libdarwin/stdlib.c

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #include "internal.h"
  24
  25 #pragma mark API
  26 void
  27 os_localtime_file(char buff[32])
  28 {
  29         struct timeval tv;
  30         struct tm curtime;
  31
  32         posix_assert_zero(gettimeofday(&tv, NULL));
  33         (void)localtime_r(&tv.tv_sec, &curtime);
  34
  35         // Return a time representation that is ideal for use in filenames, so no
  36         // spaces or things that need to be escaped.
  37         snprintf(buff, 32, "%d-%02d-%02d_%02d.%02d.%02d.%06d",
  38                         curtime.tm_year + 1900, curtime.tm_mon + 1, curtime.tm_mday,
  39                         curtime.tm_hour, curtime.tm_min, curtime.tm_sec, tv.tv_usec);
  40 }
  41
  42 // MurmurHash2 was written by Austin Appleby, and is placed in the public
  43 // domain. The author hereby disclaims copyright to this source code.
  44 uint64_t
  45 os_simple_hash(const void *buff, size_t len)
  46 {
  47         const uint64_t seed = 0;
  48 #ifdef __LP64__
  49         // MurmurHash64A
  50         const uint64_t m = 0xc6a4a7935bd1e995;
  51         const int r = 47;
  52         uint64_t h = seed ^ (len * m);
  53         const uint64_t * data = (const uint64_t *)buff;
  54         const uint64_t * end = data + (len / 8);
  55         while(data != end) {
  56                 uint64_t k = *data++;
  57                 k *= m;
  58                 k ^= k >> r;
  59                 k *= m;
  60                 h ^= k;
  61                 h *= m;
  62         }
  63         const unsigned char * data2 = (const unsigned char *)data;
  64         switch(len & 7) {
  65         case 7: h ^= ((uint64_t)data2[6]) << 48;
  66         case 6: h ^= ((uint64_t)data2[5]) << 40;
  67         case 5: h ^= ((uint64_t)data2[4]) << 32;
  68         case 4: h ^= ((uint64_t)data2[3]) << 24;
  69         case 3: h ^= ((uint64_t)data2[2]) << 16;
  70         case 2: h ^= ((uint64_t)data2[1]) << 8;
  71         case 1: h ^= ((uint64_t)data2[0]);
  72                         h *= m;
  73         };
  74         h ^= h >> r;
  75         h *= m;
  76         h ^= h >> r;
  77 #else // __LP64__
  78         // MurmurHash64B
  79         const uint32_t m = 0x5bd1e995;
  80         const int r = 24;
  81
  82         uint32_t h1 = (uint32_t)(seed) ^ len;
  83         uint32_t h2 = (uint32_t)(seed >> 32);
  84
  85         const uint32_t * data = (const uint32_t *)buff;
  86
  87 #define MIX(k, h) \
  88         (k) *= m; (k) ^= (k) >> r; (k) *= m; (h) *= m; (h) ^= (k); len -= 4;
  89
  90         while(len >= 8) {
  91                 uint32_t k[2];
  92                 memcpy(k, (const char*)data, sizeof(k));
  93                 data += sizeof(k)/sizeof(k[0]);
  94
  95                 MIX(k[0], h1)
  96                 MIX(k[1], h2)
  97         }
  98
  99         if(len >= 4) {
 100                 uint32_t k[1];
 101                 memcpy(k, (const char *)data, sizeof(k));
 102                 data += sizeof(k)/sizeof(k[0]);
 103
 104                 MIX(k[0], h1);
 105         }
 106
 107 #undef MIX
 108
 109         switch(len) {
 110         case 3: h2 ^= ((unsigned char*)data)[2] << 16;
 111         case 2: h2 ^= ((unsigned char*)data)[1] << 8;
 112         case 1: h2 ^= ((unsigned char*)data)[0];
 113                         h2 *= m;
 114         };
 115
 116         h1 ^= h2 >> 18; h1 *= m;
 117         h2 ^= h1 >> 22; h2 *= m;
 118         h1 ^= h2 >> 17; h1 *= m;
 119         h2 ^= h1 >> 19; h2 *= m;
 120
 121         uint64_t h = h1;
 122
 123         h = (h << 32) | h2;
 124 #endif // __LP64__
 125         return h;
 126 }
 127
 128 uint64_t
 129 os_simple_hash_string(const char *string)
 130 {
 131         size_t len = strlen(string);
 132         return os_simple_hash(string, len);
 133 }