104 lines
3.8 KiB
C#
104 lines
3.8 KiB
C#
//
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// Threshold.cs
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//
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// Authors:
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// Alexander Chebaturkin (chebaturkin@gmail.com)
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//
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// Copyright (C) 2012 Alexander Chebaturkin
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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using System.Collections.Generic;
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namespace Mono.CodeContracts.Static.Analysis.Numerical {
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public abstract class Threshold<T> {
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protected int NextFree;
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protected readonly List<T> Values;
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protected abstract T MinusInfinity { get; }
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protected abstract T PlusInfinity { get; }
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protected abstract T Zero { get; }
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public int Count { get { return Values.Count; } }
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protected Threshold (int size)
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{
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Values = new List<T> (size) {MinusInfinity, Zero, PlusInfinity};
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NextFree = 3;
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}
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public bool Add (T value)
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{
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if (NextFree == Values.Count)
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return false;
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var idx = 0;
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while (idx < NextFree && LessThan (Values[idx], value))
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idx++;
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if (Values[idx].Equals (value))
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return false;
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Values.Insert (idx, value);
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NextFree++;
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return true;
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}
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protected abstract bool LessThan (T a, T b);
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public T GetNext (T value)
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{
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var index = BinarySearch (value, 0, NextFree - 1);
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if (index >= 0)
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return Values[index];
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var nextIndex = ~index; //because binary search returns position of next item if not found
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return Values[nextIndex];
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}
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public T GetPrevious (T value)
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{
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var index = BinarySearch (value, 0, NextFree - 1);
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if (index >= 0)
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return Values[index];
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var nextIndex = ~index;
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return Values[nextIndex - 1];
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}
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public int BinarySearch (T value, int low, int hi)
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{
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while (low <= hi) {
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var median = low + ((hi - low) >> 1);
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if (Values[median].Equals (value))
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return median;
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if (LessThan (Values[median], value))
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low = median + 1;
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else
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hi = median - 1;
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}
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return ~low;
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}
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}
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} |