src_sz);
  76         while (src_sz >= 8) {
  77             uint64_t in_64;
  78             memcpy(&in_64, in, sizeof(uint64_t));
  79             siphashadd64bits(&sh, in_64);
  80             in += 8;
  81             src_sz -= 8;
  82         }
  83         return siphashfinish(&sh, (uint8_t *)in, src_sz);
  84     }
  85 }