@rescript/std/lib/js/random.js

The motiviation of this repo is that when ReScript users want to share their library with JS users, the JS users don't need have ReScript toolchain installed, this makes sharing code with JS users easier (more details on that topic can be found in our [Ex

'use strict';

var Caml = require("./caml.js");
var $$Array = require("./array.js");
var Int32 = require("./int32.js");
var Int64 = require("./int64.js");
var Digest = require("./digest.js");
var Caml_array = require("./caml_array.js");
var Caml_int64 = require("./caml_int64.js");
var Caml_string = require("./caml_string.js");

function random_seed(param) {
  return [(Math.floor(Math.random()*0x7fffffff))];
}

function assign(st1, st2) {
  $$Array.blit(st2.st, 0, st1.st, 0, 55);
  st1.idx = st2.idx;
}

function full_init(s, seed) {
  var combine = function (accu, x) {
    return Digest.string(accu + String(x));
  };
  var extract = function (d) {
    return ((Caml_string.get(d, 0) + (Caml_string.get(d, 1) << 8) | 0) + (Caml_string.get(d, 2) << 16) | 0) + (Caml_string.get(d, 3) << 24) | 0;
  };
  var seed$1 = seed.length === 0 ? [0] : seed;
  var l = seed$1.length;
  for(var i = 0; i <= 54; ++i){
    Caml_array.set(s.st, i, i);
  }
  var accu = "x";
  for(var i$1 = 0 ,i_finish = 54 + (
      55 > l ? 55 : l
    ) | 0; i$1 <= i_finish; ++i$1){
    var j = i$1 % 55;
    var k = i$1 % l;
    accu = combine(accu, Caml_array.get(seed$1, k));
    Caml_array.set(s.st, j, (Caml_array.get(s.st, j) ^ extract(accu)) & 1073741823);
  }
  s.idx = 0;
}

function make(seed) {
  var result = {
    st: Caml_array.make(55, 0),
    idx: 0
  };
  full_init(result, seed);
  return result;
}

function make_self_init(param) {
  return make(random_seed());
}

function copy(s) {
  var result = {
    st: Caml_array.make(55, 0),
    idx: 0
  };
  assign(result, s);
  return result;
}

function bits(s) {
  s.idx = (s.idx + 1 | 0) % 55;
  var curval = Caml_array.get(s.st, s.idx);
  var newval = Caml_array.get(s.st, (s.idx + 24 | 0) % 55) + (curval ^ (curval >>> 25) & 31) | 0;
  var newval30 = newval & 1073741823;
  Caml_array.set(s.st, s.idx, newval30);
  return newval30;
}

function $$int(s, bound) {
  if (bound > 1073741823 || bound <= 0) {
    throw {
          RE_EXN_ID: "Invalid_argument",
          _1: "Random.int",
          Error: new Error()
        };
  }
  while(true) {
    var r = bits(s);
    var v = r % bound;
    if ((r - v | 0) <= ((1073741823 - bound | 0) + 1 | 0)) {
      return v;
    }
    continue ;
  };
}

function int32(s, bound) {
  if (bound <= 0) {
    throw {
          RE_EXN_ID: "Invalid_argument",
          _1: "Random.int32",
          Error: new Error()
        };
  }
  while(true) {
    var b1 = bits(s);
    var b2 = ((bits(s) & 1) << 30);
    var r = b1 | b2;
    var v = r % bound;
    if ((r - v | 0) <= ((Int32.max_int - bound | 0) + 1 | 0)) {
      return v;
    }
    continue ;
  };
}

function int64(s, bound) {
  if (Caml.i64_le(bound, Caml_int64.zero)) {
    throw {
          RE_EXN_ID: "Invalid_argument",
          _1: "Random.int64",
          Error: new Error()
        };
  }
  while(true) {
    var b1 = Caml_int64.of_int32(bits(s));
    var b2 = Caml_int64.lsl_(Caml_int64.of_int32(bits(s)), 30);
    var b3 = Caml_int64.lsl_(Caml_int64.of_int32(bits(s) & 7), 60);
    var r = Caml_int64.or_(b1, Caml_int64.or_(b2, b3));
    var v = Caml_int64.mod_(r, bound);
    if (!Caml.i64_gt(Caml_int64.sub(r, v), Caml_int64.add(Caml_int64.sub(Int64.max_int, bound), Caml_int64.one))) {
      return v;
    }
    continue ;
  };
}

function rawfloat(s) {
  var r1 = bits(s);
  var r2 = bits(s);
  return (r1 / 1073741824.0 + r2) / 1073741824.0;
}

function $$float(s, bound) {
  return rawfloat(s) * bound;
}

function bool(s) {
  return (bits(s) & 1) === 0;
}

var $$default = {
  st: [
    987910699,
    495797812,
    364182224,
    414272206,
    318284740,
    990407751,
    383018966,
    270373319,
    840823159,
    24560019,
    536292337,
    512266505,
    189156120,
    730249596,
    143776328,
    51606627,
    140166561,
    366354223,
    1003410265,
    700563762,
    981890670,
    913149062,
    526082594,
    1021425055,
    784300257,
    667753350,
    630144451,
    949649812,
    48546892,
    415514493,
    258888527,
    511570777,
    89983870,
    283659902,
    308386020,
    242688715,
    482270760,
    865188196,
    1027664170,
    207196989,
    193777847,
    619708188,
    671350186,
    149669678,
    257044018,
    87658204,
    558145612,
    183450813,
    28133145,
    901332182,
    710253903,
    510646120,
    652377910,
    409934019,
    801085050
  ],
  idx: 0
};

function bits$1(param) {
  return bits($$default);
}

function $$int$1(bound) {
  return $$int($$default, bound);
}

function int32$1(bound) {
  return int32($$default, bound);
}

function int64$1(bound) {
  return int64($$default, bound);
}

function $$float$1(scale) {
  return rawfloat($$default) * scale;
}

function bool$1(param) {
  return bool($$default);
}

function full_init$1(seed) {
  full_init($$default, seed);
}

function init(seed) {
  full_init($$default, [seed]);
}

function self_init(param) {
  full_init$1(random_seed());
}

function get_state(param) {
  return copy($$default);
}

function set_state(s) {
  assign($$default, s);
}

var State = {
  make: make,
  make_self_init: make_self_init,
  copy: copy,
  bits: bits,
  $$int: $$int,
  int32: int32,
  int64: int64,
  $$float: $$float,
  bool: bool
};

exports.init = init;
exports.full_init = full_init$1;
exports.self_init = self_init;
exports.bits = bits$1;
exports.$$int = $$int$1;
exports.int32 = int32$1;
exports.int64 = int64$1;
exports.$$float = $$float$1;
exports.bool = bool$1;
exports.State = State;
exports.get_state = get_state;
exports.set_state = set_state;
/* No side effect */