// 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.core; | |

/** | |

* An arbitrarily large integer. | |

* | |

* **Note:** When compiling to JavaScript, integers are | |

* implemented as JavaScript numbers. When compiling to JavaScript, | |

* integers are therefore restricted to 53 significant bits because | |

* all JavaScript numbers are double-precision floating point | |

* values. The behavior of the operators and methods in the [int] | |

* class therefore sometimes differs between the Dart VM and Dart code | |

* compiled to JavaScript. | |

* | |

* It is a compile-time error for a class to attempt to extend or implement int. | |

*/ | |

abstract class int extends num { | |

/** | |

* Returns the integer value of the given environment declaration [name]. | |

* | |

* The result is the same as would be returned by: | |

* | |

* int.parse(const String.fromEnvironment(name, defaultValue: ""), | |

* (_) => defaultValue) | |

* | |

* Example: | |

* | |

* const int.fromEnvironment("defaultPort", defaultValue: 80) | |

*/ | |

external const factory int.fromEnvironment(String name, {int defaultValue}); | |

/** | |

* Bit-wise and operator. | |

* | |

* Treating both `this` and [other] as sufficiently large two's component | |

* integers, the result is a number with only the bits set that are set in | |

* both `this` and [other] | |

* | |

* Of both operands are negative, the result is negative, otherwise | |

* the result is non-negative. | |

*/ | |

int operator &(int other); | |

/** | |

* Bit-wise or operator. | |

* | |

* Treating both `this` and [other] as sufficiently large two's component | |

* integers, the result is a number with the bits set that are set in either | |

* of `this` and [other] | |

* | |

* If both operands are non-negative, the result is non-negative, | |

* otherwise the result us negative. | |

*/ | |

int operator |(int other); | |

/** | |

* Bit-wise exclusive-or operator. | |

* | |

* Treating both `this` and [other] as sufficiently large two's component | |

* integers, the result is a number with the bits set that are set in one, | |

* but not both, of `this` and [other] | |

* | |

* If the operands have the same sign, the result is non-negative, | |

* otherwise the result is negative. | |

*/ | |

int operator ^(int other); | |

/** | |

* The bit-wise negate operator. | |

* | |

* Treating `this` as a sufficiently large two's component integer, | |

* the result is a number with the opposite bits set. | |

* | |

* This maps any integer `x` to `-x - 1`. | |

*/ | |

int operator ~(); | |

/** | |

* Shift the bits of this integer to the left by [shiftAmount]. | |

* | |

* Shifting to the left makes the number larger, effectively multiplying | |

* the number by `pow(2, shiftIndex)`. | |

* | |

* There is no limit on the size of the result. It may be relevant to | |

* limit intermediate values by using the "and" operator with a suitable | |

* mask. | |

* | |

* It is an error if [shiftAmount] is negative. | |

*/ | |

int operator <<(int shiftAmount); | |

/** | |

* Shift the bits of this integer to the right by [shiftAmount]. | |

* | |

* Shifting to the right makes the number smaller and drops the least | |

* significant bits, effectively doing an integer division by | |

*`pow(2, shiftIndex)`. | |

* | |

* It is an error if [shiftAmount] is negative. | |

*/ | |

int operator >>(int shiftAmount); | |

/** | |

* Returns this integer to the power of [exponent] modulo [modulus]. | |

* | |

* The [exponent] must be non-negative and [modulus] must be | |

* positive. | |

*/ | |

int modPow(int exponent, int modulus); | |

/** | |

* Returns the modular multiplicative inverse of this integer | |

* modulo [modulus]. | |

* | |

* The [modulus] must be positive. | |

* | |

* It is an error if no modular inverse exists. | |

*/ | |

int modInverse(int modulus); | |

/** | |

* Returns the greatest common divisor of this integer and [other]. | |

* | |

* If either number is non-zero, the result is the numerically greatest | |

* integer dividing both `this` and `other`. | |

* | |

* The greatest common divisor is independent of the order, | |

* so `x.gcd(y)` is always the same as `y.gcd(x)`. | |

* | |

* For any integer `x`, `x.gcd(x)` is `x.abs()`. | |

* | |

* If both `this` and `other` is zero, the result is also zero. | |

*/ | |

int gcd(int other); | |

/** Returns true if and only if this integer is even. */ | |

bool get isEven; | |

/** Returns true if and only if this integer is odd. */ | |

bool get isOdd; | |

/** | |

* Returns the minimum number of bits required to store this integer. | |

* | |

* The number of bits excludes the sign bit, which gives the natural length | |

* for non-negative (unsigned) values. Negative values are complemented to | |

* return the bit position of the first bit that differs from the sign bit. | |

* | |

* To find the the number of bits needed to store the value as a signed value, | |

* add one, i.e. use `x.bitLength + 1`. | |

* | |

* x.bitLength == (-x-1).bitLength | |

* | |

* 3.bitLength == 2; // 00000011 | |

* 2.bitLength == 2; // 00000010 | |

* 1.bitLength == 1; // 00000001 | |

* 0.bitLength == 0; // 00000000 | |

* (-1).bitLength == 0; // 11111111 | |

* (-2).bitLength == 1; // 11111110 | |

* (-3).bitLength == 2; // 11111101 | |

* (-4).bitLength == 2; // 11111100 | |

*/ | |

int get bitLength; | |

/** | |

* Returns the least significant [width] bits of this integer as a | |

* non-negative number (i.e. unsigned representation). The returned value has | |

* zeros in all bit positions higher than [width]. | |

* | |

* (-1).toUnsigned(5) == 32 // 11111111 -> 00011111 | |

* | |

* This operation can be used to simulate arithmetic from low level languages. | |

* For example, to increment an 8 bit quantity: | |

* | |

* q = (q + 1).toUnsigned(8); | |

* | |

* `q` will count from `0` up to `255` and then wrap around to `0`. | |

* | |

* If the input fits in [width] bits without truncation, the result is the | |

* same as the input. The minimum width needed to avoid truncation of `x` is | |

* given by `x.bitLength`, i.e. | |

* | |

* x == x.toUnsigned(x.bitLength); | |

*/ | |

int toUnsigned(int width); | |

/** | |

* Returns the least significant [width] bits of this integer, extending the | |

* highest retained bit to the sign. This is the same as truncating the value | |

* to fit in [width] bits using an signed 2-s complement representation. The | |

* returned value has the same bit value in all positions higher than [width]. | |

* | |

* V--sign bit-V | |

* 16.toSigned(5) == -16 // 00010000 -> 11110000 | |

* 239.toSigned(5) == 15 // 11101111 -> 00001111 | |

* ^ ^ | |

* | |

* This operation can be used to simulate arithmetic from low level languages. | |

* For example, to increment an 8 bit signed quantity: | |

* | |

* q = (q + 1).toSigned(8); | |

* | |

* `q` will count from `0` up to `127`, wrap to `-128` and count back up to | |

* `127`. | |

* | |

* If the input value fits in [width] bits without truncation, the result is | |

* the same as the input. The minimum width needed to avoid truncation of `x` | |

* is `x.bitLength + 1`, i.e. | |

* | |

* x == x.toSigned(x.bitLength + 1); | |

*/ | |

int toSigned(int width); | |

/** | |

* Return the negative value of this integer. | |

* | |

* The result of negating an integer always has the opposite sign, except | |

* for zero, which is its own negation. | |

*/ | |

int operator -(); | |

/** | |

* Returns the absolute value of this integer. | |

* | |

* For any integer `x`, the result is the same as `x < 0 ? -x : x`. | |

*/ | |

int abs(); | |

/** | |

* Returns the sign of this integer. | |

* | |

* Returns 0 for zero, -1 for values less than zero and | |

* +1 for values greater than zero. | |

*/ | |

int get sign; | |

/** Returns `this`. */ | |

int round(); | |

/** Returns `this`. */ | |

int floor(); | |

/** Returns `this`. */ | |

int ceil(); | |

/** Returns `this`. */ | |

int truncate(); | |

/** Returns `this.toDouble()`. */ | |

double roundToDouble(); | |

/** Returns `this.toDouble()`. */ | |

double floorToDouble(); | |

/** Returns `this.toDouble()`. */ | |

double ceilToDouble(); | |

/** Returns `this.toDouble()`. */ | |

double truncateToDouble(); | |

/** | |

* Returns a String-representation of this integer. | |

* | |

* The returned string is parsable by [parse]. | |

* For any `int` [:i:], it is guaranteed that | |

* [:i == int.parse(i.toString()):]. | |

*/ | |

String toString(); | |

/** | |

* Converts [this] to a string representation in the given [radix]. | |

* | |

* In the string representation, lower-case letters are used for digits above | |

* '9', with 'a' being 10 an 'z' being 35. | |

* | |

* The [radix] argument must be an integer in the range 2 to 36. | |

*/ | |

String toRadixString(int radix); | |

/** | |

* Parse [source] as a, possibly signed, integer literal and return its value. | |

* | |

* The [source] must be a non-empty sequence of base-[radix] digits, | |

* optionally prefixed with a minus or plus sign ('-' or '+'). | |

* | |

* The [radix] must be in the range 2..36. The digits used are | |

* first the decimal digits 0..9, and then the letters 'a'..'z' with | |

* values 10 through 35. Also accepts upper-case letters with the same | |

* values as the lower-case ones. | |

* | |

* If no [radix] is given then it defaults to 10. In this case, the [source] | |

* digits may also start with `0x`, in which case the number is interpreted | |

* as a hexadecimal literal, which effectively means that the `0x` is ignored | |

* and the radix is instead set to 16. | |

* | |

* For any int [:n:] and radix [:r:], it is guaranteed that | |

* [:n == int.parse(n.toRadixString(r), radix: r):]. | |

* | |

* If the [source] is not a valid integer literal, optionally prefixed by a | |

* sign, the [onError] is called with the [source] as argument, and its return | |

* value is used instead. If no [onError] is provided, a [FormatException] | |

* is thrown. | |

* | |

* The [onError] handler can be chosen to return `null`. This is preferable | |

* to to throwing and then immediately catching the [FormatException]. | |

* Example: | |

* | |

* var value = int.parse(text, onError: (source) => null); | |

* if (value == null) ... handle the problem | |

* | |

* The [onError] function is only invoked if [source] is a [String]. It is | |

* not invoked if the [source] is, for example, `null`. | |

*/ | |

external static int parse(String source, | |

{ int radix, | |

int onError(String source) }); | |

} |