426 lines
7.9 KiB
C#
426 lines
7.9 KiB
C#
// ==++==
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ==--==
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using System;
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using Contracts = System.Diagnostics.Debug;
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using Contract = System.Diagnostics.Debug;
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//using System.Runtime.InteropServices;
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// ReSharper disable once CheckNamespace
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namespace Numerics
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{
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/*
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[StructLayout(LayoutKind.Explicit)]
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internal struct DoubleUlong
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{
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[FieldOffset(0)]
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internal double dbl;
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[FieldOffset(0)]
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internal ulong uu;
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}
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*/
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internal static class NumericsHelpers
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{
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private const int KcbitUint = 32;
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/*internal static void GetDoubleParts(double dbl, out int sign, out int exp, out ulong man, out bool fFinite)
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{
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//Contract.Ensures(Contract.ValueAtReturn(out sign) == +1 || Contract.ValueAtReturn(out sign) == -1);
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DoubleUlong du;
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du.uu = 0;
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du.dbl = dbl;
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sign = 1 - ((int)(du.uu >> 62) & 2);
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man = du.uu & 0x000FFFFFFFFFFFFF;
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exp = (int)(du.uu >> 52) & 0x7FF;
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if (exp == 0)
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{
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// Denormalized number.
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fFinite = true;
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if (man != 0)
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exp = -1074;
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}
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else if (exp == 0x7FF)
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{
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// NaN or Inifite.
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fFinite = false;
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exp = int.MaxValue;
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}
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else
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{
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fFinite = true;
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man |= 0x0010000000000000;
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exp -= 1075;
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}
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}
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internal static double GetDoubleFromParts(int sign, int exp, ulong man)
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{
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DoubleUlong du;
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du.dbl = 0;
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if (man == 0)
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du.uu = 0;
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else
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{
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// Normalize so that 0x0010 0000 0000 0000 is the highest bit set.
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int cbitShift = CbitHighZero(man) - 11;
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if (cbitShift < 0)
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man >>= -cbitShift;
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else
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man <<= cbitShift;
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exp -= cbitShift;
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Contract.Assert((man & 0xFFF0000000000000) == 0x0010000000000000);
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// Move the point to just behind the leading 1: 0x001.0 0000 0000 0000
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// (52 bits) and skew the exponent (by 0x3FF == 1023).
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exp += 1075;
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if (exp >= 0x7FF)
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{
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// Infinity.
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du.uu = 0x7FF0000000000000;
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}
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else if (exp <= 0)
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{
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// Denormalized.
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exp--;
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if (exp < -52)
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{
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// Underflow to zero.
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du.uu = 0;
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}
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else
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{
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du.uu = man >> -exp;
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Contract.Assert(du.uu != 0);
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}
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}
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else
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{
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// Mask off the implicit high bit.
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du.uu = (man & 0x000FFFFFFFFFFFFF) | ((ulong)exp << 52);
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}
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}
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if (sign < 0)
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du.uu |= 0x8000000000000000;
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return du.dbl;
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}
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*/
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// Do an in-place twos complement of d and also return the result.
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// "Dangerous" because it causes a mutation and needs to be used
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// with care for immutable types
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internal static void DangerousMakeTwosComplement(uint[] d)
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{
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// first do complement and +1 as long as carry is needed
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int i = 0;
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uint v = 0;
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for (; i < d.Length; i++)
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{
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v = ~d[i] + 1;
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d[i] = v;
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if (v != 0) { i++; break; }
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}
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if (v != 0)
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{
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// now ones complement is sufficient
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for (; i < d.Length; i++)
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{
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d[i] = ~d[i];
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}
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}
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else
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{
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//??? this is weird
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d = resize(d, d.Length + 1);
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d[d.Length - 1] = 1;
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}
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}
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// ReSharper disable once InconsistentNaming
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private static uint[] resize(uint[] v, int len)
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{
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if (v.Length == len) return v;
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uint[] ret = new uint[len];
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int n = Math.Min(v.Length, len);
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for (int i = 0; i < n; i++)
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{
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ret[i] = v[i];
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}
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return ret;
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}
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internal static void Swap<T>(ref T a, ref T b)
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{
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T tmp = a;
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a = b;
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b = tmp;
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}
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// ReSharper disable once InconsistentNaming
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/*
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internal static uint GCD(uint u1, uint u2)
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{
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const int cvMax = 32;
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if (u1 < u2)
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goto LOther;
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LTop:
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Contract.Assert(u2 <= u1);
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if (u2 == 0)
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return u1;
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for (int cv = cvMax; ; )
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{
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u1 -= u2;
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if (u1 < u2)
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break;
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if (--cv == 0)
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{
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u1 %= u2;
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break;
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}
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}
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LOther:
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Contract.Assert(u1 < u2);
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if (u1 == 0)
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return u2;
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for (int cv = cvMax; ; )
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{
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u2 -= u1;
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if (u2 < u1)
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break;
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if (--cv == 0)
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{
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u2 %= u1;
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break;
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}
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}
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goto LTop;
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}
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*/
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// ReSharper disable once InconsistentNaming
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/*
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internal static ulong GCD(ulong uu1, ulong uu2)
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{
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const int cvMax = 32;
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if (uu1 < uu2)
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goto LOther;
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LTop:
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Contract.Assert(uu2 <= uu1);
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if (uu1 <= uint.MaxValue)
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goto LSmall;
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if (uu2 == 0)
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return uu1;
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for (int cv = cvMax; ; )
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{
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uu1 -= uu2;
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if (uu1 < uu2)
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break;
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if (--cv == 0)
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{
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uu1 %= uu2;
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break;
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}
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}
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LOther:
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Contract.Assert(uu1 < uu2);
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if (uu2 <= uint.MaxValue)
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goto LSmall;
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if (uu1 == 0)
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return uu2;
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for (int cv = cvMax; ; )
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{
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uu2 -= uu1;
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if (uu2 < uu1)
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break;
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if (--cv == 0)
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{
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uu2 %= uu1;
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break;
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}
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}
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goto LTop;
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LSmall:
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uint u1 = (uint)uu1;
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uint u2 = (uint)uu2;
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if (u1 < u2)
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goto LOtherSmall;
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LTopSmall:
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Contract.Assert(u2 <= u1);
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if (u2 == 0)
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return u1;
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for (int cv = cvMax; ; )
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{
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u1 -= u2;
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if (u1 < u2)
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break;
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if (--cv == 0)
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{
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u1 %= u2;
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break;
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}
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}
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LOtherSmall:
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Contract.Assert(u1 < u2);
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if (u1 == 0)
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return u2;
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for (int cv = cvMax; ; )
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{
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u2 -= u1;
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if (u2 < u1)
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break;
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if (--cv == 0)
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{
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u2 %= u1;
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break;
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}
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}
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goto LTopSmall;
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}
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*/
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internal static ulong MakeUlong(uint uHi, uint uLo)
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{
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return ((ulong)uHi << KcbitUint) | uLo;
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}
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internal static uint GetLo(ulong uu)
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{
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return (uint)uu;
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}
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internal static uint GetHi(ulong uu)
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{
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return (uint)(uu >> KcbitUint);
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}
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/*
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internal static uint Abs(int a)
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{
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uint mask = (uint)(a >> 31);
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return ((uint)a ^ mask) - mask;
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}
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*/
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// internal static ulong Abs(long a) {
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// ulong mask = (ulong)(a >> 63);
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// return ((ulong)a ^ mask) - mask;
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// }
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private static uint CombineHash(uint u1, uint u2)
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{
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return ((u1 << 7) | (u1 >> 25)) ^ u2;
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}
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internal static int CombineHash(int n1, int n2)
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{
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return (int)CombineHash((uint)n1, (uint)n2);
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}
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internal static int CbitHighZero(uint u)
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{
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if (u == 0)
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return 32;
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int cbit = 0;
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if ((u & 0xFFFF0000) == 0)
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{
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cbit += 16;
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u <<= 16;
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}
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if ((u & 0xFF000000) == 0)
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{
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cbit += 8;
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u <<= 8;
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}
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if ((u & 0xF0000000) == 0)
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{
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cbit += 4;
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u <<= 4;
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}
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if ((u & 0xC0000000) == 0)
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{
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cbit += 2;
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u <<= 2;
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}
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if ((u & 0x80000000) == 0)
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cbit += 1;
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return cbit;
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}
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/*internal static int CbitLowZero(uint u)
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{
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if (u == 0)
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return 32;
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int cbit = 0;
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if ((u & 0x0000FFFF) == 0)
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{
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cbit += 16;
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u >>= 16;
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}
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if ((u & 0x000000FF) == 0)
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{
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cbit += 8;
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u >>= 8;
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}
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if ((u & 0x0000000F) == 0)
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{
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cbit += 4;
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u >>= 4;
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}
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if ((u & 0x00000003) == 0)
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{
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cbit += 2;
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u >>= 2;
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}
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if ((u & 0x00000001) == 0)
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cbit += 1;
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return cbit;
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}
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internal static int CbitHighZero(ulong uu)
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{
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if ((uu & 0xFFFFFFFF00000000) == 0)
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return 32 + CbitHighZero((uint)uu);
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return CbitHighZero((uint)(uu >> 32));
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}*/
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// internal static int CbitLowZero(ulong uu) {
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// if ((uint)uu == 0)
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// return 32 + CbitLowZero((uint)(uu >> 32));
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// return CbitLowZero((uint)uu);
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// }
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//
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// internal static int Cbit(uint u) {
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// u = (u & 0x55555555) + ((u >> 1) & 0x55555555);
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// u = (u & 0x33333333) + ((u >> 2) & 0x33333333);
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// u = (u & 0x0F0F0F0F) + ((u >> 4) & 0x0F0F0F0F);
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// u = (u & 0x00FF00FF) + ((u >> 8) & 0x00FF00FF);
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// return (int)((ushort)u + (ushort)(u >> 16));
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// }
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//
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// static int Cbit(ulong uu) {
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// uu = (uu & 0x5555555555555555) + ((uu >> 1) & 0x5555555555555555);
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// uu = (uu & 0x3333333333333333) + ((uu >> 2) & 0x3333333333333333);
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// uu = (uu & 0x0F0F0F0F0F0F0F0F) + ((uu >> 4) & 0x0F0F0F0F0F0F0F0F);
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// uu = (uu & 0x00FF00FF00FF00FF) + ((uu >> 8) & 0x00FF00FF00FF00FF);
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// uu = (uu & 0x0000FFFF0000FFFF) + ((uu >> 16) & 0x0000FFFF0000FFFF);
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// return (int)((uint)uu + (uint)(uu >> 32));
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// }
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}
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}
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