v8/src/math.js

// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


// Keep reference to original values of some global properties.  This
// has the added benefit that the code in this file is isolated from
// changes to these properties.
const $Infinity = global.Infinity;
const $floor = MathFloor;
const $random = MathRandom;
const $abs = MathAbs;

// Instance class name can only be set on functions. That is the only
// purpose for MathConstructor.
function MathConstructor() {}
%FunctionSetInstanceClassName(MathConstructor, 'Math');
const $Math = new MathConstructor();
$Math.__proto__ = global.Object.prototype;
%AddProperty(global, "Math", $Math, DONT_ENUM);

// ECMA 262 - 15.8.2.1
function MathAbs(x) {
  if (%_IsSmi(x)) {
    return x >= 0 ? x : -x;
  } else {
    return %Math_abs(ToNumber(x));
  }
}

// ECMA 262 - 15.8.2.2
function MathAcos(x) { return %Math_acos(ToNumber(x)); }

// ECMA 262 - 15.8.2.3
function MathAsin(x) { return %Math_asin(ToNumber(x)); }

// ECMA 262 - 15.8.2.4
function MathAtan(x) { return %Math_atan(ToNumber(x)); }

// ECMA 262 - 15.8.2.5
function MathAtan2(x, y) { return %Math_atan2(ToNumber(x), ToNumber(y)); }

// ECMA 262 - 15.8.2.6
function MathCeil(x) { return %Math_ceil(ToNumber(x)); }

// ECMA 262 - 15.8.2.7
function MathCos(x) { return %Math_cos(ToNumber(x)); }

// ECMA 262 - 15.8.2.8
function MathExp(x) { return %Math_exp(ToNumber(x)); }

// ECMA 262 - 15.8.2.9
function MathFloor(x) { return %Math_floor(ToNumber(x)); }

// ECMA 262 - 15.8.2.10
function MathLog(x) { return %Math_log(ToNumber(x)); }

// ECMA 262 - 15.8.2.11
function MathMax(arg1, arg2) {  // length == 2
  var r = -$Infinity;
  for (var i = %_ArgumentsLength() - 1; i >= 0; --i) {
    var n = ToNumber(%_Arguments(i));
    if (NUMBER_IS_NAN(n)) return n;
    // Make sure +0 is consider greater than -0.
    if (n > r || (n === 0 && r === 0 && (1 / n) > (1 / r))) r = n;
  }
  return r;
}

// ECMA 262 - 15.8.2.12
function MathMin(arg1, arg2) {  // length == 2
  var r = $Infinity;
  for (var i = %_ArgumentsLength() - 1; i >= 0; --i) {
    var n = ToNumber(%_Arguments(i));
    if (NUMBER_IS_NAN(n)) return n;
    // Make sure -0 is consider less than +0.
    if (n < r || (n === 0 && r === 0 && (1 / n) < (1 / r))) r = n;
  }
  return r;
}

// ECMA 262 - 15.8.2.13
function MathPow(x, y) { return %Math_pow(ToNumber(x), ToNumber(y)); }

// ECMA 262 - 15.8.2.14
function MathRandom() { return %Math_random(); }

// ECMA 262 - 15.8.2.15
function MathRound(x) { return %Math_round(ToNumber(x)); }

// ECMA 262 - 15.8.2.16
function MathSin(x) { return %Math_sin(ToNumber(x)); }

// ECMA 262 - 15.8.2.17
function MathSqrt(x) { return %Math_sqrt(ToNumber(x)); }

// ECMA 262 - 15.8.2.18
function MathTan(x) { return %Math_tan(ToNumber(x)); }


// -------------------------------------------------------------------

function SetupMath() {
  // Setup math constants.
  // ECMA-262, section 15.8.1.1.
  %AddProperty($Math, "E", 2.7182818284590452354, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  // ECMA-262, section 15.8.1.2.
  %AddProperty($Math, "LN10", 2.302585092994046, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  // ECMA-262, section 15.8.1.3.
  %AddProperty($Math, "LN2", 0.6931471805599453, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  // ECMA-262, section 15.8.1.4.
  %AddProperty($Math, "LOG2E", 1.4426950408889634, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  %AddProperty($Math, "LOG10E", 0.43429448190325176, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  %AddProperty($Math, "PI", 3.1415926535897932, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  %AddProperty($Math, "SQRT1_2", 0.7071067811865476, DONT_ENUM |  DONT_DELETE | READ_ONLY);
  %AddProperty($Math, "SQRT2", 1.4142135623730951, DONT_ENUM |  DONT_DELETE | READ_ONLY);

  // Setup non-enumerable functions of the Math object and
  // set their names.
  InstallFunctions($Math, DONT_ENUM, $Array(
    "random", MathRandom,
    "abs", MathAbs,
    "acos", MathAcos,
    "asin", MathAsin,
    "atan", MathAtan,
    "ceil", MathCeil,
    "cos", MathCos,
    "exp", MathExp,
    "floor", MathFloor,
    "log", MathLog,
    "round", MathRound,
    "sin", MathSin,
    "sqrt", MathSqrt,
    "tan", MathTan,
    "atan2", MathAtan2,
    "pow", MathPow,
    "max", MathMax,
    "min", MathMin
  ));
};


SetupMath();