Jo Shields a575963da9 Imported Upstream version 3.6.0
Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14
2014-08-13 10:39:27 +01:00

133 lines
4.1 KiB
C#

//
// PatriciaTrieNode.cs
//
// Authors:
// Alexander Chebaturkin (chebaturkin@gmail.com)
//
// Copyright (C) 2012 Alexander Chebaturkin
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace Mono.CodeContracts.Static.DataStructures.Patricia
{
public abstract class PatriciaTrieNode<T> : IImmutableIntMap<T>
{
public T this[int key]
{
get { return this.Lookup(key); }
}
public T Any { get; private set; }
public abstract bool Contains(int key);
public abstract int Key { get; }
public abstract int Count { get; }
public abstract IImmutableIntMap<T> Add(int key, T value);
public abstract IImmutableIntMap<T> Remove(int key);
public abstract void Visit(Action<T> action);
public abstract void Visit(Action<int, T> action);
public abstract T Lookup(int key);
public IEnumerable<int> Keys
{
get
{
var list = new List<int>(this.Count);
FillKeysTo(list);
return list;
}
}
public IEnumerable<T> Values
{
get
{
var list = new List<T>(this.Count);
FillValuesTo(list);
return list;
}
}
public void Dump(TextWriter tw)
{
Dump(tw, string.Empty);
}
protected internal abstract void FillKeysTo(List<int> list);
protected internal abstract void FillValuesTo(List<T> list);
protected internal abstract void AppendToBuilder(StringBuilder sb);
protected internal abstract void Dump(TextWriter tw, string prefix);
public override string ToString()
{
var sb = new StringBuilder();
AppendToBuilder(sb);
return sb.ToString();
}
protected static IImmutableIntMap<T> Join(PatriciaTrieNode<T> left, PatriciaTrieNode<T> right)
{
int keyLeft = left.Key;
int keyRight = right.Key;
int branchingBit = BranchingBit(keyLeft, keyRight);
var prefix = MaskWithBit(keyLeft, branchingBit);
if (IsZeroBitAt(keyLeft, branchingBit))
return new BranchNode<T>(prefix, branchingBit, left, right);
return new BranchNode<T>(prefix, branchingBit, right, left);
}
protected static bool IsZeroBitAt(int key, int branchingBit)
{
return (key & branchingBit) == 0;
}
private static int BranchingBit(int left, int right)
{
return LowestBit(left ^ right);
}
private static int LowestBit(int x)
{
return x & -x;
}
private static int MaskWithBit(int key, int mask)
{
return key & (mask - 1);
}
protected static bool MatchPrefix(int key, int prefix, int maskBit)
{
return MaskWithBit(key, maskBit) == prefix;
}
}
}