sarif-cli/notes/unique-ids.ipynb

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   "cell_type": "markdown",
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   "source": [
    "### Flake id: Splitting 64 bits between time, process, and counter"
   ]
  },
  {
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   "execution_count": 18,
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     "text": [
      "40 Wed Nov  3 11:53:47 2004\n",
      "41 Wed Sep  7 08:47:35 2039\n",
      "42 Wed May 15 00:35:11 2109\n",
      "43 Tue Sep 26 08:10:22 2248\n",
      "44 Sun Jun 22 23:20:44 2527\n",
      "45 Fri Dec 12 04:41:28 3084\n"
     ]
    }
   ],
   "source": [
    "import time\n",
    "\n",
    "# Maximum time in ms for given number of bits\n",
    "for bits in range(40, 46):\n",
    "    ms_max = 2**bits\n",
    "    print(bits, time.ctime(ms_max / 1000))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "id": "527a1f0a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'1_0000_0000_0000_0000_0000_0000_0000_0000_0000_0000_1100_0000_1100_0000_0000_0001'"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "# 42 bits are enough\n",
    "\n",
    "# Simple bit patterns for testing\n",
    "ms_since_epoch = (1<<41) + 1\n",
    "process_id = (1<<7) + 1\n",
    "counter = (1<<14) + 1\n",
    "\n",
    "flake = (ms_since_epoch << (8+15) |\n",
    "         process_id << (15) |\n",
    "         counter)\n",
    "\n",
    "f\"{flake:_b}\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "ce892afa",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(4398046511104, 256, 32768)"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "ms_max = (1<<41) * 2\n",
    "\n",
    "process_id_max = 1<<8\n",
    "\n",
    "counter_max = 1 << 15\n",
    "ms_max, process_id_max, counter_max"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "ab7600b7",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Wed May 15 00:35:11 2109'"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Max. time for id\n",
    "time.ctime(ms_max / 1000)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "id": "ebc23d69",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "('time',\n",
       " 1649714152347,\n",
       " 'bits required',\n",
       " 40.58535320753334,\n",
       " 'ratio to max',\n",
       " 2.6659445849131065)"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Builtin time since epoch, in ns, converted to ms: \n",
    "from math import log2\n",
    "time_ms = int(time.time_ns() / 1e6)\n",
    "\"time\", time_ms, \"bits required\", log2(time_ms), \"ratio to max\", 2**42/time_ms\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "7a06517b",
   "metadata": {},
   "outputs": [],
   "source": [
    "\n"
   ]
  }
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