pkg/dev_compiler/tool/input_sdk/private/js_number.dart - sdk.git - Git at Google

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 part of dart._interceptors;

 /**
  * The implementation of Dart's int & double methods.
  * These are made available as extension methods on `Number` in JS.
  */
 @JsPeerInterface(name: 'Number')
 class JSNumber extends Interceptor implements int, double {
   const JSNumber();

   int compareTo(num b) {
     if (this < b) {
       return -1;
     } else if (this > b) {
       return 1;
     } else if (this == b) {
       if (this == 0) {
         bool bIsNegative = b.isNegative;
         if (isNegative == bIsNegative) return 0;
         if (isNegative) return -1;
         return 1;
       }
       return 0;
     } else if (isNaN) {
       if (b.isNaN) {
         return 0;
       }
       return 1;
     } else {
       return -1;
     }
   }

   bool get isNegative => (this == 0) ? (1 / this) < 0 : this < 0;

   bool get isNaN => JS('bool', r'isNaN(#)', this);

   bool get isInfinite {
     return JS('bool', r'# == (1/0)', this)
         || JS('bool', r'# == (-1/0)', this);
   }

   bool get isFinite => JS('bool', r'isFinite(#)', this);

   JSNumber remainder(num b) {
     if (b is! num) throw argumentErrorValue(b);
     return JS('num', r'# % #', this, b);
   }

   JSNumber abs() => JS('num', r'Math.abs(#)', this);

   JSNumber get sign => this > 0 ? 1 : this < 0 ? -1 : this;

   static const int _MIN_INT32 = -0x80000000;
   static const int _MAX_INT32 = 0x7FFFFFFF;

   int toInt() {
     if (this >= _MIN_INT32 && this <= _MAX_INT32) {
       return JS('int', '# | 0', this);
     }
     if (JS('bool', r'isFinite(#)', this)) {
       return JS('int', r'# + 0', truncateToDouble());  // Converts -0.0 to +0.0.
     }
     // This is either NaN, Infinity or -Infinity.
     throw new UnsupportedError(JS("String", '"" + #', this));
   }

   int truncate() => toInt();

   int ceil() => ceilToDouble().toInt();

   int floor() => floorToDouble().toInt();

   int round() {
     if (this > 0) {
       // This path excludes the special cases -0.0, NaN and -Infinity, leaving
       // only +Infinity, for which a direct test is faster than [isFinite].
       if (JS('bool', r'# !== (1/0)', this)) {
         return JS('int', r'Math.round(#)', this);
       }
     } else if (JS('bool', '# > (-1/0)', this)) {
       // This test excludes NaN and -Infinity, leaving only -0.0.
       //
       // Subtraction from zero rather than negation forces -0.0 to 0.0 so code
       // inside Math.round and code to handle result never sees -0.0, which on
       // some JavaScript VMs can be a slow path.
       return JS('int', r'0 - Math.round(0 - #)', this);
     }
     // This is either NaN, Infinity or -Infinity.
     throw new UnsupportedError(JS("String", '"" + #', this));
   }

   double ceilToDouble() => JS('num', r'Math.ceil(#)', this);

   double floorToDouble() => JS('num', r'Math.floor(#)', this);

   double roundToDouble() {
     if (this < 0) {
       return JS('num', r'-Math.round(-#)', this);
     } else {
       return JS('num', r'Math.round(#)', this);
     }
   }

   double truncateToDouble() => this < 0 ? ceilToDouble() : floorToDouble();

   num clamp(num lowerLimit, num upperLimit) {
     if (lowerLimit.compareTo(upperLimit) > 0) {
       throw argumentErrorValue(lowerLimit);
     }
     if (this.compareTo(lowerLimit) < 0) return lowerLimit;
     if (this.compareTo(upperLimit) > 0) return upperLimit;
     return this;
   }

   double toDouble() => this;

   String toStringAsFixed(int fractionDigits) {
     checkInt(fractionDigits);
     if (fractionDigits < 0 || fractionDigits > 20) {
       throw new RangeError.range(fractionDigits, 0, 20, "fractionDigits");
     }
     String result = JS('String', r'#.toFixed(#)', this, fractionDigits);
     if (this == 0 && isNegative) return "-$result";
     return result;
   }

   String toStringAsExponential([int fractionDigits]) {
     String result;
     if (fractionDigits != null) {
       checkInt(fractionDigits);
       if (fractionDigits < 0 || fractionDigits > 20) {
         throw new RangeError.range(fractionDigits, 0, 20, "fractionDigits");
       }
       result = JS('String', r'#.toExponential(#)', this, fractionDigits);
     } else {
       result = JS('String', r'#.toExponential()', this);
     }
     if (this == 0 && isNegative) return "-$result";
     return result;
   }

   String toStringAsPrecision(int precision) {
     checkInt(precision);
     if (precision < 1 || precision > 21) {
       throw new RangeError.range(precision, 1, 21, "precision");
     }
     String result = JS('String', r'#.toPrecision(#)',
                        this, precision);
     if (this == 0 && isNegative) return "-$result";
     return result;
   }

   String toRadixString(int radix) {
     checkInt(radix);
     if (radix < 2 || radix > 36) {
       throw new RangeError.range(radix, 2, 36, "radix");
     }
     String result = JS('String', r'#.toString(#)', this, radix);
     const int rightParenCode = 0x29;
     if (result.codeUnitAt(result.length - 1) != rightParenCode) {
       return result;
     }
     return _handleIEtoString(result);
   }

   static String _handleIEtoString(String result) {
     // Result is probably IE's untraditional format for large numbers,
     // e.g., "8.0000000000008(e+15)" for 0x8000000000000800.toString(16).
     var match = JS('List|Null',
                    r'/^([\da-z]+)(?:\.([\da-z]+))?\(e\+(\d+)\)$/.exec(#)',
                    result);
     if (match == null) {
       // Then we don't know how to handle it at all.
       throw new UnsupportedError("Unexpected toString result: $result");
     }
     result = JS('String', '#', match[1]);
     int exponent = JS("int", "+#", match[3]);
     if (match[2] != null) {
       result = JS('String', '# + #', result, match[2]);
       exponent -= JS('int', '#.length', match[2]);
     }
     return result + "0" * exponent;
   }

   // Note: if you change this, also change the function [S].
   String toString() {
     if (this == 0 && JS('bool', '(1 / #) < 0', this)) {
       return '-0.0';
     } else {
       return JS('String', r'"" + (#)', this);
     }
   }

   int get hashCode => JS('int', '# & 0x1FFFFFFF', this);

   JSNumber operator -() => JS('num', r'-#', this);

   JSNumber operator +(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('num', '# + #', this, other);
   }

   JSNumber operator -(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('num', '# - #', this, other);
   }

   double operator /(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('num', '# / #', this, other);
   }

   JSNumber operator *(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('num', '# * #', this, other);
   }

   JSNumber operator %(num other) {
     if (other is !num) throw argumentErrorValue(other);
     // Euclidean Modulo.
     num result = JS('num', r'# % #', this, other);
     if (result == 0) return (0 as JSNumber);  // Make sure we don't return -0.0.
     if (result > 0) return result;
     if (JS('num', '#', other) < 0) {
       return result - JS('num', '#', other);
     } else {
       return result + JS('num', '#', other);
     }
   }

   bool _isInt32(value) => JS('bool', '(# | 0) === #', value, value);

   int operator ~/(num other) {
     if (_isInt32(this) && _isInt32(other) && 0 != other && -1 != other) {
       return JS('int', r'(# / #) | 0', this, other);
     } else {
       return _tdivSlow(other);
     }
   }

   int _tdivSlow(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return (JS('num', r'# / #', this, other)).toInt();
   }

   // TODO(ngeoffray): Move the bit operations below to [JSInt] and
   // make them take an int. Because this will make operations slower,
   // we define these methods on number for now but we need to decide
   // the grain at which we do the type checks.

   int operator <<(num other) {
     if (other is !num) throw argumentErrorValue(other);
     if (JS('num', '#', other) < 0) throw argumentErrorValue(other);
     return _shlPositive(other);
   }

   int _shlPositive(num other) {
     // JavaScript only looks at the last 5 bits of the shift-amount. Shifting
     // by 33 is hence equivalent to a shift by 1.
     return JS('bool', r'# > 31', other)
         ? 0
         : JS('int', r'(# << #) >>> 0', this, other);
   }

   int operator >>(num other) {
     if (other is !num) throw argumentErrorValue(other);
     if (JS('num', '#', other) < 0) throw argumentErrorValue(other);
     return _shrOtherPositive(other);
   }

   int _shrOtherPositive(num other) {
     return JS('num', '#', this) > 0
         ? _shrBothPositive(other)
         // For negative numbers we just clamp the shift-by amount.
         // `this` could be negative but not have its 31st bit set.
         // The ">>" would then shift in 0s instead of 1s. Therefore
         // we cannot simply return 0xFFFFFFFF.
         : JS('int', r'(# >> #) >>> 0', this, other > 31 ? 31 : other);
   }

   int _shrBothPositive(num other) {
     return JS('bool', r'# > 31', other)
         // JavaScript only looks at the last 5 bits of the shift-amount. In JS
         // shifting by 33 is hence equivalent to a shift by 1. Shortcut the
         // computation when that happens.
         ? 0
         // Given that `this` is positive we must not use '>>'. Otherwise a
         // number that has the 31st bit set would be treated as negative and
         // shift in ones.
         : JS('int', r'# >>> #', this, other);
   }

   int operator &(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('int', r'(# & #) >>> 0', this, other);
   }

   int operator |(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('int', r'(# | #) >>> 0', this, other);
   }

   int operator ^(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('int', r'(# ^ #) >>> 0', this, other);
   }

   bool operator <(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('bool', '# < #', this, other);
   }

   bool operator >(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('bool', '# > #', this, other);
   }

   bool operator <=(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('bool', '# <= #', this, other);
   }

   bool operator >=(num other) {
     if (other is !num) throw argumentErrorValue(other);
     return JS('bool', '# >= #', this, other);
   }

   // int members.
   // TODO(jmesserly): all numbers will have these in dynamic dispatch.
   // We can fix by checking it at dispatch time but we'd need to structure them
   // differently.

   bool get isEven => (this & 1) == 0;

   bool get isOdd => (this & 1) == 1;

   int toUnsigned(int width) {
     return this & ((1 << width) - 1);
   }

   int toSigned(int width) {
     int signMask = 1 << (width - 1);
     return (this & (signMask - 1)) - (this & signMask);
   }

   int get bitLength {
     int nonneg = this < 0 ? -this - 1 : this;
     if (nonneg >= 0x100000000) {
       nonneg = nonneg ~/ 0x100000000;
       return _bitCount(_spread(nonneg)) + 32;
     }
     return _bitCount(_spread(nonneg));
   }

   // Returns pow(this, e) % m.
   int modPow(int e, int m) {
     if (e is! int) {
       throw new ArgumentError.value(e, "exponent", "not an integer");
     }
     if (m is! int) {
       throw new ArgumentError.value(m, "modulus", "not an integer");
     }
     if (e < 0) throw new RangeError.range(e, 0, null, "exponent");
     if (m <= 0) throw new RangeError.range(m, 1, null, "modulus");
     if (e == 0) return 1;
     int b = this;
     if (b < 0 || b > m) {
       b %= m;
     }
     int r = 1;
     while (e > 0) {
       if (e.isOdd) {
         r = (r * b) % m;
       }
       e ~/= 2;
       b = (b * b) % m;
     }
     return r;
   }

   // If inv is false, returns gcd(x, y).
   // If inv is true and gcd(x, y) = 1, returns d, so that c*x + d*y = 1.
   // If inv is true and gcd(x, y) != 1, throws Exception("Not coprime").
   static int _binaryGcd(int x, int y, bool inv) {
     int s = 1;
     if (!inv) {
       while (x.isEven && y.isEven) {
         x ~/= 2;
         y ~/= 2;
         s *= 2;
       }
       if (y.isOdd) {
         var t = x;
         x = y;
         y = t;
       }
     }
     final bool ac = x.isEven;
     int u = x;
     int v = y;
     int a = 1,
         b = 0,
         c = 0,
         d = 1;
     do {
       while (u.isEven) {
         u ~/= 2;
         if (ac) {
           if (!a.isEven || !b.isEven) {
             a += y;
             b -= x;
           }
           a ~/= 2;
         } else if (!b.isEven) {
           b -= x;
         }
         b ~/= 2;
       }
       while (v.isEven) {
         v ~/= 2;
         if (ac) {
           if (!c.isEven || !d.isEven) {
             c += y;
             d -= x;
           }
           c ~/= 2;
         } else if (!d.isEven) {
           d -= x;
         }
         d ~/= 2;
       }
       if (u >= v) {
         u -= v;
         if (ac) a -= c;
         b -= d;
       } else {
         v -= u;
         if (ac) c -= a;
         d -= b;
       }
     } while (u != 0);
     if (!inv) return s*v;
     if (v != 1) throw new Exception("Not coprime");
     if (d < 0) {
       d += x;
       if (d < 0) d += x;
     } else if (d > x) {
       d -= x;
       if (d > x) d -= x;
     }
     return d;
   }

   // Returns 1/this % m, with m > 0.
   int modInverse(int m) {
     if (m is! int) {
       throw new ArgumentError.value(m, "modulus", "not an integer");
     }
     if (m <= 0) throw new RangeError.range(m, 1, null, "modulus");
     if (m == 1) return 0;
     int t = this;
     if ((t < 0) || (t >= m)) t %= m;
     if (t == 1) return 1;
     if ((t == 0) || (t.isEven && m.isEven)) {
       throw new Exception("Not coprime");
     }
     return _binaryGcd(m, t, true);
   }

   // Returns gcd of abs(this) and abs(other).
   int gcd(int other) {
     if (other is! int) {
       throw new ArgumentError.value(other, "other", "not an integer");
     }
     int x = this.abs();
     int y = other.abs();
     if (x == 0) return y;
     if (y == 0) return x;
     if ((x == 1) || (y == 1)) return 1;
     return _binaryGcd(x, y, false);
   }

   // Assumes i is <= 32-bit and unsigned.
   static int _bitCount(int i) {
     // See "Hacker's Delight", section 5-1, "Counting 1-Bits".

     // The basic strategy is to use "divide and conquer" to
     // add pairs (then quads, etc.) of bits together to obtain
     // sub-counts.
     //
     // A straightforward approach would look like:
     //
     // i = (i & 0x55555555) + ((i >>  1) & 0x55555555);
     // i = (i & 0x33333333) + ((i >>  2) & 0x33333333);
     // i = (i & 0x0F0F0F0F) + ((i >>  4) & 0x0F0F0F0F);
     // i = (i & 0x00FF00FF) + ((i >>  8) & 0x00FF00FF);
     // i = (i & 0x0000FFFF) + ((i >> 16) & 0x0000FFFF);
     //
     // The code below removes unnecessary &'s and uses a
     // trick to remove one instruction in the first line.

     i = _shru(i, 0) - (_shru(i, 1) & 0x55555555);
     i = (i & 0x33333333) + (_shru(i, 2) & 0x33333333);
     i = 0x0F0F0F0F & (i + _shru(i, 4));
     i += _shru(i, 8);
     i += _shru(i, 16);
     return (i & 0x0000003F);
   }

   static int _shru(int value, int shift) => JS('int', '# >>> #', value, shift);
   static int _shrs(int value, int shift) => JS('int', '# >> #', value, shift);
   static int _ors(int a, int b) => JS('int', '# | #', a, b);

   // Assumes i is <= 32-bit
   static int _spread(int i) {
     i = _ors(i, _shrs(i, 1));
     i = _ors(i, _shrs(i, 2));
     i = _ors(i, _shrs(i, 4));
     i = _ors(i, _shrs(i, 8));
     i = _shru(_ors(i, _shrs(i, 16)), 0);
     return i;
   }

   int operator ~() => JS('int', r'(~#) >>> 0', this);
 }
	// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	part of dart._interceptors;

	/**
	* The implementation of Dart's int & double methods.
	* These are made available as extension methods on `Number` in JS.
	*/
	@JsPeerInterface(name: 'Number')
	class JSNumber extends Interceptor implements int, double {
	const JSNumber();

	int compareTo(num b) {
	if (this < b) {
	return -1;
	} else if (this > b) {
	return 1;
	} else if (this == b) {
	if (this == 0) {
	bool bIsNegative = b.isNegative;
	if (isNegative == bIsNegative) return 0;
	if (isNegative) return -1;
	return 1;
	}
	return 0;
	} else if (isNaN) {
	if (b.isNaN) {
	return 0;
	}
	return 1;
	} else {
	return -1;
	}
	}

	bool get isNegative => (this == 0) ? (1 / this) < 0 : this < 0;

	bool get isNaN => JS('bool', r'isNaN(#)', this);

	bool get isInfinite {
	return JS('bool', r'# == (1/0)', this)
	\|\| JS('bool', r'# == (-1/0)', this);
	}

	bool get isFinite => JS('bool', r'isFinite(#)', this);

	JSNumber remainder(num b) {
	if (b is! num) throw argumentErrorValue(b);
	return JS('num', r'# % #', this, b);
	}

	JSNumber abs() => JS('num', r'Math.abs(#)', this);

	JSNumber get sign => this > 0 ? 1 : this < 0 ? -1 : this;

	static const int _MIN_INT32 = -0x80000000;
	static const int _MAX_INT32 = 0x7FFFFFFF;

	int toInt() {
	if (this >= _MIN_INT32 && this <= _MAX_INT32) {
	return JS('int', '# \| 0', this);
	}
	if (JS('bool', r'isFinite(#)', this)) {
	return JS('int', r'# + 0', truncateToDouble()); // Converts -0.0 to +0.0.
	}
	// This is either NaN, Infinity or -Infinity.
	throw new UnsupportedError(JS("String", '"" + #', this));
	}

	int truncate() => toInt();

	int ceil() => ceilToDouble().toInt();

	int floor() => floorToDouble().toInt();

	int round() {
	if (this > 0) {
	// This path excludes the special cases -0.0, NaN and -Infinity, leaving
	// only +Infinity, for which a direct test is faster than [isFinite].
	if (JS('bool', r'# !== (1/0)', this)) {
	return JS('int', r'Math.round(#)', this);
	}
	} else if (JS('bool', '# > (-1/0)', this)) {
	// This test excludes NaN and -Infinity, leaving only -0.0.
	//
	// Subtraction from zero rather than negation forces -0.0 to 0.0 so code
	// inside Math.round and code to handle result never sees -0.0, which on
	// some JavaScript VMs can be a slow path.
	return JS('int', r'0 - Math.round(0 - #)', this);
	}
	// This is either NaN, Infinity or -Infinity.
	throw new UnsupportedError(JS("String", '"" + #', this));
	}

	double ceilToDouble() => JS('num', r'Math.ceil(#)', this);

	double floorToDouble() => JS('num', r'Math.floor(#)', this);

	double roundToDouble() {
	if (this < 0) {
	return JS('num', r'-Math.round(-#)', this);
	} else {
	return JS('num', r'Math.round(#)', this);
	}
	}

	double truncateToDouble() => this < 0 ? ceilToDouble() : floorToDouble();

	num clamp(num lowerLimit, num upperLimit) {
	if (lowerLimit.compareTo(upperLimit) > 0) {
	throw argumentErrorValue(lowerLimit);
	}
	if (this.compareTo(lowerLimit) < 0) return lowerLimit;
	if (this.compareTo(upperLimit) > 0) return upperLimit;
	return this;
	}

	double toDouble() => this;

	String toStringAsFixed(int fractionDigits) {
	checkInt(fractionDigits);
	if (fractionDigits < 0 \|\| fractionDigits > 20) {
	throw new RangeError.range(fractionDigits, 0, 20, "fractionDigits");
	}
	String result = JS('String', r'#.toFixed(#)', this, fractionDigits);
	if (this == 0 && isNegative) return "-$result";
	return result;
	}

	String toStringAsExponential([int fractionDigits]) {
	String result;
	if (fractionDigits != null) {
	checkInt(fractionDigits);
	if (fractionDigits < 0 \|\| fractionDigits > 20) {
	throw new RangeError.range(fractionDigits, 0, 20, "fractionDigits");
	}
	result = JS('String', r'#.toExponential(#)', this, fractionDigits);
	} else {
	result = JS('String', r'#.toExponential()', this);
	}
	if (this == 0 && isNegative) return "-$result";
	return result;
	}

	String toStringAsPrecision(int precision) {
	checkInt(precision);
	if (precision < 1 \|\| precision > 21) {
	throw new RangeError.range(precision, 1, 21, "precision");
	}
	String result = JS('String', r'#.toPrecision(#)',
	this, precision);
	if (this == 0 && isNegative) return "-$result";
	return result;
	}

	String toRadixString(int radix) {
	checkInt(radix);
	if (radix < 2 \|\| radix > 36) {
	throw new RangeError.range(radix, 2, 36, "radix");
	}
	String result = JS('String', r'#.toString(#)', this, radix);
	const int rightParenCode = 0x29;
	if (result.codeUnitAt(result.length - 1) != rightParenCode) {
	return result;
	}
	return _handleIEtoString(result);
	}

	static String _handleIEtoString(String result) {
	// Result is probably IE's untraditional format for large numbers,
	// e.g., "8.0000000000008(e+15)" for 0x8000000000000800.toString(16).
	var match = JS('List\|Null',
	r'/^([\da-z]+)(?:\.([\da-z]+))?\(e\+(\d+)\)$/.exec(#)',
	result);
	if (match == null) {
	// Then we don't know how to handle it at all.
	throw new UnsupportedError("Unexpected toString result: $result");
	}
	result = JS('String', '#', match[1]);
	int exponent = JS("int", "+#", match[3]);
	if (match[2] != null) {
	result = JS('String', '# + #', result, match[2]);
	exponent -= JS('int', '#.length', match[2]);
	}
	return result + "0" * exponent;
	}

	// Note: if you change this, also change the function [S].
	String toString() {
	if (this == 0 && JS('bool', '(1 / #) < 0', this)) {
	return '-0.0';
	} else {
	return JS('String', r'"" + (#)', this);
	}
	}

	int get hashCode => JS('int', '# & 0x1FFFFFFF', this);

	JSNumber operator -() => JS('num', r'-#', this);

	JSNumber operator +(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('num', '# + #', this, other);
	}

	JSNumber operator -(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('num', '# - #', this, other);
	}

	double operator /(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('num', '# / #', this, other);
	}

	JSNumber operator *(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('num', '# * #', this, other);
	}

	JSNumber operator %(num other) {
	if (other is !num) throw argumentErrorValue(other);
	// Euclidean Modulo.
	num result = JS('num', r'# % #', this, other);
	if (result == 0) return (0 as JSNumber); // Make sure we don't return -0.0.
	if (result > 0) return result;
	if (JS('num', '#', other) < 0) {
	return result - JS('num', '#', other);
	} else {
	return result + JS('num', '#', other);
	}
	}

	bool _isInt32(value) => JS('bool', '(# \| 0) === #', value, value);

	int operator ~/(num other) {
	if (_isInt32(this) && _isInt32(other) && 0 != other && -1 != other) {
	return JS('int', r'(# / #) \| 0', this, other);
	} else {
	return _tdivSlow(other);
	}
	}

	int _tdivSlow(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return (JS('num', r'# / #', this, other)).toInt();
	}

	// TODO(ngeoffray): Move the bit operations below to [JSInt] and
	// make them take an int. Because this will make operations slower,
	// we define these methods on number for now but we need to decide
	// the grain at which we do the type checks.

	int operator <<(num other) {
	if (other is !num) throw argumentErrorValue(other);
	if (JS('num', '#', other) < 0) throw argumentErrorValue(other);
	return _shlPositive(other);
	}

	int _shlPositive(num other) {
	// JavaScript only looks at the last 5 bits of the shift-amount. Shifting
	// by 33 is hence equivalent to a shift by 1.
	return JS('bool', r'# > 31', other)
	? 0
	: JS('int', r'(# << #) >>> 0', this, other);
	}

	int operator >>(num other) {
	if (other is !num) throw argumentErrorValue(other);
	if (JS('num', '#', other) < 0) throw argumentErrorValue(other);
	return _shrOtherPositive(other);
	}

	int _shrOtherPositive(num other) {
	return JS('num', '#', this) > 0
	? _shrBothPositive(other)
	// For negative numbers we just clamp the shift-by amount.
	// `this` could be negative but not have its 31st bit set.
	// The ">>" would then shift in 0s instead of 1s. Therefore
	// we cannot simply return 0xFFFFFFFF.
	: JS('int', r'(# >> #) >>> 0', this, other > 31 ? 31 : other);
	}

	int _shrBothPositive(num other) {
	return JS('bool', r'# > 31', other)
	// JavaScript only looks at the last 5 bits of the shift-amount. In JS
	// shifting by 33 is hence equivalent to a shift by 1. Shortcut the
	// computation when that happens.
	? 0
	// Given that `this` is positive we must not use '>>'. Otherwise a
	// number that has the 31st bit set would be treated as negative and
	// shift in ones.
	: JS('int', r'# >>> #', this, other);
	}

	int operator &(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('int', r'(# & #) >>> 0', this, other);
	}

	int operator \|(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('int', r'(# \| #) >>> 0', this, other);
	}

	int operator ^(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('int', r'(# ^ #) >>> 0', this, other);
	}

	bool operator <(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('bool', '# < #', this, other);
	}

	bool operator >(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('bool', '# > #', this, other);
	}

	bool operator <=(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('bool', '# <= #', this, other);
	}

	bool operator >=(num other) {
	if (other is !num) throw argumentErrorValue(other);
	return JS('bool', '# >= #', this, other);
	}

	// int members.
	// TODO(jmesserly): all numbers will have these in dynamic dispatch.
	// We can fix by checking it at dispatch time but we'd need to structure them
	// differently.

	bool get isEven => (this & 1) == 0;

	bool get isOdd => (this & 1) == 1;

	int toUnsigned(int width) {
	return this & ((1 << width) - 1);
	}

	int toSigned(int width) {
	int signMask = 1 << (width - 1);
	return (this & (signMask - 1)) - (this & signMask);
	}

	int get bitLength {
	int nonneg = this < 0 ? -this - 1 : this;
	if (nonneg >= 0x100000000) {
	nonneg = nonneg ~/ 0x100000000;
	return _bitCount(_spread(nonneg)) + 32;
	}
	return _bitCount(_spread(nonneg));
	}

	// Returns pow(this, e) % m.
	int modPow(int e, int m) {
	if (e is! int) {
	throw new ArgumentError.value(e, "exponent", "not an integer");
	}
	if (m is! int) {
	throw new ArgumentError.value(m, "modulus", "not an integer");
	}
	if (e < 0) throw new RangeError.range(e, 0, null, "exponent");
	if (m <= 0) throw new RangeError.range(m, 1, null, "modulus");
	if (e == 0) return 1;
	int b = this;
	if (b < 0 \|\| b > m) {
	b %= m;
	}
	int r = 1;
	while (e > 0) {
	if (e.isOdd) {
	r = (r * b) % m;
	}
	e ~/= 2;
	b = (b * b) % m;
	}
	return r;
	}

	// If inv is false, returns gcd(x, y).
	// If inv is true and gcd(x, y) = 1, returns d, so that cx + dy = 1.
	// If inv is true and gcd(x, y) != 1, throws Exception("Not coprime").
	static int _binaryGcd(int x, int y, bool inv) {
	int s = 1;
	if (!inv) {
	while (x.isEven && y.isEven) {
	x ~/= 2;
	y ~/= 2;
	s *= 2;
	}
	if (y.isOdd) {
	var t = x;
	x = y;
	y = t;
	}
	}
	final bool ac = x.isEven;
	int u = x;
	int v = y;
	int a = 1,
	b = 0,
	c = 0,
	d = 1;
	do {
	while (u.isEven) {
	u ~/= 2;
	if (ac) {
	if (!a.isEven \|\| !b.isEven) {
	a += y;
	b -= x;
	}
	a ~/= 2;
	} else if (!b.isEven) {
	b -= x;
	}
	b ~/= 2;
	}
	while (v.isEven) {
	v ~/= 2;
	if (ac) {
	if (!c.isEven \|\| !d.isEven) {
	c += y;
	d -= x;
	}
	c ~/= 2;
	} else if (!d.isEven) {
	d -= x;
	}
	d ~/= 2;
	}
	if (u >= v) {
	u -= v;
	if (ac) a -= c;
	b -= d;
	} else {
	v -= u;
	if (ac) c -= a;
	d -= b;
	}
	} while (u != 0);
	if (!inv) return s*v;
	if (v != 1) throw new Exception("Not coprime");
	if (d < 0) {
	d += x;
	if (d < 0) d += x;
	} else if (d > x) {
	d -= x;
	if (d > x) d -= x;
	}
	return d;
	}

	// Returns 1/this % m, with m > 0.
	int modInverse(int m) {
	if (m is! int) {
	throw new ArgumentError.value(m, "modulus", "not an integer");
	}
	if (m <= 0) throw new RangeError.range(m, 1, null, "modulus");
	if (m == 1) return 0;
	int t = this;
	if ((t < 0) \|\| (t >= m)) t %= m;
	if (t == 1) return 1;
	if ((t == 0) \|\| (t.isEven && m.isEven)) {
	throw new Exception("Not coprime");
	}
	return _binaryGcd(m, t, true);
	}

	// Returns gcd of abs(this) and abs(other).
	int gcd(int other) {
	if (other is! int) {
	throw new ArgumentError.value(other, "other", "not an integer");
	}
	int x = this.abs();
	int y = other.abs();
	if (x == 0) return y;
	if (y == 0) return x;
	if ((x == 1) \|\| (y == 1)) return 1;
	return _binaryGcd(x, y, false);
	}

	// Assumes i is <= 32-bit and unsigned.
	static int _bitCount(int i) {
	// See "Hacker's Delight", section 5-1, "Counting 1-Bits".

	// The basic strategy is to use "divide and conquer" to
	// add pairs (then quads, etc.) of bits together to obtain
	// sub-counts.
	//
	// A straightforward approach would look like:
	//
	// i = (i & 0x55555555) + ((i >> 1) & 0x55555555);
	// i = (i & 0x33333333) + ((i >> 2) & 0x33333333);
	// i = (i & 0x0F0F0F0F) + ((i >> 4) & 0x0F0F0F0F);
	// i = (i & 0x00FF00FF) + ((i >> 8) & 0x00FF00FF);
	// i = (i & 0x0000FFFF) + ((i >> 16) & 0x0000FFFF);
	//
	// The code below removes unnecessary &'s and uses a
	// trick to remove one instruction in the first line.

	i = _shru(i, 0) - (_shru(i, 1) & 0x55555555);
	i = (i & 0x33333333) + (_shru(i, 2) & 0x33333333);
	i = 0x0F0F0F0F & (i + _shru(i, 4));
	i += _shru(i, 8);
	i += _shru(i, 16);
	return (i & 0x0000003F);
	}

	static int _shru(int value, int shift) => JS('int', '# >>> #', value, shift);
	static int _shrs(int value, int shift) => JS('int', '# >> #', value, shift);
	static int _ors(int a, int b) => JS('int', '# \| #', a, b);

	// Assumes i is <= 32-bit
	static int _spread(int i) {
	i = _ors(i, _shrs(i, 1));
	i = _ors(i, _shrs(i, 2));
	i = _ors(i, _shrs(i, 4));
	i = _ors(i, _shrs(i, 8));
	i = _shru(_ors(i, _shrs(i, 16)), 0);
	return i;
	}

	int operator ~() => JS('int', r'(~#) >>> 0', this);
	}