| // 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 fixnum; |
| |
| /** |
| * An immutable 32-bit signed integer, in the range [-2^31, 2^31 - 1]. |
| * Arithmetic operations may overflow in order to maintain this range. |
| */ |
| class int32 implements intx { |
| |
| /** |
| * The maximum positive value attainable by an [int32], namely |
| * 2147483647. |
| */ |
| static const int32 MAX_VALUE = const int32._internal(0x7FFFFFFF); |
| |
| /** |
| * The minimum positive value attainable by an [int32], namely |
| * -2147483648. |
| */ |
| static int32 MIN_VALUE = const int32._internal(0x80000000); |
| |
| /** |
| * An [int32] constant equal to 0. |
| */ |
| static int32 ZERO = const int32._internal(0); |
| |
| /** |
| * An [int32] constant equal to 1. |
| */ |
| static int32 ONE = const int32._internal(1); |
| |
| /** |
| * An [int32] constant equal to 2. |
| */ |
| static int32 TWO = const int32._internal(2); |
| |
| // Hex digit char codes |
| static const int _CC_0 = 48; // '0'.codeUnitAt(0) |
| static const int _CC_9 = 57; // '9'.codeUnitAt(0) |
| static const int _CC_a = 97; // 'a'.codeUnitAt(0) |
| static const int _CC_z = 122; // 'z'.codeUnitAt(0) |
| static const int _CC_A = 65; // 'A'.codeUnitAt(0) |
| static const int _CC_Z = 90; // 'Z'.codeUnitAt(0) |
| |
| static int _decodeHex(int c) { |
| if (c >= _CC_0 && c <= _CC_9) { |
| return c - _CC_0; |
| } else if (c >= _CC_a && c <= _CC_z) { |
| return c - _CC_a + 10; |
| } else if (c >= _CC_A && c <= _CC_Z) { |
| return c - _CC_A + 10; |
| } else { |
| return -1; // bad char code |
| } |
| } |
| |
| /** |
| * Parses a [String] in a given [radix] between 2 and 16 and returns an |
| * [int32]. |
| */ |
| // TODO(rice) - Make this faster by converting several digits at once. |
| static int32 parseRadix(String s, int radix) { |
| if ((radix <= 1) || (radix > 16)) { |
| throw "Bad radix: $radix"; |
| } |
| int32 x = ZERO; |
| for (int i = 0; i < s.length; i++) { |
| int c = s.codeUnitAt(i); |
| int digit = _decodeHex(c); |
| if (digit < 0 || digit >= radix) { |
| throw new Exception("Non-radix code unit: $c"); |
| } |
| x = (x * radix) + digit; |
| } |
| return x; |
| } |
| |
| /** |
| * Parses a decimal [String] and returns an [int32]. |
| */ |
| static int32 parseInt(String s) => new int32.fromInt(int.parse(s)); |
| |
| /** |
| * Parses a hexadecimal [String] and returns an [int32]. |
| */ |
| static int32 parseHex(String s) => parseRadix(s, 16); |
| |
| // Assumes i is <= 32-bit. |
| 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 -= ((i >> 1) & 0x55555555); |
| i = (i & 0x33333333) + ((i >> 2) & 0x33333333); |
| i = ((i + (i >> 4)) & 0x0F0F0F0F); |
| i += (i >> 8); |
| i += (i >> 16); |
| return (i & 0x0000003F); |
| } |
| |
| // Assumes i is <= 32-bit |
| static int _numberOfLeadingZeros(int i) { |
| i |= i >> 1; |
| i |= i >> 2; |
| i |= i >> 4; |
| i |= i >> 8; |
| i |= i >> 16; |
| return _bitCount(~i); |
| } |
| |
| static int _numberOfTrailingZeros(int i) => _bitCount((i & -i) - 1); |
| |
| // The internal value, kept in the range [MIN_VALUE, MAX_VALUE]. |
| final int _i; |
| |
| const int32._internal(int i) : _i = i; |
| |
| /** |
| * Constructs an [int32] from an [int]. Only the low 32 bits of the input |
| * are used. |
| */ |
| int32.fromInt(int i) : _i = (i & 0x7fffffff) - (i & 0x80000000); |
| |
| // Convert an [int] or [intx] to an [int32]. Note that an [int64] |
| // will be truncated. |
| int _convert(other) { |
| if (other == null) { |
| throw new ArgumentError(null); |
| } else if (other is intx) { |
| return other.toInt32()._i; |
| } else if (other is int) { |
| return other; |
| } else { |
| throw new Exception("Can't retrieve 32-bit int from $other"); |
| } |
| } |
| |
| // The +, -, * , &, |, and ^ operaters deal with types as follows: |
| // |
| // int32 + int => int32 |
| // int32 + int32 => int32 |
| // int32 + int64 => int64 |
| // |
| // The %, ~/ and remainder operators return an int32 even with an int64 |
| // argument, since the result cannot be greater than the value on the |
| // left-hand side: |
| // |
| // int32 % int => int32 |
| // int32 % int32 => int32 |
| // int32 % int64 => int32 |
| |
| intx operator +(other) { |
| if (other is int64) { |
| return this.toInt64() + other; |
| } |
| return new int32.fromInt(_i + _convert(other)); |
| } |
| |
| intx operator -(other) { |
| if (other is int64) { |
| return this.toInt64() - other; |
| } |
| return new int32.fromInt(_i - _convert(other)); |
| } |
| |
| int32 operator -() => new int32.fromInt(-_i); |
| |
| intx operator *(other) { |
| if (other is int64) { |
| return this.toInt64() * other; |
| } |
| // TODO(rice) - optimize |
| return (this.toInt64() * other).toInt32(); |
| } |
| |
| int32 operator %(other) { |
| if (other is int64) { |
| // Result will be int32 |
| return (this.toInt64() % other).toInt32(); |
| } |
| return new int32.fromInt(_i % _convert(other)); |
| } |
| |
| int32 operator ~/(other) { |
| if (other is int64) { |
| // Result will be int32 |
| return (this.toInt64() ~/ other).toInt32(); |
| } |
| return new int32.fromInt(_i ~/ _convert(other)); |
| } |
| |
| int32 remainder(other) { |
| if (other is int64) { |
| // Result will be int32 |
| int64 t = this.toInt64(); |
| return (t - (t ~/ other) * other).toInt32(); |
| } |
| return this - (this ~/ other) * other; |
| } |
| |
| int32 operator &(other) { |
| if (other is int64) { |
| return (this.toInt64() & other).toInt32(); |
| } |
| return new int32.fromInt(_i & _convert(other)); |
| } |
| |
| int32 operator |(other) { |
| if (other is int64) { |
| return (this.toInt64() | other).toInt32(); |
| } |
| return new int32.fromInt(_i | _convert(other)); |
| } |
| |
| int32 operator ^(other) { |
| if (other is int64) { |
| return (this.toInt64() ^ other).toInt32(); |
| } |
| return new int32.fromInt(_i ^ _convert(other)); |
| } |
| |
| int32 operator ~() => new int32.fromInt(~_i); |
| |
| int32 operator <<(int n) { |
| if (n < 0) { |
| throw new ArgumentError("$n"); |
| } |
| n &= 31; |
| return new int32.fromInt(_i << n); |
| } |
| |
| int32 operator >>(int n) { |
| if (n < 0) { |
| throw new ArgumentError("$n"); |
| } |
| n &= 31; |
| int value; |
| if (_i >= 0) { |
| value = _i >> n; |
| } else { |
| value = (_i >> n) | (0xffffffff << (32 - n)); |
| } |
| return new int32.fromInt(value); |
| } |
| |
| int32 shiftRightUnsigned(int n) { |
| if (n < 0) { |
| throw new ArgumentError("$n"); |
| } |
| n &= 31; |
| int value; |
| if (_i >= 0) { |
| value = _i >> n; |
| } else { |
| value = (_i >> n) & ((1 << (32 - n)) - 1); |
| } |
| return new int32.fromInt(value); |
| } |
| |
| /** |
| * Returns [true] if this [int32] has the same numeric value as the |
| * given object. The argument may be an [int] or an [intx]. |
| */ |
| bool operator ==(other) { |
| if (other == null) { |
| return false; |
| } |
| if (other is int64) { |
| return this.toInt64() == other; |
| } |
| return _i == _convert(other); |
| } |
| |
| int compareTo(Comparable other) { |
| if (other is int64) { |
| return this.toInt64().compareTo(other); |
| } |
| return _i.compareTo(_convert(other)); |
| } |
| |
| bool operator <(other) { |
| if (other is int64) { |
| return this.toInt64() < other; |
| } |
| return _i < _convert(other); |
| } |
| |
| bool operator <=(other) { |
| if (other is int64) { |
| return this.toInt64() < other; |
| } |
| return _i <= _convert(other); |
| } |
| |
| bool operator >(other) { |
| if (other is int64) { |
| return this.toInt64() < other; |
| } |
| return _i > _convert(other); |
| } |
| |
| bool operator >=(other) { |
| if (other is int64) { |
| return this.toInt64() < other; |
| } |
| return _i >= _convert(other); |
| } |
| |
| bool get isEven => (_i & 0x1) == 0; |
| bool get isMaxValue => _i == 2147483647; |
| bool get isMinValue => _i == -2147483648; |
| bool get isNegative => _i < 0; |
| bool get isOdd => (_i & 0x1) == 1; |
| bool get isZero => _i == 0; |
| |
| int get hashCode => _i; |
| |
| int32 abs() => _i < 0 ? new int32.fromInt(-_i) : this; |
| |
| int numberOfLeadingZeros() => _numberOfLeadingZeros(_i); |
| int numberOfTrailingZeros() => _numberOfTrailingZeros(_i); |
| |
| List<int> toBytes() { |
| List<int> result = new List<int>(4); |
| result[0] = _i & 0xff; |
| result[1] = (_i >> 8) & 0xff; |
| result[2] = (_i >> 16) & 0xff; |
| result[3] = (_i >> 24) & 0xff; |
| return result; |
| } |
| |
| int toInt() => _i; |
| int32 toInt32() => this; |
| int64 toInt64() => new int64.fromInt(_i); |
| |
| String toString() => _i.toString(); |
| String toHexString() => _i.toRadixString(16); |
| String toRadixString(int radix) => _i.toRadixString(radix); |
| } |